Overall Green Tropical Cyclone for CHALANE-20 in Mozambique, Zimbabwe, Madagascar, Botswana from 24 Dec 2020 18:00 UTC to 30 Dec 2020 06:00 UTC

GDACS is a cooperation framework between the United Nations, the European Commission and disaster managers worldwide to improve awareness, information exchange and coordination in the first phase after major sudden-onset disasters.

Overall Green Tropical Cyclone for CHALANE-20

in Mozambique, Zimbabwe, Madagascar, Botswana

Global Telecommunication Service

GTS (Global Telecommunication Service) is the official Warning and Alerting channel by the World Meteorological Organization (WMO) adopted by several Warning Organizations. As soon as a new GTS message regarding Tropical Cyclones(WT) or Tsunami(WE) the messages are processed and possibly assigned to the specific event. When a new GTS message is present an new tab in the specific event report page is present.The presence of a GTS message is shown in the homepage with a dedicated icon.

Click on the messages list to visualize on the right the detailed text.

Measurements Levels

SOURCE	GAUGE LOCATION	LAT	LON	TIME (UTC)	HEIGHT (m)	PERIOD (min)

30/12 18:46 WTIO31FMEE301828

30/12 18:46 WTIO30FMEE301828

30/12 12:42 WTIO31FMEE301216

30/12 12:42 WTIO30FMEE301216

30/12 12:17 WTIO24FMEE301215CCA

30/12 12:06 WTIO24FMEE301205

30/12 07:17 WTXS51PGTW300900

30/12 07:16 WTXS31PGTW300900

30/12 06:40 WTIO31FMEE300623

30/12 06:40 WTIO30FMEE300623

30/12 06:14 WTIO24FMEE300613

30/12 00:54 WTIO31FMEE300048

30/12 00:54 WTIO30FMEE300048

30/12 00:24 WTIO24FMEE300020

29/12 20:50 WTXS51PGTW292100

29/12 20:49 WTXS31PGTW292100

29/12 18:22 WTIO31FMEE291813

29/12 18:22 WTIO30FMEE291813

29/12 18:08 WTIO24FMEE291805

29/12 13:17 WTIO31FMEE291308

29/12 13:17 WTIO30FMEE291308

29/12 12:32 WTIO24FMEE291229

29/12 07:22 WTIO31FMEE290649

29/12 07:22 WTIO30FMEE290649

29/12 06:27 WTIO24FMEE290624

29/12 00:29 WTIO31FMEE290016

29/12 00:29 WTIO30FMEE290016

29/12 00:07 WTIO24FMEE290005

28/12 18:25 WTIO31FMEE281822

28/12 18:25 WTIO30FMEE281822

28/12 18:10 WTIO24FMEE281806

28/12 12:56 WTIO31FMEE281256

28/12 12:56 WTIO30FMEE281256

28/12 12:04 WTIO24FMEE281203

27/12 00:08 WTIO24FMEE270008

26/12 19:09 WTIO31FMEE261840

26/12 19:09 WTIO30FMEE261840

26/12 18:33 WTIO24FMEE261832

26/12 13:02 WTIO31FMEE261301

26/12 13:02 WTIO30FMEE261301

26/12 12:27 WTIO22FMEE261225

26/12 07:24 WTIO31FMEE260723

26/12 07:24 WTIO30FMEE260723

26/12 06:27 WTIO22FMEE260626

26/12 01:10 WTIO31FMEE260048

26/12 01:10 WTIO30FMEE260048

26/12 00:37 WTIO22FMEE260036

25/12 19:01 WTIO31FMEE251849

25/12 19:01 WTIO30FMEE251849

25/12 18:31 WTIO22FMEE251830

25/12 12:31 WTIO31FMEE251212

25/12 12:31 WTIO30FMEE251212

25/12 12:03 WTIO22FMEE251150

25/12 06:47 WTIO31FMEE250628

25/12 06:47 WTIO30FMEE250628

25/12 06:16 WTIO22FMEE250615

25/12 00:55 WTIO31FMEE250013

25/12 00:55 WTIO30FMEE250013

25/12 00:13 WTIO22FMEE250011

24/12 18:16 WTIO31FMEE241806

24/12 18:16 WTIO30FMEE241806

24/12 18:16 WTIO22FMEE241805

Original Message :

WTIO31 FMEE 301828
CMRS / CENTRE DES CYCLONES TROPICAUX DE LA REUNION
BULLETIN D'ANALYSE ET DE PREVISION CYCLONIQUE (SUD-OUEST OCEAN
INDIEN)

0.A NUMERO DU BULLETIN : 29/4/20202021
1.A DEPRESSION SUR TERRE 4 (CHALANE)

2.A POSITION A 1800 UTC LE 30/12/2020 :
DANS UN RAYON DE 60 MN AUTOUR DU POINT 18.9 S / 31.2 E
(DIX-HUIT DEGRES NEUF SUD ET TRENTE UN DEGRES DEUX EST)
DEPLACEMENT: OUEST 15 KT

3.A ANALYSE DE DVORAK: NON RENSEIGNE
4.A PRESSION AU CENTRE: 1005 HPA
5.A VENT MAX (MOYEN/10 MN): 25 KT
RAYON DES VENTS MAXIMAUX (RVM): NON RENSEIGNE

6.A EXTENSION DES VENTS PAR QUADRANTS (KM):
NON RENSEIGNE

7.A COTE/DIAM PREMIERE ISOBARE FERMEE: NON RENSEIGNE
8.A EXTENSION VERTICALE DE LA CIRCULATION CYCLONIQUE: MOYENNE

1.B PREVISIONS (EXTENSIONS DES VENTS FORTS EN KM):
12H: 31/12/2020 06 UTC: 19.8 S / 27.6 E, VENT MAX= 025 KT, DEPRESSION
SUR TERRE

24H: 31/12/2020 18 UTC: 20.9 S / 24.4 E, VENT MAX= 025 KT, DEPRESSION
SUR TERRE

36H: 01/01/2021 06 UTC: 21.3 S / 21.7 E, VENT MAX= 025 KT, DEPRESSION
SUR TERRE

48H: 01/01/2021 18 UTC: 21.5 S / 19.2 E, VENT MAX= 025 KT, DEPRESSION
SUR TERRE

60H: 02/01/2021 06 UTC: 21.5 S / 16.7 E, VENT MAX= 025 KT, DEPRESSION
SUR TERRE

2.B TENDANCE ULTERIEURE:
NON RENSEIGNE

2.C COMMENTAIRES:
AU COURS DES DERNIERES 6 HEURES, LA CONVECTION PROFONDE ASSOCIEE AU
COEUR DU SYSTEME S'EST EFFONDREE RAPIDEMENT. ELLE SE DEVELOPPE
LOCALEMENT PAR CONTRE LOIN DU CENTRE EN PERIPHERIE DE LA CIRCULATION
EN INTERACTION AVEC LES HAUTS PLATEAUX PRESENTS A L'INTERIEUR DES
TERRES. ALORS QUE L'IMAGERIE SATELLITE NE MET EN EVIDENCE QUE LA
CIRCULATION DE MOYENNE A HAUTE TROPOSPHERE, PROBABLEMENT DECALEE A
L'OUEST EN RAISON DU CISAILLEMENT DE VENT DE SECTEUR EST-SUD-EST
ASSEZ FORT, IL N'EST PLUS POSSIBLE DE DISTINGUER LA CIRCULATION DE
BASSES COUCHES. LA POSITION INITIALE EST PAR CONSEQUENT TRES
INCERTAINE.

CHALANE POURSUIT SON DA PLACEMENT RAPIDE VERS L'OUEST, SUR LA FACADE
NORD DE LA DORSALE SUBTROPICALE REMPLACEE DEMAIN PAR UNE SECONDE
DORSALE POSITIONNEE SUR L'ATLANTIQUE SUD. LES TRAJECTOIRES PROPOSEES
PAR LES MODELES NUMERIQUES DEVIENNENT PLUS ERRATIQUES A MESURE QUE LE
SYSTEME PERD EN DEFINITION EN S'ENFONCANT DANS LES TERRES, CE QUI
REND LA PREVISION DE TRAJECTOIRE PLUS IMPRECISE. CEPENDANT, UNE
MAJORITE CONTINUE DE PROPOSER UN DEPLACEMENT EN DIRECTION GENERALE DE
L'OUEST.

SI LES PLUIES EN LIEN DIRECT AVEC CHALANE ONT BAISSE A L'HEURE
ACTUELLE, ELLES POURRAIENT PAR MOMENT REPRENDRE A PROXIMITE DU
MINIMUM RESIDUEL AU COURS DES 2 A 3 PROCHAINS JOURS. LES CUMULS DE
PLUIES POURRAIENT ALORS ATTEINDRE 50 A 100 MM EN 24H SUR CERTAINES
ZONES SITUEES LE LONG DE LA TRAJECTOIRE PREVUE ET DEPASSER LOCALEMENT
LES 150 MM. CES PLUIES PEUVENT OCCASIONNER DES CRUES ECLAIRS ET DES
INONDATIONS. ELLES VONT SE PROPAGER LOIN A L'INTERIEUR DES TERRES SUR
LE ZIMBABWE, LE BOTSWANA A PARTIR DU 31 DECEMBRE, ET MA ME LA NAMIBIE
(PARTIE ORIENTALE NOTAMMENT) LE 01 JANVIER.

CECI EST LE DERNIER BULLETIN SUR CE SYSTEME. DES INFORMATIONS
ADDITIONNELLES SERONT DISPONIBLES DANS LE BULLETIN QUOTIDIEN AWIO21
FMEE DE SUIVI DE L'ACTIVITE CONVECTIVE SUR LE BASSIN, EMIS VERS 12Z.=

>

Original Message :

WTIO30 FMEE 301828
RSMC / TROPICAL CYCLONE CENTER / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)

0.A WARNING NUMBER: 29/4/20202021
1.A OVERLAND DEPRESSION 4 (CHALANE)

2.A POSITION 2020/12/30 AT 1800 UTC:
WITHIN 60 NM RADIUS OF POINT 18.9 S / 31.2 E
(EIGHTEEN DECIMAL NINE DEGREES SOUTH AND
THIRTY ONE DECIMAL TWO DEGREES EAST)
MOVEMENT: WEST 15 KT

3.A DVORAK ANALYSIS: NIL
4.A CENTRAL PRESSURE: 1005 HPA
5.A MAX AVERAGE WIND SPEED (10 MN): 25 KT
RADIUS OF MAXIMUM WINDS (RMW): NIL

6.A EXTENSION OF WIND BY QUADRANTS (KM):
NIL

7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): NIL
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: MEDIUM

1.B FORECASTS (WINDS RADII IN KM):
12H: 2020/12/31 06 UTC: 19.8 S / 27.6 E, VENT MAX= 025 KT, OVERLAND
DEPRESSION

24H: 2020/12/31 18 UTC: 20.9 S / 24.4 E, VENT MAX= 025 KT, OVERLAND
DEPRESSION

36H: 2021/01/01 06 UTC: 21.3 S / 21.7 E, VENT MAX= 025 KT, OVERLAND
DEPRESSION

48H: 2021/01/01 18 UTC: 21.5 S / 19.2 E, VENT MAX= 025 KT, OVERLAND
DEPRESSION

60H: 2021/01/02 06 UTC: 21.5 S / 16.7 E, VENT MAX= 025 KT, OVERLAND
DEPRESSION

2.B LONGER-RANGE OUTLOOK:
NIL

2.C ADDITIONAL INFORMATION:
OVER THE LAST 6 HOURS, THE DEEP CONVECTION ASSOCIATED WITH THE CORE
OF THE SYSTEM HAS COLLAPSED RAPIDLY. IT IS DEVELOPING LOCALLY,
HOWEVER, FAR FROM THE CENTER, ON THE PERIPHERY OF THE CIRCULATION IN
INTERACTION WITH THE HIGHLANDS INLAND. WHILE SATELLITE IMAGERY SHOWS
ONLY THE MID TO UPPER TROPOSPHERE CIRCULATION, PROBABLY SHIFTED TO
THE WEST DUE TO THE STRONG EAST-SOUTHEAST WIND SHEAR, IT IS NO LONGER
POSSIBLE TO DISTINGUISH THE LOW-LEVEL CIRCULATION. THE INITIAL
POSITION IS THEREFORE VERY UNCERTAIN.

CHALANE CONTINUES TO TRACK RAPIDLY WESTWARD, ON THE NORTHERN FACE OF
THE SUBTROPICAL RIDGE WHICH WILL BE REPLACED TOMORROW BY AN OTHER
RIDGE CENTERED OVER THE SOUTHERN ATLANTIC. AVAILABLE TRACK GUIDANCE
BECOME MORE ERRATIC AS THE SYSTEM LOOSES ITS DEFINITION OVER LAND,
MAKING THE TRACK FORECAST RATHER UNCERTAIN. HOWEVER, THERE IS STILL A
CONSENSUS OVER A GLOBALLY WESTWARD TRACK.

IF RAINFALL DIRECTLY RELATED TO CHALANE HAS DECREASED AT THE MOMENT,
IT COULD AT TIMES RESUME NEAR THE RESIDUAL LOW PRESSURE SYSTEM OVER
THE NEXT 2-3 DAYS. CUMULATIVE RAINFALL COULD THEN REACH 50 TO 100 MM
IN 24 HOURS ON SOME AREAS ALONG THE FORECAST TRACK AND LOCALLY EXCEED
150 MM. THESE RAINS MAY CAUSE FLASH FLOODS AND FLOODS. THEY WILL
SPREAD FAR INLAND OVER ZIMBABWE, BOTSWANA FROM DECEMBER 31, AND EVEN
NAMIBIA (EASTERN PART IN PARTICULAR) ON JANUARY 1.

THIS IS THE LAST ADVISORY ON THIS SYSTEM. ADDITIONAL INFORMATION WILL
BE AVAILABLE ON OUR DAILY TROPICAL WEATHER DISCUSSION BULLETIN AWIO20
FMEE ISSUED AT 12Z.=

>

Original Message :

WTIO31 FMEE 301216
CMRS / CENTRE DES CYCLONES TROPICAUX DE LA REUNION
BULLETIN D'ANALYSE ET DE PREVISION CYCLONIQUE (SUD-OUEST OCEAN
INDIEN)

0.A NUMERO DU BULLETIN : 28/4/20202021
1.A DEPRESSION SUR TERRE 4 (CHALANE)

2.A POSITION A 1200 UTC LE 30/12/2020 :
DANS UN RAYON DE 35 MN AUTOUR DU POINT 19.3 S / 32.9 E
(DIX-NEUF DEGRES TROIS SUD ET TRENTE DEUX DEGRES NEUF EST)
DEPLACEMENT: OUEST 15 KT

3.A ANALYSE DE DVORAK: NON RENSEIGNE
4.A PRESSION AU CENTRE: 1000 HPA
5.A VENT MAX (MOYEN/10 MN): 25 KT
RAYON DES VENTS MAXIMAUX (RVM): 28 KM

6.A EXTENSION DES VENTS PAR QUADRANTS (KM):
NON RENSEIGNE

7.A COTE/DIAM PREMIERE ISOBARE FERMEE: 1006 HPA / 400 KM
8.A EXTENSION VERTICALE DE LA CIRCULATION CYCLONIQUE: PROFONDE

1.B PREVISIONS (EXTENSIONS DES VENTS FORTS EN KM):
12H: 31/12/2020 00 UTC: 19.6 S / 29.5 E, VENT MAX= 025 KT, DEPRESSION
SUR TERRE

24H: 31/12/2020 12 UTC: 20.6 S / 26.5 E, VENT MAX= 025 KT, DEPRESSION
SUR TERRE

36H: 01/01/2021 00 UTC: 21.1 S / 23.1 E, VENT MAX= 025 KT, DEPRESSION
SUR TERRE

48H: 01/01/2021 12 UTC: 21.3 S / 20.6 E, VENT MAX= 025 KT, DEPRESSION
SUR TERRE

60H: 02/01/2021 00 UTC: 21.3 S / 18.3 E, VENT MAX= 025 KT, DEPRESSION
SUR TERRE

2.B TENDANCE ULTERIEURE:
NON RENSEIGNE

2.C COMMENTAIRES:
CHALANE CONTINUE DE S'ENFONCER DANS LES TERRES. BIEN QUE DESORMAIS
DIFFCILE A LOCALISE AVEC PRECISION, SON CENTRE EST ACTUELLEMENT SITUE
A PROXIMITE DE LA FRONTIERE ENTRE LE MOZAMBIQUE ET LE ZIMBABWE.
CEPENDANT, SOUS L'INFLUENCE D'UN FORT CISAILLEMENT DE SECTEUR EST, LA
CONVECTION EST PLUTOT LOCALISEE A L'OUEST DU SYSTEME. AINSI LES
FORTES PLUIES ASSOCIEES AU SYSTEME ONT DEJA QUITTE LE MOZAMBIQUE ET
CONCERNENT DESORMAIS LA PROVINCE DU MANICALAND.

CHALANE POURSUIT SON DA PLACEMENT RAPIDE VERS L'OUEST, SUR LA FACADE
NORD DE LA DORSALE SUBTROPICALE REMPLACEE DEMAIN PAR UNE SECONDE
DORSALE POSITIONNEE SUR L'ATLANTIQUE SUD. LES TRAJECTOIRES PROPOSEES
PAR LES MODELES NUMERIQUES DEVIENNENT PLUS ERRATIQUES A MESURE QUE LE
SYSTEME PERD EN DEFINITION EN S'ENFONCANT DANS LES TERRES, CE QUI
REND LA PREVISION DE TRAJECTOIRE PLUS IMPRECISE. CEPENDANT, UNE
MAJORITE CONTINUE DE PROPOSER UN DEPLACEMENT EN DIRECTION GENERALE DE
L'OUEST.

CHALANE GENERE ACTUELLEMENT DES FORTES PLUIES SUR LA MOITIE EST DU
ZIMBABWE (MANICALAND): DES CUMULS DE 50 A 100 MM SONT ATTENDUS AU
COURS DES PROCHAINES 24H. LES PLUIES POURRAIENT DEPASSER LOCALEMENT
LES 150MM EN 24H. CES PLUIES PEUVENT OCCASIONNER DES CRUES ECLAIRS ET
DES INONDATIONS QUI VONT SE PROPAGER LOIN A L'INTERIEUR DES TERRES
SUR LE ZIMBABWE, LE BOTSWANA A PARTIR DU 31 JANVIER, ET MA ME LA
NAMIBIE LE 01 JANVIER.=

>

Original Message :

WTIO30 FMEE 301216
RSMC / TROPICAL CYCLONE CENTER / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)

0.A WARNING NUMBER: 28/4/20202021
1.A OVERLAND DEPRESSION 4 (CHALANE)

2.A POSITION 2020/12/30 AT 1200 UTC:
WITHIN 35 NM RADIUS OF POINT 19.3 S / 32.9 E
(NINETEEN DECIMAL THREE DEGREES SOUTH AND
THIRTY TWO DECIMAL NINE DEGREES EAST)
MOVEMENT: WEST 15 KT

3.A DVORAK ANALYSIS: NIL
4.A CENTRAL PRESSURE: 1000 HPA
5.A MAX AVERAGE WIND SPEED (10 MN): 25 KT
RADIUS OF MAXIMUM WINDS (RMW): 28 KM

6.A EXTENSION OF WIND BY QUADRANTS (KM):
NIL

7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1006 HPA / 400 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: DEEP

1.B FORECASTS (WINDS RADII IN KM):
12H: 2020/12/31 00 UTC: 19.6 S / 29.5 E, VENT MAX= 025 KT, OVERLAND
DEPRESSION

24H: 2020/12/31 12 UTC: 20.6 S / 26.5 E, VENT MAX= 025 KT, OVERLAND
DEPRESSION

36H: 2021/01/01 00 UTC: 21.1 S / 23.1 E, VENT MAX= 025 KT, OVERLAND
DEPRESSION

48H: 2021/01/01 12 UTC: 21.3 S / 20.6 E, VENT MAX= 025 KT, OVERLAND
DEPRESSION

60H: 2021/01/02 00 UTC: 21.3 S / 18.3 E, VENT MAX= 025 KT, OVERLAND
DEPRESSION

2.B LONGER-RANGE OUTLOOK:
NIL

2.C ADDITIONAL INFORMATION:
CHALANE KEEPS ON TRACKING INLAND. ITS CENTER BECOMES DIFFICULT TO
LOCATE WITH PRECISION BUT IS CURRENTLY LOCATED NEAR THE BORDER
BETWEEN MOZAMBIQUE AND ZIMBABWE. HOWEVER, UNDER THE INFLUENCE OF A
STRONG EASTERLY SHEAR, CONVECTION IS NOW LOCATED OVER A WIDE WESTERN
SEMI-CIRCLE. THUS, HEAVY RAINFALL ASSOCIATED TO CHALANE HAVE ALREADY
CEASED OVER MOZAMBIQUE AND CURRENTLY AFFECTS THE MANICALAND PROVINCE.

CHALANE CONTINUES TO TRACK RAPIDLY WESTWARD, ON THE NORTHERN FACE OF
THE SUBTROPICAL RIDGE WHICH WILL BE REPLACED TOMORROW BY AN OTHER
RIDGE CENTERED OVER THE SOUTHERN ATLANTIC. AVAILABLE TRACK GUIDANCE
BECOME MORE ERRATIC AS THE SYSTEM LOOSES ITS DEFINITION OVER LAND,
MAKING THE TRACK FORECAST RATHER UNCERTAIN. HOWEVER, THERE IS STILL A
CONSENSUS OVER A GLOBALLY WESTWARD TRACK.

CHALANE CURRENTLY GENERATES HEAVY RAINS OVER EASTERN ZIMBABWE
(MANICALAND): 50 TO 100MM OF CUMULATED RAINFALL ARE AWAITED OVER THE
NEXT 24 HRS ON THESE REGIONS, LOCALLY EXCEEDING 150MM. THESE HEAVY
RAINS CAN TRIGGER FLASH FLOODS AND CAUSE LARGE-SCALE FLOODS AS THEY
PROPAGATE FAR INLAND OVER ZIMBABWE, BOTSWANA FROM THE 31RST OF
JANUARY AND EVEN NAMIBIA ON THE 1RST OF JANUARY.=

>

Original Message :

WTIO24 FMEE 301215 CCA
***************CORRECTIVE**************
SECURITE
WARNING FOR METAREA VII
ISSUED BY METEO-FRANCE/TROPICAL CYCLONE CENTER/LA REUNION 30/12/2020
AT 1200 UTC.
WARNING NUMBER: 028/4 (SOUTH-WEST INDIAN OCEAN)
10 MINUTES AVERAGE WIND SPEED IN KNOTS (KT)
(WIND GUSTS AT SEA MAY BE ABOUT 40% STRONGER THAN THE AVERAGED WIND)
MINIMUM SEA LEVEL PRESSURE IN HECTOPASCAL (HPA)
(INDICATIVE FIGURE).

WARNING
BEGINNING OF VALIDITY: WEDNESDAY 30/12/2020 AT 1200 UTC.

PHENOMENON: OVERLAND DEPRESSION 4 (CHALANE) 1000 HPA
POSITION: WITHIN 35 NM RADIUS OF POINT 19.3 S / 32.9 E
(NINETEEN DECIMAL THREE DEGREES SOUTH AND
THIRTY TWO DECIMAL NINE DEGREES EAST) AT 1200 UTC
MOVEMENT: WEST 15 KT

THREAT AREAS:
SQUALLY WEATHER NOW ONLY LOCATED INLAND.

NORTH-EASTERLY WINDS ALONG THE MOZAMBICAN COASTLINE LOCALLY REACHING
NEAR GALE FORCE BETWEEN 19S AND 21S.
STRONG GUSTS UNDER SQUALLS.

FORECAST POSITION AND INTENSITY:
12H, VALID 2020/12/31 AT 00 UTC:
19.6 S / 29.5 E, MAX WIND = 25 KT, OVERLAND DEPRESSION

24H, VALID 2020/12/31 AT 12 UTC:
20.6 S / 26.5 E, MAX WIND = 25 KT, OVERLAND DEPRESSION

OTHER INFORMATION:
LAST WARNING ON THIS SYSTEM.=

>

Original Message :

WTIO24 FMEE 301205
SECURITE
WARNING FOR METAREA VII
ISSUED BY METEO-FRANCE/TROPICAL CYCLONE CENTER/LA REUNION 30/12/2020
AT 1200 UTC.
WARNING NUMBER: 028/4 (SOUTH-WEST INDIAN OCEAN)
10 MINUTES AVERAGE WIND SPEED IN KNOTS (KT)
(WIND GUSTS AT SEA MAY BE ABOUT 40% STRONGER THAN THE AVERAGED WIND)
MINIMUM SEA LEVEL PRESSURE IN HECTOPASCAL (HPA)
(INDICATIVE FIGURE).

WARNING
BEGINNING OF VALIDITY: WEDNESDAY 30/12/2020 AT 1200 UTC.

PHENOMENON: OVERLAND DEPRESSION 4 (CHALANE) 1000 HPA
POSITION: WITHIN 35 NM RADIUS OF POINT 19.3 S / 32.9 E
(NINETEEN DECIMAL THREE DEGREES SOUTH AND
THIRTY TWO DECIMAL NINE DEGREES EAST) AT 1200 UTC
MOVEMENT: WEST 15 KT

THREAT AREAS:
SQUALLY WEATHER EXTENDING FROM THE MOZAMBICAN COASTLINE UP TO 60 NM
OFF THE COAST BETWEEN 18S AND 21S

NORTH-EASTERLY WINDS ALONG THE MOZAMBICAN COASTLINE LOCALLY REACHING
NEAR GALE FORCE BETWEEN 19S AND 21S.
STRONG GUSTS UNDER SQUALLS.

FORECAST POSITION AND INTENSITY:
12H, VALID 2020/12/31 AT 00 UTC:
19.6 S / 29.5 E, MAX WIND = 25 KT, OVERLAND DEPRESSION

24H, VALID 2020/12/31 AT 12 UTC:
20.6 S / 26.5 E, MAX WIND = 25 KT, OVERLAND DEPRESSION

OTHER INFORMATION:
LAST WARNING ON THIS SYSTEM.=

>

Original Message :

WTXS51 PGTW 300900
WARNING ATCG MIL 07S SIO 201230064358
2020123006 07S CHALANE 012 01 260 14 SATL SYNP 020
T000 194S 0346E 045 R034 055 NE QD 075 SE QD 055 SW QD 040 NW QD
T012 196S 0317E 030
T024 201S 0285E 020
AMP 000HR DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
012HR DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
024HR DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
SUBJ: TROPICAL CYCLONE 07S (CHALANE) WARNING NR 012
1. TROPICAL CYCLONE 07S (CHALANE) WARNING NR 012
01 ACTIVE TROPICAL CYCLONE IN SOUTHIO
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
300600Z --- NEAR 19.4S 34.6E
MOVEMENT PAST SIX HOURS - 260 DEGREES AT 14 KTS
POSITION ACCURATE TO WITHIN 020 NM
POSITION BASED ON CENTER LOCATED BY A COMBINATION OF
SATELLITE AND SYNOPTIC DATA
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT
075 NM SOUTHEAST QUADRANT
055 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
REPEAT POSIT: 19.4S 34.6E
---
FORECASTS:
12 HRS, VALID AT:
301800Z --- 19.6S 31.7E
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
VECTOR TO 24 HR POSIT: 260 DEG/ 15 KTS
---
24 HRS, VALID AT:
310600Z --- 20.1S 28.5E
MAX SUSTAINED WINDS - 020 KT, GUSTS 030 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
---
REMARKS:
300900Z POSITION NEAR 19.5S 33.9E.
30DEC20. TROPICAL CYCLONE 07S (CHALANE), LOCATED APPROXIMATELY
20 NM NORTH-NORTHWEST OF BEIRA, MOZAMBIQUE, HAS TRACKED WESTWARD AT
14 KNOTS OVER THE PAST SIX HOURS. THIS IS THE FINAL WARNING ON
THIS SYSTEM BY THE JOINT TYPHOON WRNCEN PEARL HARBOR HI. THE
SYSTEM WILL BE CLOSELY MONITORED FOR SIGNS OF REGENERATION.
//
0720122118 130S 620E 25
0720122200 134S 621E 20
0720122206 137S 620E 20
0720122212 139S 617E 25
0720122218 145S 616E 25
0720122300 150S 614E 25
0720122306 150S 611E 25
0720122312 149S 608E 25
0720122318 147S 605E 30
0720122400 147S 600E 30
0720122406 154S 592E 30
0720122412 154S 582E 30
0720122418 159S 574E 35
0720122500 158S 565E 35
0720122506 159S 556E 35
0720122512 160S 548E 35
0720122518 160S 539E 35
0720122600 160S 531E 35
0720122606 162S 525E 35
0720122612 168S 510E 35
0720122618 176S 497E 35
0720122700 178S 486E 30
0720122706 182S 476E 30
0720122712 187S 466E 30
0720122718 191S 457E 30
0720122800 196S 446E 30
0720122806 200S 434E 35
0720122812 201S 426E 35
0720122818 199S 419E 40
0720122900 198S 416E 45
0720122906 197S 396E 45
0720122912 196S 385E 55
0720122912 196S 385E 55
0720122918 194S 373E 60
0720122918 194S 373E 60
0720123000 192S 361E 60
0720123000 192S 361E 60
0720123006 194S 346E 45
NNNN

>

Original Message :

WTXS31 PGTW 300900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 07S (CHALANE) WARNING NR 012//
RMKS/
1. TROPICAL CYCLONE 07S (CHALANE) WARNING NR 012
01 ACTIVE TROPICAL CYCLONE IN SOUTHIO
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
300600Z --- NEAR 19.4S 34.6E
MOVEMENT PAST SIX HOURS - 260 DEGREES AT 14 KTS
POSITION ACCURATE TO WITHIN 020 NM
POSITION BASED ON CENTER LOCATED BY A COMBINATION OF
SATELLITE AND SYNOPTIC DATA
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT
075 NM SOUTHEAST QUADRANT
055 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
REPEAT POSIT: 19.4S 34.6E
---
FORECASTS:
12 HRS, VALID AT:
301800Z --- 19.6S 31.7E
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
VECTOR TO 24 HR POSIT: 260 DEG/ 15 KTS
---
24 HRS, VALID AT:
310600Z --- 20.1S 28.5E
MAX SUSTAINED WINDS - 020 KT, GUSTS 030 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
---
REMARKS:
300900Z POSITION NEAR 19.5S 33.9E.
30DEC20. TROPICAL CYCLONE 07S (CHALANE), LOCATED APPROXIMATELY 20 NM
NORTH-NORTHWEST OF BEIRA, MOZAMBIQUE, HAS TRACKED WESTWARD AT
14 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY SHOWS THE SYSTEM HAS RAPIDLY ERODED AFTER IT MADE LANDFALL
ALONG THE EASTERN COAST OF NORTHERN MOZAMBIQUE. THE INITIAL POSITION
IS PLACED WITH HIGH CONFIDENCE BASED ON A DEFINED LOW LEVEL
CIRCULATION FEATURE IN THE 300410Z 37GHZ SSMIS MICROWAVE IMAGE AND
TRIANGULATED FROM NEARBY SURFACE OBSERVATIONS. THE INITIAL INTENSITY
OF 45KTS IS EXTRAPOLATED FROM THE MAXIMUM WIND OBSERVATION FROM
BEIRA AIRPORT OF SE/38KTS AT 300300Z WHEN THE TC WAS WITHIN 20NM. TC
CHALANE WILL CONTINUE TO RAPIDLY ERODE AS IT DRAGS ACROSS THE RUGGED
TERRAIN, LEADING TO DISSIPATION BY TAU 12 AFTER IT CROSSES INTO
ZIMBABWE. THIS IS THE FINAL WARNING ON THIS SYSTEM BY THE JOINT
TYPHOON WRNCEN PEARL HARBOR HI. THE SYSTEM WILL BE CLOSELY MONITORED
FOR SIGNS OF REGENERATION.//
NNNN

>

Original Message :

WTIO31 FMEE 300623
CMRS / CENTRE DES CYCLONES TROPICAUX DE LA REUNION
BULLETIN D'ANALYSE ET DE PREVISION CYCLONIQUE (SUD-OUEST OCEAN
INDIEN)

0.A NUMERO DU BULLETIN : 27/4/20202021
1.A TEMPETE TROPICALE MODEREE 4 (CHALANE)

2.A POSITION A 0600 UTC LE 30/12/2020 :
DANS UN RAYON DE 20 MN AUTOUR DU POINT 19.3 S / 34.7 E
(DIX-NEUF DEGRES TROIS SUD ET TRENTE QUATRE DEGRES SEPT EST)
DEPLACEMENT: OUEST 10 KT

3.A ANALYSE DE DVORAK: NON RENSEIGNE
4.A PRESSION AU CENTRE: 992 HPA
5.A VENT MAX (MOYEN/10 MN): 45 KT
RAYON DES VENTS MAXIMAUX (RVM): 28 KM

6.A EXTENSION DES VENTS PAR QUADRANTS (KM):
28 KT NE: 185 SE: 185 SO: 0 NO: 0
34 KT NE: 110 SE: 110 SO: 0 NO: 0

7.A COTE/DIAM PREMIERE ISOBARE FERMEE: 1006 HPA / 400 KM
8.A EXTENSION VERTICALE DE LA CIRCULATION CYCLONIQUE: PROFONDE

1.B PREVISIONS (EXTENSIONS DES VENTS FORTS EN KM):
12H: 30/12/2020 18 UTC: 19.4 S / 31.1 E, VENT MAX= 025 KT, DEPRESSION
SUR TERRE

24H: 31/12/2020 06 UTC: 20.2 S / 27.7 E, VENT MAX= 025 KT, DEPRESSION
SUR TERRE

36H: 31/12/2020 18 UTC: 21.1 S / 25.1 E, VENT MAX= 025 KT, DEPRESSION
SUR TERRE

48H: 01/01/2021 06 UTC: 21.8 S / 22.5 E, VENT MAX= 025 KT, DEPRESSION
SUR TERRE

60H: 01/01/2021 18 UTC: 21.9 S / 20.3 E, VENT MAX= 025 KT, DEPRESSION
SUR TERRE

72H: 02/01/2021 06 UTC: 22.3 S / 17.6 E, VENT MAX= 025 KT, DEPRESSION
SUR TERRE

2.B TENDANCE ULTERIEURE:
NON RENSEIGNE

2.C COMMENTAIRES:
CHALANE A ATTERRI AU COURS DES DERNIERES HEURES MAIS CONSERVE UNE
CONFIGURATION NUAGEUSE RELATIVEMENT IMPRESSIONNANTE, AVEC UN CDO TRES
DEVELOPPE ET ACTIF. LES IMAGES MICRO-ONDES DE LA MATINEE REVELENT
TOUJOURS QUE LA CONVECTION LA PLUS FORTE EST LOCALISEE DANS LE
DEMI-CERCLE NORD SOUS L'INFLUENCE DE LA CONTRAINTE CISAILLE DE
SECTEUR SUD-EST EN MOYENNE TROPO. EN PARTICULIER L'IMAGE 91GHZ SSMIS
DE 0410Z REVELE DES NOYAUX CONVECTIFS PARTICULIA REMENT PUISSANTS
DANS LE DEMI-CERCLE NORD-EST ET QUI GENERENT ACUTELLEMENT DES FORTES
PLUIES SUR LE MOZAMBIQUE.

CHALANE POURSUIT SON DA PLACEMENT RAPIDE VERS L'OUEST, SUR LA FACADE
NORD DE LA DORSALE SUBTROPICALE. L'ATTERRISSAGE A EU LIEU AU NORD DE
BEIRA. AU DELA DE 24H, LES PREVISIONS DE TRAJECTOIRE DES MODELES
DEVIENNENT DE PLUS EN PLUS ERRATIQUES A MESURE QUE LE SYSTEME PERD EN
DEFINITION EN S'ENFONCANT DANS LES TERRES. CEPENDANT, UNE MAJORITE
CONTINUE DE PROPOSER UN DEPLACEMENT EN DIRECTION GENERALE DE L'OUEST.
L'INCERTITUDE RESTE IMPORTANTE LE LONG DE CETTE TRAJECTOIRE.

LE SYSTEME A ATTERRI ET RESTE SOUMIS A UNE CONTRAINTE CISAILLEE DE
SUD-EST MODEREE EN MOYENNE TROPOSPHERE. IL CONTINUE CEPENDANT DE
GENERER DES FORTES PLUIES, NOTAMMENT AU SEIN DU DEMI-CERCLE NORD.

CHALANE GENERE ACTUELLEMENT DES CONDITIONS METEROLOGIQUES DANGEREUSES
DANS LA REGION DE BEIRA:
- EN TERMES DE VENTS, LES RAFALES PEUVENT ENCORE DEPASSER LES 100 A
120KM/H SUR LA COTE.
- EN TERMES DE PRECIPITATIONS, DES CUMULS A PLUS DE 100 MM EN 24H
SONT ATTENDUS. EN RAISON DU CISAILLEMENT, LES PLUIES VONT
PRINCIPALEMENT CONCERNER LES REGIONS SITUEES A DROITE DE LA
TRAJECTOIRE (AU NORD DU SYSTEME) ET POURRAIENT Y DEPASSER LOCALEMENT
LES 200MM EN 24H. CES PLUIES PEUVENT OCCASIONNER DES CRUES ECLAIRS ET
DES INONDATIONS QUI VONT SE PROPAGER LOIN A L'INTERIEUR DES TERRES
SUR LE ZIMBABWE LE 31 DECEMBRE, LE BOTSWANA LE 01 JANVIER, ET MA ME
LA NAMIBIE LE 02 JANVIER.
- LA SURCOTE CYCLONIQUE DE L'ORDRE DE 1M A 2,5M AU LIEU DE
L'ATTERRISSAGE ET AU SUD DE CELUI-CI VA DECROITRE DANS LES PROCHAINES
HEURES AVEC LA BASCULE DES VENTS AU SECTEUR NORD. COUPLE A LA MAREE
DESCENDANTE ET A UNE MER DU VENT EN NETTE BAISSE, LE RISQUE DE
SUBSMERSION COTIERE S'AFFAIBLIT RAPIDEMENT EN MATINEE.=

>

Original Message :

WTIO30 FMEE 300623
RSMC / TROPICAL CYCLONE CENTER / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)

0.A WARNING NUMBER: 27/4/20202021
1.A MODERATE TROPICAL STORM 4 (CHALANE)

2.A POSITION 2020/12/30 AT 0600 UTC:
WITHIN 20 NM RADIUS OF POINT 19.3 S / 34.7 E
(NINETEEN DECIMAL THREE DEGREES SOUTH AND
THIRTY FOUR DECIMAL SEVEN DEGREES EAST)
MOVEMENT: WEST 10 KT

3.A DVORAK ANALYSIS: NIL
4.A CENTRAL PRESSURE: 992 HPA
5.A MAX AVERAGE WIND SPEED (10 MN): 45 KT
RADIUS OF MAXIMUM WINDS (RMW): 28 KM

6.A EXTENSION OF WIND BY QUADRANTS (KM):
28 KT NE: 185 SE: 185 SW: 0 NW: 0
34 KT NE: 110 SE: 110 SW: 0 NW: 0

7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1006 HPA / 400 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: DEEP

1.B FORECASTS (WINDS RADII IN KM):
12H: 2020/12/30 18 UTC: 19.4 S / 31.1 E, VENT MAX= 025 KT, OVERLAND
DEPRESSION

24H: 2020/12/31 06 UTC: 20.2 S / 27.7 E, VENT MAX= 025 KT, OVERLAND
DEPRESSION

36H: 2020/12/31 18 UTC: 21.1 S / 25.1 E, VENT MAX= 025 KT, OVERLAND
DEPRESSION

48H: 2021/01/01 06 UTC: 21.8 S / 22.5 E, VENT MAX= 025 KT, OVERLAND
DEPRESSION

60H: 2021/01/01 18 UTC: 21.9 S / 20.3 E, VENT MAX= 025 KT, OVERLAND
DEPRESSION

72H: 2021/01/02 06 UTC: 22.3 S / 17.6 E, VENT MAX= 025 KT, OVERLAND
DEPRESSION

2.B LONGER-RANGE OUTLOOK:
NIL

2.C ADDITIONAL INFORMATION:
CHALANE MADE LANFALL OVER THE LAST HOURS BUT KEEPS A RELATIVELY
IMPRESSING CLOUD PATTERN, WITH A WELL DEFINED AND ACTIVE CDO. THIS
MORNING MW IMAGES STILL SHOW THAT CONVECTION IS MAINLY LOCATED OVER
THE NNORTHERN HALF OF THE SYSTEM UNDER THE INFLUENCE OF THE MID-LEVEL
SOUTH-EASTERLY SHEAR. THE 0410 SSMIS 91GHZ IMAGE ILLUSTRATES THE
STRONG CONVECTION CURRENTLY OCCURING CLOSE TO THE CENTER IN THE
NORTH-EASTERN QUADRANT, WHICH GENERATES SEVERE RAINFALL OVER
MOZAMBIQUE.

CHALANE KEEPS ON HEADING WESTWARD, ON THE NORTHERN FACE OF THE
SUBTROPICAL RIDGE. THE LANDING OCCURRED NORTH OF BEIRA. FROM TOMORROW
ONWARDS, THE AVAILABLE TRACK GUIDANCE BECOMES MORE AND MORE ERRATIC
AS THE SYSTEM LOOSES ITS DEFINITION OVERLAND. HOWEVER, THE CONSENSUS
STILL SUGGEST A GLOBALLY WESTWARD MOTION. THE UNCERTAINTY IS HIGH
ALONG THIS TRACK.

CHALANE MADE LANFALL AND REMAINS SUBJECT TO A MODERATE SOUTH-EASTERLY
MID-LEVEL SHEAR. THE STORM CONTINUES TO GENERATE HEAVY RAINFALL,
ESPECIALLY WITHIN THE NORTHERN SEMI-CIRCLE.

CHALANE IS CURRENTLY GENERATING DANGEROUS WEATHER CONDITIONS OVER THE
BEIRA REGION:
- IN TERMS OF WINDS, GUSTS EXCEEDING 100 TO 120 KM/H REMAIN POSSIBLE
ON THE COASTLINE.
- IN TERMS OF PRECIPITATIONS, ACCUMULATIONS OF MORE THAN 100 MM IN 24
HOURS ARE EXPECTED. DUE TO THE SHEAR, THE RAINS WILL MAINLY CONCERN
THE REGIONS LOCATED ON THE RIGHT OF THE TRAJECTORY (NORTH OF THE
SYSTEM) AND COULD EXCEED 200MM/24H THERE. THESE RAINS CAN CAUSE FLASH
FLOODS AND LARGE-SCALE FLOODS THAT WILL SPREAD FAR INLAND OVER
ZIMBABWE ON DECEMBER 31, BOTSWANA ON JANUARY 01, AND EVEN NAMIBIA ON
JANUARY 02.
- THE STORM SURGE OF ABOUT 1M TO 2.5M AT THE LANDING SITE AND SOUTH
OF IT WILL DECREASE OVER THE NEXT HOUTS WITH THE WINDS VEERING
NORTHERLY. COUPLED WITH THE DECREASING WIND WAVES HEIGHT AND THE
BEGINNING OF THE LOW TIDE, THE COASTAL SUBMERSION RISK IS EXPECTED TO
RAPIDLY WEAKEN THIS MORNING.=

>

Original Message :

WTIO24 FMEE 300613
SECURITE
GALE WARNING FOR METAREA VII
ISSUED BY METEO-FRANCE/TROPICAL CYCLONE CENTER/LA REUNION 30/12/2020
AT 0600 UTC.
WARNING NUMBER: 027/4 (SOUTH-WEST INDIAN OCEAN)
10 MINUTES AVERAGE WIND SPEED IN KNOTS (KT)
(WIND GUSTS AT SEA MAY BE ABOUT 40% STRONGER THAN THE AVERAGED WIND)
MINIMUM SEA LEVEL PRESSURE IN HECTOPASCAL (HPA)
(INDICATIVE FIGURE).

GALE WARNING
BEGINNING OF VALIDITY: WEDNESDAY 30/12/2020 AT 0600 UTC.

PHENOMENON: MODERATE TROPICAL STORM 4 (CHALANE) 992 HPA
POSITION: WITHIN 20 NM RADIUS OF POINT 19.3 S / 34.7 E
(NINETEEN DECIMAL THREE DEGREES SOUTH AND
THIRTY FOUR DECIMAL SEVEN DEGREES EAST) AT 0600 UTC
MOVEMENT: WEST 10 KT

THREAT AREAS:
SQUALLY WEATHER EXTENDING FROM THE MOZAMBICAN COASTLINE UP TO 60 NM
OFF THE COAST BETWEEN 18S AND 21S

GALE FORCE WINDS 35/45 KT AND VERY ROUGH TO HIGH SEAS EXTENDING UP TO
60 NM IN THE EASTERN SEMI-CIRCLE.
NEAR GALE FORCE WINDS 30 KT AND ROUGH TO VERY ROUGH SEAS EXTENDING UP
TO 100 NM IN THE EASTERN SEMI-CIRCLE.
STRONG GUSTS UNDER SQUALLS.

FORECAST POSITION AND INTENSITY:
12H, VALID 2020/12/30 AT 18 UTC:
19.4 S / 31.1 E, MAX WIND = 25 KT, OVERLAND DEPRESSION

24H, VALID 2020/12/31 AT 06 UTC:
20.2 S / 27.7 E, MAX WIND = 25 KT, OVERLAND DEPRESSION

OTHER INFORMATION:
NIL=

>

Original Message :

WTIO31 FMEE 300048
CMRS / CENTRE DES CYCLONES TROPICAUX DE LA REUNION
BULLETIN D'ANALYSE ET DE PREVISION CYCLONIQUE (SUD-OUEST OCEAN
INDIEN)

0.A NUMERO DU BULLETIN : 26/4/20202021
1.A FORTE TEMPETE TROPICALE 4 (CHALANE)

2.A POSITION A 0000 UTC LE 30/12/2020 :
DANS UN RAYON DE 20 MN AUTOUR DU POINT 19.6 S / 35.8 E
(DIX-NEUF DEGRES SIX SUD ET TRENTE CINQ DEGRES HUIT EST)
DEPLACEMENT: OUEST 12 KT

3.A ANALYSE DE DVORAK: 4.0/4.0/D 1.0/24 H

4.A PRESSION AU CENTRE: 983 HPA
5.A VENT MAX (MOYEN/10 MN): 60 KT
RAYON DES VENTS MAXIMAUX (RVM): 28 KM

6.A EXTENSION DES VENTS PAR QUADRANTS (KM):
28 KT NE: 185 SE: 220 SO: 165 NO: 130
34 KT NE: 95 SE: 150 SO: 130 NO: 95
48 KT NE: 65 SE: 65 SO: 60 NO: 55

7.A COTE/DIAM PREMIERE ISOBARE FERMEE: 1006 HPA / 400 KM
8.A EXTENSION VERTICALE DE LA CIRCULATION CYCLONIQUE: PROFONDE

1.B PREVISIONS (EXTENSIONS DES VENTS FORTS EN KM):
12H: 30/12/2020 12 UTC: 19.5 S / 33.1 E, VENT MAX= 035 KT, TEMPETE
TROPICALE MODEREE
28 KT NE: 230 SE: 270 SO: 270 NO: 175
34 KT NE: 130 SE: 150 SO: 140 NO: 130

24H: 31/12/2020 00 UTC: 19.7 S / 29.5 E, VENT MAX= 025 KT, DEPRESSION
SUR TERRE

36H: 31/12/2020 12 UTC: 20.3 S / 26.8 E, VENT MAX= 025 KT, DEPRESSION
SUR TERRE

48H: 01/01/2021 00 UTC: 20.9 S / 24.2 E, VENT MAX= 025 KT, DEPRESSION
SUR TERRE

60H: 01/01/2021 12 UTC: 22.2 S / 20.5 E, VENT MAX= 025 KT, DEPRESSION
SUR TERRE

2.B TENDANCE ULTERIEURE:
NON RENSEIGNE

2.C COMMENTAIRES:
T=CI=4.0+.

LA CONFIGURATION NUAGEUSE DE CHALANE A PEU EVOLUE AU COURS DE CES 6
DERNIERES HEURES. SUR LES DERNIERES DONNA ES MICRO-ONDE AMSR DE 2221Z
LA CONVECTION PROFONDE CONTINUE PRESENTE UNE FORTE DISSYMA TRIE,
SURTOUT PRESENT DANS LE DEMI-CERCLE NORD MAINTENANT. DE PLUS UN TILT
EXISTE EGALEMENT ENTRE LES CENTRES DE CIRCULATION DE BASSES COUCHES
ET D'ALTITUDE, TRADUISANT L'EFFET D'UNE CONTRAINTE DE SUD-EST SUR LE
SYSTEME. NEANMOINS LE SYSTEME CONTINUE DE BENEFICIER D'UNE BONNE
DIVERGENCE COTE EQUATORIAL, ET POURSUIT UNE INTENSIFICATION LENTE.

CHALANE POURSUIT SON DA PLACEMENT RAPIDE VERS L'OUEST, SUR LA FACADE
NORD DE LA DORSALE SUBTROPICALE. L'ATTERRISSAGE EST ATTENDU DANS LES
TOUTES PROCHAINES HEURES A PROXIMITE NORD DE LA VILLE DE BEIRA.

PEU DE CHANGEMENT EN TERMES DE PREVISION D'INTENSITE:
LES CONDITIONS ENVIRONNEMENTALES SONT PLUTA T FAVORABLES AU
DEVELOPPEMENT DU SYSTEME : CISAILLEMENT MODA RA , POTENTIEL OCA
ANIQUE FAVORABLE, BONNE ALIMENTATION DU FLUX DE MOUSSON QUI DESCEND
JUSQU'AU MILIEU DU CANAL. TOUTEFOIS ON NOTE LA PRESENCE DE BEAUCOUP
D'AIR SEC DANS L'ENVIRONNEMENT IMMEDIAT DU SYSTEME CE QUI POURRAIT
FREINER LE RYTHME D'INTENSIFICATION D'ICI L'ARRIVEE SUR TERRE,
D'AUTANT QU'UNE PETITE CONTRAINTE DE SUD-EST POURRAIT EGALEMENT SE
METTRE EN PLACE, NEANMOINS ATTENUEE PAR LA GRANDE VITESSE DE
DEPLACEMENT DU SYSTEME.

SUIVANT CE SCA NARIO, LA MENACE REPRESENTA E PAR CHALANE EST BIEN RA
ELLE POUR LA REGION DE BEIRA:
- EN TERMES DE VENTS, DES RAFALES DESTRUCTRICES (DEPASSANT LES 150
KM/H) SONT POSSIBLES A MOINS DE 60 KM DU CENTRE. (CHALANE EST UN
SYSTEME ASSEZ COMPACTE)
- EN TERMES DE PRECIPITATIONS, DES CUMULS A PLUS DE 100 MM EN 24H
SONT POSSIBLES. EN RAISON DU CISAILLEMENT, LES PLUIES VONT
PRINCIPALEMENT CONCERNER LES REGIONS SITUEES A DROITE DE LA
TRAJECTOIRE (AU NORD DU SYSTEME). CES PLUIES PEUVENT OCCASIONNER DES
CRUES ECLAIRS ET DES INONDATIONS QUI VONT SE PROPAGER LOIN A
L'INTERIEUR DES TERRES SUR LE ZIMBABWE LE 31 DECEMBRE, LE BOTSWANA LE
01 JANVIER, ET MA ME LA NAMIBIE LE 02 JANVIER.
- UNE SURCOTE CYCLONIQUE DE L'ORDRE DE 1M A 2,5M EST POSSIBLE AU
LIEU DE L'ATTERRISSAGE ET AU SUD DE CELUI-CI. COUPLEE A DES VAGUES
POUVANT DEPASSER LES 6M, ET A LA MAREE HAUTE (EN PHASE AVEC LE TIMING
DE L'ATTERRISSAGE SUR LA PREVISION ACTUELLE), CETTE SURCOTE SERA
ASSOCIEE A DES SUBMERSIONS ET DES INONDATIONS COTIERES.=

>

Original Message :

WTIO30 FMEE 300048
RSMC / TROPICAL CYCLONE CENTER / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)

0.A WARNING NUMBER: 26/4/20202021
1.A SEVERE TROPICAL STORM 4 (CHALANE)

2.A POSITION 2020/12/30 AT 0000 UTC:
WITHIN 20 NM RADIUS OF POINT 19.6 S / 35.8 E
(NINETEEN DECIMAL SIX DEGREES SOUTH AND
THIRTY FIVE DECIMAL EIGHT DEGREES EAST)
MOVEMENT: WEST 12 KT

3.A DVORAK ANALYSIS: 4.0/4.0/D 1.0/24 H

4.A CENTRAL PRESSURE: 983 HPA
5.A MAX AVERAGE WIND SPEED (10 MN): 60 KT
RADIUS OF MAXIMUM WINDS (RMW): 28 KM

6.A EXTENSION OF WIND BY QUADRANTS (KM):
28 KT NE: 185 SE: 220 SW: 165 NW: 130
34 KT NE: 95 SE: 150 SW: 130 NW: 95
48 KT NE: 65 SE: 65 SW: 60 NW: 55

7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1006 HPA / 400 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: DEEP

1.B FORECASTS (WINDS RADII IN KM):
12H: 2020/12/30 12 UTC: 19.5 S / 33.1 E, VENT MAX= 035 KT, MODERATE
TROPICAL STORM
28 KT NE: 230 SE: 270 SW: 270 NW: 175
34 KT NE: 130 SE: 150 SW: 140 NW: 130

24H: 2020/12/31 00 UTC: 19.7 S / 29.5 E, VENT MAX= 025 KT, OVERLAND
DEPRESSION

36H: 2020/12/31 12 UTC: 20.3 S / 26.8 E, VENT MAX= 025 KT, OVERLAND
DEPRESSION

48H: 2021/01/01 00 UTC: 20.9 S / 24.2 E, VENT MAX= 025 KT, OVERLAND
DEPRESSION

60H: 2021/01/01 12 UTC: 22.2 S / 20.5 E, VENT MAX= 025 KT, OVERLAND
DEPRESSION

2.B LONGER-RANGE OUTLOOK:
NIL

2.C ADDITIONAL INFORMATION:
T=CI=4.0+.

THE CLOUD PATTERN OF CHALANE HAS CHANGED LITTLE OVER THE LAST 6
HOURS. ACCORDING TO THE LAST AMSR DATA OF 2221Z THE DEEP CONVECTION
CONTINUES TO PRESENT A STRONG ASYMMETRY, ESPECIALLY PRESENT IN THE
NORTHERN SEMICIRCLE NOW. MOREOVER, A TILT ALSO EXISTS BETWEEN THE LOW
AND HIGH ALTITUDE CIRCULATION CENTERS, REFLECTING THE EFFECT OF A
SOUTHEASTERLYCONSTRAINTE ON THE SYSTEM.NEVERTHELESS, THE SYSTEM
CONTINUES TO BENEFIT FROM A GOOD DIVERGENCE ON THE EQUATORIAL SIDE,
AND GOES ON A SLOW INTENSIFICATION.

CHALANE CONTINUES ITS RAPID WESTWARD MOVEMENT, ON THE NORTHERN FACE
OF THE SUBTROPICAL RIDGE. THE LANDING IS FORECAST IN THE NEXT FEW
HOURS NEAR THE NORTH SIDE OF THE CITY OF BEIRA.

LITTLE CHANGE IN TERMS OF INTENSITY FORECAST:
THE ENVIRONMENTAL CONDITIONS ARE RATHER FAVORABLE FOR THE DEVELOPMENT
OF THE SYSTEM: MODERATE SHEAR, FAVORABLE OCEANIC POTENTIAL, GOOD
FEEDING OF THE MONSOON FLOW WHICH GOES DOWN TO THE MIDDLE OF THE
CHANNEL. HOWEVER, WE NOTE THE PRESENCE OF A LOT OF DRY AIR IN THE
IMMEDIATE ENVIRONMENT OF THE SYSTEM WHICH COULD SLOW DOWN THE RATE OF
INTENSIFICATION BY THE TIME OF THE ARRIVAL ON LAND, ESPECIALLY AS A
SMALL SOUTHEASTERN CONSTRAINT COULD ALSO BE IN PLACE, HOWEVER LIMITED
BY THE HIGH SPEED OF THE SYSTEM.

WITH THIS SCENARIO, THE THREAT REPRESENTED BY CHALANE IS VERY REAL
FOR THE BEIRA REGION:
- IN TERMS OF WINDS, DESTRUCTIVE GUSTS (EXCEEDING 150 KM/H) ARE
POSSIBLE LESS THAN 60 KM FROM THE CENTER. (CHALANE IS A RATHER
COMPACT SYSTEM).
- IN TERMS OF PRECIPITATION, ACCUMULATIONS OF MORE THAN 100 MM IN 24
HOURS ARE POSSIBLE. DUE TO THE SHEAR, THE RAINS WILL MAINLY CONCERN
THE REGIONS LOCATED ON THE RIGHT OF THE TRAJECTORY (NORTH OF THE
SYSTEM). THESE RAINS CAN CAUSE FLASH FLOODS AND FLOODS THAT WILL
SPREAD FAR INLAND OVER ZIMBABWE ON DECEMBER 31, BOTSWANA ON JANUARY
01, AND EVEN NAMIBIA ON JANUARY 02.
- A STORM SURGE OF ABOUT 1M TO 2.5M IS POSSIBLE AT THE LANDING SITE
AND SOUTH OF IT. COUPLED WITH WAVES THAT CAN EXCEED 6M, AND AT HIGH
TIDE (IN PHASE WITH THE TIMING OF THE LANDING ON THE CURRENT
FORECAST), THIS STORM SURGE WILL BE ASSOCIATED WITH COASTAL FLOODING
AND SUBMERSION.=

>

Original Message :

WTIO24 FMEE 300020
SECURITE
STORM WARNING FOR METAREA VII
ISSUED BY METEO-FRANCE/TROPICAL CYCLONE CENTER/LA REUNION 30/12/2020
AT 0000 UTC.
WARNING NUMBER: 026/4 (SOUTH-WEST INDIAN OCEAN)
10 MINUTES AVERAGE WIND SPEED IN KNOTS (KT)
(WIND GUSTS AT SEA MAY BE ABOUT 40% STRONGER THAN THE AVERAGED WIND)
MINIMUM SEA LEVEL PRESSURE IN HECTOPASCAL (HPA)
(INDICATIVE FIGURE).

STORM WARNING
BEGINNING OF VALIDITY: WEDNESDAY 30/12/2020 AT 0000 UTC.

PHENOMENON: SEVERE TROPICAL STORM 4 (CHALANE) 983 HPA
POSITION: WITHIN 20 NM RADIUS OF POINT 19.6 S / 35.8 E
(NINETEEN DECIMAL SIX DEGREES SOUTH AND
THIRTY FIVE DECIMAL EIGHT DEGREES EAST) AT 0000 UTC
MOVEMENT: WEST 12 KT

THREAT AREAS:
SQUALLY WEATHER IN A RADIUS OF 80 NM FROM THE CENTER, EXTENDING UP TO
300 NM IN THE NORTHERN SEMI-CERCLE.

STORM FORCE WINDS 50/60 KT AND HIGH TO VERY HIGH SEAS WITHIN A 30 NM
RADIUS FROM THE CENTRE, EXTENDING UP TO 35 NM IN THE SOUTHERN
SEMI-CIRCLE AND THE NORTH-EASTERN QUADRANT.
GALE FORCE WINDS 35/45 KT AND VERY ROUGH TO HIGH SEAS WITHIN A 50 NM
RADIUS FROM THE CENTRE, EXTENDING UP TO 70 NM IN THE SOUTH-WESTERN
QUADRANT AND UP TO 80 NM IN THE SOUTH-EASTERN QUADRANT.
NEAR GALE FORCE WINDS 30 KT AND ROUGH TO VERY ROUGH SEAS WITHIN A 70
NM RADIUS FROM THE CENTRE, EXTENDING UP TO 90 NM IN THE SOUTH-WESTERN
QUADRANT, UP TO 100 NM IN THE NORTH-EASTERN QUADRANT AND UP TO 120 NM
IN THE SOUTH-EASTERN QUADRANT.
STRONG GUSTS UNDER SQUALLS.

FORECAST POSITION AND INTENSITY:
12H, VALID 2020/12/30 AT 12 UTC:
19.5 S / 33.1 E, MAX WIND = 35 KT, MODERATE TROPICAL STORM
28 KT NE: 125 NM SE: 145 NM SW: 145 NM NW: 95 NM
34 KT NE: 70 NM SE: 80 NM SW: 75 NM NW: 70 NM

24H, VALID 2020/12/31 AT 00 UTC:
19.7 S / 29.5 E, MAX WIND = 25 KT, OVERLAND DEPRESSION

OTHER INFORMATION:
NIL=

>

Original Message :

WTXS51 PGTW 292100
WARNING ATCG MIL 07S SIO 201229195039
2020122918 07S CHALANE 011 01 260 08 SATL 060
T000 197S 0377E 060 R050 020 NE QD 025 SE QD 025 SW QD 020 NW QD R034 060 NE QD 070 SE QD 065 SW QD 055 NW QD
T012 197S 0350E 050 R050 010 NE QD 020 SE QD 020 SW QD 010 NW QD R034 050 NE QD 060 SE QD 050 SW QD 030 NW QD
T024 199S 0318E 025
AMP
012HR DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
024HR DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
SUBJ: TROPICAL CYCLONE 07S (CHALANE) WARNING NR 011
1. TROPICAL CYCLONE 07S (CHALANE) WARNING NR 011
01 ACTIVE TROPICAL CYCLONE IN SOUTHIO
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
291800Z --- NEAR 19.7S 37.7E
MOVEMENT PAST SIX HOURS - 260 DEGREES AT 08 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 020 NM NORTHEAST QUADRANT
025 NM SOUTHEAST QUADRANT
025 NM SOUTHWEST QUADRANT
020 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT
070 NM SOUTHEAST QUADRANT
065 NM SOUTHWEST QUADRANT
055 NM NORTHWEST QUADRANT
REPEAT POSIT: 19.7S 37.7E
---
FORECASTS:
12 HRS, VALID AT:
300600Z --- 19.7S 35.0E
MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
RADIUS OF 050 KT WINDS - 010 NM NORTHEAST QUADRANT
020 NM SOUTHEAST QUADRANT
020 NM SOUTHWEST QUADRANT
010 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT
060 NM SOUTHEAST QUADRANT
050 NM SOUTHWEST QUADRANT
030 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 265 DEG/ 15 KTS
---
24 HRS, VALID AT:
301800Z --- 19.9S 31.8E
MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
---
REMARKS:
292100Z POSITION NEAR 19.7S 37.0E.
29DEC20. TROPICAL CYCLONE 07S (CHALANE), LOCATED APPROXIMATELY
205 NM NORTHWEST OF EUROPA ISLAND, HAS TRACKED WESTWARD AT 08
KNOTS OVER THE PAST SIX HOURS.
MAXIMUM SIGNIFICANT WAVE HEIGHT AT 291800Z IS 18 FEET. NEXT
WARNINGS AT 300900Z.//
0720122118 130S 620E 25
0720122200 134S 621E 20
0720122206 137S 620E 20
0720122212 139S 617E 25
0720122218 145S 616E 25
0720122300 150S 614E 25
0720122306 150S 611E 25
0720122312 149S 608E 25
0720122318 147S 605E 30
0720122400 147S 600E 30
0720122406 154S 592E 30
0720122412 154S 582E 30
0720122418 159S 574E 35
0720122500 158S 565E 35
0720122506 159S 556E 35
0720122512 160S 548E 35
0720122518 160S 539E 35
0720122600 160S 531E 35
0720122606 162S 525E 35
0720122612 168S 510E 35
0720122618 176S 497E 35
0720122700 178S 486E 30
0720122706 182S 476E 30
0720122712 187S 466E 30
0720122718 191S 457E 30
0720122800 196S 446E 30
0720122806 200S 434E 35
0720122812 201S 426E 35
0720122818 199S 419E 40
0720122900 198S 416E 45
0720122906 197S 396E 45
0720122912 196S 385E 55
0720122912 196S 385E 55
0720122918 197S 377E 60
0720122918 197S 377E 60
NNNN

>

Original Message :

WTXS31 PGTW 292100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 07S (CHALANE) WARNING NR 011//
RMKS/
1. TROPICAL CYCLONE 07S (CHALANE) WARNING NR 011
01 ACTIVE TROPICAL CYCLONE IN SOUTHIO
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
291800Z --- NEAR 19.7S 37.7E
MOVEMENT PAST SIX HOURS - 260 DEGREES AT 08 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 020 NM NORTHEAST QUADRANT
025 NM SOUTHEAST QUADRANT
025 NM SOUTHWEST QUADRANT
020 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT
070 NM SOUTHEAST QUADRANT
065 NM SOUTHWEST QUADRANT
055 NM NORTHWEST QUADRANT
REPEAT POSIT: 19.7S 37.7E
---
FORECASTS:
12 HRS, VALID AT:
300600Z --- 19.7S 35.0E
MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
RADIUS OF 050 KT WINDS - 010 NM NORTHEAST QUADRANT
020 NM SOUTHEAST QUADRANT
020 NM SOUTHWEST QUADRANT
010 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT
060 NM SOUTHEAST QUADRANT
050 NM SOUTHWEST QUADRANT
030 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 265 DEG/ 15 KTS
---
24 HRS, VALID AT:
301800Z --- 19.9S 31.8E
MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
---
REMARKS:
292100Z POSITION NEAR 19.7S 37.0E.
29DEC20. TROPICAL CYCLONE 07S (CHALANE), LOCATED APPROXIMATELY
205 NM NORTHWEST OF EUROPA ISLAND, HAS TRACKED WESTWARD AT 08
KNOTS OVER THE PAST SIX HOURS. TC 07S HAS CONTINUED TO CONSOLIDATE
OVER THE PAST SEVERAL HOURS AROUND THE OBSCURED LOW LEVEL
CIRCULATION CENTER (LLCC) EVIDENT IN THE ENHANCED INFRARED SATELLITE
LOOP (EIR). THE SYSTEM CONTINUES TO TRACK WEST ALONG THE SUBTROPICAL
RIDGE (STR) TO THE SOUTH WITH ALL STEERING WINDS IN PHASE FROM AN
EASTERLY DIRECTION. THE INITIAL LOCATION IS ASSESSED WITH HIGH
CONFIDENCE BASED ON THE LOW LEVEL BANDING EVIDENT IN A TIMELY
291740Z GMI 37GHZ IMAGE. THE INITIAL INTENSITY OF 60KTS IS HEDGED
SLIGHTLY HIGHER THAN A DVORAK CURRENT INTENSITY (CI) ESTIMATE FROM
FMEE (T3.5/55KTS) AND NEAR A PGTW CI OF T4.0/65KTS AND A 291614Z
CIMMS SATCON INTENSITY ESTIMATE OF 60KTS WITH HIGH CONFIDENCE.
ANALYSIS OF TC 07S INDICATES A FAVORABLE ENVIRONMENT WITH VERY WARM
(31 CELSIUS) SST IN THE MOZAMBIQUE CHANNEL AND FAIR UPPER LEVEL
OUTFLOW OFFSET SLIGHTLY BY MODERATE (15-20KTS) VERTICAL WIND SHEAR
(VWS). TC CHALANE WILL CONTINUE TO TRACK WEST ALONG THE STR TOWARDS
BEIRA, MOZAMBIQUE THROUGH TAU 12 AT WHICH POINT IT WILL MAKE
LANDFALL AND RAPIDLY DISSIPATE BY TAU 24 AS IT TRACKS FURTHER WEST
OVER THE RUGGED TERRAIN OF ZIMBABWE. NUMERICAL MODELS ARE IN TIGHT
AGREEMENT THROUGH TAU 12 WITH ONLY A 43NM SPREAD THAT INCREASES TO A
MAX OF 56NM BY TAU 24. THIS GOOD AGREEMENT IN MODEL TRACK GUIDANCE
LENDS HIGH CONFIDENCE IN THE JTWC TRACK FORECAST WHICH IS PLACED
NEAR THE MULTI-MODEL CONSENSUS. MAXIMUM SIGNIFICANT WAVE HEIGHT AT
291800Z IS 18 FEET. NEXT WARNING AT 300900Z.//
NNNN

>

Original Message :

WTIO31 FMEE 291813
CMRS / CENTRE DES CYCLONES TROPICAUX DE LA REUNION
BULLETIN D'ANALYSE ET DE PREVISION CYCLONIQUE (SUD-OUEST OCEAN
INDIEN)

0.A NUMERO DU BULLETIN : 25/4/20202021
1.A FORTE TEMPETE TROPICALE 4 (CHALANE)

2.A POSITION A 1800 UTC LE 29/12/2020 :
DANS UN RAYON DE 20 MN AUTOUR DU POINT 19.7 S / 37.3 E
(DIX-NEUF DEGRES SEPT SUD ET TRENTE SEPT DEGRES TROIS EST)
DEPLACEMENT: OUEST 10 KT

3.A ANALYSE DE DVORAK: 4.0/4.0/D 1.0/18 H

4.A PRESSION AU CENTRE: 986 HPA
5.A VENT MAX (MOYEN/10 MN): 55 KT
RAYON DES VENTS MAXIMAUX (RVM): 28 KM

6.A EXTENSION DES VENTS PAR QUADRANTS (KM):
28 KT NE: 165 SE: 165 SO: 130 NO: 110
34 KT NE: 85 SE: 120 SO: 95 NO: 75
48 KT NE: 55 SE: 55 SO: 60 NO: 35

7.A COTE/DIAM PREMIERE ISOBARE FERMEE: 1006 HPA / 400 KM
8.A EXTENSION VERTICALE DE LA CIRCULATION CYCLONIQUE: PROFONDE

1.B PREVISIONS (EXTENSIONS DES VENTS FORTS EN KM):
12H: 30/12/2020 06 UTC: 19.7 S / 34.4 E, VENT MAX= 050 KT, FORTE
TEMPETE TROPICALE
28 KT NE: 215 SE: 205 SO: 240 NO: 150
34 KT NE: 120 SE: 120 SO: 110 NO: 120
48 KT NE: 65 SE: 55 SO: 75 NO: 55

24H: 30/12/2020 18 UTC: 19.9 S / 31.5 E, VENT MAX= 025 KT, DEPRESSION
SUR TERRE

36H: 31/12/2020 06 UTC: 20.7 S / 28.3 E, VENT MAX= 025 KT, DEPRESSION
SUR TERRE

48H: 31/12/2020 18 UTC: 21.7 S / 25.1 E, VENT MAX= 025 KT, DEPRESSION
SUR TERRE

60H: 01/01/2021 06 UTC: 22.5 S / 22.8 E, VENT MAX= 025 KT, DEPRESSION
SUR TERRE

72H: 01/01/2021 18 UTC: 22.9 S / 20.1 E, VENT MAX= 020 KT, DEPRESSION
SUR TERRE

2.B TENDANCE ULTERIEURE:
NON RENSEIGNE

2.C COMMENTAIRES:
T=CI=4.0.

LA CONFIGURATION NUAGEUSE DE CHALANE A EVOLUE AU COURS DE CES 6
DERNIERES HEURES, LA CONVECTION PROFONDE PRESENTE UNE FORTE DISSYMA
TRIE, SURTOUT PRESENT DANS LE DEMI-CERCLE NORD MAINTENANT. DE PLUS UN
TILT EXISTE EGALEMENT ENTRE LES CENTRES DE CIRCULATION DE BASSES
COUCHES ET D'ALTITUDE, TRADUISANT L'EFFET D'UNE CONTRAINTE DE SUD-EST
SUR LE SYSTEME. NEANMOINS LE SYSTEME CONTINUE DE BENEFICIER D'UNE
BONNE DIVERGENCE COTE EQUATORIAL, ET POURSUIT UNE INTENSIFICATION
LENTE.

CHALANE POURSUIT SON DA PLACEMENT RAPIDE VERS L'OUEST, SUR LA FACADE
NORD DE LA DORSALE SUBTROPICALE. L'ATTERRISSAGE EST ENVISAGE EN FIN
DE NUIT VOIRE DEBUT DE MATINEE A PROXIMITE NORD DE LA VILLE DE
BEIRA.

PEU DE CHANGEMENT EN TERMES DE PREVISION D'INTENSITE:
LES CONDITIONS ENVIRONNEMENTALES SONT PLUTA T FAVORABLES AU
DEVELOPPEMENT DU SYSTEME : CISAILLEMENT MODA RA , POTENTIEL OCA
ANIQUE FAVORABLE, BONNE ALIMENTATION DU FLUX DE MOUSSON QUI DESCEND
JUSQU'AU MILIEU DU CANAL. TOUTEFOIS ON NOTE LA PRESENCE DE BEAUCOUP
D'AIR SEC DANS L'ENVIRONNEMENT IMMEDIAT DU SYSTEME CE QUI POURRAIT
FREINER LE RYTHME D'INTENSIFICATION D'ICI L'ARRIVEE SUR TERRE,
D'AUTANT QU'UNE PETITE CONTRAINTE DE SUD-EST POURRAIT EGALEMENT SE
METTRE EN PLACE, NEANMOINS ATTENUEE PAR LA VITESSE DE DEPLACEMENT DU
SYSTEME.

SUIVANT CE SCA NARIO, LA MENACE REPRESENTA E PAR CHALANE EST BIEN RA
ELLE POUR LA REGION DE BEIRA:
- EN TERMES DE VENTS, DES RAFALES DESTRUCTRICES (DEPASSANT LES 150
KM/H) SONT POSSIBLES A MOINS DE 60 KM DU CENTRE. (CHALANE EST UN
SYSTEME ASSEZ COMPACTE)
- EN TERMES DE PRECIPITATIONS, DES CUMULS A PLUS DE 100 MM EN 24H
SONT POSSIBLES. EN RAISON DU CISAILLEMENT, LES PLUIES VONT
PRINCIPALEMENT CONCERNER LES REGIONS SITUEES A DROITE DE LA
TRAJECTOIRE (AU NORD DU SYSTEME). CES PLUIES PEUVENT OCCASIONNER DES
CRUES ECLAIRS ET DES INONDATIONS QUI VONT SE PROPAGER LOIN A
L'INTERIEUR DES TERRES SUR LE ZIMBABWE LE 31 DECEMBRE, LE BOTSWANA LE
01 JANVIER, ET MA ME LA NAMIBIE LE 02 JANVIER.
- UNE SURCOTE CYCLONIQUE DE L'ORDRE DE 1M A 2,5M EST POSSIBLE AU
LIEU DE L'ATTERRISSAGE ET AU SUD DE CELUI-CI. COUPLEE A DES VAGUES
POUVANT DEPASSER LES 6M, ET A LA MAREE HAUTE (EN PHASE AVEC LE TIMING
DE L'ATTERRISSAGE SUR LA PREVISION ACTUELLE), CETTE SURCOTE SERA
ASSOCIEE A DES SUBMERSIONS ET DES INONDATIONS COTIERES.=

>

Original Message :

WTIO30 FMEE 291813
RSMC / TROPICAL CYCLONE CENTER / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)

0.A WARNING NUMBER: 25/4/20202021
1.A SEVERE TROPICAL STORM 4 (CHALANE)

2.A POSITION 2020/12/29 AT 1800 UTC:
WITHIN 20 NM RADIUS OF POINT 19.7 S / 37.3 E
(NINETEEN DECIMAL SEVEN DEGREES SOUTH AND
THIRTY SEVEN DECIMAL THREE DEGREES EAST)
MOVEMENT: WEST 10 KT

3.A DVORAK ANALYSIS: 4.0/4.0/D 1.0/18 H

4.A CENTRAL PRESSURE: 986 HPA
5.A MAX AVERAGE WIND SPEED (10 MN): 55 KT
RADIUS OF MAXIMUM WINDS (RMW): 28 KM

6.A EXTENSION OF WIND BY QUADRANTS (KM):
28 KT NE: 165 SE: 165 SW: 130 NW: 110
34 KT NE: 85 SE: 120 SW: 95 NW: 75
48 KT NE: 55 SE: 55 SW: 60 NW: 35

7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1006 HPA / 400 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: DEEP

1.B FORECASTS (WINDS RADII IN KM):
12H: 2020/12/30 06 UTC: 19.7 S / 34.4 E, VENT MAX= 050 KT, SEVERE
TROPICAL STORM
28 KT NE: 215 SE: 205 SW: 240 NW: 150
34 KT NE: 120 SE: 120 SW: 110 NW: 120
48 KT NE: 65 SE: 55 SW: 75 NW: 55

24H: 2020/12/30 18 UTC: 19.9 S / 31.5 E, VENT MAX= 025 KT, OVERLAND
DEPRESSION

36H: 2020/12/31 06 UTC: 20.7 S / 28.3 E, VENT MAX= 025 KT, OVERLAND
DEPRESSION

48H: 2020/12/31 18 UTC: 21.7 S / 25.1 E, VENT MAX= 025 KT, OVERLAND
DEPRESSION

60H: 2021/01/01 06 UTC: 22.5 S / 22.8 E, VENT MAX= 025 KT, OVERLAND
DEPRESSION

72H: 2021/01/01 18 UTC: 22.9 S / 20.1 E, VENT MAX= 020 KT, OVERLAND
DEPRESSION

2.B LONGER-RANGE OUTLOOK:
NIL

2.C ADDITIONAL INFORMATION:
T=CI=4.0.

THE CLOUD PATTERN OF CHALANE HAS EVOLVED OVER THE LAST 6 HOURS, THE
DEEP CONVECTION PRESENTS A STRONG ASYMMETRY, ESPECIALLY PRESENT IN
THE NORTHERN SEMICIRCLE NOW. MOREOVER, A TILT ALSO EXISTS BETWEEN THE
LOW AND HIGH ALTITUDE CIRCULATION CENTERS, REFLECTING THE EFFECT OF A
SOUTHEASTERLYCONSTRAINTE ON THE SYSTEM.NEVERTHELESS, THE SYSTEM
CONTINUES TO BENEFIT FROM A GOOD DIVERGENCE ON THE EQUATORIAL SIDE,
AND GOES ON A SLOW INTENSIFICATION.

CHALANE CONTINUES ITS RAPID WESTWARD MOVEMENT, ON THE NORTHERN FACE
OF THE SUBTROPICAL RIDGE. THE LANDING IS FORECAST LATER TONIGHT OR
EARLY TOMORROW MORNING NEAR THE NORTH SIDE OF THE CITY OF BEIRA.

LITTLE CHANGE IN TERMS OF INTENSITY FORECAST:
THE ENVIRONMENTAL CONDITIONS ARE RATHER FAVORABLE FOR THE DEVELOPMENT
OF THE SYSTEM: MODERATE SHEAR, FAVORABLE OCEANIC POTENTIAL, GOOD
FEEDING OF THE MONSOON FLOW WHICH GOES DOWN TO THE MIDDLE OF THE
CHANNEL. HOWEVER, WE NOTE THE PRESENCE OF A LOT OF DRY AIR IN THE
IMMEDIATE ENVIRONMENT OF THE SYSTEM WHICH COULD SLOW DOWN THE RATE OF
INTENSIFICATION BY THE TIME OF THE ARRIVAL ON LAND, ESPECIALLY AS A
SMALL SOUTHEASTERN CONSTRAINT COULD ALSO BE IN PLACE, HOWEVER LIMITED
BY THE SPEED OF THE SYSTEM.

WITH THIS SCENARIO, THE THREAT REPRESENTED BY CHALANE IS VERY REAL
FOR THE BEIRA REGION:
- IN TERMS OF WINDS, DESTRUCTIVE GUSTS (EXCEEDING 150 KM/H) ARE
POSSIBLE LESS THAN 60 KM FROM THE CENTER. (CHALANE IS A RATHER
COMPACT SYSTEM).
- IN TERMS OF PRECIPITATION, ACCUMULATIONS OF MORE THAN 100 MM IN 24
HOURS ARE POSSIBLE. DUE TO THE SHEAR, THE RAINS WILL MAINLY CONCERN
THE REGIONS LOCATED ON THE RIGHT OF THE TRAJECTORY (NORTH OF THE
SYSTEM). THESE RAINS CAN CAUSE FLASH FLOODS AND FLOODS THAT WILL
SPREAD FAR INLAND OVER ZIMBABWE ON DECEMBER 31, BOTSWANA ON JANUARY
01, AND EVEN NAMIBIA ON JANUARY 02.
- A STORM SURGE OF ABOUT 1M TO 2.5M IS POSSIBLE AT THE LANDING SITE
AND SOUTH OF IT. COUPLED WITH WAVES THAT CAN EXCEED 6M, AND AT HIGH
TIDE (IN PHASE WITH THE TIMING OF THE LANDING ON THE CURRENT
FORECAST), THIS STORM SURGE WILL BE ASSOCIATED WITH COASTAL FLOODING
AND SUBMERSION.=

>

Original Message :

WTIO24 FMEE 291805
SECURITE
STORM WARNING FOR METAREA VII
ISSUED BY METEO-FRANCE/TROPICAL CYCLONE CENTER/LA REUNION 29/12/2020
AT 1800 UTC.
WARNING NUMBER: 025/4 (SOUTH-WEST INDIAN OCEAN)
10 MINUTES AVERAGE WIND SPEED IN KNOTS (KT)
(WIND GUSTS AT SEA MAY BE ABOUT 40% STRONGER THAN THE AVERAGED WIND)
MINIMUM SEA LEVEL PRESSURE IN HECTOPASCAL (HPA)
(INDICATIVE FIGURE).

STORM WARNING
BEGINNING OF VALIDITY: TUESDAY 29/12/2020 AT 1800 UTC.

PHENOMENON: SEVERE TROPICAL STORM 4 (CHALANE) 986 HPA
POSITION: WITHIN 20 NM RADIUS OF POINT 19.7 S / 37.3 E
(NINETEEN DECIMAL SEVEN DEGREES SOUTH AND
THIRTY SEVEN DECIMAL THREE DEGREES EAST) AT 1800 UTC
MOVEMENT: WEST 10 KT

THREAT AREAS:
SQUALLY WEATHER IN A RADIUS OF 70 NM FROM THE CENTER, EXTENDING UP TO
350 NM IN THE NORTHERN SEMI-CERCLE.

STORM FORCE WINDS 50/55 KT AND HIGH TO VERY HIGH SEAS WITHIN A 20 NM
RADIUS FROM THE CENTRE, EXTENDING UP TO 30 NM IN THE SOUTHERN
SEMI-CIRCLE AND THE NORTH-EASTERN QUADRANT.
GALE FORCE WINDS 35/45 KT AND VERY ROUGH TO HIGH SEAS WITHIN A 40 NM
RADIUS FROM THE CENTRE, EXTENDING UP TO 45 NM IN THE NORTH-EASTERN
QUADRANT, UP TO 50 NM IN THE SOUTH-WESTERN QUADRANT AND UP TO 65 NM
IN THE SOUTH-EASTERN QUADRANT.
NEAR GALE FORCE WINDS 30 KT AND ROUGH TO VERY ROUGH SEAS WITHIN A 60
NM RADIUS FROM THE CENTRE, EXTENDING UP TO 70 NM IN THE SOUTH-WESTERN
QUADRANT AND UP TO 90 NM IN THE EASTERN SEMI-CIRCLE.
STRONG GUSTS UNDER SQUALLS.

FORECAST POSITION AND INTENSITY:
12H, VALID 2020/12/30 AT 06 UTC:
19.7 S / 34.4 E, MAX WIND = 50 KT, SEVERE TROPICAL STORM
28 KT NE: 115 NM SE: 110 NM SW: 130 NM NW: 80 NM
34 KT NE: 65 NM SE: 65 NM SW: 60 NM NW: 65 NM
48 KT NE: 35 NM SE: 30 NM SW: 40 NM NW: 30 NM

24H, VALID 2020/12/30 AT 18 UTC:
19.9 S / 31.5 E, MAX WIND = 25 KT, OVERLAND DEPRESSION

OTHER INFORMATION:
NIL=

>

Original Message :

WTIO31 FMEE 291308
CMRS / CENTRE DES CYCLONES TROPICAUX DE LA REUNION
BULLETIN D'ANALYSE ET DE PREVISION CYCLONIQUE (SUD-OUEST OCEAN
INDIEN)

0.A NUMERO DU BULLETIN : 24/4/20202021
1.A FORTE TEMPETE TROPICALE 4 (CHALANE)

2.A POSITION A 1200 UTC LE 29/12/2020 :
DANS UN RAYON DE 20 MN AUTOUR DU POINT 19.6 S / 38.4 E
(DIX-NEUF DEGRES SIX SUD ET TRENTE HUIT DEGRES QUATRE EST)
DEPLACEMENT: OUEST 14 KT

3.A ANALYSE DE DVORAK: 3.5/3.5/D 1.0/24 H

4.A PRESSION AU CENTRE: 988 HPA
5.A VENT MAX (MOYEN/10 MN): 50 KT
RAYON DES VENTS MAXIMAUX (RVM): 22 KM

6.A EXTENSION DES VENTS PAR QUADRANTS (KM):
28 KT NE: 165 SE: 165 SO: 130 NO: 95
34 KT NE: 85 SE: 120 SO: 95 NO: 65
48 KT NE: 35 SE: 35 SO: 40 NO: 30

7.A COTE/DIAM PREMIERE ISOBARE FERMEE: 1006 HPA / 300 KM
8.A EXTENSION VERTICALE DE LA CIRCULATION CYCLONIQUE: PROFONDE

1.B PREVISIONS (EXTENSIONS DES VENTS FORTS EN KM):
12H: 30/12/2020 00 UTC: 19.6 S / 35.8 E, VENT MAX= 070 KT, CYCLONE
TROPICAL
28 KT NE: 140 SE: 195 SO: 140 NO: 100
34 KT NE: 100 SE: 110 SO: 110 NO: 95
48 KT NE: 65 SE: 75 SO: 65 NO: 65
64 KT NE: 45 SE: 55 SO: 55 NO: 55

24H: 30/12/2020 12 UTC: 19.7 S / 33.2 E, VENT MAX= 040 KT, TEMPETE
TROPICALE MODEREE
28 KT NE: 220 SE: 195 SO: 75 NO: 75
34 KT NE: 65 SE: 85 SO: 35 NO: 35

36H: 31/12/2020 00 UTC: 20.0 S / 29.6 E, VENT MAX= 025 KT, DEPRESSION
SUR TERRE

48H: 31/12/2020 12 UTC: 20.9 S / 26.6 E, VENT MAX= 025 KT, DEPRESSION
SUR TERRE

60H: 01/01/2021 00 UTC: 21.8 S / 24.1 E, VENT MAX= 025 KT, DEPRESSION
SUR TERRE

72H: 01/01/2021 12 UTC: 22.2 S / 21.7 E, VENT MAX= 025 KT, DEPRESSION
SUR TERRE

2.B TENDANCE ULTERIEURE:
96H: 02/01/2021 12 UTC: 21.9 S / 16.4 E, VENT MAX= 025 KT, DEPRESSION
SUR TERRE

2.C COMMENTAIRES:
T=CI=3.5+

LA CONFIGURATION NUAGEUSE DE CHALANE A EVOLUE AU COURSDE CES 6
DERNIERES HEURES, EN CONFIGUATION CDO. TEMPORAIREMENT, SUR CERTAINES
IMAGES VISIBLES, UN OEIL DECHIQUETA EST APPARU.
LES ESTIMATIONS OBJECTIVES ET SUBJECTIVES PERMETTENT DE MAINTENIR UNE
INTENSITE DE 50KT.

CHALANE POURSUIT SON DA PLACEMENT RAPIDE VERS L'OUEST, SUR LA FACADE
NORD DE LA DORSALE SUBTROPICALE. L'ATTERRISSAGE EST ENVISAGE EN FIN
DE NUIT PROCHAINE, VOIRE DEBUT DE MATINEE A PROXIMITE NORD DE LA
VILLE DE BEIRA.

PEU DE CHANGEMENT EN TERMES DE PREVISION D'INTENSITE:
LES CONDITIONS ENVIRONNEMENTALES SONT PLUTA T FAVORABLES AU
DEVELOPPEMENT DU SYSTEME : CISAILLEMENT MODA RA , POTENTIEL OCA
ANIQUE FAVORABLE, BONNE ALIMENTATION DU FLUX DE MOUSSON QUI DESCEND
JUSQU'AU MILIEU DU CANAL. TOUTEFOIS ON NOTE LA PRESENCE DE BEAUCOUP
D'AIR SEC DANS L'ENVIRONNEMENT IMMEDIAT DU SYSTEME CE QUI POURRAIT
FREINER LE RYTHME D'INTENSIFICATION D'ICI L'ARRIVEE SUR TERRE,
D'AUTANT QU'UNE PETITE CONTRAINTE DE SUD-EST POURRAIT EGALEMENT SE
METTRE EN PLACE.

SUIVANT CE SCA NARIO, LA MENACE REPRESENTA E PAR CHALANE EST BIEN RA
ELLE POUR LA REGION DE BEIRA:
- EN TERMES DE VENTS, DES RAFALES DESTRUCTRICES (DEPASSANT LES 150
KM/H) SONT POSSIBLES A MOINS DE 60 KM DU CENTRE. (CHALANE EST UN
SYSTEME ASSEZ COMPACTE)
- EN TERMES DE PRECIPITATIONS, DES CUMULS A PLUS DE 100 MM EN 24H
SONT POSSIBLES. EN RAISON DU CISAILLEMENT, LES PLUIES VONT
PRINCIPALEMENT CONCERNER LES REGIONS SITUEES A DROITE DE LA
TRAJECTOIRE (AU NORD DU SYSTEME). CES PLUIES PEUVENT OCCASIONNER DES
CRUES ECLAIRS ET DES INONDATIONS QUI VONT SE PROPAGER LOIN A
L'INTERIEUR DES TERRES SUR LE ZIMBABWE LE 31 DECEMBRE, LE BOTSWANA LE
01 JANVIER, ET MA ME LA NAMIBIE LE 02 JANVIER.
- UNE SURCOTE CYCLONIQUE DE L'ORDRE DE 1M A 2,5M EST POSSIBLE AU
LIEU DE L'ATTERRISSAGE ET AU SUD DE CELUI-CI. COUPLEE A DES VAGUES
POUVANT DEPASSER LES 6M, ET A LA MAREE HAUTE (EN PHASE AVEC LE TIMING
DE L'ATTERRISSAGE SUR LA PREVISION ACTUELLE), CETTE SURCOTE SERA
ASSOCIEE A DES SUBMERSIONS ET DES INONDATIONS COTIERES.=

>

Original Message :

WTIO30 FMEE 291308
RSMC / TROPICAL CYCLONE CENTER / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)

0.A WARNING NUMBER: 24/4/20202021
1.A SEVERE TROPICAL STORM 4 (CHALANE)

2.A POSITION 2020/12/29 AT 1200 UTC:
WITHIN 20 NM RADIUS OF POINT 19.6 S / 38.4 E
(NINETEEN DECIMAL SIX DEGREES SOUTH AND
THIRTY EIGHT DECIMAL FOUR DEGREES EAST)
MOVEMENT: WEST 14 KT

3.A DVORAK ANALYSIS: 3.5/3.5/D 1.0/24 H

4.A CENTRAL PRESSURE: 988 HPA
5.A MAX AVERAGE WIND SPEED (10 MN): 50 KT
RADIUS OF MAXIMUM WINDS (RMW): 22 KM

6.A EXTENSION OF WIND BY QUADRANTS (KM):
28 KT NE: 165 SE: 165 SW: 130 NW: 95
34 KT NE: 85 SE: 120 SW: 95 NW: 65
48 KT NE: 35 SE: 35 SW: 40 NW: 30

7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1006 HPA / 300 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: DEEP

1.B FORECASTS (WINDS RADII IN KM):
12H: 2020/12/30 00 UTC: 19.6 S / 35.8 E, VENT MAX= 070 KT, TROPICAL
CYCLONE
28 KT NE: 140 SE: 195 SW: 140 NW: 100
34 KT NE: 100 SE: 110 SW: 110 NW: 95
48 KT NE: 65 SE: 75 SW: 65 NW: 65
64 KT NE: 45 SE: 55 SW: 55 NW: 55

24H: 2020/12/30 12 UTC: 19.7 S / 33.2 E, VENT MAX= 040 KT, MODERATE
TROPICAL STORM
28 KT NE: 220 SE: 195 SW: 75 NW: 75
34 KT NE: 65 SE: 85 SW: 35 NW: 35

36H: 2020/12/31 00 UTC: 20.0 S / 29.6 E, VENT MAX= 025 KT, OVERLAND
DEPRESSION

48H: 2020/12/31 12 UTC: 20.9 S / 26.6 E, VENT MAX= 025 KT, OVERLAND
DEPRESSION

60H: 2021/01/01 00 UTC: 21.8 S / 24.1 E, VENT MAX= 025 KT, OVERLAND
DEPRESSION

72H: 2021/01/01 12 UTC: 22.2 S / 21.7 E, VENT MAX= 025 KT, OVERLAND
DEPRESSION

2.B LONGER-RANGE OUTLOOK:
96H: 2021/01/02 12 UTC: 21.9 S / 16.4 E, VENT MAX= 025 KT, OVERLAND
DEPRESSION

2.C ADDITIONAL INFORMATION:
T=CI=3.5+

THE CLOUD PATTERN OF CHALANE HAS EVOLVED OVER THE LAST 6 HOURS, IN
CDO PATTERN. TEMPORARILY, ON SOME VISIBLE IMAGES, AN EYE HAS
APPEARED.
OBJECTIVE AND SUBJECTIVE ESTIMATES ALLOW TO MAINTAIN AN INTENSITY OF
50KT.

CHALANE CONTINUES ITS RAPID WESTWARD MOVEMENT, ON THE NORTHERN FACE
OF THE SUBTROPICAL RIDGE. THE LANDING IS FORECAST LATER TONIGHT OR
EARLY TOMORROW MORNING NEAR THE NORTH SIDE OF THE CITY OF BEIRA.

LITTLE CHANGE IN TERMS OF INTENSITY FORECAST:
THE ENVIRONMENTAL CONDITIONS ARE RATHER FAVORABLE FOR THE DEVELOPMENT
OF THE SYSTEM: MODERATE SHEAR, FAVORABLE OCEANIC POTENTIAL, GOOD
FEEDING OF THE MONSOON FLOW WHICH GOES DOWN TO THE MIDDLE OF THE
CHANNEL. HOWEVER, WE NOTE THE PRESENCE OF A LOT OF DRY AIR IN THE
IMMEDIATE ENVIRONMENT OF THE SYSTEM WHICH COULD SLOW DOWN THE RATE OF
INTENSIFICATION BY THE TIME OF THE ARRIVAL ON LAND, ESPECIALLY AS A
SMALL SOUTHEASTERN CONSTRAINT COULD ALSO BE IN PLACE.

WITH THIS SCENARIO, THE THREAT REPRESENTED BY CHALANE IS VERY REAL
FOR THE BEIRA REGION:
- IN TERMS OF WINDS, DESTRUCTIVE GUSTS (EXCEEDING 150 KM/H) ARE
POSSIBLE LESS THAN 60 KM FROM THE CENTER. (CHALANE IS A RATHER
COMPACT SYSTEM).
- IN TERMS OF PRECIPITATION, ACCUMULATIONS OF MORE THAN 100 MM IN 24
HOURS ARE POSSIBLE. DUE TO THE SHEAR, THE RAINS WILL MAINLY CONCERN
THE REGIONS LOCATED ON THE RIGHT OF THE TRAJECTORY (NORTH OF THE
SYSTEM). THESE RAINS CAN CAUSE FLASH FLOODS AND FLOODS THAT WILL
SPREAD FAR INLAND OVER ZIMBABWE ON DECEMBER 31, BOTSWANA ON JANUARY
01, AND EVEN NAMIBIA ON JANUARY 02.
- A STORM SURGE OF ABOUT 1M TO 2.5M IS POSSIBLE AT THE LANDING SITE
AND SOUTH OF IT. COUPLED WITH WAVES THAT CAN EXCEED 6M, AND AT HIGH
TIDE (IN PHASE WITH THE TIMING OF THE LANDING ON THE CURRENT
FORECAST), THIS STORM SURGE WILL BE ASSOCIATED WITH COASTAL FLOODING
AND SUBMERSION.=

>

Original Message :

WTIO24 FMEE 291229
SECURITE
STORM WARNING FOR METAREA VII
ISSUED BY METEO-FRANCE/TROPICAL CYCLONE CENTER/LA REUNION 29/12/2020
AT 1200 UTC.
WARNING NUMBER: 024/4 (SOUTH-WEST INDIAN OCEAN)
10 MINUTES AVERAGE WIND SPEED IN KNOTS (KT)
(WIND GUSTS AT SEA MAY BE ABOUT 40% STRONGER THAN THE AVERAGED WIND)
MINIMUM SEA LEVEL PRESSURE IN HECTOPASCAL (HPA)
(INDICATIVE FIGURE).

STORM WARNING
BEGINNING OF VALIDITY: TUESDAY 29/12/2020 AT 1200 UTC.

PHENOMENON: SEVERE TROPICAL STORM 4 (CHALANE) 988 HPA
POSITION: WITHIN 20 NM RADIUS OF POINT 19.6 S / 38.4 E
(NINETEEN DECIMAL SIX DEGREES SOUTH AND
THIRTY EIGHT DECIMAL FOUR DEGREES EAST) AT 1200 UTC
MOVEMENT: WEST 14 KT

THREAT AREAS:
SQUALLY WEATHER IN A RADIUS OF 60 NM FROM THE CENTER, EXTENDING UP TO
90 NM IN THE NORTH-EASTERN QUADRANT

STORM FORCE WINDS 50 KT AND HIGH TO VERY HIGH SEAS WITHIN A 15 NM
RADIUS FROM THE CENTRE, EXTENDING UP TO 20 NM IN THE SOUTHERN
SEMI-CIRCLE AND THE NORTH-EASTERN QUADRANT.
GALE FORCE WINDS 35/45 KT AND VERY ROUGH TO HIGH SEAS WITHIN A 35 NM
RADIUS FROM THE CENTRE, EXTENDING UP TO 45 NM IN THE NORTH-EASTERN
QUADRANT, UP TO 50 NM IN THE SOUTH-WESTERN QUADRANT AND UP TO 65 NM
IN THE SOUTH-EASTERN QUADRANT.
NEAR GALE FORCE WINDS 30 KT AND ROUGH TO VERY ROUGH SEAS WITHIN A 50
NM RADIUS FROM THE CENTRE, EXTENDING UP TO 70 NM IN THE SOUTH-WESTERN
QUADRANT AND UP TO 90 NM IN THE EASTERN SEMI-CIRCLE.
STRONG GUSTS UNDER SQUALLS.

FORECAST POSITION AND INTENSITY:
12H, VALID 2020/12/30 AT 00 UTC:
19.6 S / 35.8 E, MAX WIND = 70 KT, TROPICAL CYCLONE
28 KT NE: 75 NM SE: 105 NM SW: 75 NM NW: 55 NM
34 KT NE: 55 NM SE: 60 NM SW: 60 NM NW: 50 NM
48 KT NE: 35 NM SE: 40 NM SW: 35 NM NW: 35 NM
64 KT NE: 25 NM SE: 30 NM SW: 30 NM NW: 30 NM

24H, VALID 2020/12/30 AT 12 UTC:
19.7 S / 33.2 E, MAX WIND = 40 KT, MODERATE TROPICAL STORM
28 KT NE: 120 NM SE: 105 NM SW: 40 NM NW: 40 NM
34 KT NE: 35 NM SE: 45 NM SW: 20 NM NW: 20 NM

OTHER INFORMATION:
NIL=

>

Original Message :

WTIO31 FMEE 290649
CMRS / CENTRE DES CYCLONES TROPICAUX DE LA REUNION
BULLETIN D'ANALYSE ET DE PREVISION CYCLONIQUE (SUD-OUEST OCEAN
INDIEN)

0.A NUMERO DU BULLETIN : 23/4/20202021
1.A FORTE TEMPETE TROPICALE 4 (CHALANE)

2.A POSITION A 0600 UTC LE 29/12/2020 :
DANS UN RAYON DE 20 MN AUTOUR DU POINT 19.8 S / 39.6 E
(DIX-NEUF DEGRES HUIT SUD ET TRENTE NEUF DEGRES SIX EST)
DEPLACEMENT: OUEST 13 KT

3.A ANALYSE DE DVORAK: 3.5/3.5/D 1.5/24 H

4.A PRESSION AU CENTRE: 990 HPA
5.A VENT MAX (MOYEN/10 MN): 50 KT
RAYON DES VENTS MAXIMAUX (RVM): 22 KM

6.A EXTENSION DES VENTS PAR QUADRANTS (KM):
28 KT NE: 165 SE: 165 SO: 130 NO: 95
34 KT NE: 85 SE: 120 SO: 95 NO: 65
48 KT NE: 30 SE: 30 SO: 30 NO: 30

7.A COTE/DIAM PREMIERE ISOBARE FERMEE: 1007 HPA / 400 KM
8.A EXTENSION VERTICALE DE LA CIRCULATION CYCLONIQUE: PROFONDE

1.B PREVISIONS (EXTENSIONS DES VENTS FORTS EN KM):
12H: 29/12/2020 18 UTC: 19.7 S / 36.9 E, VENT MAX= 065 KT, CYCLONE
TROPICAL
28 KT NE: 120 SE: 175 SO: 155 NO: 95
34 KT NE: 95 SE: 95 SO: 110 NO: 75
48 KT NE: 65 SE: 75 SO: 65 NO: 65
64 KT NE: 45 SE: 55 SO: 45 NO: 55

24H: 30/12/2020 06 UTC: 19.7 S / 34.3 E, VENT MAX= 050 KT, FORTE
TEMPETE TROPICALE
28 KT NE: 100 SE: 175 SO: 75 NO: 85
34 KT NE: 75 SE: 100 SO: 65 NO: 65
48 KT NE: 55 SE: 55 SO: 45 NO: 45

36H: 30/12/2020 18 UTC: 19.8 S / 31.9 E, VENT MAX= 030 KT, DEPRESSION
SUR TERRE

48H: 31/12/2020 06 UTC: 20.3 S / 28.6 E, VENT MAX= 025 KT, DEPRESSION
SUR TERRE

60H: 31/12/2020 18 UTC: 21.2 S / 25.4 E, VENT MAX= 020 KT, DEPRESSION
SUR TERRE

72H: 01/01/2021 06 UTC: 21.9 S / 23.3 E, VENT MAX= 020 KT, DEPRESSION
SUR TERRE

2.B TENDANCE ULTERIEURE:
NON RENSEIGNE

2.C COMMENTAIRES:
T=CI=3.5

CHALANE CONTINUE DE PRESENTER UNE CONFIGURATION NUAGEUSE EN BANDE
INCIRVEE EN AMELIORATION AVEC UN OEIL EN BANDE APPARU SUR L'IMAGERIE
MICRO-ONDES DE CE MATIN. L'INTENSITE EST ESTIMEE A 50 KT DANS LA
LIMITE SUPERIEURE DES ESTIMATIONS OBJECTIVES ET SUBJECTIVES
DISPONIBLES.

CHALANE POURSUIVRA DONC SON DA PLACEMENT VERS L'OUEST ET FINIRA PAR
TOUCHER LE MOZAMBIQUE. CHALANE A ACCELERE DEPUIS LA FIN DE NUIT ET LE
TIMING DE L'ARRIVEE SUR TERRE A ETE AJUSTE EN ACCORD AVEC LES MODELES
LES PLUS RAPIDES. CHALANE DEVRAIT DONC TOUCHER LA COTE EN FIN DE NUIT
PROCHAINE OU TOUT DEBUT DE MATINEE.

LES CONDITIONS ENVIRONNEMENTALES SONT PLUTA T FAVORABLES AU
DEVELOPPEMENT DU SYSTEME : CISAILLEMENT MODA RA , POTENTIEL OCA
ANIQUE FAVORABLE, BONNE ALIMENTATION DU FLUX DE MOUSSON QUI DESCEND
JUSQU'AU MILIEU DU CANAL. TOUTEFOIS ON NOTE LA PRESENCE DE BEAUCOUP
D'AIR SEC DANS L'ENVIRONNEMENT IMMEDIAT DU SYSTEME CE QUI POURRAIT
FREINER LE RYTHME D'INTENSIFICATION D'ICI L'ARRIVEE SUR TERRE,
D'AUTANT QU'UNE PETITE CONTRAINTE DE SUD-EST POURRAIT EGALEMENT SE
METTRE EN PLACE. LA PREVISION D'INTENSITE EST PROCHE DU SCENARIO
PROPOSE PAR LE DERNIER RUN D'AROME MAIS RESTE MOINS AGRESSIVE QUE
HWRF.

SUIVANT CE SCA NARIO, LA MENACE REPRESENTA E PAR CHALANE EST BIEN RA
ELLE POUR LA REGION DE BEIRA:
- EN TERME DE VENTS, DES RAFALES DESTRUCTRICES (DEPASSANT LES 150
KM/H) SONT POSSIBLES A MOINS DE 60 KM DU CENTRE. (CHALANE EST UN
SYSTEME ASSEZ COMPACTE)
- EN TERME DE PRECIPITATIONS, DES CUMULS A PLUS DE 100 MM EN 24H SONT
POSSIBLES. CES PLUIES POUVANT OCCAISONNER DES CRUES ECLAIRS ET DES
INONDATIONS VONT SE PROPAGER LOIN A L'INTERIEUR DES TERRES SUR LE
ZIMBABWE LE 31 DECEMBRE ET LE BOTSWANA LE 01 JANVIER.
- UNE SURCOTE CYCLONIQUE DE L'ORDRE DE 2M EST POSSIBLE PRES ET JUSTE
AU SUD DE LA ZONE D'ATTERRISSAGE. COUPLEE A LA HOULE CYCLONIQUE ET LA
MAREE HAUTE (EN PHASE AVEC LE TIMING DE L'ATTERRISSAGE SUR LA
PREVISION ACTUELLE), CETTE SURCOTE SERA ASSOCIEE A DES SUBMERSIONS ET
DES INONDATIONS COTIERES.=

>

Original Message :

WTIO30 FMEE 290649
RSMC / TROPICAL CYCLONE CENTER / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)

0.A WARNING NUMBER: 23/4/20202021
1.A SEVERE TROPICAL STORM 4 (CHALANE)

2.A POSITION 2020/12/29 AT 0600 UTC:
WITHIN 20 NM RADIUS OF POINT 19.8 S / 39.6 E
(NINETEEN DECIMAL EIGHT DEGREES SOUTH AND
THIRTY NINE DECIMAL SIX DEGREES EAST)
MOVEMENT: WEST 13 KT

3.A DVORAK ANALYSIS: 3.5/3.5/D 1.5/24 H

4.A CENTRAL PRESSURE: 990 HPA
5.A MAX AVERAGE WIND SPEED (10 MN): 50 KT
RADIUS OF MAXIMUM WINDS (RMW): 22 KM

6.A EXTENSION OF WIND BY QUADRANTS (KM):
28 KT NE: 165 SE: 165 SW: 130 NW: 95
34 KT NE: 85 SE: 120 SW: 95 NW: 65
48 KT NE: 30 SE: 30 SW: 30 NW: 30

7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1007 HPA / 400 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: DEEP

1.B FORECASTS (WINDS RADII IN KM):
12H: 2020/12/29 18 UTC: 19.7 S / 36.9 E, VENT MAX= 065 KT, TROPICAL
CYCLONE
28 KT NE: 120 SE: 175 SW: 155 NW: 95
34 KT NE: 95 SE: 95 SW: 110 NW: 75
48 KT NE: 65 SE: 75 SW: 65 NW: 65
64 KT NE: 45 SE: 55 SW: 45 NW: 55

24H: 2020/12/30 06 UTC: 19.7 S / 34.3 E, VENT MAX= 050 KT, SEVERE
TROPICAL STORM
28 KT NE: 100 SE: 175 SW: 75 NW: 85
34 KT NE: 75 SE: 100 SW: 65 NW: 65
48 KT NE: 55 SE: 55 SW: 45 NW: 45

36H: 2020/12/30 18 UTC: 19.8 S / 31.9 E, VENT MAX= 030 KT, OVERLAND
DEPRESSION

48H: 2020/12/31 06 UTC: 20.3 S / 28.6 E, VENT MAX= 025 KT, OVERLAND
DEPRESSION

60H: 2020/12/31 18 UTC: 21.2 S / 25.4 E, VENT MAX= 020 KT, OVERLAND
DEPRESSION

72H: 2021/01/01 06 UTC: 21.9 S / 23.3 E, VENT MAX= 020 KT, OVERLAND
DEPRESSION

2.B LONGER-RANGE OUTLOOK:
NIL

2.C ADDITIONAL INFORMATION:
T=CI=3.5

CHALANE CONTINUES TO SHOW AN IMPROVED BANDED CLOUD PATTERN WITH A
BANDING EYE THAT APPEARED ON THIS MORNING'S MICROWAVE IMAGERY.
INTENSITY IS ESTIMATED AT 50 KT WITHIN THE UPPER LIMIT OF AVAILABLE
OBJECTIVE AND SUBJECTIVE ESTIMATES.

CHALANE WILL THEREFORE CONTINUE ITS WESTWARD MOVEMENT AND WILL
EVENTUALLY REACH MOZAMBIQUE. CHALANE HAS BEEN ACCELERATING SINCE LATE
NIGHT AND THE TIMING OF THE ARRIVAL ON LAND HAS BEEN ADJUSTED IN
ACCORDANCE WITH THE FASTEST GUIDANCE. CHALANE SHOULD REACH THE COAST
LATE NEXT NIGHT OR EARLY IN THE MORNING.

THE ENVIRONMENTAL CONDITIONS ARE RATHER FAVORABLE FOR THE DEVELOPMENT
OF THE SYSTEM: MODERATE SHEAR, FAVORABLE OCEANIC POTENTIAL, GOOD
FEEDING OF THE MONSOON FLOW WHICH GOES DOWN TO THE MIDDLE OF THE
CHANNEL. HOWEVER, WE NOTE THE PRESENCE OF A LOT OF DRY AIR IN THE
IMMEDIATE ENVIRONMENT OF THE SYSTEM WHICH COULD SLOW DOWN THE RATE OF
INTENSIFICATION BY THE TIME OF THE ARRIVAL ON LAND, ESPECIALLY AS A
SMALL SOUTHEASTERLY SHEAR CONSTRAINT COULD ALSO BE IN PLACE. THE
INTENSITY FORECAST IS CLOSE TO THE SCENARIO PROPOSED BY THE LAST RUN
OF THE AROME BUT REMAINS LESS AGGRESSIVE THAN HWRF.

ACCORDING TO THIS SCENARIO, THE THREAT REPRESENTED BY CHALANE IS VERY
REAL FOR THE BEIRA REGION:
- IN TERMS OF WINDS, DESTRUCTIVE GUSTS (EXCEEDING 150 KM/H) ARE
POSSIBLE AT LESS THAN 60 KM FROM THE CENTER. (CHALANE IS A RATHER
COMPACT SYSTEM).
- IN TERMS OF PRECIPITATION, ACCUMULATIONS OF MORE THAN 100 MM IN 24
HOURS ARE POSSIBLE. THESE RAINS, WHICH CAN CAUSE FLASH FLOODS AND
FLOODS, WILL SPREAD FAR INLAND OVER ZIMBABWE ON 31 DECEMBER AND
BOTSWANA ON 01 JANUARY.
- A STORM SURGE OF ABOUT 2M IS POSSIBLE NEAR AND JUST SOUTH OF THE
LANDING ZONE. COUPLED WITH CYCLONIC SWELL AND HIGH WATER (IN LINE
WITH THE TIMING OF THE LANDING ON THE CURRENT FORECAST), THIS SURGE
WILL BE ASSOCIATED WITH COASTAL FLOODINGS.=

>

Original Message :

WTIO24 FMEE 290624
SECURITE
STORM WARNING FOR METAREA VII
ISSUED BY METEO-FRANCE/TROPICAL CYCLONE CENTER/LA REUNION 29/12/2020
AT 0600 UTC.
WARNING NUMBER: 023/4 (SOUTH-WEST INDIAN OCEAN)
10 MINUTES AVERAGE WIND SPEED IN KNOTS (KT)
(WIND GUSTS AT SEA MAY BE ABOUT 40% STRONGER THAN THE AVERAGED WIND)
MINIMUM SEA LEVEL PRESSURE IN HECTOPASCAL (HPA)
(INDICATIVE FIGURE).

STORM WARNING
BEGINNING OF VALIDITY: TUESDAY 29/12/2020 AT 0600 UTC.

PHENOMENON: SEVERE TROPICAL STORM 4 (CHALANE) 990 HPA
POSITION: WITHIN 20 NM RADIUS OF POINT 19.8 S / 39.6 E
(NINETEEN DECIMAL EIGHT DEGREES SOUTH AND
THIRTY NINE DECIMAL SIX DEGREES EAST) AT 0600 UTC
MOVEMENT: WEST 13 KT

THREAT AREAS:
SQUALLY WEATHER IN A RADIUS OF 100 NM FROM THE CENTER, EXTENDING UP
TO 160 NM IN THE NORTH-EASTERN QUADRANT.

STORM FORCE WINDS 50 KT AND HIGH TO VERY HIGH SEAS WITHIN A 15 NM
RADIUS FROM THE CENTRE.
GALE FORCE WINDS 35/45 KT AND VERY ROUGH TO HIGH SEAS WITHIN A 35 NM
RADIUS FROM THE CENTRE, EXTENDING UP TO 45 NM IN THE NORTH-EASTERN
QUADRANT, UP TO 50 NM IN THE SOUTH-WESTERN QUADRANT AND UP TO 65 NM
IN THE SOUTH-EASTERN QUADRANT.
NEAR GALE FORCE WINDS 30 KT AND ROUGH TO VERY ROUGH SEAS WITHIN A 50
NM RADIUS FROM THE CENTRE, EXTENDING UP TO 70 NM IN THE SOUTH-WESTERN
QUADRANT AND UP TO 90 NM IN THE EASTERN SEMI-CIRCLE.
STRONG GUSTS UNDER SQUALLS.

FORECAST POSITION AND INTENSITY:
12H, VALID 2020/12/29 AT 18 UTC:
19.7 S / 36.9 E, MAX WIND = 65 KT, TROPICAL CYCLONE
28 KT NE: 65 NM SE: 95 NM SW: 85 NM NW: 50 NM
34 KT NE: 50 NM SE: 50 NM SW: 60 NM NW: 40 NM
48 KT NE: 35 NM SE: 40 NM SW: 35 NM NW: 35 NM
64 KT NE: 25 NM SE: 30 NM SW: 25 NM NW: 30 NM

24H, VALID 2020/12/30 AT 06 UTC:
19.7 S / 34.3 E, MAX WIND = 50 KT, SEVERE TROPICAL STORM
28 KT NE: 55 NM SE: 95 NM SW: 40 NM NW: 45 NM
34 KT NE: 40 NM SE: 55 NM SW: 35 NM NW: 35 NM
48 KT NE: 30 NM SE: 30 NM SW: 25 NM NW: 25 NM

OTHER INFORMATION:
NIL=

>

Original Message :

WTIO31 FMEE 290016
CMRS / CENTRE DES CYCLONES TROPICAUX DE LA REUNION
BULLETIN D'ANALYSE ET DE PREVISION CYCLONIQUE (SUD-OUEST OCEAN
INDIEN)

0.A NUMERO DU BULLETIN : 22/4/20202021
1.A TEMPETE TROPICALE MODEREE 4 (CHALANE)

2.A POSITION A 0000 UTC LE 29/12/2020 :
DANS UN RAYON DE 20 MN AUTOUR DU POINT 19.7 S / 41.0 E
(DIX-NEUF DEGRES SEPT SUD ET QUARANTE UN DEGRES ZERO EST)
DEPLACEMENT: OUEST 8 KT

3.A ANALYSE DE DVORAK: 3.0/3.0/D 0.5/6 H

4.A PRESSION AU CENTRE: 995 HPA
5.A VENT MAX (MOYEN/10 MN): 40 KT
RAYON DES VENTS MAXIMAUX (RVM): 46 KM

6.A EXTENSION DES VENTS PAR QUADRANTS (KM):
28 KT NE: 165 SE: 150 SO: 95 NO: 0
34 KT NE: 55 SE: 55 SO: 55 NO: 0
48 KT NE: 0 SE: 0 SO: 0 NO: 0
64 KT NE: 0 SE: 0 SO: 0 NO: 0

7.A COTE/DIAM PREMIERE ISOBARE FERMEE: 1007 HPA / 400 KM
8.A EXTENSION VERTICALE DE LA CIRCULATION CYCLONIQUE: PROFONDE

1.B PREVISIONS (EXTENSIONS DES VENTS FORTS EN KM):
12H: 29/12/2020 12 UTC: 19.7 S / 39.1 E, VENT MAX= 050 KT, FORTE
TEMPETE TROPICALE
28 KT NE: 130 SE: 155 SO: 150 NO: 130
34 KT NE: 85 SE: 85 SO: 120 NO: 85
48 KT NE: 55 SE: 75 SO: 75 NO: 55

24H: 30/12/2020 00 UTC: 19.5 S / 36.7 E, VENT MAX= 060 KT, FORTE
TEMPETE TROPICALE
28 KT NE: 150 SE: 185 SO: 140 NO: 100
34 KT NE: 95 SE: 110 SO: 120 NO: 95
48 KT NE: 65 SE: 85 SO: 65 NO: 65

36H: 30/12/2020 12 UTC: 19.5 S / 34.3 E, VENT MAX= 040 KT, DEPRESSION
SUR TERRE
28 KT NE: 230 SE: 185 SO: 220 NO: 75
34 KT NE: 55 SE: 95 SO: 35 NO: 65

48H: 31/12/2020 00 UTC: 19.3 S / 31.9 E, VENT MAX= 025 KT, DEPRESSION
SUR TERRE

2.B TENDANCE ULTERIEURE:
NON RENSEIGNE

2.C COMMENTAIRES:
T=CI=3.0

AU COURS DES 6 HEURES PASSA ES, LA CONFIGURATION NUAGEUSE DE CHALANE
EN BANDE INCURVA E S'EST MAINTENUE PRESENTANT UN REGAIN D'ACTIVITE
CONVECTIVE A PROXIMITE DU CENTRE. UNE CONFIGURATION EN CENTRE NOYE
DANS LA MASSE POURRAIT S'ESQUISSER PROCHAINEMENT. PEU DE TEMPS APRES
LE PRECEDENT BULLETIN, LES DONNEES ASCAT DE 1817UTC ONT PERMIS DE
VALIDER LES 35KT DANS LE PARTIE SUD-EST DU SYSTEME. ACTUELLEMENT,
L'ANALYSE DVORAK PERMET DE NOTER UNE INTENSITE QUI CONTINUE
D'AUGMENTER, LAISSANT UNE ESTIMATION DE VENTS MAXIMAUX DE L'ORDRE DE
40KT.

PAS DE CHANGEMENT EN TERME DE PREVISION, LE SCENARIO D'UN DEPLACEMENT
ASSEZ RAPIDE PILOTA PAR LA DORSALE DE BASSES ET MOYENNE TROPOPHERE
INSTALLEE SUR LE SUD DU CANAL, EST MAINTENU. CHALANE POURSUIVRA DONC
SON DA PLACEMENT VERS L'OUEST ET FINIRA PAR TOUCHER LE MOZAMBIQUE.
LES MODA LES SONT EN ASSEZ BON ACCORD SUR LA DIRECTION ET EN TERME DE
VITESSE DE DEPLACEMENT, LES MODELES QUI ETAIENT UN PEU PLUS LENTS ONT
EUX AUSSI ACCELERER LEUR TRAJECTOIRE. LE MA TA ORE ATTA RRIRA DANS
PRA S DE 30H SUR LES CA TES MOZAMBICAINES.

LES CONDITIONS ENVIRONNEMENTALES RESTENT DONC FAVORABLES AU
DEVELOPPEMENT DU SYSTEME : CISAILLEMENT MODA RA , POTENTIEL OCA
ANIQUE FAVORABLE, BONNE ALIMENTATION DU FLUX DE MOUSSON QUI DESCEND
JUSQU'AU MILIEU DU CANAL. LE SCA NARIO D'UNE INTENSIFICATION RA GULIA
RE EST DONC MAINTENU PAR LE CMRS EN ACCORD AVEC LES MODA LES EUROPA
ENS. CHALANE DEVRAIT DONC ATTEINDRE LE MOZAMBIQUE AU STADE DE CYCLONE
TROPICAL DANS PRA S DE 30H.

SUIVANT CE SCA NARIO, LA MENACE REPRESENTA E PAR CHALANE RESTE BIEN
RA ELLE, OCCASIONNANT DES VENTS FORTS, DE FORTES PRA CIPITATIONS
AINSI QUE DES PHA NOMA NES DE HOULE CYCLONIQUE ET SURCOTE
PRINCIPALEMENT AU SUD DE LA ZONE D'ATTERISSAGE. LES HABITANTS DE LA
REGION AUTOUR DE BEIRA, SOIT DE LA VILLE DE CHINDE AU NORD ET
INHASSORO AU SUD, SONT INVITES A SE TENIR INFORMES DE L'EVOLUTION DE
LA SITUATION.=

>

Original Message :

WTIO30 FMEE 290016
RSMC / TROPICAL CYCLONE CENTER / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)

0.A WARNING NUMBER: 22/4/20202021
1.A MODERATE TROPICAL STORM 4 (CHALANE)

2.A POSITION 2020/12/29 AT 0000 UTC:
WITHIN 20 NM RADIUS OF POINT 19.7 S / 41.0 E
(NINETEEN DECIMAL SEVEN DEGREES SOUTH AND
FORTY ONE DECIMAL ZERO DEGREES EAST)
MOVEMENT: WEST 8 KT

3.A DVORAK ANALYSIS: 3.0/3.0/D 0.5/6 H

4.A CENTRAL PRESSURE: 995 HPA
5.A MAX AVERAGE WIND SPEED (10 MN): 40 KT
RADIUS OF MAXIMUM WINDS (RMW): 46 KM

6.A EXTENSION OF WIND BY QUADRANTS (KM):
28 KT NE: 165 SE: 150 SW: 95 NW: 0
34 KT NE: 55 SE: 55 SW: 55 NW: 0
48 KT NE: 0 SE: 0 SW: 0 NW: 0
64 KT NE: 0 SE: 0 SW: 0 NW: 0

7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1007 HPA / 400 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: DEEP

1.B FORECASTS (WINDS RADII IN KM):
12H: 2020/12/29 12 UTC: 19.7 S / 39.1 E, VENT MAX= 050 KT, SEVERE
TROPICAL STORM
28 KT NE: 130 SE: 155 SW: 150 NW: 130
34 KT NE: 85 SE: 85 SW: 120 NW: 85
48 KT NE: 55 SE: 75 SW: 75 NW: 55

24H: 2020/12/30 00 UTC: 19.5 S / 36.7 E, VENT MAX= 060 KT, SEVERE
TROPICAL STORM
28 KT NE: 150 SE: 185 SW: 140 NW: 100
34 KT NE: 95 SE: 110 SW: 120 NW: 95
48 KT NE: 65 SE: 85 SW: 65 NW: 65

36H: 2020/12/30 12 UTC: 19.5 S / 34.3 E, VENT MAX= 040 KT, OVERLAND
DEPRESSION
28 KT NE: 230 SE: 185 SW: 220 NW: 75
34 KT NE: 55 SE: 95 SW: 35 NW: 65

48H: 2020/12/31 00 UTC: 19.3 S / 31.9 E, VENT MAX= 025 KT, OVERLAND
DEPRESSION

2.B LONGER-RANGE OUTLOOK:
NIL

2.C ADDITIONAL INFORMATION:
T=CI=3.0

OVER THE PAST 6 HOURS, THE CURVED BAND CLOUD PATTERN OF CHALANE HAS
BEEN MAINTAINED WITH INCREASED CONVECTIVE ACTIVITY CLOSE TO THE
CENTER. A CENTRAL DENSE OVERCAST (CDO) PATTERN MAY BE EXPECTED SOON.
SHORTLY AFTER THE PREVIOUS BULLETIN, THE 1817UTC ASCAT DATA ALLOWED
TO VALIDATE THE 35KT IN THE SOUTH-EAST PART OF THE SYSTEM. CURRENTLY,
THE DVORAK ANALYSIS ALLOWS TO NOTE AN INTENSITY WHICH CONTINUES TO
INCREASE, LEAVING AN ESTIMATE OF MAXIMUM WINDS OF THE ORDER OF 40KT.

NO CHANGE IN TERMS OF FORECAST, THE SCENARIO OF A RATHER FAST
MOVEMENT DRIVEN BY THE RIDGE OF LOW AND MEDIUM TROPOPHERE INSTALLED
ON THE SOUTH OF THE CHANNEL, IS MAINTAINED. CHALANE WILL THUS
CONTINUE ITS WESTWARD MOVEMENT AND WILL EVENTUALLY TOUCH MOZAMBIQUE.
THE MODELS ARE IN FAIRLY GOOD AGREEMENT ON THE DIRECTION AND IN TERMS
OF SPEED OF MOVEMENT, THE MODELS THAT WERE A LITTLE SLOWER HAVE ALSO
ACCELERATED THEIR TRACK. THE METEOR WILL LAND IN ABOUT 30H ON THE
MOZAMBICAN COASTS.

THE ENVIRONMENTAL CONDITIONS THUS REMAIN FAVORABLE FOR THE
DEVELOPMENT OF THE SYSTEM: MODERATE SHEAR, FAVORABLE OCEANIC
POTENTIAL, GOOD FEEDING OF THE MONSOON FLOW WHICH GOES DOWN TO THE
MIDDLE OF THE CHANNEL. THE SCENARIO OF A REGULAR INTENSIFICATION IS
THUS MAINTAINED BY THE CMRS IN AGREEMENT WITH THE EUROPEAN MODELS.
CHALANE SHOULD THUS REACH MOZAMBIQUE AT THE STAGE OF A TROPICAL
CYCLONE IN NEARLY 30H.

ACCORDING TO THIS SCENARIO, THE THREAT REPRESENTED BY CHALANE REMAINS
VERY REAL, CAUSING STRONG WINDS, HEAVY RAINFALL AS WELL AS CYCLONIC
SWELL PHENOMENA AND SURGES MAINLY IN THE SOUTH OF THE LANDING AREA.
THE INHABITANTS OF THE REGION AROUND BEIRA, I.E. FROM THE TOWN OF
CHINDE IN THE NORTH AND INHASSORO IN THE SOUTH, ARE INVITED TO KEEP
THEMSELVES INFORMED OF THE EVOLUTION OF THE SITUATION.=

>

Original Message :

WTIO24 FMEE 290005
SECURITE
GALE WARNING FOR METAREA VII
ISSUED BY METEO-FRANCE/TROPICAL CYCLONE CENTER/LA REUNION 29/12/2020
AT 0000 UTC.
WARNING NUMBER: 022/4 (SOUTH-WEST INDIAN OCEAN)
10 MINUTES AVERAGE WIND SPEED IN KNOTS (KT)
(WIND GUSTS AT SEA MAY BE ABOUT 40% STRONGER THAN THE AVERAGED WIND)
MINIMUM SEA LEVEL PRESSURE IN HECTOPASCAL (HPA)
(INDICATIVE FIGURE).

GALE WARNING
BEGINNING OF VALIDITY: TUESDAY 29/12/2020 AT 0000 UTC.

PHENOMENON: MODERATE TROPICAL STORM 4 (CHALANE) 995 HPA
POSITION: WITHIN 20 NM RADIUS OF POINT 19.7 S / 41.0 E
(NINETEEN DECIMAL SEVEN DEGREES SOUTH AND
FORTY ONE DECIMAL ZERO DEGREES EAST) AT 0000 UTC
MOVEMENT: WEST 8 KT

THREAT AREAS:
SQUALLY WEATHER IN A RADIUS OF 100 NM FROM THE CENTER, EXTENDING UP
TO 160 NM IN THE NORTH-EASTERN QUADRANT.

GALE FORCE WINDS 35/40 KT AND VERY ROUGH TO HIGH SEAS EXTENDING UP TO
30 NM IN THE SOUTHERN SEMI-CIRCLE AND THE NORTH-EASTERN QUADRANT.
NEAR GALE FORCE WINDS 30 KT AND ROUGH TO VERY ROUGH SEAS EXTENDING UP
TO 50 NM IN THE SOUTH-WESTERN QUADRANT, UP TO 80 NM IN THE
SOUTH-EASTERN QUADRANT AND UP TO 90 NM IN THE NORTH-EASTERN QUADRANT.
STRONG GUSTS UNDER SQUALLS.

FORECAST POSITION AND INTENSITY:
12H, VALID 2020/12/29 AT 12 UTC:
19.7 S / 39.1 E, MAX WIND = 50 KT, SEVERE TROPICAL STORM
28 KT NE: 70 NM SE: 85 NM SW: 80 NM NW: 70 NM
34 KT NE: 45 NM SE: 45 NM SW: 65 NM NW: 45 NM
48 KT NE: 30 NM SE: 40 NM SW: 40 NM NW: 30 NM

24H, VALID 2020/12/30 AT 00 UTC:
19.5 S / 36.7 E, MAX WIND = 60 KT, SEVERE TROPICAL STORM
28 KT NE: 80 NM SE: 100 NM SW: 75 NM NW: 55 NM
34 KT NE: 50 NM SE: 60 NM SW: 65 NM NW: 50 NM
48 KT NE: 35 NM SE: 45 NM SW: 35 NM NW: 35 NM

OTHER INFORMATION:
NIL=

>

Original Message :

WTIO31 FMEE 281822
CMRS / CENTRE DES CYCLONES TROPICAUX DE LA REUNION
BULLETIN D'ANALYSE ET DE PREVISION CYCLONIQUE (SUD-OUEST OCEAN
INDIEN)

0.A NUMERO DU BULLETIN : 21/4/20202021
1.A TEMPETE TROPICALE MODEREE 4 (CHALANE)

2.A POSITION A 1800 UTC LE 28/12/2020 :
DANS UN RAYON DE 20 MN AUTOUR DU POINT 19.8 S / 41.5 E
(DIX-NEUF DEGRES HUIT SUD ET QUARANTE UN DEGRES CINQ EST)
DEPLACEMENT: OUEST 9 KT

3.A ANALYSE DE DVORAK: 2.5/2.5/D 0.5/12 H

4.A PRESSION AU CENTRE: 999 HPA
5.A VENT MAX (MOYEN/10 MN): 35 KT
RAYON DES VENTS MAXIMAUX (RVM): 65 KM

6.A EXTENSION DES VENTS PAR QUADRANTS (KM):
28 KT NE: 280 SE: 130 SO: 75 NO: 220
34 KT NE: 55 SE: 55 SO: 0 NO: 55
48 KT NE: 0 SE: 0 SO: 0 NO: 0
64 KT NE: 0 SE: 0 SO: 0 NO: 0

7.A COTE/DIAM PREMIERE ISOBARE FERMEE: 1007 HPA / 400 KM
8.A EXTENSION VERTICALE DE LA CIRCULATION CYCLONIQUE: PROFONDE

1.B PREVISIONS (EXTENSIONS DES VENTS FORTS EN KM):
12H: 29/12/2020 06 UTC: 19.8 S / 40.2 E, VENT MAX= 045 KT, TEMPETE
TROPICALE MODEREE
28 KT NE: 305 SE: 215 SO: 215 NO: 260
34 KT NE: 150 SE: 95 SO: 100 NO: 130

24H: 29/12/2020 18 UTC: 19.5 S / 38.1 E, VENT MAX= 055 KT, FORTE
TEMPETE TROPICALE
28 KT NE: 325 SE: 230 SO: 215 NO: 260
34 KT NE: 155 SE: 110 SO: 110 NO: 130
48 KT NE: 65 SE: 65 SO: 65 NO: 55

36H: 30/12/2020 06 UTC: 19.4 S / 35.6 E, VENT MAX= 065 KT, CYCLONE
TROPICAL
28 KT NE: 350 SE: 250 SO: 215 NO: 250
34 KT NE: 175 SE: 140 SO: 120 NO: 130
48 KT NE: 75 SE: 85 SO: 75 NO: 75
64 KT NE: 65 SE: 75 SO: 45 NO: 55

48H: 30/12/2020 18 UTC: 19.5 S / 33.2 E, VENT MAX= 030 KT, DEPRESSION
SUR TERRE
28 KT NE: 370 SE: 270 SO: 215 NO: 250

60H: 31/12/2020 06 UTC: 18.7 S / 30.6 E, VENT MAX= 025 KT, DEPRESSION
SUR TERRE

2.B TENDANCE ULTERIEURE:
NON RENSEIGNE

2.C COMMENTAIRES:
T=CI=2.5+

AU COURS DES DERNIA RES 6 HEURES, LA CONFIGURATION NUAGEUSE DE
CHALANE S'EST ORGANISA E EN BANDE INCURVA E LAISSANT UNE ESTIMATION
DE VENT DE 35KT D'APRA S L'ANALYSE DVORAK. AVEC CE SEUIL, CHALANE EST
CLASSA E TEMPA TE TROPICALE MODA RA E A 18UTC. L'ACTIVITA
CONVECTIVE SE SITUE PRINCIPALEMENT DANS LE DEMI-CERCLE NORD-EST.
L'ABSENCE DE DONNA ES RA CENTES ASCAT NE PERMETTENT PAS DE VALIDER
CETTE ESTIMATION ET LA DISSYMA TRIE DES VENTS OBSERVA S DANS LE
QUADRANT SUD-OUEST (IL Y A PRA S DE 12H) NE PEUT PAS A TRE LEVA E.

PILOTA E PAR LA DORSALE DE BASSES ET MOYENNE TROPOPHERE INSTALLEE SUR
LE SUD DU CANAL, CHALANE POURSUIVRA SON DA PLACEMENT VERS L'OUEST
AVANT DE TOUCHER LE MOZAMBIQUE. LES MODA LES SONT EN ASSEZ BON ACCORD
SUR LA DIRECTION MAIS ILS DIFFA RENT QUELQUE PEU SUR LA VITESSE DE DA
PLACEMENT. LE CMRS A OPTA POUR UN DA PLACEMENT RELATIVEMENT RAPIDE,
LAISSANT LE MA TA ORE ATTERRIR DANS PRA S DE 36H SUR LES CA TES
MOZAMBICAINES, EN LIEN AVEC UNE INTENSIFICATION RA GULIA RE.

LES CONDITIONS ENVIRONNEMENTALES RESTENT FAVORABLES AU DEVELOPPEMENT
DU SYSTEME : CISAILLEMENT MODA RA , POTENTIEL OCA ANIQUE FAVORABLE,
BONNE ALIMENTATION DU FLUX DE MOUSSON QUI DESCEND JUSQU'AU MILIEU DU
CANAL. LE SCA NARIO D'UNE INTENSIFICATION RA GULIA RE EST DONC PRISE
PAR LE CMRS EN ACCORD AVEC LES MODA LES EUROPA ENS. CHALANE DEVRAIT
DONC ATTEINDRE LE MOZAMBIQUE AU STADE DE CYCLONE TROPICAL DANS PRA S
DE 36H.

SUIVANT CE SCA NARIO, LA MENACE REPRESENTA E PAR CHALANE EST RA ELLE,
OCCASIONNANT DES VENTS FORTS, DE FORTES PRA CIPITATIONS AINSI QUE DES
PHA NOMA NES DE HOULE CYCLONIQUE ET SURCOTE PRINCIPALEMENT AU SUD DE
LA ZONE D'ATTERISSAGE. LES HABITANTS DE LA REGION AUTOUR DE BEIRA,
SOIT DE LA VILLE DE CHINDE AU NORD ET INHASSORO AU SUD, SONT INVITES
A SE TENIR INFORMES DE L'EVOLUTION DE LA SITUATION.=

>

Original Message :

WTIO30 FMEE 281822
RSMC / TROPICAL CYCLONE CENTER / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)

0.A WARNING NUMBER: 21/4/20202021
1.A MODERATE TROPICAL STORM 4 (CHALANE)

2.A POSITION 2020/12/28 AT 1800 UTC:
WITHIN 20 NM RADIUS OF POINT 19.8 S / 41.5 E
(NINETEEN DECIMAL EIGHT DEGREES SOUTH AND
FORTY ONE DECIMAL FIVE DEGREES EAST)
MOVEMENT: WEST 9 KT

3.A DVORAK ANALYSIS: 2.5/2.5/D 0.5/12 H

4.A CENTRAL PRESSURE: 999 HPA
5.A MAX AVERAGE WIND SPEED (10 MN): 35 KT
RADIUS OF MAXIMUM WINDS (RMW): 65 KM

6.A EXTENSION OF WIND BY QUADRANTS (KM):
28 KT NE: 280 SE: 130 SW: 75 NW: 220
34 KT NE: 55 SE: 55 SW: 0 NW: 55
48 KT NE: 0 SE: 0 SW: 0 NW: 0
64 KT NE: 0 SE: 0 SW: 0 NW: 0

7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1007 HPA / 400 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: DEEP

1.B FORECASTS (WINDS RADII IN KM):
12H: 2020/12/29 06 UTC: 19.8 S / 40.2 E, VENT MAX= 045 KT, MODERATE
TROPICAL STORM
28 KT NE: 305 SE: 215 SW: 215 NW: 260
34 KT NE: 150 SE: 95 SW: 100 NW: 130

24H: 2020/12/29 18 UTC: 19.5 S / 38.1 E, VENT MAX= 055 KT, SEVERE
TROPICAL STORM
28 KT NE: 325 SE: 230 SW: 215 NW: 260
34 KT NE: 155 SE: 110 SW: 110 NW: 130
48 KT NE: 65 SE: 65 SW: 65 NW: 55

36H: 2020/12/30 06 UTC: 19.4 S / 35.6 E, VENT MAX= 065 KT, TROPICAL
CYCLONE
28 KT NE: 350 SE: 250 SW: 215 NW: 250
34 KT NE: 175 SE: 140 SW: 120 NW: 130
48 KT NE: 75 SE: 85 SW: 75 NW: 75
64 KT NE: 65 SE: 75 SW: 45 NW: 55

48H: 2020/12/30 18 UTC: 19.5 S / 33.2 E, VENT MAX= 030 KT, OVERLAND
DEPRESSION
28 KT NE: 370 SE: 270 SW: 215 NW: 250

60H: 2020/12/31 06 UTC: 18.7 S / 30.6 E, VENT MAX= 025 KT, OVERLAND
DEPRESSION

2.B LONGER-RANGE OUTLOOK:
NIL

2.C ADDITIONAL INFORMATION:
T=CI=2.5+

DURING THE LAST 6 HOURS, THE CHALANE CLOUD PATTERN WAS ORGANIZED IN A
CURVED BAND LEAVING A WIND ESTIMATE OF 35KT ACCORDING TO THE DVORAK
ANALYSIS. WITH THIS THRESHOLD, CHALANE IS CLASSIFIED AS A MODERATE
TROPICAL STORM AT 18UTC. THE CONVECTIVE ACTIVITY IS MAINLY LOCATED IN
THE NORTHEAST SEMI-CIRCLE. THE ABSENCE OF RECENT ASCAT SWATH DATA
DOES NOT ALLOW TO VALIDATE THIS ESTIMATE AND THE ASYMMETRY OF WINDS
OBSERVED IN THE SOUTH-WEST QUADRANT (NEARLY 12 HOURS AGO) CANNOT BE
LIFTED.

DRIVEN BY THE RIDGE OF LOW AND MEDIUM TROPOPHERE INSTALLED ON THE
SOUTH OF THE CHANNEL, CHALANE WILL CONTINUE ITS WESTWARD MOVEMENT
BEFORE REACHING MOZAMBIQUE. THE MODELS ARE IN FAIRLY GOOD AGREEMENT
ON THE DIRECTION BUT THEY DIFFER SOMEWHAT ON THE SPEED OF MOVEMENT.
THE RSMC HAS OPTED FOR A RELATIVELY FAST DISPLACEMENT, ALLOWING THE
METEOR TO LAND IN ABOUT 36 HOURS ON THE MOZAMBICAN COAST, IN
CONNECTION WITH A REGULAR INTENSIFICATION.

THE ENVIRONMENTAL CONDITIONS REMAIN FAVORABLE FOR THE DEVELOPMENT OF
THE SYSTEM: MODERATE SHEAR, FAVORABLE OCEANIC POTENTIAL, GOOD SUPPLY
OF THE MONSOON FLOW WHICH GOES DOWN TO THE MIDDLE OF THE CHANNEL. THE
SCENARIO OF A REGULAR INTENSIFICATION IS THEREFORE TAKEN BY THE RSMC
IN AGREEMENT WITH EUROPEAN NUMERICAL MODELS. CHALANE SHOULD THEREFORE
REACH MOZAMBIQUE AT THE TROPICAL CYCLONE STAGE IN ABOUT 36 HOURS.

ACCORDING TO THIS SCENARIO, THE THREAT REPRESENTED BY CHALANE IS
REAL, CAUSING STRONG WINDS, HEAVY RAINFALL AS WELL AS CYCLONIC SWELL
AND SURGE PHENOMENA, MAINLY IN THE SOUTH OF THE LANDING AREA. THE
INHABITANTS OF THE REGION AROUND BEIRA, FROM THE CITY OF CHINDE IN
THE NORTH AND INHASSORO IN THE SOUTH, ARE INVITED TO KEEP THEMSELVES
INFORMED OF THE EVOLUTION OF THE SITUATION=

>

Original Message :

WTIO24 FMEE 281806
SECURITE
GALE WARNING FOR METAREA VII
ISSUED BY METEO-FRANCE/TROPICAL CYCLONE CENTER/LA REUNION 28/12/2020
AT 1800 UTC.
WARNING NUMBER: 021/4 (SOUTH-WEST INDIAN OCEAN)
10 MINUTES AVERAGE WIND SPEED IN KNOTS (KT)
(WIND GUSTS AT SEA MAY BE ABOUT 40% STRONGER THAN THE AVERAGED WIND)
MINIMUM SEA LEVEL PRESSURE IN HECTOPASCAL (HPA)
(INDICATIVE FIGURE).

GALE WARNING
BEGINNING OF VALIDITY: MONDAY 28/12/2020 AT 1800 UTC.

PHENOMENON: MODERATE TROPICAL STORM 4 (CHALANE) 999 HPA
POSITION: WITHIN 20 NM RADIUS OF POINT 19.8 S / 41.5 E
(NINETEEN DECIMAL EIGHT DEGREES SOUTH AND
FORTY ONE DECIMAL FIVE DEGREES EAST) AT 1800 UTC
MOVEMENT: WEST 9 KT

THREAT AREAS:
SQUALLY WEATHER IN A RADIUS OF 60 NM FROM THE CENTER, EXTENDING UP TO
160 NM IN THE NORTHEASTERN SEMI-CERCLE.

GALE FORCE WINDS 35 KT AND VERY ROUGH TO HIGH SEAS EXTENDING UP TO 30
NM IN THE NORTHERN SEMI-CIRCLE AND THE SOUTH-EASTERN QUADRANT.
NEAR GALE FORCE WINDS 30 KT AND ROUGH TO VERY ROUGH SEAS WITHIN A 40
NM RADIUS FROM THE CENTRE, EXTENDING UP TO 70 NM IN THE SOUTH-EASTERN
QUADRANT, UP TO 120 NM IN THE NORTH-WESTERN QUADRANT AND UP TO 150 NM
IN THE NORTH-EASTERN QUADRANT.
STRONG GUSTS UNDER SQUALLS.

FORECAST POSITION AND INTENSITY:
12H, VALID 2020/12/29 AT 06 UTC:
19.8 S / 40.2 E, MAX WIND = 45 KT, MODERATE TROPICAL STORM
28 KT NE: 165 NM SE: 115 NM SW: 115 NM NW: 140 NM
34 KT NE: 80 NM SE: 50 NM SW: 55 NM NW: 70 NM

24H, VALID 2020/12/29 AT 18 UTC:
19.5 S / 38.1 E, MAX WIND = 55 KT, SEVERE TROPICAL STORM
28 KT NE: 175 NM SE: 125 NM SW: 115 NM NW: 140 NM
34 KT NE: 85 NM SE: 60 NM SW: 60 NM NW: 70 NM
48 KT NE: 35 NM SE: 35 NM SW: 35 NM NW: 30 NM

OTHER INFORMATION:
NIL=

>

Original Message :

WTIO31 FMEE 281256
CMRS / CENTRE DES CYCLONES TROPICAUX DE LA REUNION
BULLETIN D'ANALYSE ET DE PREVISION CYCLONIQUE (SUD-OUEST OCEAN
INDIEN)

0.A NUMERO DU BULLETIN : 20/4/20202021
1.A DEPRESSION TROPICALE 4 (CHALANE)

2.A POSITION A 1200 UTC LE 28/12/2020 :
DANS UN RAYON DE 20 MN AUTOUR DU POINT 20.4 S / 42.7 E
(VINGT DEGRES QUATRE SUD ET QUARANTE DEUX DEGRES SEPT EST)
DEPLACEMENT: OUEST-SUD-OUEST 10 KT

3.A ANALYSE DE DVORAK: 2.5/2.5/D 0.5/12 H

4.A PRESSION AU CENTRE: 1001 HPA
5.A VENT MAX (MOYEN/10 MN): 30 KT
RAYON DES VENTS MAXIMAUX (RVM): 65 KM

6.A EXTENSION DES VENTS PAR QUADRANTS (KM):
28 KT NE: 280 SE: 130 SO: 0 NO: 220
34 KT NE: 0 SE: 0 SO: 0 NO: 0
48 KT NE: 0 SE: 0 SO: 0 NO: 0
64 KT NE: 0 SE: 0 SO: 0 NO: 0

7.A COTE/DIAM PREMIERE ISOBARE FERMEE: 1009 HPA / 700 KM
8.A EXTENSION VERTICALE DE LA CIRCULATION CYCLONIQUE: PROFONDE

1.B PREVISIONS (EXTENSIONS DES VENTS FORTS EN KM):
12H: 29/12/2020 00 UTC: 20.2 S / 41.6 E, VENT MAX= 035 KT, TEMPETE
TROPICALE MODEREE
28 KT NE: 315 SE: 280 SO: 165 NO: 250
34 KT NE: 100 SE: 140 SO: 130 NO: 110

24H: 29/12/2020 12 UTC: 20.0 S / 40.0 E, VENT MAX= 040 KT, TEMPETE
TROPICALE MODEREE
28 KT NE: 335 SE: 295 SO: 165 NO: 250
34 KT NE: 120 SE: 165 SO: 140 NO: 110

36H: 30/12/2020 00 UTC: 19.8 S / 37.1 E, VENT MAX= 050 KT, FORTE
TEMPETE TROPICALE
28 KT NE: 360 SE: 315 SO: 165 NO: 250
34 KT NE: 140 SE: 185 SO: 155 NO: 110
48 KT NE: 65 SE: 75 SO: 65 NO: 55

48H: 30/12/2020 12 UTC: 19.8 S / 34.4 E, VENT MAX= 035 KT, DEPRESSION
SUR TERRE
28 KT NE: 390 SE: 335 SO: 175 NO: 240
34 KT NE: 155 SE: 215 SO: 165 NO: 110

60H: 31/12/2020 00 UTC: 19.9 S / 32.3 E, VENT MAX= 030 KT, DEPRESSION
SUR TERRE
28 KT NE: 405 SE: 350 SO: 165 NO: 240

2.B TENDANCE ULTERIEURE:
NON RENSEIGNE

2.C COMMENTAIRES:
LA CIRCULATION RESIDUELLE DE CHALANA EST RESSORTIE SUR MER DANS LE
CANAL DU MOZAMBIQUE PRES DE 20S A PROXIMITE DE LE VILLE DE MOROMDAVA.
LES DERNIERES DONNA ES ASCAT DE 05H45UTC CONFIRMENT LE STADE DE DT
AVEC DES VENTS DE L'ORDRE DE 30KT DANS LE DEMI-CERCLE EST AINSI QUE
DANS LE NORD DE LA CIRCULATION.

LES CONDITIONS ENVIRONNEMENTALES SONT FAVORABLES AU DEVELOPPEMENT DU
SYSTEME. SITUA SOUS LA DORSALE D'ALTITUDE, SUR DES EAUX AU POTENTIEL
OCEANIQUE TRES FAVORABLE, IL BENEFICIE D'UNE BONNE ALIMENTATION DU
FLUX DE MOUSSON QUI DESCEND JUSQU'AU MILIEU DU CANAL.

SI IL Y A UN BON ACCORD CONCERNANT LA DIRECTION DE DEPLACEMENT
ATTENDU DU SYSTEME, EN DIRECTION DE L'OUEST SUR LE BORDURE NORD DE LA
DORSALE DE BASSES ET MOYENNE TROPOPHERE INSTALLEE SUR LE SUD DU
CANAL.
ON NOTE UNE DIFFERENCE NOTABLE DE VITESSE DE DEPLACEMENT ENTRE LES
MODELES. IFS ETANT PLUS CREUX DES AUJOURD'HUI ACCELERE LE SYSTEME
SOUS L'INFLUENCE PREDOMINANT D'UN FLUX DIRECTEUR PLUS ELEVE EN
MOYENNE TROPO.

LES MODELES NUMERIQUES APPRA HENDENT ENCORE MAL L'INTENSITE ACTUELLE
DU SYSTEME, ET DIFFERENT BEAUCOUP DANS LE TIMING D'ATTERRISSAGE ET
DANS LEUR PREVISION D'INTENSITA . LA PRESENCE EN PARTICULIER D'UNE
CONTRAINTE D'EST EN FIN DE PERIODE POURRAIT AVOIR UNE INFLUENCE
VARIABLE SUIVANT LA VITESSE DE DEPLACEMENT EN DIRECTION DE L'OUEST DU
SYSTEME.

MALGRA L'INCERTITUDE SUR LE TIMING, ET LA MENACE REPRESENTA E PAR CE
SYSTEME, LES HABITANTS DE LA REGION AUTOUR DE BEIRA, SOIT DE LA VILLE
DE CHINDE AU NORD ET INHASSORO AU SUD, SONT INVITES A SE TENIR
INFORMES DE L'EVOLUTION DE LA SITUATION.=

>

Original Message :

WTIO30 FMEE 281256
RSMC / TROPICAL CYCLONE CENTER / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)

0.A WARNING NUMBER: 20/4/20202021
1.A TROPICAL DEPRESSION 4 (CHALANE)

2.A POSITION 2020/12/28 AT 1200 UTC:
WITHIN 20 NM RADIUS OF POINT 20.4 S / 42.7 E
(TWENTY DECIMAL FOUR DEGREES SOUTH AND
FORTY TWO DECIMAL SEVEN DEGREES EAST)
MOVEMENT: WEST-SOUTH-WEST 10 KT

3.A DVORAK ANALYSIS: 2.5/2.5/D 0.5/12 H

4.A CENTRAL PRESSURE: 1001 HPA
5.A MAX AVERAGE WIND SPEED (10 MN): 30 KT
RADIUS OF MAXIMUM WINDS (RMW): 65 KM

6.A EXTENSION OF WIND BY QUADRANTS (KM):
28 KT NE: 280 SE: 130 SW: 0 NW: 220
34 KT NE: 0 SE: 0 SW: 0 NW: 0
48 KT NE: 0 SE: 0 SW: 0 NW: 0
64 KT NE: 0 SE: 0 SW: 0 NW: 0

7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1009 HPA / 700 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: DEEP

1.B FORECASTS (WINDS RADII IN KM):
12H: 2020/12/29 00 UTC: 20.2 S / 41.6 E, VENT MAX= 035 KT, MODERATE
TROPICAL STORM
28 KT NE: 315 SE: 280 SW: 165 NW: 250
34 KT NE: 100 SE: 140 SW: 130 NW: 110

24H: 2020/12/29 12 UTC: 20.0 S / 40.0 E, VENT MAX= 040 KT, MODERATE
TROPICAL STORM
28 KT NE: 335 SE: 295 SW: 165 NW: 250
34 KT NE: 120 SE: 165 SW: 140 NW: 110

36H: 2020/12/30 00 UTC: 19.8 S / 37.1 E, VENT MAX= 050 KT, SEVERE
TROPICAL STORM
28 KT NE: 360 SE: 315 SW: 165 NW: 250
34 KT NE: 140 SE: 185 SW: 155 NW: 110
48 KT NE: 65 SE: 75 SW: 65 NW: 55

48H: 2020/12/30 12 UTC: 19.8 S / 34.4 E, VENT MAX= 035 KT, OVERLAND
DEPRESSION
28 KT NE: 390 SE: 335 SW: 175 NW: 240
34 KT NE: 155 SE: 215 SW: 165 NW: 110

60H: 2020/12/31 00 UTC: 19.9 S / 32.3 E, VENT MAX= 030 KT, OVERLAND
DEPRESSION
28 KT NE: 405 SE: 350 SW: 165 NW: 240

2.B LONGER-RANGE OUTLOOK:
NIL

2.C ADDITIONAL INFORMATION:
REMNANT LOW OF CHALANE HAS LEFT MADAGASCAR AND MOVED OUT TO SEA IN
THE MOZAMBIQUE CHANNEL.
THE LAST ASCAT DATA OF 05H45UTC CONFIRM THE STAGE OF DT WITH WINDS OF
THE ORDER OF 30KT IN THE EASTERN SEMICIRCLE AS WELL AS IN THE NORTH
OF THE CIRCULATION.

OVER THE ENVIRONMENTAL CONDITIONS ARE FAVORABLE FOR DEVELOPMENT.
LOCATED UNDER THE HIGH ALTITUDE RIDGE, OVER SEAS WITH A VERY
FAVORABLE OCEANIC POTENTIAL THE SYSTEM BENEFITS FROM A GOOD SUPPLY OF
MONSOON FLOW THAT GOES DOWN TO THE MIDDLE OF THE CHANNEL.

IF THERE IS A GOOD AGREEMENT ON THE EXPECTED DIRECTION OF MOVEMENT OF
THE SYSTEM, WESTWARD ON THE NORTHERN EDGE OF THE LOW AND MIDDLE
TROPOPHERE RIDGE INSTALLED ON THE SOUTH SIDE OF THE CANAL.
THERE IS A NOTICEABLE DIFFERENCE IN SPEED OF MOVEMENT BETWEEN THE
MODELS. THE LOWER YAWS OF TODAY ACCELERATE THE SYSTEM UNDER THE
PREDOMINANT INFLUENCE OF A MEDIUM LEVEL STEERING FLOW.

NWP STILL DO NOT FULLY ANALYSE THE CURRENT INTENSITY OF THE SYSTEM,
AND DIFFER A LOT IN THE LANDING TIMING AND IN THEIR INTENSITY
FORECAST.
THE PRESENCE IN PARTICULAR OF AN EASTERLY CONSTRAINT AT THE END OF
THE PERIOD COULD HAVE A VARIABLE INFLUENCE DEPENDING ON THE SPEED OF
WESTWARD MOVEMENT OF THE SYSTEM.

DESPITE THE UNCERTAINTY ABOUT THE TIMING, AND THE THREAT REPRESENTED
BY THIS SYSTEM, THE INHABITANTS OF THE REGION AROUND BEIRA, FROM THE
CITY OF CHINDE IN THE NORTH TO THE INHASSORO IN THE SOUTH, ARE
INVITED TO KEEP THEMSELVES INFORMED ABOUT THE EVOLUTION OF THE
SITUATION.=

>

Original Message :

WTIO24 FMEE 281203
SECURITE
NEAR GALE WARNING FOR METAREA VII
ISSUED BY METEO-FRANCE/TROPICAL CYCLONE CENTER/LA REUNION 28/12/2020
AT 1200 UTC.
WARNING NUMBER: 020/4 (SOUTH-WEST INDIAN OCEAN)
10 MINUTES AVERAGE WIND SPEED IN KNOTS (KT)
(WIND GUSTS AT SEA MAY BE ABOUT 40% STRONGER THAN THE AVERAGED WIND)
MINIMUM SEA LEVEL PRESSURE IN HECTOPASCAL (HPA)
(INDICATIVE FIGURE).

NEAR GALE WARNING
BEGINNING OF VALIDITY: MONDAY 28/12/2020 AT 1200 UTC.

PHENOMENON: TROPICAL DEPRESSION 4 (CHALANE) 1001 HPA
POSITION: WITHIN 20 NM RADIUS OF POINT 20.4 S / 42.7 E
(TWENTY DECIMAL FOUR DEGREES SOUTH AND
FORTY TWO DECIMAL SEVEN DEGREES EAST) AT 1200 UTC
MOVEMENT: WEST-SOUTH-WEST 10 KT

THREAT AREAS:
SQUALLY WEATHER EXTENDING UP TO 90 NM FROM THE CENTER IN THE EASTERN
SEMI-CERCLE, UP TO 400 NM IN THE NORTHWESTERN QUADRANT.

NEAR GALE FORCE WINDS 30 KT AND ROUGH TO VERY ROUGH SEAS EXTENDING UP
TO 70 NM IN THE SOUTH-EASTERN QUADRANT, UP TO 120 NM IN THE
NORTH-WESTERN QUADRANT AND UP TO 150 NM IN THE NORTH-EASTERN
QUADRANT.
STRONG GUSTS UNDER SQUALLS.

FORECAST POSITION AND INTENSITY:
12H, VALID 2020/12/29 AT 00 UTC:
20.2 S / 41.6 E, MAX WIND = 35 KT, MODERATE TROPICAL STORM
28 KT NE: 170 NM SE: 150 NM SW: 90 NM NW: 135 NM
34 KT NE: 55 NM SE: 75 NM SW: 70 NM NW: 60 NM

24H, VALID 2020/12/29 AT 12 UTC:
20.0 S / 40.0 E, MAX WIND = 40 KT, MODERATE TROPICAL STORM
28 KT NE: 180 NM SE: 160 NM SW: 90 NM NW: 135 NM
34 KT NE: 65 NM SE: 90 NM SW: 75 NM NW: 60 NM

OTHER INFORMATION:
NIL=

>

Original Message :

WTIO24 FMEE 270008
SECURITE
NEAR GALE WARNING FOR METAREA VII
ISSUED BY METEO-FRANCE/TROPICAL CYCLONE CENTER/LA REUNION 27/12/2020
AT 0000 UTC.
WARNING NUMBER: 019/4 (SOUTH-WEST INDIAN OCEAN)
10 MINUTES AVERAGE WIND SPEED IN KNOTS (KT)
(WIND GUSTS AT SEA MAY BE ABOUT 40% STRONGER THAN THE AVERAGED WIND)
MINIMUM SEA LEVEL PRESSURE IN HECTOPASCAL (HPA)
(INDICATIVE FIGURE).

NEAR GALE WARNING
BEGINNING OF VALIDITY: SUNDAY 27/12/2020 AT 0000 UTC.

PHENOMENON: OVERLAND DEPRESSION 4 (CHALANE) 1005 HPA
POSITION: WITHIN 20 NM RADIUS OF POINT 17.8 S / 49.2 E
(SEVENTEEN DECIMAL EIGHT DEGREES SOUTH AND
FORTY NINE DECIMAL TWO DEGREES EAST) AT 0000 UTC
MOVEMENT: WEST-SOUTH-WEST 8 KT

THREAT AREAS:
SQUALLY WEATHER EXTENDING UP TO 200 NM FROM THE CENTER, UP TO 450 NM
IN THE NORTHEASTERN QUADRANT.

NEAR GALE FORCE WINDS 30 KT AND ROUGH TO VERY ROUGH SEAS EXTENDING UP
TO 75 NM IN THE SOUTH-EASTERN QUADRANT.
STRONG GUSTS UNDER SQUALLS.

FORECAST POSITION AND INTENSITY:
12H, VALID 2020/12/27 AT 12 UTC:
18.3 S / 47.1 E, MAX WIND = 25 KT, OVERLAND DEPRESSION

24H, VALID 2020/12/28 AT 00 UTC:
19.3 S / 45.1 E, MAX WIND = 20 KT, OVERLAND DEPRESSION

OTHER INFORMATION:
LAST WARNING CONCERNING THIS SYSTEM BEFORE A POSSIBLE
REINTENSIFICATION OVER THE MOZAMBIQUE CHANNEL.=

>

Original Message :

WTIO31 FMEE 261840
CMRS / CENTRE DES CYCLONES TROPICAUX DE LA REUNION
BULLETIN D'ANALYSE ET DE PREVISION CYCLONIQUE (SUD-OUEST OCEAN
INDIEN)

0.A NUMERO DU BULLETIN : 18/4/20202021
1.A DEPRESSION TROPICALE 4 (CHALANE)

2.A POSITION A 1800 UTC LE 26/12/2020 :
DANS UN RAYON DE 30 MN AUTOUR DU POINT 17.6 S / 49.8 E
(DIX-SEPT DEGRES SIX SUD ET QUARANTE NEUF DEGRES HUIT EST)
DEPLACEMENT: OUEST 15 KT

3.A ANALYSE DE DVORAK: 2.5/2.5/D 0.5/6 H

4.A PRESSION AU CENTRE: 1000 HPA
5.A VENT MAX (MOYEN/10 MN): 30 KT
RAYON DES VENTS MAXIMAUX (RVM): NON RENSEIGNE

6.A EXTENSION DES VENTS PAR QUADRANTS (KM):
28 KT NE: 0 SE: 150 SO: 185 NO: 150
34 KT NE: 0 SE: 0 SO: 0 NO: 0
48 KT NE: 0 SE: 0 SO: 0 NO: 0
64 KT NE: 0 SE: 0 SO: 0 NO: 0

7.A COTE/DIAM PREMIERE ISOBARE FERMEE: 1005 HPA / 600 KM
8.A EXTENSION VERTICALE DE LA CIRCULATION CYCLONIQUE: MOYENNE

1.B PREVISIONS (EXTENSIONS DES VENTS FORTS EN KM):
12H: 27/12/2020 06 UTC: 18.1 S / 47.2 E, VENT MAX= 025 KT, DEPRESSION
SUR TERRE

24H: 27/12/2020 18 UTC: 18.6 S / 45.1 E, VENT MAX= 020 KT, DEPRESSION
SUR TERRE

36H: 28/12/2020 06 UTC: 19.6 S / 43.8 E, VENT MAX= 025 KT, ZONE
PERTURBEE

48H: 28/12/2020 18 UTC: 20.0 S / 42.6 E, VENT MAX= 030 KT, DEPRESSION
TROPICALE
28 KT NE: 10 SE: 35 SO: 100 NO: 55

60H: 29/12/2020 06 UTC: 20.1 S / 41.1 E, VENT MAX= 040 KT, TEMPETE
TROPICALE MODEREE
28 KT NE: 45 SE: 130 SO: 100 NO: 75
34 KT NE: 35 SE: 120 SO: 55 NO: 65

72H: 29/12/2020 18 UTC: 20.3 S / 39.1 E, VENT MAX= 050 KT, FORTE
TEMPETE TROPICALE
28 KT NE: 55 SE: 140 SO: 85 NO: 75
34 KT NE: 45 SE: 130 SO: 55 NO: 65
48 KT NE: 35 SE: 55 SO: 45 NO: 45

2.B TENDANCE ULTERIEURE:
96H: 30/12/2020 18 UTC: 20.7 S / 34.7 E, VENT MAX= 060 KT, FORTE
TEMPETE TROPICALE
28 KT NE: 55 SE: 140 SO: 85 NO: 75
34 KT NE: 45 SE: 130 SO: 55 NO: 65
48 KT NE: 35 SE: 55 SO: 45 NO: 45

2.C COMMENTAIRES:
FT=CI=2.5

AU COURS DES 6 DERNIERES HEURES, LA CONVECTION EST RESTEE INTENSE
DANS LA PARTIE OUEST DU SYSTEME. L'IMAGE 37GHZ DE LA PASSE SSMIS DE
1556Z ET LA BASCULE A L'OUEST DU VENT OBSERVE A LA STATION DE L'ILE
DE STE MARIE A 17Z SUGGERENT FORTEMENT QU'UN NOUVEAU CENTRE DE
CIRCULATION S'EST RECONSTITUE AU PLUS PROCHE DE LA CONVECTION AU
COURS DES DERNIERES HEURES, EMERGEANT DE LA CIRCULATION PRECEDEMMENT
TRES ALLONGEE SOUS L'EFFET DES CONDITIONS ENVIRONNEMENTALES
DEFAVORABLES. DE PLUS, A PARTIR DE 18Z, LE VENT A BASCULE AU SECTEUR
NORD-NORD-EST A TAMATAVE. CELA SUGGERE QUE CHALANE S'APPRETE OU EST
D'ORES ET DEJA EN TRAIN D'ATTERRIR SUR LA COTE MALGACHE, A PROXIMITE
DE MAHAVELONA (FOULPOINTE) AU SUD DE L'ILE STE MARIE. L'INTENSITE
ANALYSEE DU SYSTEME EST EN ACCORD AVEC L'ANALYSE DVORAK ET LES
OBSERVATIONS AU SOL DISPONIBLES.

CE "SAUT" DU CENTRE DE CIRCULATION A AVANCE LE TIMING D'ATTERRISSAGE
DU SYSTEME. LE PRINCIPAL DANGER ASSOCIE A CE SYSTEME RESTENT LES
FORTES PLUIES, POUVANT GENERER DES CRUES ECLAIRS ET DES INONDATIONS.
CELLES-CI SE PRODUISENT MEME LOIN DU CENTRE DANS LE SECTEUR SUD. LES
HABITANTS DE LA ZONE SONT INVITES A SUIVRE L'EVOLUTION DE CE SYSTEME
AUPRES DES AUTORITES LOCALES.

EN DEBUT DE SEMAINE PROCHAINE, LE SYSTEME DEVRAIT RESSORTIR DANS LE
CANAL DU MOZAMBIQUE OU LES CONDITIONS APPARAISSENT FAVORABLES A UNE
REINTENSIFICATION (CISAILLEMENT FAIBLE, BONNE DIVERGENCE D'ALTITUDE
COTE NORD, BONNE ALIMENTATION DE BASSES COUCHES COTE NORD ET COTE SUD
AVEC UNE POUSSEE D'ALIZE ET POTENTIEL OCEANIQUE TRES FAVORABLE) DANS
UN PREMIER TEMPS. UNE DORSALE DE BASSE ET MOYENNE TROPOSPHERE
OCCUPANT LE SUD DU CANAL, UN DEPLACEMENT EN DIRECTION GENERALE DE
L'OUEST RESTE ENVISAGE.
COMPTE TENU DE L'ETAT INITIAL DE LA CIRCULATION, DE L'INCERTITUDE SUR
LA LOCALISATION DE LA SORTIE SUR MER ET DU MANQUE D'ACCORD SUR UN
CREUSEMENT DANS LE CANAL PARMI LES GUIDANCES DISPONIBLES, CETTE
SECONDE PARTIE DE LA PREVISION RESTE ENCORE TRES INCERTAINE.=

>

Original Message :

WTIO30 FMEE 261840
RSMC / TROPICAL CYCLONE CENTER / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)

0.A WARNING NUMBER: 18/4/20202021
1.A TROPICAL DEPRESSION 4 (CHALANE)

2.A POSITION 2020/12/26 AT 1800 UTC:
WITHIN 30 NM RADIUS OF POINT 17.6 S / 49.8 E
(SEVENTEEN DECIMAL SIX DEGREES SOUTH AND
FORTY NINE DECIMAL EIGHT DEGREES EAST)
MOVEMENT: WEST 15 KT

3.A DVORAK ANALYSIS: 2.5/2.5/D 0.5/6 H

4.A CENTRAL PRESSURE: 1000 HPA
5.A MAX AVERAGE WIND SPEED (10 MN): 30 KT
RADIUS OF MAXIMUM WINDS (RMW): NIL

6.A EXTENSION OF WIND BY QUADRANTS (KM):
28 KT NE: 0 SE: 150 SW: 185 NW: 150
34 KT NE: 0 SE: 0 SW: 0 NW: 0
48 KT NE: 0 SE: 0 SW: 0 NW: 0
64 KT NE: 0 SE: 0 SW: 0 NW: 0

7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1005 HPA / 600 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: MEDIUM

1.B FORECASTS (WINDS RADII IN KM):
12H: 2020/12/27 06 UTC: 18.1 S / 47.2 E, VENT MAX= 025 KT, OVERLAND
DEPRESSION

24H: 2020/12/27 18 UTC: 18.6 S / 45.1 E, VENT MAX= 020 KT, OVERLAND
DEPRESSION

36H: 2020/12/28 06 UTC: 19.6 S / 43.8 E, VENT MAX= 025 KT, ZONE OF
DISTURBED WEATHER

48H: 2020/12/28 18 UTC: 20.0 S / 42.6 E, VENT MAX= 030 KT, TROPICAL
DEPRESSION
28 KT NE: 10 SE: 35 SW: 100 NW: 55

60H: 2020/12/29 06 UTC: 20.1 S / 41.1 E, VENT MAX= 040 KT, MODERATE
TROPICAL STORM
28 KT NE: 45 SE: 130 SW: 100 NW: 75
34 KT NE: 35 SE: 120 SW: 55 NW: 65

72H: 2020/12/29 18 UTC: 20.3 S / 39.1 E, VENT MAX= 050 KT, SEVERE
TROPICAL STORM
28 KT NE: 55 SE: 140 SW: 85 NW: 75
34 KT NE: 45 SE: 130 SW: 55 NW: 65
48 KT NE: 35 SE: 55 SW: 45 NW: 45

2.B LONGER-RANGE OUTLOOK:
96H: 2020/12/30 18 UTC: 20.7 S / 34.7 E, VENT MAX= 060 KT, SEVERE
TROPICAL STORM
28 KT NE: 55 SE: 140 SW: 85 NW: 75
34 KT NE: 45 SE: 130 SW: 55 NW: 65
48 KT NE: 35 SE: 55 SW: 45 NW: 45

2.C ADDITIONAL INFORMATION:
FT=CI=2.5

OVER THE LAST 6 HOURS, CONVECTION REMAINED STRONG OVER THE WESTERN
HALF OF THE SYSTEM. SSMIS 1556Z 37GHZ IMAGE AND THE WIND GROUND
OBSERVATION DATA IN STE MARIE ISLAND VEERING WESTERLY FROM 17Z
STRONGLY SUGGEST THAT A NEW CIRCULATION CENTER HAS APPEARED CLOSER TO
THE MAIN CONVECTION OVER THE LAST HOURS, EMERGING FROM THE ELONGATED
CIRCULATION AFFECTED BY THE UNCONDUCIVE ENVIRONMENT. MOREOVER, FROM
18Z, THE WIND HAS VEERED NORTH-NORTH-EASTERLY IN TAMATAVE. THIS
SUGGEST THAT CHALANE IS ABOUT TO OR IS ALREADY MAKING LANDFALL ON THE
MALAGASY COASTLINE, NEAR MAHAVELONA (FOULPOINTE) SOUTH OF STE MARIE
ISLAND.
THE CURRENT INTENSITY ESTIMATE IS BASED ON DVORAK ANALYSIS IN
AGREEMENT WITH AVAILABLE GROUND OBS DATA.

THIS "JUMP" MADE BY THE CIRCULATION CENTER ALLOWED THE SYSTEM TO MAKE
LANDFALL EARLIER THAN ANTICIPATED. THE MAIN DANGER ASSOCIATED WITH
THIS SYSTEM REMAIN THE HEAVY RAINS, WHICH CAN GENERATE FLASH FLOODS
AND WIDESPREAD FLOODS. THESE OCCUR EVEN FAR FROM THE CENTER IN THE
SOUTHERN SECTOR. THE INHABITANTS OF THE AREA ARE INVITED TO FOLLOW
THE EVOLUTION OF THIS SYSTEM WITH THE LOCAL AUTHORITIES.

EARLY NEXT WEEK, THE SYSTEM SHOULD COME BACK OVER OPEN WATERS IN THE
MOZAMBIQUE CHANNEL, WHERE ENVIRONMENTAL CONDITIONS APPEAR TO BE
FAVORABLE FOR REINTENSIFICATION (WEAK SHEAR, GOOD UPPER OUTLFOW,
LOW-LEVEL NORTHERLY AND TRADE WIND FLOW FUELING A GOOD SURFACE
CONVERGENCE AND HIGH OCEANIC HEAT CONTENT) AT FIRST. A LOW/MID LEVEL
RIDGE OCCUPYING THE SOUTHERN HALF OF THE CHANNEL SHOULD DRIVE A
GENERALLY WESTWARD MOTION OF THE STORM.
GIVEN THE INITIAL STATE OF THE SYSTEM, THE UNCERTAINTY UPON THE
LOCALISATION OF REENTRY OVER WATER AND THE LACK OF AGREEMENT ON THE
POSSIBILITY OF REINTENSIFICATION AMONG THE AVAILABLE GUIDANCE, THERE
IS NOT A STRONG DEGREE OF CONFIDENCE ASSOCIATED WITH THIS SECOND PART
OF THE FORECAST.=

>

Original Message :

WTIO24 FMEE 261832
SECURITE
NEAR GALE WARNING FOR METAREA VII
ISSUED BY METEO-FRANCE/TROPICAL CYCLONE CENTER/LA REUNION 26/12/2020
AT 1800 UTC.
WARNING NUMBER: 018/4 (SOUTH-WEST INDIAN OCEAN)
10 MINUTES AVERAGE WIND SPEED IN KNOTS (KT)
(WIND GUSTS AT SEA MAY BE ABOUT 40% STRONGER THAN THE AVERAGED WIND)
MINIMUM SEA LEVEL PRESSURE IN HECTOPASCAL (HPA)
(INDICATIVE FIGURE).

NEAR GALE WARNING
BEGINNING OF VALIDITY: SATURDAY 26/12/2020 AT 1800 UTC.

PHENOMENON: TROPICAL DEPRESSION 4 (CHALANE) 1000 HPA
POSITION: WITHIN 30 NM RADIUS OF POINT 17.6 S / 49.8 E
(SEVENTEEN DECIMAL SIX DEGREES SOUTH AND
FORTY NINE DECIMAL EIGHT DEGREES EAST) AT 1800 UTC
MOVEMENT: WEST 15 KT

THREAT AREAS:
SQUALLY WEATHER EXTENDING UP TO 200 NM FROM THE CENTER.

NEAR GALE FORCE WINDS 30 KT AND ROUGH TO VERY ROUGH SEAS EXTENDING UP
TO 80 NM IN THE NORTH-WESTERN AND SOUTH-EASTERN QUADRANTS, AND UP TO
100 NM IN THE SOUTH-WESTERN QUADRANT.
STRONG GUSTS UNDER SQUALLS.

FORECAST POSITION AND INTENSITY:
12H, VALID 2020/12/27 AT 06 UTC:
18.1 S / 47.2 E, MAX WIND = 25 KT, OVERLAND DEPRESSION

24H, VALID 2020/12/27 AT 18 UTC:
18.6 S / 45.1 E, MAX WIND = 20 KT, OVERLAND DEPRESSION

OTHER INFORMATION:
NIL.=

>

Original Message :

WTIO31 FMEE 261301
CMRS / CENTRE DES CYCLONES TROPICAUX DE LA REUNION
BULLETIN D'ANALYSE ET DE PREVISION CYCLONIQUE (SUD-OUEST OCEAN
INDIEN)

0.A NUMERO DU BULLETIN : 17/4/20202021
1.A DEPRESSION TROPICALE 4 (CHALANE)

2.A POSITION A 1200 UTC LE 26/12/2020 :
DANS UN RAYON DE 25 MN AUTOUR DU POINT 16.6 S / 51.7 E
(SEIZE DEGRES SIX SUD ET CINQUANTE UN DEGRES SEPT EST)
DEPLACEMENT: OUEST-SUD-OUEST 9 KT

3.A ANALYSE DE DVORAK: 2.0/2.0/D 0.5/12 H

4.A PRESSION AU CENTRE: 1000 HPA
5.A VENT MAX (MOYEN/10 MN): 30 KT
RAYON DES VENTS MAXIMAUX (RVM): NON RENSEIGNE

6.A EXTENSION DES VENTS PAR QUADRANTS (KM):
28 KT NE: 0 SE: 150 SO: 185 NO: 150

7.A COTE/DIAM PREMIERE ISOBARE FERMEE: 1005 HPA / 600 KM
8.A EXTENSION VERTICALE DE LA CIRCULATION CYCLONIQUE: MOYENNE

1.B PREVISIONS (EXTENSIONS DES VENTS FORTS EN KM):
12H: 27/12/2020 00 UTC: 17.2 S / 49.9 E, VENT MAX= 035 KT, TEMPETE
TROPICALE MODEREE
28 KT NE: 45 SE: 150 SO: 95 NO: 150
34 KT NE: 35 SE: 35 SO: 35 NO: 65

24H: 27/12/2020 12 UTC: 17.7 S / 47.9 E, VENT MAX= 030 KT, DEPRESSION
SUR TERRE
28 KT NE: 0 SE: 220 SO: 0 NO: 0

36H: 28/12/2020 00 UTC: 18.3 S / 45.8 E, VENT MAX= 020 KT, DEPRESSION
SUR TERRE

48H: 28/12/2020 12 UTC: 19.4 S / 43.5 E, VENT MAX= 025 KT, ZONE
PERTURBEE

60H: 29/12/2020 00 UTC: 19.8 S / 42.3 E, VENT MAX= 030 KT, DEPRESSION
TROPICALE
28 KT NE: 10 SE: 35 SO: 100 NO: 55

72H: 29/12/2020 12 UTC: 19.9 S / 40.6 E, VENT MAX= 040 KT, TEMPETE
TROPICALE MODEREE
28 KT NE: 45 SE: 130 SO: 100 NO: 75
34 KT NE: 35 SE: 120 SO: 55 NO: 65

2.B TENDANCE ULTERIEURE:
96H: 30/12/2020 12 UTC: 19.8 S / 35.0 E, VENT MAX= 055 KT, FORTE
TEMPETE TROPICALE
28 KT NE: 55 SE: 140 SO: 85 NO: 75
34 KT NE: 45 SE: 130 SO: 55 NO: 65
48 KT NE: 35 SE: 55 SO: 45 NO: 45

120H: 31/12/2020 12 UTC: 19.9 S / 30.3 E, VENT MAX= 020 KT,
DEPRESSION SUR TERRE

2.C COMMENTAIRES:
FT=CI=2.0

DEPUIS 06Z, L'ACTIVITE CONVECTIVE S'EST NETTEMENT RENFORCEE DANS LE
DEMI-CERCLE OUEST. LES IMAGES VISIBLES DE CETTE APRES MIDI MONTRENT
LA PRESENCE D'UNE NETTE CIRCULATION EN MOYENNE TROPOSPHERE ASSOCIE A
CETTE ACTIVITE CONVECTIVE. LE CENTRE DE SURFACE SEMBLE QUANT A LUI SE
SITUAIT PLUS AU NORD EN ACCORD AVEC LES DERNIERES IMAGES MICRO-ONDES
ET OBSERVATIONS DE LA STATION DE L'ILE SAINTE-MARIE SITUE A PRES DE
200KM A L'OUEST SUD OUEST DU CENTRE.

LA DEPRESSION CHALANE VA PROBABLEMENT ATTERIR EN FIN DE NUIT, DEBUT
DE MATINEE DE DEMAIN ENTRE LA PENINSULE DE MASOALA ET MAHAVELONA, AU
STADE MINIMAL DE TEMPETE TROPICALE MODEREE OU AU STADE DE DEPRESSION
TROPICALE. LE PRINCIPAL DANGER ASSOCIE A CE SYSTEME RESTE LES FORTES
PLUIES, POUVANT GENERER DES CRUES ECLAIRS ET DES INONDATIONS.
CELLES-CI POURRONT SE PRODUIRE MEME LOIN DU CENTRE DANS LE SECTEUR
SUD. LES HABITANTS DE LA ZONE SONT INVITES A SUIVRE L'EVOLUTION DE CE
SYSTEME AUPRES DES AUTORITES LOCALES. LA DEGRADATION DES CONDITIONS
METEOROLOGIQUES A D'AILLEURS DEJA COMMENCEE.

EN DEBUT DE SEMAINE PROCHAINE, LE SYSTEME DEVRAIT RESSORTIR DANS LE
CANAL DU MOZAMBIQUE OU LES CONDITIONS APPARAISSENT FAVORABLES A UNE
REINTENSIFICATION (CISAILLEMENT FAIBLE, BONNE DIVERGENCE D'ALTITUDE
COTE NORD, BONNE ALIMENTATION DE BASSES COUCHES COTE NORD ET COTE SUD
AVEC UNE POUSSEE D'ALIZE ET POTENTIEL OCEANIQUE TRES FAVORABLE) DANS
UN PREMIER TEMPS. UNE DORSALE DE BASSE ET MOYENNE TROPOSPHERE
OCCUPANT LE SUD DU CANAL, UN DEPLACEMENT EN DIRECTION GENERALE DE
L'OUEST RESTE ENVISAGE. COMPTE TENU DE L'ETAT INITIAL DE LA
CIRCULATION ET DU FAIT QU'IL N'Y A PAS UNANIMITE DANS LES GUIDANCES
NUMERIQUES POUR ENVISAGER UN CREUSEMENT DANS LE CANAL, CETTE PRESENTE
PREVISION RESTE ENCORE TRES INCERTAINE.=

>

Original Message :

WTIO30 FMEE 261301
RSMC / TROPICAL CYCLONE CENTER / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)

0.A WARNING NUMBER: 17/4/20202021
1.A TROPICAL DEPRESSION 4 (CHALANE)

2.A POSITION 2020/12/26 AT 1200 UTC:
WITHIN 25 NM RADIUS OF POINT 16.6 S / 51.7 E
(SIXTEEN DECIMAL SIX DEGREES SOUTH AND
FIFTY ONE DECIMAL SEVEN DEGREES EAST)
MOVEMENT: WEST-SOUTH-WEST 9 KT

3.A DVORAK ANALYSIS: 2.0/2.0/D 0.5/12 H

4.A CENTRAL PRESSURE: 1000 HPA
5.A MAX AVERAGE WIND SPEED (10 MN): 30 KT
RADIUS OF MAXIMUM WINDS (RMW): NIL

6.A EXTENSION OF WIND BY QUADRANTS (KM):
28 KT NE: 0 SE: 150 SW: 185 NW: 150

7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1005 HPA / 600 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: MEDIUM

1.B FORECASTS (WINDS RADII IN KM):
12H: 2020/12/27 00 UTC: 17.2 S / 49.9 E, VENT MAX= 035 KT, MODERATE
TROPICAL STORM
28 KT NE: 45 SE: 150 SW: 95 NW: 150
34 KT NE: 35 SE: 35 SW: 35 NW: 65

24H: 2020/12/27 12 UTC: 17.7 S / 47.9 E, VENT MAX= 030 KT, OVERLAND
DEPRESSION
28 KT NE: 0 SE: 220 SW: 0 NW: 0

36H: 2020/12/28 00 UTC: 18.3 S / 45.8 E, VENT MAX= 020 KT, OVERLAND
DEPRESSION

48H: 2020/12/28 12 UTC: 19.4 S / 43.5 E, VENT MAX= 025 KT, ZONE OF
DISTURBED WEATHER

60H: 2020/12/29 00 UTC: 19.8 S / 42.3 E, VENT MAX= 030 KT, TROPICAL
DEPRESSION
28 KT NE: 10 SE: 35 SW: 100 NW: 55

72H: 2020/12/29 12 UTC: 19.9 S / 40.6 E, VENT MAX= 040 KT, MODERATE
TROPICAL STORM
28 KT NE: 45 SE: 130 SW: 100 NW: 75
34 KT NE: 35 SE: 120 SW: 55 NW: 65

2.B LONGER-RANGE OUTLOOK:
96H: 2020/12/30 12 UTC: 19.8 S / 35.0 E, VENT MAX= 055 KT, SEVERE
TROPICAL STORM
28 KT NE: 55 SE: 140 SW: 85 NW: 75
34 KT NE: 45 SE: 130 SW: 55 NW: 65
48 KT NE: 35 SE: 55 SW: 45 NW: 45

120H: 2020/12/31 12 UTC: 19.9 S / 30.3 E, VENT MAX= 020 KT, OVERLAND
DEPRESSION

2.C ADDITIONAL INFORMATION:
FT=CI=2.0

SINCE 06Z, CONVECTIVE ACTIVITY STRONGLY INCREASED IN THE WESTERN
SEMI-CIRCLE. LAST VISIBLE IMAGES, SHOW THE EXISTENCE OF A DEFINED MID
LEVEL CIRCULATION RELATED TO THIS BURST. THE LOW LEVEL CENTER SEEMS
TO LINGERING A BIT NORTH IN AGREEMENT WITH LATEST MICROWAVE AND
GROUND DATA FROM SAINTE MARIE AIRPORT (AROUND 200KM WEST SOUTH WEST
OF THE CENTER)

CHALANE WILL PROBABLU LAND LATE NEXT NIGHT OR IN THE FOLLOWING EARLY
MORNING BETWEEN MASOALA PENINSULA AND MAHAVELONA AS A MODERATE
TROPICAL STORM OR A TROPICAL DEPRESSION. THE MAIN DANGER ASSOCIATED
WITH THIS SYSTEM IS THE HEAVY RAINS, WHICH CAN GENERATE FLASH FLOODS
AND WIDESPREAD FLOODS. THESE CAN OCCUR EVEN FAR FROM THE CENTER IN
THE SOUTHERN SECTOR. THE INHABITANTS OF THE AREA ARE INVITED TO
FOLLOW THE EVOLUTION OF THIS SYSTEM WITH THE LOCAL AUTHORITIES. THE
DETERIORATION OF THE METEOROLOGICAL CONDITIONS IN THE AREA HAS
ALREADY BEGUN.

EARLY NEXT WEEK, THE SYSTEM SHOULD COME BACK OVER OPEN WATERS IN THE
MOZAMBIQUE CHANNEL, WHERE ENVIRONMENTAL CONDITIONS APPEAR TO BE
FAVORABLE FOR REINTENSIFICATION (WEAK SHEAR, GOOD UPPER OUTLFOW,
LOW-LEVEL NORTHERLY AND TRADE WIND FLOW FUELING A GOOD SURFACE
CONVERGENCE AND HIGH OCEANIC HEAT CONTENT) AT FIRST. A LOW/MID LEVEL
RIDGE OCCUPYING THE SOUTHERN HALF OF THE CHANNEL SHOULD DRIVE A
GENERALLY WESTWARD MOTION OF THE STORM. GIVEN THE INITIAL STATE OF
THE SYSTEM AND THE FACT THAT THERE IS NO UNANIMITY IN THE NUMERICAL
GUIDANCE TO CONSIDER STRENGTHENING IN THE CHANNEL, THERE IS NOT A
STRONG DEGREE OF CONFIDENCE ASSOCIATED WITH THIS FORECASTY=

>

Original Message :

WTIO22 FMEE 261225
SECURITE
NEAR GALE WARNING FOR METAREA VII AND METAREA VIII (S)
ISSUED BY METEO-FRANCE/TROPICAL CYCLONE CENTER/LA REUNION 26/12/2020
AT 1200 UTC.
WARNING NUMBER: 017/4 (SOUTH-WEST INDIAN OCEAN)
10 MINUTES AVERAGE WIND SPEED IN KNOTS (KT)
(WIND GUSTS AT SEA MAY BE ABOUT 40% STRONGER THAN THE AVERAGED WIND)
MINIMUM SEA LEVEL PRESSURE IN HECTOPASCAL (HPA)
(INDICATIVE FIGURE).

NEAR GALE WARNING
BEGINNING OF VALIDITY: SATURDAY 26/12/2020 AT 1200 UTC.

PHENOMENON: TROPICAL DEPRESSION 4 (CHALANE) 1000 HPA
POSITION: WITHIN 25 NM RADIUS OF POINT 16.6 S / 51.7 E
(SIXTEEN DECIMAL SIX DEGREES SOUTH AND
FIFTY ONE DECIMAL SEVEN DEGREES EAST) AT 1200 UTC
MOVEMENT: WEST-SOUTH-WEST 9 KT

THREAT AREAS:
SQUALLY WEATHER EXTENDING UP TO 200 NM FROM THE CENTER.

NEAR GALE FORCE WINDS 30 KT AND ROUGH TO VERY ROUGH SEAS EXTENDING UP
TO 80 NM IN THE NORTH-WESTERN AND SOUTH-EASTERN QUADRANTS, AND UP TO
100 NM IN THE SOUTH-WESTERN QUADRANT.
STRONG GUSTS UNDER SQUALLS.

FORECAST POSITION AND INTENSITY:
12H, VALID 2020/12/27 AT 00 UTC:
17.2 S / 49.9 E, MAX WIND = 35 KT, MODERATE TROPICAL STORM
28 KT NE: 25 NM SE: 80 NM SW: 50 NM NW: 80 NM
34 KT NE: 20 NM SE: 20 NM SW: 20 NM NW: 35 NM

24H, VALID 2020/12/27 AT 12 UTC:
17.7 S / 47.9 E, MAX WIND = 30 KT, OVERLAND DEPRESSION
28 KT NE: 0 NM SE: 120 NM SW: 0 NM NW: 0 NM

OTHER INFORMATION:
NIL.=

>

Original Message :

WTIO31 FMEE 260723
CMRS / CENTRE DES CYCLONES TROPICAUX DE LA REUNION
BULLETIN D'ANALYSE ET DE PREVISION CYCLONIQUE (SUD-OUEST OCEAN
INDIEN)

0.A NUMERO DU BULLETIN : 16/4/20202021
1.A DEPRESSION TROPICALE 4 (CHALANE)

2.A POSITION A 0600 UTC LE 26/12/2020 :
DANS UN RAYON DE 25 MN AUTOUR DU POINT 16.1 S / 52.7 E
(SEIZE DEGRES UN SUD ET CINQUANTE DEUX DEGRES SEPT EST)
DEPLACEMENT: OUEST-SUD-OUEST 6 KT

3.A ANALYSE DE DVORAK: 2.0/2.0/D 0.5/6 H

4.A PRESSION AU CENTRE: 1001 HPA
5.A VENT MAX (MOYEN/10 MN): 30 KT
RAYON DES VENTS MAXIMAUX (RVM): NON RENSEIGNE

6.A EXTENSION DES VENTS PAR QUADRANTS (KM):
28 KT NE: 0 SE: 280 SO: 240 NO: 0

7.A COTE/DIAM PREMIERE ISOBARE FERMEE: 1008 HPA / 700 KM
8.A EXTENSION VERTICALE DE LA CIRCULATION CYCLONIQUE: MOYENNE

1.B PREVISIONS (EXTENSIONS DES VENTS FORTS EN KM):
12H: 26/12/2020 18 UTC: 16.6 S / 50.9 E, VENT MAX= 035 KT, TEMPETE
TROPICALE MODEREE
28 KT NE: 95 SE: 350 SO: 305 NO: 95
34 KT NE: 75 SE: 165 SO: 140 NO: 85

24H: 27/12/2020 06 UTC: 17.3 S / 48.8 E, VENT MAX= 035 KT, DEPRESSION
SUR TERRE
28 KT NE: 0 SE: 350 SO: 0 NO: 0
34 KT NE: 0 SE: 175 SO: 0 NO: 0

36H: 27/12/2020 18 UTC: 18.3 S / 46.1 E, VENT MAX= 020 KT, DEPRESSION
SUR TERRE

48H: 28/12/2020 06 UTC: 19.7 S / 44.4 E, VENT MAX= 020 KT, ZONE
PERTURBEE

60H: 28/12/2020 18 UTC: 19.9 S / 43.5 E, VENT MAX= 025 KT,
PERTURBATION TROPICALE

72H: 29/12/2020 06 UTC: 19.6 S / 41.8 E, VENT MAX= 035 KT, TEMPETE
TROPICALE MODEREE
28 KT NE: 195 SE: 350 SO: 305 NO: 110
34 KT NE: 165 SE: 215 SO: 140 NO: 95

2.B TENDANCE ULTERIEURE:
96H: 30/12/2020 06 UTC: 19.1 S / 37.1 E, VENT MAX= 055 KT, FORTE
TEMPETE TROPICALE
28 KT NE: 250 SE: 350 SO: 305 NO: 120
34 KT NE: 205 SE: 230 SO: 140 NO: 100
48 KT NE: 95 SE: 130 SO: 75 NO: 85

120H: 31/12/2020 06 UTC: 19.0 S / 32.0 E, VENT MAX= 020 KT,
DEPRESSION SUR TERRE

2.C COMMENTAIRES:
FT=CI=2.0

DEPUIS 00Z, APRES UNE IMPRESSION VISUELLE D'AMELIORATION LA
CONFIGURATION NUAGEUSE DE CHALANE NE SEMBLE PAS S'ETRE AMELIORE SUR
LES DERNIERS IMAGES. BIEN QU'UNE CIRCULATION FERMEE SOIT POSSIBLEMENT
PRESENTE EN MOYENNE TROPOSPHERE AU COEUR DE L'ACTIVITE CONVECTIVE
(SSMIS 0321Z), LES DERNIERS DONNES SEMBLENT INDIQUER QUE LE CENTRE DE
SURFACE RESTE EN MARGE NORD DE CETTE ZONE. LES DERNIERES IMAGES
VISIBLES AINSI QUE LA PASSE ASCAT DE 0603Z MONTRENT QUE LA
CIRCULATION EST TRES ALLONGEE EN DIRECTION DU NORD-EST.

MALGRE DES CONDITIONS ENVIRONMENTALES FAVORABLES EN ALTITUDE, CHALANE
SEMBLE PEINER A S'ORGANISER. LA PRESENTE PREVISION D'INTENSITE RESTE
DONC ASSEZ INCERTAINE A COURTE ECHEANCE. ELLE CONTINUE TOUTEFOIS
D'ENVISAGER UNE POSSIBLE RE-INTENSIFICATION AU STADE DE TEMPETE A
L'APPROCHE DES COTES MAIS CELA POURRAIT NE PAS ETRE LE CAS.

EN TERMES DE TRAJECTOIRE, PAS DE CHANGEMENT : LE SYSTEME SE DEPLACE
SUR LA FACADE NORD-OUEST DES HAUTES PRESSIONS SUBTROPICALES DE BASSE
A MOYENNE TROPOSPHERE, EN DIRECTION DE L'OUEST SUD-OUEST.

CHALANE DEVRAIT DONC TOUCHER AU COURS DES PROCHAINES 24H LA ZONE
ENTRE LA PENINSULE DE MASOALA ET MAHAVELONA). LE PRINCIPAL DANGER
ASSOCIE A CE SYSTEME RESTE LES FORTES PLUIES, POUVANT GENERER DES
CRUES ECLAIRS ET DES INONDATIONS. CELLES-CI POURRONT SE PRODUIRE MEME
LOIN DU CENTRE DANS LE SECTEUR SUD. LES HABITANTS DE LA ZONE SONT
INVITES A SUIVRE L'EVOLUTION DE CE SYSTEME AUPRES DES AUTORITES
LOCALES. LA DEGRADATION DES CONDITIONS METEOROLOGIQUES DANS LE
SECTEUR VA SE FAIRE AU FIL DE LA JOURNEE.

EN DEBUT DE SEMAINE PROCHAINE, LE SYSTEME DEVRAIT RESSORTIR DANS LE
CANAL DU MOZAMBIQUE OU LES CONDITIONS APPARAISSENT FAVORABLES A UNE
REINTENSIFICATION (CISAILLEMENT FAIBLE, BONNE DIVERGENCE D'ALTITUDE
COTE NORD, BONNE ALIMENTATION DE BASSES COUCHES COTE NORD ET
POTENTIEL OCEANIQUE TRES FAVORABLE) DANS UN PREMIER TEMPS. UNE
DORSALE DE BASSE ET MOYENNE TROPOSPHERE OCCUPANT LE SUD DU CANAL, UN
DEPLACEMENT EN DIRECTION GENERALE DE L'OUEST RESTE ENVISAGE. COMPTE
TENU DE L'ETAT INITIAL DE LA CIRCULATION ET DU FAIT QU'IL N'Y A PAS
UNANIMITE DANS LES GUIDANCES NUMERIQUES POUR ENVISAGER UN CREUSEMENT
DANS LE CANAL, CETTE PRESENTE PREVISION RESTE ENCORE ASSEZ
INCERTAINE.=

>

Original Message :

WTIO30 FMEE 260723
RSMC / TROPICAL CYCLONE CENTER / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)

0.A WARNING NUMBER: 16/4/20202021
1.A TROPICAL DEPRESSION 4 (CHALANE)

2.A POSITION 2020/12/26 AT 0600 UTC:
WITHIN 25 NM RADIUS OF POINT 16.1 S / 52.7 E
(SIXTEEN DECIMAL ONE DEGREES SOUTH AND
FIFTY TWO DECIMAL SEVEN DEGREES EAST)
MOVEMENT: WEST-SOUTH-WEST 6 KT

3.A DVORAK ANALYSIS: 2.0/2.0/D 0.5/6 H

4.A CENTRAL PRESSURE: 1001 HPA
5.A MAX AVERAGE WIND SPEED (10 MN): 30 KT
RADIUS OF MAXIMUM WINDS (RMW): NIL

6.A EXTENSION OF WIND BY QUADRANTS (KM):
28 KT NE: 0 SE: 280 SW: 240 NW: 0

7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1008 HPA / 700 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: MEDIUM

1.B FORECASTS (WINDS RADII IN KM):
12H: 2020/12/26 18 UTC: 16.6 S / 50.9 E, VENT MAX= 035 KT, MODERATE
TROPICAL STORM
28 KT NE: 95 SE: 350 SW: 305 NW: 95
34 KT NE: 75 SE: 165 SW: 140 NW: 85

24H: 2020/12/27 06 UTC: 17.3 S / 48.8 E, VENT MAX= 035 KT, OVERLAND
DEPRESSION
28 KT NE: 0 SE: 350 SW: 0 NW: 0
34 KT NE: 0 SE: 175 SW: 0 NW: 0

36H: 2020/12/27 18 UTC: 18.3 S / 46.1 E, VENT MAX= 020 KT, OVERLAND
DEPRESSION

48H: 2020/12/28 06 UTC: 19.7 S / 44.4 E, VENT MAX= 020 KT, ZONE OF
DISTURBED WEATHER

60H: 2020/12/28 18 UTC: 19.9 S / 43.5 E, VENT MAX= 025 KT, TROPICAL
DISTURBANCE

72H: 2020/12/29 06 UTC: 19.6 S / 41.8 E, VENT MAX= 035 KT, MODERATE
TROPICAL STORM
28 KT NE: 195 SE: 350 SW: 305 NW: 110
34 KT NE: 165 SE: 215 SW: 140 NW: 95

2.B LONGER-RANGE OUTLOOK:
96H: 2020/12/30 06 UTC: 19.1 S / 37.1 E, VENT MAX= 055 KT, SEVERE
TROPICAL STORM
28 KT NE: 250 SE: 350 SW: 305 NW: 120
34 KT NE: 205 SE: 230 SW: 140 NW: 100
48 KT NE: 95 SE: 130 SW: 75 NW: 85

120H: 2020/12/31 06 UTC: 19.0 S / 32.0 E, VENT MAX= 020 KT, OVERLAND
DEPRESSION

2.C ADDITIONAL INFORMATION:
FT=CI=2.0

SINCE 00Z, AFTER A VISUAL IMPRESSION OF IMPROVEMENT THE CLOUD
CONFIGURATION OF THE CHALANE DOES NOT SEEM TO HAVE IMPROVED ON THE
LAST IMAGES. ALTHOUGH A CLOSED CIRCULATION IS POSSIBLY PRESENT IN THE
MID TROPOSPHERE AT THE HEART OF THE CONVECTIVE ACTIVITY (0321Z SSMIS)
, THE LATEST DATA SEEMS TO INDICATE THAT THE SURFACE CENTER REMAINS
AT THE NORTHERN MARGIN OF THIS AREA. THE LAST VISIBLE IMAGES AS WELL
AS THE 0603Z ASCAT SWATH SHOW THAT THE CIRCULATION IS VERY ELONGATED
TOWARDS THE NORTHEAST.

CHALANE INNER CORE ORGANISATION HARDLY BENEFITS FROM THE GOOD GOOD
ENVIRONMENTAL CONDITIONS IN UPPER LEVELS. THIS INTENSITY FORECAST IS
THUS ASSOCIATED TO RELATIVELY HIGH UNCERTAINTY. A POSSIBLE
RE-INTENSIFICATION AS A TROPICAL STORM CONTINUE TO BE REFLECTED BUT
IT MAY NOT HAPPEN.

NO CHANGE IN TERMS OF TRACK FORECAST : THE SYSTEM IS MOVING ON THE
NORTH-WESTERN EDGE OF THE SUBTROPICAL LOW/MID-LEVEL HIGH PRESSURES.

CHALANE SHOULD THEREFORE MADE LANDFALL DURING THE NEXT 24 HOURS
BETWEEN MASOALA PENINSULA AND MAHAVELONA. THE MAIN DANGER ASSOCIATED
WITH THIS SYSTEM IS THE HEAVY RAINS, WHICH CAN GENERATE FLASH FLOODS
AND WIDESPREAD FLOODS. THESE CAN OCCUR EVEN FAR FROM THE CENTER IN
THE SOUTHERN SECTOR. THE INHABITANTS OF THE AREA ARE INVITED TO
FOLLOW THE EVOLUTION OF THIS SYSTEM WITH THE LOCAL AUTHORITIES. THE
DETERIORATION OF THE METEOROLOGICAL CONDITIONS IN THE AREA WILL OCCUR
DURING THE COURSE OF THE DAY.

EARLY NEXT WEEK, THE SYSTEM SHOULD TRACK BACK OVER OPEN WATERS IN THE
MOZAMBIQUE CHANNEL, WHERE ENVIRONMENTAL CONDITIONS APPEAR TO BE
FAVORABLE FOR REINTENSIFICATION (WEAK SHEAR, GOOD UPPER OUTLFOW,
LOW-LEVEL NORTHERLY FLOW FUELING A GOOD SURFACE CONVERGENCE AND HIGH
OCEANIC HEAT CONTENT) AT FIRST. A LOW/MID LEVEL RIDGE OCCUPYING THE
SOUTHERN HALF OF THE CHANNEL SHOULD DRIVE A GENERALLY WESTWARD MOTION
OF THE STORM. GIVEN THE INITIAL STATE OF THE SYSTEM AND THE FACT THAT
THERE IS NO UNANIMITY IN THE NUMERICAL GUIDANCE TO CONSIDER
STRENGTHENING IN THE CHANNEL, THERE IS NOT A STRONG DEGREE OF
CONFIDENCE ASSOCIATED WITH THIS FORECAST.=

>

Original Message :

WTIO22 FMEE 260626
SECURITE
NEAR GALE WARNING FOR METAREA VII AND METAREA VIII (S)
ISSUED BY METEO-FRANCE/TROPICAL CYCLONE CENTER/LA REUNION 26/12/2020
AT 0600 UTC.
WARNING NUMBER: 016/4 (SOUTH-WEST INDIAN OCEAN)
10 MINUTES AVERAGE WIND SPEED IN KNOTS (KT)
(WIND GUSTS AT SEA MAY BE ABOUT 40% STRONGER THAN THE AVERAGED WIND)
MINIMUM SEA LEVEL PRESSURE IN HECTOPASCAL (HPA)
(INDICATIVE FIGURE).

NEAR GALE WARNING
BEGINNING OF VALIDITY: SATURDAY 26/12/2020 AT 0600 UTC.

PHENOMENON: TROPICAL DEPRESSION 4 (CHALANE) 1001 HPA
POSITION: WITHIN 25 NM RADIUS OF POINT 16.1 S / 52.7 E
(SIXTEEN DECIMAL ONE DEGREES SOUTH AND
FIFTY TWO DECIMAL SEVEN DEGREES EAST) AT 0600 UTC
MOVEMENT: WEST-SOUTH-WEST 6 KT

THREAT AREAS:
SQUALLY WEATHER EXTENDING UP TO 200 NM FROM THE CENTER IN THE
SOUTHERN SEMI-CIRCLE.

NEAR GALE FORCE WINDS 30 KT AND ROUGH TO VERY ROUGH SEAS EXTENDING UP
TO 130 NM IN THE SOUTH-WESTERN QUADRANT AND UP TO 150 NM IN THE
SOUTH-EASTERN QUADRANT.
STRONG GUSTS UNDER SQUALLS.

FORECAST POSITION AND INTENSITY:
12H, VALID 2020/12/26 AT 18 UTC:
16.6 S / 50.9 E, MAX WIND = 35 KT, MODERATE TROPICAL STORM
28 KT NE: 50 NM SE: 190 NM SW: 165 NM NW: 50 NM
34 KT NE: 40 NM SE: 90 NM SW: 75 NM NW: 45 NM

24H, VALID 2020/12/27 AT 06 UTC:
17.3 S / 48.8 E, MAX WIND = 35 KT, OVERLAND DEPRESSION
28 KT NE: 0 NM SE: 190 NM SW: 0 NM NW: 0 NM
34 KT NE: 0 NM SE: 95 NM SW: 0 NM NW: 0 NM

OTHER INFORMATION:
NIL.=

>

Original Message :

WTIO31 FMEE 260048
CMRS / CENTRE DES CYCLONES TROPICAUX DE LA REUNION
BULLETIN D'ANALYSE ET DE PREVISION CYCLONIQUE (SUD-OUEST OCEAN
INDIEN)

0.A NUMERO DU BULLETIN : 15/4/20202021
1.A DEPRESSION TROPICALE 4 (CHALANE)

2.A POSITION A 0000 UTC LE 26/12/2020 :
DANS UN RAYON DE 20 MN AUTOUR DU POINT 15.8 S / 53.5 E
(QUINZE DEGRES HUIT SUD ET CINQUANTE TROIS DEGRES CINQ EST)
DEPLACEMENT: OUEST-NORD-OUEST 3 KT

3.A ANALYSE DE DVORAK: 1.5/2.0/W 1.5/24 H

4.A PRESSION AU CENTRE: 1001 HPA
5.A VENT MAX (MOYEN/10 MN): 30 KT
RAYON DES VENTS MAXIMAUX (RVM): NON RENSEIGNE

6.A EXTENSION DES VENTS PAR QUADRANTS (KM):
28 KT NE: 0 SE: 370 SO: 0 NO: 0

7.A COTE/DIAM PREMIERE ISOBARE FERMEE: 1007 HPA / 1100 KM
8.A EXTENSION VERTICALE DE LA CIRCULATION CYCLONIQUE: MOYENNE

1.B PREVISIONS (EXTENSIONS DES VENTS FORTS EN KM):
12H: 26/12/2020 12 UTC: 16.2 S / 51.6 E, VENT MAX= 030 KT, DEPRESSION
TROPICALE
28 KT NE: 0 SE: 185 SO: 110 NO: 85

24H: 27/12/2020 00 UTC: 16.7 S / 49.7 E, VENT MAX= 035 KT, TEMPETE
TROPICALE MODEREE
28 KT NE: 45 SE: 100 SO: 35 NO: 0
34 KT NE: 35 SE: 55 SO: 0 NO: 0

36H: 27/12/2020 12 UTC: 17.5 S / 47.1 E, VENT MAX= 020 KT, DEPRESSION
SUR TERRE

48H: 28/12/2020 00 UTC: 18.8 S / 44.7 E, VENT MAX= 020 KT, DEPRESSION
SUR TERRE

60H: 28/12/2020 12 UTC: 19.6 S / 43.3 E, VENT MAX= 025 KT, ZONE
PERTURBEE

72H: 29/12/2020 00 UTC: 19.1 S / 42.3 E, VENT MAX= 030 KT, DEPRESSION
TROPICALE
28 KT NE: 110 SE: 165 SO: 0 NO: 100

2.B TENDANCE ULTERIEURE:
96H: 30/12/2020 00 UTC: 18.3 S / 38.1 E, VENT MAX= 050 KT, FORTE
TEMPETE TROPICALE
28 KT NE: 75 SE: 230 SO: 110 NO: 100
34 KT NE: 65 SE: 110 SO: 100 NO: 95
48 KT NE: 55 SE: 65 SO: 65 NO: 65

120H: 31/12/2020 00 UTC: 17.8 S / 33.1 E, VENT MAX= 020 KT,
DEPRESSION SUR TERRE

2.C COMMENTAIRES:
FT=1.5;CI=2.0

L'IMAGERIE PROCHE-INFRAROUGE MSG-1 A PERMIS DE LOCALISER DURANT LA
NUIT LE CENTRE DE BASSES COUCHES A ENVIRON 60 MN AU NORD DE LA
CONVECTION PROFONDE. LA PASS SCATSAT DE 1630Z, NON RECUE AVANT LE
BULLETIN PRECEDENT, NE MONTRE DES VENTS A 30 KT QUE DANS LE QUADRANT
SUD-EST. L'INTENSITE FINALE EST MAINTENUE A 30 KT.
RECEMMENT LE CENTRE A NETTEMENT RALENTIT SA PROGRESSION VERS
L'OUEST-NORD-OUEST, ALORS QU'UNE PUISSANTE BOUFFEE CONVECTIVE SE MET
EN PLACE AU SUD ASSOCIEE A UNE BELLE DIVERGENCE D'ALTITUDE. IL N'EST
PAS IMPOSSIBLE QU'UN NOUVEAU CENTRE SE REFORME PLUS AU SUD AU SEIN DE
LA CONVECTION PROFONDE AU COURS DES PROCHAINES HEURES.

LE CISAILLEMENT DEVRAIT RESTER ASSEZ FAIBLE MALGRE UNE PETITE
CONTRAINTE DE SECTEUR EST. LE SYSTEME DEVRAIT MAINTENANT POUVOIR
EVOLUER DANS DES CONDITIONS ENVIRONNEMENTALES PLUS HUMIDES EN MOYENNE
TROPOSPHERE ET DONC PLUS FAVORABLES A SON DEVELOPPEMENT A L'APPROCHE
DES COTES MALGACHES. CEPENDANT, LES GUIDANCES D'INTENSITE DISPONIBLES
RESTENT GLOBALEMENT MITIGEES QUAND A LA CAPACITE DE CHALANE A
S'INTENSIFIER DE FACON SIGNIFICATIVE AVANT SON ATTERRISSAGE. LA
PRESENTE PREVISION D'INTENSITE RESTE DONC ASSEZ INCERTAINE. ELLE
CONTINUE TOUTEFOIS D'ENVISAGER UNE POSSIBLE RE-INTENSIFICATION AU
STADE DE TEMPETE A L'APPROCHE DES COTES.

EN TERMES DE TRAJECTOIRE, PAS DE CHANGEMENT : LE SYSTEME SE DEPLACE
SUR LA FACADE NORD-OUEST DES HAUTES PRESSIONS SUBTROPICALES DE BASSE
A MOYENNE TROPOSPHERE.

CHALANE DEVRAIT DONC TOUCHER AU COURS DES PROCHAINES 24H LA ZONE
ENTRE LE CAP EST AU NORD ET TAMATAVE AU SUD. LE PRINCIPAL DANGER
ASSOCIE A CE SYSTEME SONT LES FORTES PLUIES, POUVANT GENERER DES
CRUES ECLAIRS ET DES INONDATIONS. CELLES-CI POURRONT SE PRODUIRE MEME
LOIN DU CENTRE DANS LE SECTEUR SUD. LES HABITANTS DE LA ZONE SONT
INVITES A SUIVRE L'EVOLUTION DE CE SYSTEME AUPRES DES AUTORITES
LOCALES. LA DEGRADATION DES CONDITIONS METEOROLOGIQUES DANS LE
SECTEUR VA SE FAIRE AU FIL DE LA JOURNEE.

EN DA BUT DE SEMAINE PROCHAINE, LE SYSTEME DEVRAIT RESSORTIR DANS LE
CANAL DU MOZAMBIQUE OU LES CONDITIONS APPARAISSENT FAVORABLES A UNE
REINTENSIFICATION (CISAILLEMENT FAIBLE, BONNE DIVERGENCE D'ALTITUDE
COTE NORD, BONNE ALIMENTATION DE BASSES COUCHES COTE NORD ET
POTENTIEL OCEANIQUE TRES FAVORABLE) DANS UN PREMIER TEMPS. UNE
DORSALE DE BASSE ET MOYENNE TROPOSPHERE OCCUPANT LE SUD DU CANAL, UN
DEPLACEMENT EN DIRECTION GENERALE DE L'OUEST RESTE ENVISAGE. COMPTE
TENU DE L'ETAT INITIAL DE LA CIRCULATION ET DU FAIT QU'IL N'Y A PAS
UNANIMITE DANS LES GUIDANCES NUMERIQUES POUR ENVISAGER UN CREUSEMENT
DANS LE CANAL, IL N'Y A PAS UN DEGRE DE CONFIANCE FORT ASSOCIE A
CETTE PREVISION.=

>

Original Message :

WTIO30 FMEE 260048
RSMC / TROPICAL CYCLONE CENTER / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)

0.A WARNING NUMBER: 15/4/20202021
1.A TROPICAL DEPRESSION 4 (CHALANE)

2.A POSITION 2020/12/26 AT 0000 UTC:
WITHIN 20 NM RADIUS OF POINT 15.8 S / 53.5 E
(FIFTEEN DECIMAL EIGHT DEGREES SOUTH AND
FIFTY THREE DECIMAL FIVE DEGREES EAST)
MOVEMENT: WEST-NORTH-WEST 3 KT

3.A DVORAK ANALYSIS: 1.5/2.0/W 1.5/24 H

4.A CENTRAL PRESSURE: 1001 HPA
5.A MAX AVERAGE WIND SPEED (10 MN): 30 KT
RADIUS OF MAXIMUM WINDS (RMW): NIL

6.A EXTENSION OF WIND BY QUADRANTS (KM):
28 KT NE: 0 SE: 370 SW: 0 NW: 0

7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1007 HPA / 1100 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: MEDIUM

1.B FORECASTS (WINDS RADII IN KM):
12H: 2020/12/26 12 UTC: 16.2 S / 51.6 E, VENT MAX= 030 KT, TROPICAL
DEPRESSION
28 KT NE: 0 SE: 185 SW: 110 NW: 85

24H: 2020/12/27 00 UTC: 16.7 S / 49.7 E, VENT MAX= 035 KT, MODERATE
TROPICAL STORM
28 KT NE: 45 SE: 100 SW: 35 NW: 0
34 KT NE: 35 SE: 55 SW: 0 NW: 0

36H: 2020/12/27 12 UTC: 17.5 S / 47.1 E, VENT MAX= 020 KT, OVERLAND
DEPRESSION

48H: 2020/12/28 00 UTC: 18.8 S / 44.7 E, VENT MAX= 020 KT, OVERLAND
DEPRESSION

60H: 2020/12/28 12 UTC: 19.6 S / 43.3 E, VENT MAX= 025 KT, ZONE OF
DISTURBED WEATHER

72H: 2020/12/29 00 UTC: 19.1 S / 42.3 E, VENT MAX= 030 KT, TROPICAL
DEPRESSION
28 KT NE: 110 SE: 165 SW: 0 NW: 100

2.B LONGER-RANGE OUTLOOK:
96H: 2020/12/30 00 UTC: 18.3 S / 38.1 E, VENT MAX= 050 KT, SEVERE
TROPICAL STORM
28 KT NE: 75 SE: 230 SW: 110 NW: 100
34 KT NE: 65 SE: 110 SW: 100 NW: 95
48 KT NE: 55 SE: 65 SW: 65 NW: 65

120H: 2020/12/31 00 UTC: 17.8 S / 33.1 E, VENT MAX= 020 KT, OVERLAND
DEPRESSION

2.C ADDITIONAL INFORMATION:
FT=1.5;CI=2.0

THE NEAR-INFRARED MSG-1 IMAGERY ALLOWED TO LOCATE FAIRLY WELL THE LOW
LEVELS CENTER DURING THE NIGHT. IT WAS LOCATED ABOUT 60 MN NORTH OF
THE DEEP CONVECTION. THE SCATSAT PASS OF 1630Z, NOT RECEIVED BEFORE
THE PREVIOUS BULLETIN, SHOWS WINDS OF 30 KT ONLY IN THE SOUTHEAST
QUADRANT. THE FINAL INTENSITY IS MAINTAINED AT 30 KT.
RECENTLY THE CENTER HAS CLEARLY SLOWED DOWN ITS PROGRESSION TOWARDS
THE WEST-NORTHWEST, WHILE A POWERFUL CONVECTIVE BURST IS SET UP IN
THE SOUTH ASSOCIATED WITH SOME WELL DEFINED UPPER LEVELS OUTFLOW. IT
IS NOT IMPOSSIBLE THAT A NEW CENTER WILL REFORM FURTHER SOUTH WITHIN
THE DEEP CONVECTION OVER THE NEXT FEW HOURS.

THE SHEAR SHOULD REMAIN FAIRLY LOW DESPITE A SMALL EASTERLY
CONSTRAINT. THE SYSTEM SHOULD NOW BE ABLE TO EVOLVE IN MOISTER
ENVIRONMENTAL CONDITIONS IN THE MIDDLE TROPOSPHERE AND THEREFORE MORE
FAVORABLE TO ITS DEVELOPMENT AS IT APPROACHES THE MALAGASY COAST..
HOWEVER, INTENSITY GUIDANCES ARE NOT KEEN ON SUGGESTING AN
INTENSIFICATION OF CHALANE PRIOR TO ITS LANDFALL. THIS INTENSITY
FORECAST IS THUS ASSOCIATED TO RELATIVELY HIGH UNCERTAINTY. A
POSSIBLE RE-INTENSIFICATION AS A TROPICAL STORM CONTINUE TO BE
REFLECTED.

NO CHANGE IN TERMS OF TRACK FORECAST : THE SYSTEM IS MOVING ON THE
NORTH-WESTERN EDGE OF THE SUBTROPICAL LOW/MID-LEVEL HIGH PRESSURES.

CHALANE SHOULD THEREFORE MADE LANDFALL DURING THE NEXT 24 HOURS
BETWEEN CAP EAST TO THE NORTH AND TAMATAVE TO THE SOUTH. THE MAIN
DANGER ASSOCIATED WITH THIS SYSTEM IS THE HEAVY RAINS, WHICH CAN
GENERATE FLASH FLOODS AND WIDESPREAD FLOODS. THESE CAN OCCUR EVEN FAR
FROM THE CENTER IN THE SOUTHERN SECTOR. THE INHABITANTS OF THE AREA
ARE INVITED TO FOLLOW THE EVOLUTION OF THIS SYSTEM WITH THE LOCAL
AUTHORITIES. THE DETERIORATION OF THE METEOROLOGICAL CONDITIONS IN
THE AREA WILL OCCUR DURING THE COURSE OF THE DAY.

EARLY NEXT WEEK, THE SYSTEM SHOULD TRACK BACK OVER OPEN WATERS IN THE
MOZAMBIQUE CHANNEL, WHERE ENVIRONMENTAL CONDITIONS APPEAR TO BE
FAVORABLE FOR REINTENSIFICATION (WEAK SHEAR, GOOD UPPER OUTLFOW,
LOW-LEVEL NORTHERLY FLOW FUELING A GOOD SURFACE CONVERGENCE AND HIGH
OCEANIC HEAT CONTENT) AT FIRST. A LOW/MID LEVEL RIDGE OCCUPYING THE
SOUTHERN HALF OF THE CHANNEL SHOULD DRIVE A GENERALLY WESTWARD MOTION
OF THE STORM. GIVEN THE INITIAL STATE OF THE SYSTEM AND THE FACT THAT
THERE IS NO UNANIMITY IN THE NUMERICAL GUIDANCE TO CONSIDER
STRENGTHENING IN THE CHANNEL, THERE IS NOT A STRONG DEGREE OF
CONFIDENCE ASSOCIATED WITH THIS FORECAST.=

>

Original Message :

WTIO22 FMEE 260036
SECURITE
NEAR GALE WARNING FOR METAREA VII AND METAREA VIII (S)
ISSUED BY METEO-FRANCE/TROPICAL CYCLONE CENTER/LA REUNION 26/12/2020
AT 0000 UTC.
WARNING NUMBER: 015/4 (SOUTH-WEST INDIAN OCEAN)
10 MINUTES AVERAGE WIND SPEED IN KNOTS (KT)
(WIND GUSTS AT SEA MAY BE ABOUT 40% STRONGER THAN THE AVERAGED WIND)
MINIMUM SEA LEVEL PRESSURE IN HECTOPASCAL (HPA)
(INDICATIVE FIGURE).

NEAR GALE WARNING
BEGINNING OF VALIDITY: SATURDAY 26/12/2020 AT 0000 UTC.

PHENOMENON: TROPICAL DEPRESSION 4 (CHALANE) 1001 HPA
POSITION: WITHIN 20 NM RADIUS OF POINT 15.8 S / 53.5 E
(FIFTEEN DECIMAL EIGHT DEGREES SOUTH AND
FIFTY THREE DECIMAL FIVE DEGREES EAST) AT 0000 UTC
MOVEMENT: WEST-NORTH-WEST 3 KT

THREAT AREAS:
SQUALLY WEATHER EXTENDING UP TO 200 NM FROM THE CENTER IN THE
SOUTHERN SEMI-CIRCLE.

NEAR GALE FORCE WINDS 30 KT AND ROUGH TO VERY ROUGH SEAS EXTENDING UP
TO 200 NM IN THE SOUTH-EASTERN QUADRANT.
STRONG GUSTS UNDER SQUALLS.

FORECAST POSITION AND INTENSITY:
12H, VALID 2020/12/26 AT 12 UTC:
16.2 S / 51.6 E, MAX WIND = 30 KT, TROPICAL DEPRESSION
28 KT NE: 0 NM SE: 100 NM SW: 60 NM NW: 45 NM

24H, VALID 2020/12/27 AT 00 UTC:
16.7 S / 49.7 E, MAX WIND = 35 KT, MODERATE TROPICAL STORM
28 KT NE: 25 NM SE: 55 NM SW: 20 NM NW: 0 NM
34 KT NE: 20 NM SE: 30 NM SW: 0 NM NW: 0 NM

OTHER INFORMATION:
NIL.=

>

Original Message :

WTIO31 FMEE 251849
CMRS / CENTRE DES CYCLONES TROPICAUX DE LA REUNION
BULLETIN D'ANALYSE ET DE PREVISION CYCLONIQUE (SUD-OUEST OCEAN
INDIEN)

0.A NUMERO DU BULLETIN : 14/4/20202021
1.A DEPRESSION TROPICALE 4 (CHALANE)

2.A POSITION A 1800 UTC LE 25/12/2020 :
DANS UN RAYON DE 30 MN AUTOUR DU POINT 16.0 S / 53.7 E
(SEIZE DEGRES ZERO SUD ET CINQUANTE TROIS DEGRES SEPT EST)
DEPLACEMENT: OUEST 11 KT

3.A ANALYSE DE DVORAK: 1.5/2.5/W 1.0/24 H

4.A PRESSION AU CENTRE: 1001 HPA
5.A VENT MAX (MOYEN/10 MN): 30 KT
RAYON DES VENTS MAXIMAUX (RVM): NON RENSEIGNE

6.A EXTENSION DES VENTS PAR QUADRANTS (KM):
28 KT NE: 0 SE: 350 SO: 185 NO: 0

7.A COTE/DIAM PREMIERE ISOBARE FERMEE: 1006 HPA / 1000 KM
8.A EXTENSION VERTICALE DE LA CIRCULATION CYCLONIQUE: MOYENNE

1.B PREVISIONS (EXTENSIONS DES VENTS FORTS EN KM):
12H: 26/12/2020 06 UTC: 16.0 S / 52.0 E, VENT MAX= 030 KT, DEPRESSION
TROPICALE
28 KT NE: 0 SE: 175 SO: 95 NO: 0

24H: 26/12/2020 18 UTC: 16.1 S / 50.3 E, VENT MAX= 035 KT, TEMPETE
TROPICALE MODEREE
28 KT NE: 65 SE: 165 SO: 95 NO: 75
34 KT NE: 45 SE: 45 SO: 45 NO: 45

36H: 27/12/2020 06 UTC: 16.6 S / 48.8 E, VENT MAX= 025 KT, DEPRESSION
SUR TERRE

48H: 27/12/2020 18 UTC: 17.7 S / 46.8 E, VENT MAX= 020 KT, DEPRESSION
SUR TERRE

60H: 28/12/2020 06 UTC: 19.4 S / 44.4 E, VENT MAX= 025 KT,
PERTURBATION TROPICALE

72H: 28/12/2020 18 UTC: 19.7 S / 42.9 E, VENT MAX= 030 KT, DEPRESSION
TROPICALE
28 KT NE: 120 SE: 120 SO: 85 NO: 55

2.B TENDANCE ULTERIEURE:
96H: 29/12/2020 18 UTC: 19.4 S / 39.1 E, VENT MAX= 045 KT, TEMPETE
TROPICALE MODEREE
28 KT NE: 285 SE: 390 SO: 280 NO: 155
34 KT NE: 220 SE: 240 SO: 150 NO: 85

120H: 30/12/2020 18 UTC: 18.9 S / 34.6 E, VENT MAX= 030 KT,
DEPRESSION SUR TERRE
28 KT NE: 345 SE: 390 SO: 0 NO: 0

2.C COMMENTAIRES:
FT=1.5;CI=2.5

CHALANE EST PASSE VERS 14 UTC A PROXIMITE SUD DE TROMELIN OU LA
PRESSION (CORRIGEE DE LA MAREE BAROMETRIQUE) N'EST PAS DESCENDUE
EN-DESSOUS DE 1001.5 HPA (AVEC DES VENTS FAIBLES A 8 KT) PERMETTANT
D'ESTIMER DE FACON FIABLE LA PRESSION CENTRALE. LA CONFIGURATION
NUAGEUSE S'EST DEGRADEE AU COURS DES DERNIERES 24H AVEC UN CENTRE
PLUS ELOIGNE DE LA MASSE CONVECTIVE. EN CONSEQUENCE, LE SYSTEME A ETE
RETROGRADE AU STADE DE DEPRESSION TROPICALE.

LE CISAILLEMENT DEVRAIT RESTER ASSEZ FAIBLE MALGRE UNE PETITE
CONTRAINTE DE SECTEUR EST. L'ENVIRONNEMENT DE MOYENNE TROPOSPHERE
RESTE TOUTEFOIS SEC, NOTAMMENT AU NORD-OUEST DU SYSTEME. A COURT
TERME, LE SYSTEME DEVRAIT POUVOIR EVOLUER DANS DES CONDITIONS
ENVIRONNEMENTALES PLUS HUMIDES ET DONC PLUS FAVORABLES A SON
DEVELOPPEMENT A L'APPROCHE DES COTES MALGACHES. CEPENDANT, LES
GUIDANCES D'INTENSITE DISPONIBLES RESTENT GLOBALEMENT MITIGEES QUAND
A LA CAPACITE DE CHALANE A S'INTENSIFIER DE FACON SIGNIFICATIVE AVANT
SON ATTERRISSAGE. LA PRESENTE PREVISION D'INTENSITE RESTE DONC ASSEZ
INCERTAINE. ELLE CONTINUE TOUTEFOIS D'ENVISAGER UNE POSSIBLE
RE-INTENSIFICATION AU STADE DE TEMPETE A L'APPROCHE DES COTES.

EN TERMES DE TRAJECTOIRE, PAS DE CHANGEMENT : LE SYSTEME SE DEPLACE
SUR LA FACADE NORD-OUEST DES HAUTES PRESSIONS SUBTROPICALES DE BASSE
A MOYENNE TROPOSPHERE.

CHALANE DEVRAIT DONC TOUCHER D'ICI DEMAIN SOIR LA ZONE CAP EST OU DE
L'ILE SAINTE-MARIE. LE PRINCIPAL DANGER ASSOCIEE A CE SYSTEME SERONT
LES FORTES PLUIES, ASSOCIEES A DES CRUES ECLAIRS NOTAMMENT ET QUI
POURRONT SE PRODUIRE MEME LOIN DU CENTRE DANS LE SECTEUR SUD. LES
HABITANTS DE LA ZONE SONT INVITES A SUIVRE L'EVOLUTION DE CE SYSTEME
AUPRES DES AUTORITES LOCALES. LA DEGRADATION DES CONDITIONS
METEOROLOGIQUES DANS LE SECTEUR POURRAIT COMMENCER EN FIN DE NUIT OU
DEMAIN MATIN.

EN DA BUT DE SEMAINE PROCHAINE, LE SYSTEME DEVRAIT RESSORTIR DANS LE
CANAL DU MOZAMBIQUE OU LES CONDITIONS APPARAISSENT FAVORABLES A UNE
REINTENSIFICATION (CISAILLEMENT FAIBLE, BONNE DIVERGENCE D'ALTITUDE
COTE NORD, BONNE ALIMENTATION DE BASSES COUCHES COTE NORD ET
POTENTIEL OCEANIQUE TRES FAVORABLE) DANS UN PREMIER TEMPS. UNE
DORSALE DE BASSE ET MOYENNE TROPOSPHERE OCCUPANT LE SUD DU CANAL, UN
DEPLACEMENT EN DIRECTION GENERALE DE L'OUEST RESTE ENVISAGE. EN FIN
DE PA RIODE, UNE HAUSSE DU CISAILLEMENT POURRAIT RALENTIR LE RYTHME
DE RENFORCEMENT DU SYSTEME.=

>

Original Message :

WTIO30 FMEE 251849
RSMC / TROPICAL CYCLONE CENTER / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)

0.A WARNING NUMBER: 14/4/20202021
1.A TROPICAL DEPRESSION 4 (CHALANE)

2.A POSITION 2020/12/25 AT 1800 UTC:
WITHIN 30 NM RADIUS OF POINT 16.0 S / 53.7 E
(SIXTEEN DECIMAL ZERO DEGREES SOUTH AND
FIFTY THREE DECIMAL SEVEN DEGREES EAST)
MOVEMENT: WEST 11 KT

3.A DVORAK ANALYSIS: 1.5/2.5/W 1.0/24 H

4.A CENTRAL PRESSURE: 1001 HPA
5.A MAX AVERAGE WIND SPEED (10 MN): 30 KT
RADIUS OF MAXIMUM WINDS (RMW): NIL

6.A EXTENSION OF WIND BY QUADRANTS (KM):
28 KT NE: 0 SE: 350 SW: 185 NW: 0

7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1006 HPA / 1000 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: MEDIUM

1.B FORECASTS (WINDS RADII IN KM):
12H: 2020/12/26 06 UTC: 16.0 S / 52.0 E, VENT MAX= 030 KT, TROPICAL
DEPRESSION
28 KT NE: 0 SE: 175 SW: 95 NW: 0

24H: 2020/12/26 18 UTC: 16.1 S / 50.3 E, VENT MAX= 035 KT, MODERATE
TROPICAL STORM
28 KT NE: 65 SE: 165 SW: 95 NW: 75
34 KT NE: 45 SE: 45 SW: 45 NW: 45

36H: 2020/12/27 06 UTC: 16.6 S / 48.8 E, VENT MAX= 025 KT, OVERLAND
DEPRESSION

48H: 2020/12/27 18 UTC: 17.7 S / 46.8 E, VENT MAX= 020 KT, OVERLAND
DEPRESSION

60H: 2020/12/28 06 UTC: 19.4 S / 44.4 E, VENT MAX= 025 KT, TROPICAL
DISTURBANCE

72H: 2020/12/28 18 UTC: 19.7 S / 42.9 E, VENT MAX= 030 KT, TROPICAL
DEPRESSION
28 KT NE: 120 SE: 120 SW: 85 NW: 55

2.B LONGER-RANGE OUTLOOK:
96H: 2020/12/29 18 UTC: 19.4 S / 39.1 E, VENT MAX= 045 KT, MODERATE
TROPICAL STORM
28 KT NE: 285 SE: 390 SW: 280 NW: 155
34 KT NE: 220 SE: 240 SW: 150 NW: 85

120H: 2020/12/30 18 UTC: 18.9 S / 34.6 E, VENT MAX= 030 KT, OVERLAND
DEPRESSION
28 KT NE: 345 SE: 390 SW: 0 NW: 0

2.C ADDITIONAL INFORMATION:
FT=1.5;CI=2.5

CHALANE PASSED AROUND 14 UTC IN THE SOUTHERN VICINITY OF TROMELIN
WHERE THE PRESSURE (CORRECTED FOR THE BAROMETRIC TIDE) DID NOT FALL
BELOW 1001.5 HPA (WITH WEAK WINDS AT 8 KT) ALLOWING A RELIABLE
ESTIMATE OF THE CENTRAL PRESSURE. THE CLOUD PATTERN HAS DETERIORATED
DURING THE LAST 24 HOURS WITH A CENTER FARTHER AWAY FROM THE
CONVECTIVE MASS. AS A CONSEQUENCE, THE SYSTEM HAS BEEN DOWNGRADED TO
THE TROPICAL DEPRESSION STAGE.

THE SHEAR IS EXPECTED TO GRADUALLY WEAKEN TODAY, AS CHALANE SHIFTS
UNDER THE UPPER RIDGE AXIS. THE MID-LEVEL ENVIRONMENT REMAINS DRY,
ESPECIALLY NORTHWESTWARD. AT SHORT RANGE, THE DEPRESSION SHOULD BEGIN
TO BENEFIT FROM MORE CONDUCIVE CONDITIONS, WITH HIGHER ENVIRONMENTAL
AIR MOISTURE AS IT NEARS THE MADAGASCAN COASTLINE. HOWEVER, INTENSITY
GUIDANCES ARE NOT KEEN ON SUGGESTING AN INTENSIFICATION OF CHALANE
PRIOR TO ITS LANDFALL. THIS INTENSITY FORECAST IS THUS ASSOCIATED TO
RELATIVELY HIGH UNCERTAINTY. A POSSIBLE RE-INTENSIFICATION AS A
TROPICAL STORM CONTINUE TO BE REFLECTED.

NO CHANGE IN TERMS OF TRACK FORECAST : THE SYSTEM IS MOVING ON THE
NORTH-WESTERN EDGE OF THE SUBTROPICAL LOW/MID-LEVEL HIGH PRESSURES.

CHALANE SHOULD THEREFORE REACH THE AREA OF EASTERN CAPE OR
SAINTE-MARIE ISLAND BY TOMORROW EVENING OR NIGHT. THE MAIN DANGER
ASSOCIATED WITH THIS SYSTEM WILL BE THE HEAVY RAINS, ASSOCIATED WITH
FLASH FLOODS IN PARTICULAR WHICH COULD OCCUR EVEN FAR FROM THE CENTER
IN THE SOUTHERN SECTOR. THE INHABITANTS OF THE AREA ARE INVITED TO
FOLLOW THE EVOLUTION OF THIS SYSTEM WITH THE LOCAL AUTHORITIES. THE
DETERIORATION OF THE METEOROLOGICAL CONDITIONS IN THE SECTOR COULD
START AT THE END OF THE NIGHT OR TOMORROW MORNING.

EARLY NEXT WEEK, THE SYSTEM SHOULD TRACK BACK OVER OPEN WATERS IN THE
MOZAMBIQUE CHANNEL, WHERE ENVIRONMENTAL CONDITIONS APPEAR TO BE
FAVORABLE FOR REINTENSIFICATION (WEAK SHEAR, GOOD UPPER OUTLFOW,
LOW-LEVEL NORTHERLY FLOW FUELING A GOOD SURFACE CONVERGENCE AND HIGH
OCEANIC HEAT CONTENT) AT FIRST. A LOW/MID LEVEL RIDGE OCCUPYING THE
SOUTHERN HALF OF THE CHANNEL SHOULD DRIVE A GENERALLY WESTWARD MOTION
OF THE STORM. AT THE END OF THE FORECAST RANGE, INCREASING WINDSHEAR
MAY LIMIT THE STRENGTHENING TREND.=

>

Original Message :

WTIO22 FMEE 251830
SECURITE
NEAR GALE WARNING FOR METAREA VII AND METAREA VIII (S)
ISSUED BY METEO-FRANCE/TROPICAL CYCLONE CENTER/LA REUNION 25/12/2020
AT 1800 UTC.
WARNING NUMBER: 014/4 (SOUTH-WEST INDIAN OCEAN)
10 MINUTES AVERAGE WIND SPEED IN KNOTS (KT)
(WIND GUSTS AT SEA MAY BE ABOUT 40% STRONGER THAN THE AVERAGED WIND)
MINIMUM SEA LEVEL PRESSURE IN HECTOPASCAL (HPA)
(INDICATIVE FIGURE).

NEAR GALE WARNING
BEGINNING OF VALIDITY: FRIDAY 25/12/2020 AT 1800 UTC.

PHENOMENON: TROPICAL DEPRESSION 4 (CHALANE) 1001 HPA
POSITION: WITHIN 30 NM RADIUS OF POINT 16.0 S / 53.7 E
(SIXTEEN DECIMAL ZERO DEGREES SOUTH AND
FIFTY THREE DECIMAL SEVEN DEGREES EAST) AT 1800 UTC
MOVEMENT: WEST 11 KT

THREAT AREAS:
SQUALLY WEATHER EXTENDING UP TO 200 NM FROM THE CENTER IN THE
SOUTHERN SEMI-CIRCLE.

NEAR GALE FORCE WINDS 30 KT AND ROUGH TO VERY ROUGH SEAS EXTENDING UP
TO 100 NM IN THE SOUTH-WESTERN QUADRANT AND UP TO 190 NM IN THE
SOUTH-EASTERN QUADRANT.
STRONG GUSTS UNDER SQUALLS.

FORECAST POSITION AND INTENSITY:
12H, VALID 2020/12/26 AT 06 UTC:
16.0 S / 52.0 E, MAX WIND = 30 KT, TROPICAL DEPRESSION
28 KT NE: 0 NM SE: 95 NM SW: 50 NM NW: 0 NM

24H, VALID 2020/12/26 AT 18 UTC:
16.1 S / 50.3 E, MAX WIND = 35 KT, MODERATE TROPICAL STORM
28 KT NE: 35 NM SE: 90 NM SW: 50 NM NW: 40 NM
34 KT NE: 25 NM SE: 25 NM SW: 25 NM NW: 25 NM

OTHER INFORMATION:
NIL.=

>

Original Message :

WTIO31 FMEE 251212
CMRS / CENTRE DES CYCLONES TROPICAUX DE LA REUNION
BULLETIN D'ANALYSE ET DE PREVISION CYCLONIQUE (SUD-OUEST OCEAN
INDIEN)

0.A NUMERO DU BULLETIN : 13/4/20202021
1.A TEMPETE TROPICALE MODEREE 4 (CHALANE)

2.A POSITION A 1200 UTC LE 25/12/2020 :
DANS UN RAYON DE 20 MN AUTOUR DU POINT 16.2 S / 55.0 E
(SEIZE DEGRES DEUX SUD ET CINQUANTE CINQ DEGRES ZERO EST)
DEPLACEMENT: OUEST 8 KT

3.A ANALYSE DE DVORAK: 2.0/2.5/W 0.5/6 H

4.A PRESSION AU CENTRE: 997 HPA
5.A VENT MAX (MOYEN/10 MN): 35 KT
RAYON DES VENTS MAXIMAUX (RVM): NON RENSEIGNE

6.A EXTENSION DES VENTS PAR QUADRANTS (KM):
28 KT NE: 0 SE: 465 SO: 150 NO: 0
34 KT NE: 0 SE: 220 SO: 0 NO: 0

7.A COTE/DIAM PREMIERE ISOBARE FERMEE: 1006 HPA / 1000 KM
8.A EXTENSION VERTICALE DE LA CIRCULATION CYCLONIQUE: MOYENNE

1.B PREVISIONS (EXTENSIONS DES VENTS FORTS EN KM):
12H: 26/12/2020 00 UTC: 16.4 S / 53.1 E, VENT MAX= 035 KT, TEMPETE
TROPICALE MODEREE
28 KT NE: 45 SE: 250 SO: 75 NO: 75
34 KT NE: 35 SE: 35 SO: 30 NO: 65

24H: 26/12/2020 12 UTC: 16.7 S / 51.2 E, VENT MAX= 040 KT, TEMPETE
TROPICALE MODEREE
28 KT NE: 45 SE: 175 SO: 65 NO: 75
34 KT NE: 35 SE: 75 SO: 30 NO: 65

36H: 27/12/2020 00 UTC: 17.2 S / 49.1 E, VENT MAX= 030 KT, DEPRESSION
SUR TERRE
28 KT NE: 175 SE: 260 SO: 250 NO: 55

48H: 27/12/2020 12 UTC: 18.0 S / 46.9 E, VENT MAX= 020 KT, DEPRESSION
SUR TERRE

60H: 28/12/2020 00 UTC: 19.4 S / 45.1 E, VENT MAX= 020 KT, DEPRESSION
SUR TERRE

72H: 28/12/2020 12 UTC: 19.7 S / 43.7 E, VENT MAX= 025 KT,
PERTURBATION TROPICALE

2.B TENDANCE ULTERIEURE:
96H: 29/12/2020 12 UTC: 19.6 S / 40.2 E, VENT MAX= 040 KT, TEMPETE
TROPICALE MODEREE
28 KT NE: 45 SE: 165 SO: 45 NO: 75
34 KT NE: 35 SE: 55 SO: 35 NO: 65

120H: 30/12/2020 12 UTC: 19.3 S / 35.7 E, VENT MAX= 050 KT, FORTE
TEMPETE TROPICALE
28 KT NE: 400 SE: 260 SO: 250 NO: 75
34 KT NE: 45 SE: 120 SO: 55 NO: 65
48 KT NE: 40 SE: 60 SO: 50 NO: 50

2.C COMMENTAIRES:
T=2.0;CI=2.5+

AU COURS DES 12 DERNIERES HEURES, LA CONVECTION A NETTEMENT FAIBLIT
PRES DU CENTRE DE CIRCULATION. LE VORTEX DE NUAGES DE BASSES COUCHES
QUI LE MATERIALISE EST AINSI APPARU AU NORD DE LA CONVECTION A PARTIR
DE 09Z. LA PASSE SCATSAT DE 0430Z CE MATIN CONFIRME L'AFFAIBLISSEMENT
SUGGERE PAR LA DEGRADATION FRANCHE DE LA CONFIGURATION NUAGEUSE, AVEC
DU COUP DE VENT SEULEMENT PRESENT DANS LE QUADRANT SUD-EST.

LE CISAILLEMENT DEVRAIT CONTINUER DE FAIBLIR PROGRESSIVEMENT, CHALANE
SE DECALANT SOUS L'AXE DE LA DORSALE D'ALTITUDE. L'ENVIRONNEMENT DE
MOYENNE TROPOSPHERE RESTE TOUTEFOIS SEC, NOTAMMENT AU NORD-OUEST DU
SYSTEME. EN COURS DE NUIT PROCHAINE, LA TEMPETE DEVRAIT POUVOIR
EVOLUER DANS DES CONDITIONS ENVIRONNEMENTALES PLUS HUMIDES ET DONC
PLUS FAVORABLES A SON DEVELOPPEMENT A L'APPROCHE DES COTES MALGACHES.
CEPENDANT, LES GUIDANCES D'INTENSITE DISPONIBLES RESTENT GLOBALEMENT
MITIGEES QUAND A LA CAPACITE DE CHALANE A S'INTENSIFIER DE FACON
SIGNIFICATIVE AVANT SON ATTERRISSAGE. LA PRESENTE PREVISION
D'INTENSITE RESTE DONC ASSEZ INCERTAINE.

EN TERMES DE TRAJECTOIRE, PAS DE CHANGEMENT : LE SYSTEME SE DEPLACE
SUR LA FACADE NORD-OUEST DES HAUTES PRESSIONS SUBTROPICALES DE BASSE
A MOYENNE TROPOSPHERE.

LES HABITANTS DE LA MOITIE NORD DE LA COTE EST DE MADAGASCAR (AU NORD
DE 20S PRINCIPALEMENT,NOTAMMENT ENTRE LES VILLES DE TOAMASINA AU SUD
ET DE ANTALAHA AU NORD) SONT INVITES A SUIVRE L'EVOLUTION DE CE
SYSTEME AU COURS DES PROCHAINS JOURS AUPRES DES AUTORITES LOCALES. LA
DEGRADATION DES CONDITIONS METEOROLOGIQUES DANS LE SECTEUR POURRAIT
COMMENCER CETTE NUIT AVEC UN ATTERRISSAGE POSSIBLE DANS LA NUIT DE
SAMEDI A DIMANCHE.

EN DA BUT DE SEMAINE PROCHAINE, LE SYSTEME DEVRAIT RESSORTIR DANS LE
CANAL DU MOZAMBIQUE OU LES CONDITIONS APPARAISSENT FAVORABLES A UNE
REINTENSIFICATION (CISAILLEMENT FAIBLE, BONNE DIVERGENCE D'ALTITUDE
COTE NORD, BONNE ALIMENTATION DE BASSES COUCHES COTE NORD ET
POTENTIEL OCEANIQUE TRES FAVORABLE) DANS UN PREMIER TEMPS. UNE
DORSALE DE BASSE ET MOYENNE TROPOSPHERE OCCUPANT LE SUD DU CANAL, UN
DEPLACEMENT EN DIRECTION GENERALE DE L'OUEST RESTE ENVISAGE. EN FIN
DE PA RIODE, UN CISAILLEMENT DE SECTEUR OUEST EN MOYENNE TROPOPSHERE
POURRAIT RALENTIR LE RYTHME DE RENFORCEMENT DU SYSTEME.=

>

Original Message :

WTIO30 FMEE 251212
RSMC / TROPICAL CYCLONE CENTER / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)

0.A WARNING NUMBER: 13/4/20202021
1.A MODERATE TROPICAL STORM 4 (CHALANE)

2.A POSITION 2020/12/25 AT 1200 UTC:
WITHIN 20 NM RADIUS OF POINT 16.2 S / 55.0 E
(SIXTEEN DECIMAL TWO DEGREES SOUTH AND
FIFTY FIVE DECIMAL ZERO DEGREES EAST)
MOVEMENT: WEST 8 KT

3.A DVORAK ANALYSIS: 2.0/2.5/W 0.5/6 H

4.A CENTRAL PRESSURE: 997 HPA
5.A MAX AVERAGE WIND SPEED (10 MN): 35 KT
RADIUS OF MAXIMUM WINDS (RMW): NIL

6.A EXTENSION OF WIND BY QUADRANTS (KM):
28 KT NE: 0 SE: 465 SW: 150 NW: 0
34 KT NE: 0 SE: 220 SW: 0 NW: 0

7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1006 HPA / 1000 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: MEDIUM

1.B FORECASTS (WINDS RADII IN KM):
12H: 2020/12/26 00 UTC: 16.4 S / 53.1 E, VENT MAX= 035 KT, MODERATE
TROPICAL STORM
28 KT NE: 45 SE: 250 SW: 75 NW: 75
34 KT NE: 35 SE: 35 SW: 30 NW: 65

24H: 2020/12/26 12 UTC: 16.7 S / 51.2 E, VENT MAX= 040 KT, MODERATE
TROPICAL STORM
28 KT NE: 45 SE: 175 SW: 65 NW: 75
34 KT NE: 35 SE: 75 SW: 30 NW: 65

36H: 2020/12/27 00 UTC: 17.2 S / 49.1 E, VENT MAX= 030 KT, OVERLAND
DEPRESSION
28 KT NE: 175 SE: 260 SW: 250 NW: 55

48H: 2020/12/27 12 UTC: 18.0 S / 46.9 E, VENT MAX= 020 KT, OVERLAND
DEPRESSION

60H: 2020/12/28 00 UTC: 19.4 S / 45.1 E, VENT MAX= 020 KT, OVERLAND
DEPRESSION

72H: 2020/12/28 12 UTC: 19.7 S / 43.7 E, VENT MAX= 025 KT, TROPICAL
DISTURBANCE

2.B LONGER-RANGE OUTLOOK:
96H: 2020/12/29 12 UTC: 19.6 S / 40.2 E, VENT MAX= 040 KT, MODERATE
TROPICAL STORM
28 KT NE: 45 SE: 165 SW: 45 NW: 75
34 KT NE: 35 SE: 55 SW: 35 NW: 65

120H: 2020/12/30 12 UTC: 19.3 S / 35.7 E, VENT MAX= 050 KT, SEVERE
TROPICAL STORM
28 KT NE: 400 SE: 260 SW: 250 NW: 75
34 KT NE: 45 SE: 120 SW: 55 NW: 65
48 KT NE: 40 SE: 60 SW: 50 NW: 50

2.C ADDITIONAL INFORMATION:
T=2.0;CI=2.5+

OVER THE LAST 12 HRS, DEEP CONVECTION CLEARLY WEAKENED NEAR THE
CIRCULATION CENTER. THE ASSOCIATED LOW-LEVEL CLOUD VORTEX THEN
APPEARED FROM 09Z ON SAT IMAGES, NORTH OF THE MAIN CONVECTION. THIS
MORNING 0430Z SCATSAT SWATH CONFIRMS THE WEAKENING OF THE SYSTEM
SUGGESTED BY THIS DETERIORATING CLOUD PATTERN, WITH GALE FORCE WINDS
ONLY LOCATED WITHIN THE SOUTH-EASTERN QUADRANT.

THE SHEAR IS EXPECTED TO GRADUALLY WEAKEN TODAY, AS CHALANE SHIFTS
UNDER THE UPPER RIDGE AXIS. THE MID-LEVEL ENVIRONMENT REMAINS DRY,
ESPECIALLY NORTHWESTWARD. FROM TONIGHT, THE STORM SHOULD BEGIN TO
BENEFIT FROM MORE CONDUCIVE CONDITIONS, WITH HIGHER ENVIRONMENTAL AIR
MOISTURE AS IT NEARS THE MADAGASCAN COASTLINE. HOWEVER, INTENSITY
GUIDANCES ARE NOT KEEN ON SUGGESTING AN INTENSIFICATION OF CHALANE
PRIOR TO ITS LANDFALL. THIS INTENSITY FORECAST IS THUS ASSOCIATED TO
RELATIVELY HIGH UNCERTAINTY.

NO CHANGE IN TERMS OF TRACK FORECAST : THE SYSTEM IS MOVING ON THE
NORTH-WESTERN EDGE OF THE SUBTROPICAL LOW/MID-LEVEL HIGH PRESSURES.

THE INHABITANTS OF THE NORTHERN HALF OF THE EASTERN MADAGASCAN COAST
(NORTH OF 20S MAINLY, NOTABLY BETWEEN THE CITIES OF TOAMASINA IN THE
SOUTH AND ANTALAHA IN THE NORTH) ARE INVITED TO MONITOR THE EVOLUTION
OF THIS SYSTEM AND FOLLOW LOCAL AUTHORITIES INSTRUCTIONS. SEVERE
WEATHER CONDITIONS SHOULD BEGIN TO AFFECT THE AREA TONIGHT, WITH A
LANDFALL EXPECTED SATURDAY NIGHT.

EARLY NEXT WEEK, THE SYSTEM SHOULD TRACK BACK OVER OPEN WATERS IN THE
MOZAMBIQUE CHANNEL, WHERE ENVIRONMENTAL CONDITIONS APPEAR TO BE
FAVORABLE FOR REINTENSIFICATION (WEAK SHEAR, GOOD UPPER OUTLFOW,
LOW-LEVEL NORTHERLY FLOW FUELING A GOOD SURFACE CONVERGENCE AND HIGH
OCEANIC HEAT CONTENT) AT FIRST. A LOW/MID LEVEL RIDGE OCCUPYING THE
SOUTHERN HALF OF THE CHANNEL SHOULD DRIVE A GENERALLY WESTWARD MOTION
OF THE STORM. AT THE END OF THE FORECAST RANGE, A MID-ELVEL WESTERLY
SHEAR COULD LIMIT THE STRENGTHENING TREND.=

>

Original Message :

WTIO22 FMEE 251150
SECURITE
GALE WARNING FOR METAREA VII AND METAREA VIII (S)
ISSUED BY METEO-FRANCE/TROPICAL CYCLONE CENTER/LA REUNION 25/12/2020
AT 1200 UTC.
WARNING NUMBER: 013/4 (SOUTH-WEST INDIAN OCEAN)
10 MINUTES AVERAGE WIND SPEED IN KNOTS (KT)
(WIND GUSTS AT SEA MAY BE ABOUT 40% STRONGER THAN THE AVERAGED WIND)
MINIMUM SEA LEVEL PRESSURE IN HECTOPASCAL (HPA)
(INDICATIVE FIGURE).

GALE WARNING
BEGINNING OF VALIDITY: FRIDAY 25/12/2020 AT 1200 UTC.

PHENOMENON: MODERATE TROPICAL STORM 4 (CHALANE) 997 HPA
POSITION: WITHIN 20 NM RADIUS OF POINT 16.2 S / 55.0 E
(SIXTEEN DECIMAL TWO DEGREES SOUTH AND
FIFTY FIVE DECIMAL ZERO DEGREES EAST) AT 1200 UTC
MOVEMENT: WEST 8 KT

THREAT AREAS:
SQUALLY WEATHER EXTENDING UP TO 200 NM FROM THE CENTER IN THE
SOUTHERN SEMI-CIRCLE.

GALE FORCE WINDS 35 KT AND VERY ROUGH TO HIGH SEAS EXTENDING UP TO
120 NM IN THE SOUTH-EASTERN QUADRANT.
NEAR GALE FORCE WINDS 30 KT AND ROUGH TO VERY ROUGH SEAS EXTENDING UP
TO 80 NM IN THE SOUTH-WESTERN QUADRANT AND UP TO 250 NM IN THE
SOUTH-EASTERN QUADRANT.
STRONG GUSTS UNDER SQUALLS.

FORECAST POSITION AND INTENSITY:
12H, VALID 2020/12/26 AT 00 UTC:
16.4 S / 53.1 E, MAX WIND = 35 KT, MODERATE TROPICAL STORM
28 KT NE: 25 NM SE: 135 NM SW: 40 NM NW: 40 NM
34 KT NE: 20 NM SE: 20 NM SW: 15 NM NW: 35 NM

24H, VALID 2020/12/26 AT 12 UTC:
16.7 S / 51.2 E, MAX WIND = 40 KT, MODERATE TROPICAL STORM
28 KT NE: 25 NM SE: 95 NM SW: 35 NM NW: 40 NM
34 KT NE: 20 NM SE: 40 NM SW: 15 NM NW: 35 NM

OTHER INFORMATION:
NIL.=

>

Original Message :

WTIO31 FMEE 250628
CMRS / CENTRE DES CYCLONES TROPICAUX DE LA REUNION
BULLETIN D'ANALYSE ET DE PREVISION CYCLONIQUE (SUD-OUEST OCEAN
INDIEN)

0.A NUMERO DU BULLETIN : 12/4/20202021
1.A TEMPETE TROPICALE MODEREE 4 (CHALANE)

2.A POSITION A 0600 UTC LE 25/12/2020 :
DANS UN RAYON DE 30 MN AUTOUR DU POINT 16.0 S / 55.9 E
(SEIZE DEGRES ZERO SUD ET CINQUANTE CINQ DEGRES NEUF EST)
DEPLACEMENT: OUEST-SUD-OUEST 8 KT

3.A ANALYSE DE DVORAK: 2.5/3.0/W 0.5/6 H

4.A PRESSION AU CENTRE: 995 HPA
5.A VENT MAX (MOYEN/10 MN): 40 KT
RAYON DES VENTS MAXIMAUX (RVM): 46 KM

6.A EXTENSION DES VENTS PAR QUADRANTS (KM):
28 KT NE: 0 SE: 295 SO: 220 NO: 0
34 KT NE: 0 SE: 205 SO: 130 NO: 0

7.A COTE/DIAM PREMIERE ISOBARE FERMEE: 1006 HPA / 1000 KM
8.A EXTENSION VERTICALE DE LA CIRCULATION CYCLONIQUE: MOYENNE

1.B PREVISIONS (EXTENSIONS DES VENTS FORTS EN KM):
12H: 25/12/2020 18 UTC: 16.2 S / 53.5 E, VENT MAX= 040 KT, TEMPETE
TROPICALE MODEREE
28 KT NE: 45 SE: 120 SO: 75 NO: 95
34 KT NE: 35 SE: 55 SO: 20 NO: 65

24H: 26/12/2020 06 UTC: 16.3 S / 51.7 E, VENT MAX= 045 KT, TEMPETE
TROPICALE MODEREE
28 KT NE: 45 SE: 100 SO: 65 NO: 75
34 KT NE: 35 SE: 55 SO: 10 NO: 65

36H: 26/12/2020 18 UTC: 16.5 S / 50.0 E, VENT MAX= 050 KT, FORTE
TEMPETE TROPICALE
28 KT NE: 55 SE: 65 SO: 65 NO: 75
34 KT NE: 45 SE: 55 SO: 55 NO: 65
48 KT NE: 35 SE: 45 SO: 45 NO: 45

48H: 27/12/2020 06 UTC: 16.9 S / 48.1 E, VENT MAX= 020 KT, DEPRESSION
SUR TERRE

60H: 27/12/2020 18 UTC: 17.7 S / 46.2 E, VENT MAX= 020 KT, DEPRESSION
SUR TERRE

72H: 28/12/2020 06 UTC: 18.6 S / 44.6 E, VENT MAX= 020 KT, DEPRESSION
SUR TERRE

2.B TENDANCE ULTERIEURE:
96H: 29/12/2020 06 UTC: 18.6 S / 40.9 E, VENT MAX= 045 KT, TEMPETE
TROPICALE MODEREE
28 KT NE: 215 SE: 360 SO: 295 NO: 100
34 KT NE: 205 SE: 240 SO: 130 NO: 65

120H: 30/12/2020 06 UTC: 18.4 S / 37.0 E, VENT MAX= 065 KT, CYCLONE
TROPICAL
28 KT NE: 260 SE: 360 SO: 295 NO: 120
34 KT NE: 250 SE: 260 SO: 130 NO: 95
48 KT NE: 110 SE: 110 SO: 110 NO: 80
64 KT NE: 60 SE: 80 SO: 80 NO: 60

2.C COMMENTAIRES:
T=2.5+;CI=3.0-

APRES S'ETRE MAINTENUE PRES DU CENTRE DE CIRCULATION EN COURS DE NUIT
DERNIERE, LA CONVECTION A ASSEZ NETTEMENT FAIBLI AU COURS DES
DERNIERES HEURES PROBABLEMENT SOUS L'EFFET DU CYCLE DIURNE. LES
POUSSEES CONVECTIVES LES PLUS FORTES SONT DESORMAIS SITUEES ASSEZ
LOIN DU CENTRE DANS LE DEMI-CERCLE SUD. LA STRUCTURE INTERNE DU
SYSTEME AFFICHEE SUR LES IMAGES MICRO-ONDES DE LA MATINEE (AMSU-B DE
0247Z) ILLUSTRE CETTE ASYMMETRIE AVEC DE L'AIR SEC OCCUPANT TOUJOURS
LE DEMI-CERCLE NORD. LES DONNEES D'ANALYSE DU CIMSS PROPOSENT ENCORE
UNE CONTRAINTE D'ALTITUDE DE SECTEUR NORD-EST DE 15KT, EN BAISSE.

LE CISAILLEMENT DEVRAIT PROGRESSIVEMENT FAIBLIR AUJOURD'HUI, CHALANE
SE DECALANT SOUS L'AXE DE LA DORSALE D'ALTITUDE. L'ENVIRONNEMENT DE
MOYENNE TROPOSPHERE RESTE TOUTEFOIS SEC, NOTAMMENT AU NORD-OUEST DU
SYSTEME. A PARTIR DE CE SOIR, LA TEMPETE DEVRAIT POUVOIR EVOLUER DANS
DES CONDITIONS ENVIRONNEMENTALES PLUS FAVORABLES A TOUT POINT DE VUE,
ET NOTAMMENT PROFITER D'UNE BONNE DIVERGENCE D'ALTITUDE COTE
EQUATORIAL A L'APPROCHE DES COTES MALGACHES. CEPENDANT, LES GUIDANCES
D'INTENSITE DISPONIBLES RESTENT MITIGEES QUAND A LA CAPACITE DE
CHALANE A S'INTENSIFIER DE FACON SIGNIFICATIVE AVANT SON
ATTERRISSAGE, MEME SI QUELQUES MODELES COMME HWRF LE PROPOSE
DESORMAIS. LA PRESENTE PREVISION D'INTENSITE RESTE DONC ASSEZ
INCERTAINE.

EN TERMES DE TRAJECTOIRE, PAS DE CHANGEMENT : LE SYSTEME SE DEPLACE
SUR LA FACADE NORD-OUEST DES HAUTES PRESSIONS SUBTROPICALES DE BASSE
A MOYENNE TROPOSPHERE. UN RALENTISSEMENT EST POSSIBLE LA NUIT
PROCHAINE ALORS QU'UN COL BAROMETRIQUE CIRCULE TEMPORAIREMENT LOIN AU
SUD.

EN DA BUT DE SEMAINE PROCHAINE, LE SYSTEME DEVRAIT RESSORTIR DANS LE
CANAL DU MOZAMBIQUE OU LES CONDITIONS APPARAISSENT FAVORABLES A UNE
REINTENSIFICATION (CISAILLEMENT FAIBLE, BONNE DIVERGENCE D'ALTITUDE
COTE NORD, BONNE ALIMENTATION DE BASSES COUCHES COTE NORD ET
POTENTIEL OCEANIQUE TRES FAVORABLE). UNE DORSALE DE BASSE ET MOYENNE
TROPOSPHERE OCCUPANT LE SUD DU CANAL, UN DEPLACEMENT EN DIRECTION
GENERALE DE L'OUEST RESTE ENVISAGE.

LES HABITANTS DE LA MOITIE NORD DE LA COTE EST DE MADAGASCAR (AU NORD
DE 20S PRINCIPALEMENT,NOTAMMENT ENTRE LES VILLES DE TOAMASINA AU SUD
ET DE SAMBAVA AU NORD) SONT INVITES A SUIVRE L'EVOLUTION DE CE
SYSTEME AU COURS DES PROCHAINS JOURS AUPRES DES AUTORITES LOCALES. LA
DEGRADATION DES CONDITIONS METEOROLOGIQUES DANS LE SECTEUR POURRAIT
COMMENCER DANS LA NUIT DE VENDREDI A SAMEDI AVEC UN ATTERRISSAGE
POSSIBLE DANS LA NUIT DE SAMEDI A DIMANCHE OU DIMANCHE MATIN.=

>

Original Message :

WTIO30 FMEE 250628
RSMC / TROPICAL CYCLONE CENTER / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)

0.A WARNING NUMBER: 12/4/20202021
1.A MODERATE TROPICAL STORM 4 (CHALANE)

2.A POSITION 2020/12/25 AT 0600 UTC:
WITHIN 30 NM RADIUS OF POINT 16.0 S / 55.9 E
(SIXTEEN DECIMAL ZERO DEGREES SOUTH AND
FIFTY FIVE DECIMAL NINE DEGREES EAST)
MOVEMENT: WEST-SOUTH-WEST 8 KT

3.A DVORAK ANALYSIS: 2.5/3.0/W 0.5/6 H

4.A CENTRAL PRESSURE: 995 HPA
5.A MAX AVERAGE WIND SPEED (10 MN): 40 KT
RADIUS OF MAXIMUM WINDS (RMW): 46 KM

6.A EXTENSION OF WIND BY QUADRANTS (KM):
28 KT NE: 0 SE: 295 SW: 220 NW: 0
34 KT NE: 0 SE: 205 SW: 130 NW: 0

7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1006 HPA / 1000 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: MEDIUM

1.B FORECASTS (WINDS RADII IN KM):
12H: 2020/12/25 18 UTC: 16.2 S / 53.5 E, VENT MAX= 040 KT, MODERATE
TROPICAL STORM
28 KT NE: 45 SE: 120 SW: 75 NW: 95
34 KT NE: 35 SE: 55 SW: 20 NW: 65

24H: 2020/12/26 06 UTC: 16.3 S / 51.7 E, VENT MAX= 045 KT, MODERATE
TROPICAL STORM
28 KT NE: 45 SE: 100 SW: 65 NW: 75
34 KT NE: 35 SE: 55 SW: 10 NW: 65

36H: 2020/12/26 18 UTC: 16.5 S / 50.0 E, VENT MAX= 050 KT, SEVERE
TROPICAL STORM
28 KT NE: 55 SE: 65 SW: 65 NW: 75
34 KT NE: 45 SE: 55 SW: 55 NW: 65
48 KT NE: 35 SE: 45 SW: 45 NW: 45

48H: 2020/12/27 06 UTC: 16.9 S / 48.1 E, VENT MAX= 020 KT, OVERLAND
DEPRESSION

60H: 2020/12/27 18 UTC: 17.7 S / 46.2 E, VENT MAX= 020 KT, OVERLAND
DEPRESSION

72H: 2020/12/28 06 UTC: 18.6 S / 44.6 E, VENT MAX= 020 KT, OVERLAND
DEPRESSION

2.B LONGER-RANGE OUTLOOK:
96H: 2020/12/29 06 UTC: 18.6 S / 40.9 E, VENT MAX= 045 KT, MODERATE
TROPICAL STORM
28 KT NE: 215 SE: 360 SW: 295 NW: 100
34 KT NE: 205 SE: 240 SW: 130 NW: 65

120H: 2020/12/30 06 UTC: 18.4 S / 37.0 E, VENT MAX= 065 KT, TROPICAL
CYCLONE
28 KT NE: 260 SE: 360 SW: 295 NW: 120
34 KT NE: 250 SE: 260 SW: 130 NW: 95
48 KT NE: 110 SE: 110 SW: 110 NW: 80
64 KT NE: 60 SE: 80 SW: 80 NW: 60

2.C ADDITIONAL INFORMATION:
T=2.5+;CI=3.0-

CONVECTION MAINTAINED ALL NIGHT NEAR THE CIRCULATION CENTER, BUT
CLEARLY WEAKENED OVER THE LAST HOURS PROBABLY BECAUSE OF THE DIURNAL
CYCLE. THE STRONGEST CONVECTIVE BURST ARE CURRENTLY LOCATED QUITE FAR
FROM THE CENTER IN THE SOUTHERN SEMI-CIRCLE. THE INNER STRUCTURE
REVEALED BY THE LAST MW IMAGES (0247Z AMSU-B) ILLUSTRATE THIS
ASYMMETRY WITH DRY AIR OCCUPYING THE NORTHERN SEMI-CIRCLE. CIMSS
ANLAYSIS DATA STILL SUGGEST A WEAKENING 15-KT NORTHEASTERLY UPPER
SHEAR CONSTRAINT.

THE SHEAR IS EXPECTED TO GRADUALLY WEAKEN TODAY, AS CHALANE SHIFTS
UNDER THE UPPER RIDGE AXIS. THE MID-LEVEL ENVIRONMENT REMAINS DRY,
ESPECIALLY NORTHWESTWARD. FROM TONIGHT, THE STORM SHOULD BEGIN TO
BENEFIT FROM MORE CONDUCIVE CONDITIONS, WITH A GOOD UPPER DIVERGENCE
EQUATORWARD AS IT NEARS THE MADAGASCAN COASTLINE. HOWEVER, INTENSITY
GUIDANCES ARE NOT KEEN ON SUGGESTING AN INTENSIFICATION OF CHALANE
PRIOR TO ITS LANDFALL, ALTHOUGH SOME MODELS LIKE HWRF ARE NOW
SUGGESTING IT. THIS INTENSITY FORECAST IS THUS ASSOCIATED TO
RELATIVELY HIGH UNCERTAINTY.

NO CHANGE IN TERMS OF TRACK FORECAST : THE SYSTEM IS MOVING ON THE
NORTH-WESTERN EDGE OF THE SUBTROPICAL LOW/MID-LEVEL HIGH PRESSURES. A
SLOWDOWN IS POSSIBLE TONIGHT AS A FLAT LOW TEMPORARILY PASSES FAR TO
THE SOUTH.

EARLY NEXT WEEK, THE SYSTEM SHOULD TRACK BACK OVER OPEN WATERS IN THE
MOZAMBIQUE CHANNEL, WHERE ENVIRONEMTAL CONDITIONS APPEAR TO BE
FAVORABLE FOR REINTENSIFICATION (WEAK SHEAR, GOOD UPPER OUTLFOW,
LOW-LEVEL NORTHERLY FLOW FUELING A GOOD SURFACE CONVERGENCE AND HIGH
OCEANIC HEAT CONTENT). A LOW/MID LEVEL RIDGE OCCUPYING THE SOUTHERN
HALF OF THE CHANNEL SHOULD DRIVE A GENERALLY WESTWARD MOTION OF THE
STORM.

THE INHABITANTS OF THE NORTHERN HALF OF THE EASTERN MADAGASCAN COAST
(NORTH OF 20S MAINLY, NOTABLY BETWEEN THE CITIES OF TOAMASINA IN THE
SOUTH AND SAMBAVA IN THE NORTH) ARE INVITED TO MONITOR THE EVOLUTION
OF THIS SYSTEM AND FOLLOW LOCAL AUTHORITIES INSTRUCTIONS. SEVERE
WEATHER CONDITIONS OVER LAND SHOULD BEGIN FRIDAY NIGHT OR SATURDAY
WITH A LANDFALL EXPECTED SATURDAY NIGHT OR SUNDAY MORNING.=

>

Original Message :

WTIO22 FMEE 250615
SECURITE
GALE WARNING FOR METAREA VII AND METAREA VIII (S)
ISSUED BY METEO-FRANCE/TROPICAL CYCLONE CENTER/LA REUNION 25/12/2020
AT 0600 UTC.
WARNING NUMBER: 012/4 (SOUTH-WEST INDIAN OCEAN)
10 MINUTES AVERAGE WIND SPEED IN KNOTS (KT)
(WIND GUSTS AT SEA MAY BE ABOUT 40% STRONGER THAN THE AVERAGED WIND)
MINIMUM SEA LEVEL PRESSURE IN HECTOPASCAL (HPA)
(INDICATIVE FIGURE).

GALE WARNING
BEGINNING OF VALIDITY: FRIDAY 25/12/2020 AT 0600 UTC.

PHENOMENON: MODERATE TROPICAL STORM 4 (CHALANE) 995 HPA
POSITION: WITHIN 30 NM RADIUS OF POINT 16.0 S / 55.9 E
(SIXTEEN DECIMAL ZERO DEGREES SOUTH AND
FIFTY FIVE DECIMAL NINE DEGREES EAST) AT 0600 UTC
MOVEMENT: WEST-SOUTH-WEST 8 KT

THREAT AREAS:
SQUALLY WEATHER EXTENDING UP TO 160 NM FROM THE CENTER IN THE
SOUTHERN SEMI-CIRCLE.

GALE FORCE WINDS 35/40 KT AND VERY ROUGH TO HIGH SEAS EXTENDING UP TO
70 NM IN THE SOUTH-WESTERN QUADRANT AND UP TO 110 NM IN THE
SOUTH-EASTERN QUADRANT.
NEAR GALE FORCE WINDS 30 KT AND ROUGH TO VERY ROUGH SEAS EXTENDING UP
TO 120 NM IN THE SOUTH-WESTERN QUADRANT AND UP TO 160 NM IN THE
SOUTH-EASTERN QUADRANT.
STRONG GUSTS UNDER SQUALLS.

FORECAST POSITION AND INTENSITY:
12H, VALID 2020/12/25 AT 18 UTC:
16.2 S / 53.5 E, MAX WIND = 40 KT, MODERATE TROPICAL STORM
28 KT NE: 25 NM SE: 65 NM SW: 40 NM NW: 50 NM
34 KT NE: 20 NM SE: 30 NM SW: 10 NM NW: 35 NM

24H, VALID 2020/12/26 AT 06 UTC:
16.3 S / 51.7 E, MAX WIND = 45 KT, MODERATE TROPICAL STORM
28 KT NE: 25 NM SE: 55 NM SW: 35 NM NW: 40 NM
34 KT NE: 20 NM SE: 30 NM SW: 5 NM NW: 35 NM

OTHER INFORMATION:
NIL.=

>

Original Message :

WTIO31 FMEE 250013
CMRS / CENTRE DES CYCLONES TROPICAUX DE LA REUNION
BULLETIN D'ANALYSE ET DE PREVISION CYCLONIQUE (SUD-OUEST OCEAN
INDIEN)

0.A NUMERO DU BULLETIN : 11/4/20202021
1.A TEMPETE TROPICALE MODEREE 4 (CHALANE)

2.A POSITION A 0000 UTC LE 25/12/2020 :
DANS UN RAYON DE 20 MN AUTOUR DU POINT 15.7 S / 56.5 E
(QUINZE DEGRES SEPT SUD ET CINQUANTE SIX DEGRES CINQ EST)
DEPLACEMENT: OUEST-SUD-OUEST 8 KT

3.A ANALYSE DE DVORAK: 3.0/3.0/D 0.5/24 H

4.A PRESSION AU CENTRE: 995 HPA
5.A VENT MAX (MOYEN/10 MN): 40 KT
RAYON DES VENTS MAXIMAUX (RVM): NON RENSEIGNE

6.A EXTENSION DES VENTS PAR QUADRANTS (KM):
28 KT NE: 0 SE: 295 SO: 285 NO: 0
34 KT NE: 0 SE: 205 SO: 205 NO: 0

7.A COTE/DIAM PREMIERE ISOBARE FERMEE: 1006 HPA / 1000 KM
8.A EXTENSION VERTICALE DE LA CIRCULATION CYCLONIQUE: PROFONDE

1.B PREVISIONS (EXTENSIONS DES VENTS FORTS EN KM):
12H: 25/12/2020 12 UTC: 15.7 S / 54.6 E, VENT MAX= 040 KT, TEMPETE
TROPICALE MODEREE
28 KT NE: 85 SE: 380 SO: 335 NO: 85
34 KT NE: 75 SE: 195 SO: 150 NO: 75

24H: 26/12/2020 00 UTC: 15.6 S / 53.1 E, VENT MAX= 045 KT, TEMPETE
TROPICALE MODEREE
28 KT NE: 100 SE: 380 SO: 335 NO: 85
34 KT NE: 95 SE: 205 SO: 150 NO: 75

36H: 26/12/2020 12 UTC: 15.6 S / 51.8 E, VENT MAX= 045 KT, TEMPETE
TROPICALE MODEREE
28 KT NE: 120 SE: 380 SO: 335 NO: 85
34 KT NE: 110 SE: 215 SO: 150 NO: 75

48H: 27/12/2020 00 UTC: 16.0 S / 50.2 E, VENT MAX= 050 KT, FORTE
TEMPETE TROPICALE
28 KT NE: 140 SE: 380 SO: 335 NO: 85
34 KT NE: 130 SE: 220 SO: 150 NO: 75
48 KT NE: 65 SE: 100 SO: 110 NO: 55

60H: 27/12/2020 12 UTC: 16.6 S / 47.9 E, VENT MAX= 030 KT, DEPRESSION
SUR TERRE
28 KT NE: 150 SE: 380 SO: 335 NO: 75

72H: 28/12/2020 00 UTC: 17.6 S / 45.6 E, VENT MAX= 025 KT, DEPRESSION
SUR TERRE

2.B TENDANCE ULTERIEURE:
96H: 29/12/2020 00 UTC: 18.8 S / 42.2 E, VENT MAX= 040 KT, TEMPETE
TROPICALE MODEREE
28 KT NE: 215 SE: 380 SO: 335 NO: 95
34 KT NE: 205 SE: 260 SO: 150 NO: 75

120H: 30/12/2020 00 UTC: 18.5 S / 38.5 E, VENT MAX= 060 KT, FORTE
TEMPETE TROPICALE
28 KT NE: 260 SE: 380 SO: 335 NO: 110
34 KT NE: 250 SE: 280 SO: 150 NO: 100
48 KT NE: 110 SE: 140 SO: 110 NO: 90

2.C COMMENTAIRES:
T=CI=3.0-

LA CONFIGURATION NUAGEUSE DU SYSTEME S'EST LEGEREMENT AMELIOREE EN
FIN DE JOURNA E, A LA FAVEUR DES BOUFFEES REGULIERES DE CONVECTION
ORAGEUSE, LE CENTRE SEMBLE PLUS PRES, VOIRE SOUS LA BORDURE DE LA
CONVECTION, DANS UNE CONFIGURATION QUI RESTE CISAILLEE.
L'ESTIMATION FINALE D'INTENSITE EST LAISSEE A 40 KT (CONFIRME SUR LES
PASS ASCAT DE CET APRES-MIDI).

EN COURS DE JOURNA E, LE CISAILLEMENT DEVRAIT BAISSER AVEC UN SYSTEME
EVOLUANT PRESQU'EN PHASE AVEC LA DORSALE D'ALTITUDE. L'ENVIRONNEMENT
RESTE PAR CONTRE BIEN SEC EN MOYENNE TROPOSPHERE NOTAMMENT AU NORD DU
SYSTEME ET CELA DEVRAIT SE MAINTENIR JUSQU'EN FIN DE JOURNA E.
PAR LA SUITE, LE SYSTEME EST TOUJOURS PREVU EVOLUER DANS UN
ENVIRONNEMENT PLUS HUMIDE ET MOINS CISAILLE AVEC UNE EXCELLENTE
DIVERGENCE D'ALTITUDE COTE EQUATORIAL A L'APPROCHE DES COTES
MALGACHES. LES GUIDANCES DYNAMIQUES ANALYSENT MAL LA TENDANCE EN
COURS A L'INTENSIFICATION ET NE PROPOSENT TOUJOURS PEU OU PAS
D'INTENSIFICATION FRANCHE SUR CETTE PERIODE. LA PRESENTE PREVISION
D'INTENSITE RESTE DONC ASSEZ INCERTAINE.

EN TERME DE TRAJECTOIRE, PAS DE CHANGEMENT : LE SYSTEME SE DEPLACE
SUR LA FACADE NORD A NORD-OUEST DES HAUTES PRESSIONS SUBTROPICALES DE
BASSE A MOYENNE TROPOSPHERE. UN RALENTISSEMENT EST POSSIBLE LA NUIT
PROCHAINE ALORS QU'UN COL BAROMETRIQUE CIRCULE TEMPORAIREMENT LOIN AU
SUD.

EN PREMIERE PARTIE DE SEMAINE PROCHAINE, LE SYSTEME DEVRAIT SORTIR
DANS LE CANAL DU MOZAMBIQUE OU LES CONDITIONS APPARAISSENT FAVORABLES
A UNE INTENSIFICATION (CISAILLEMENT FAIBLE, BONNE DIVERGENCE
D'ALTITUDE COTE NORD, BONNE ALIMENTATION DE BASSES COUCHES COTE NORD
ET POTENTIEL OCEANIQUE FAVORABLE). UN DEPLACEMENT EN DIRECTION
GENERALE DE L'OUEST RESTE ENVISAGEE.

LES HABITANTS DE LA MOITIE NORD DE LA COTE EST DE MADAGASCAR (AU NORD
DE 20S PRINCIPALEMENT,NOTAMMENT ENTRE LES VILLES DE TOAMASINA AU SUD
ET DE SAMBAVA AU NORD) SONT INVITES A SUIVRE L'EVOLUTION DE CE
SYSTEME AU COURS DES PROCHAINS JOURS AUPRES DES AUTORITES LOCALES. LA
DEGRADATION DES CONDITIONS METEOROLOGIQUES DANS LE SECTEUR POURRAIT
COMMENCER DANS LA NUIT DE VENDREDI A SAMEDI AVEC UN ATTERRISSAGE
POSSIBLE DANS LA NUIT DE SAMEDI A DIMANCHE OU DIMANCHE MATIN.=

>

Original Message :

WTIO30 FMEE 250013
RSMC / TROPICAL CYCLONE CENTER / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)

0.A WARNING NUMBER: 11/4/20202021
1.A MODERATE TROPICAL STORM 4 (CHALANE)

2.A POSITION 2020/12/25 AT 0000 UTC:
WITHIN 20 NM RADIUS OF POINT 15.7 S / 56.5 E
(FIFTEEN DECIMAL SEVEN DEGREES SOUTH AND
FIFTY SIX DECIMAL FIVE DEGREES EAST)
MOVEMENT: WEST-SOUTH-WEST 8 KT

3.A DVORAK ANALYSIS: 3.0/3.0/D 0.5/24 H

4.A CENTRAL PRESSURE: 995 HPA
5.A MAX AVERAGE WIND SPEED (10 MN): 40 KT
RADIUS OF MAXIMUM WINDS (RMW): NIL

6.A EXTENSION OF WIND BY QUADRANTS (KM):
28 KT NE: 0 SE: 295 SW: 285 NW: 0
34 KT NE: 0 SE: 205 SW: 205 NW: 0

7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1006 HPA / 1000 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: DEEP

1.B FORECASTS (WINDS RADII IN KM):
12H: 2020/12/25 12 UTC: 15.7 S / 54.6 E, VENT MAX= 040 KT, MODERATE
TROPICAL STORM
28 KT NE: 85 SE: 380 SW: 335 NW: 85
34 KT NE: 75 SE: 195 SW: 150 NW: 75

24H: 2020/12/26 00 UTC: 15.6 S / 53.1 E, VENT MAX= 045 KT, MODERATE
TROPICAL STORM
28 KT NE: 100 SE: 380 SW: 335 NW: 85
34 KT NE: 95 SE: 205 SW: 150 NW: 75

36H: 2020/12/26 12 UTC: 15.6 S / 51.8 E, VENT MAX= 045 KT, MODERATE
TROPICAL STORM
28 KT NE: 120 SE: 380 SW: 335 NW: 85
34 KT NE: 110 SE: 215 SW: 150 NW: 75

48H: 2020/12/27 00 UTC: 16.0 S / 50.2 E, VENT MAX= 050 KT, SEVERE
TROPICAL STORM
28 KT NE: 140 SE: 380 SW: 335 NW: 85
34 KT NE: 130 SE: 220 SW: 150 NW: 75
48 KT NE: 65 SE: 100 SW: 110 NW: 55

60H: 2020/12/27 12 UTC: 16.6 S / 47.9 E, VENT MAX= 030 KT, OVERLAND
DEPRESSION
28 KT NE: 150 SE: 380 SW: 335 NW: 75

72H: 2020/12/28 00 UTC: 17.6 S / 45.6 E, VENT MAX= 025 KT, OVERLAND
DEPRESSION

2.B LONGER-RANGE OUTLOOK:
96H: 2020/12/29 00 UTC: 18.8 S / 42.2 E, VENT MAX= 040 KT, MODERATE
TROPICAL STORM
28 KT NE: 215 SE: 380 SW: 335 NW: 95
34 KT NE: 205 SE: 260 SW: 150 NW: 75

120H: 2020/12/30 00 UTC: 18.5 S / 38.5 E, VENT MAX= 060 KT, SEVERE
TROPICAL STORM
28 KT NE: 260 SE: 380 SW: 335 NW: 110
34 KT NE: 250 SE: 280 SW: 150 NW: 100
48 KT NE: 110 SE: 140 SW: 110 NW: 90

2.C ADDITIONAL INFORMATION:
T=CI=3.0-

THE CLOUD PATTERN HAS CHANGED LITTLE AT THE END OF THE DAY, THANKS TO
THE REGULAR THUNDERSTORM CONVECTION GUSTS, THE CENTER SEEMS TO BE
LOCATED NEAREST, SEE UNDER THE EDGE OF THE CONVECTION, WITHIN A
PATTERN REMAINING SHEARED. THE FINAL INTENSITY ESTIMATE IS LEFT AT 40
KT (BASED ON THIS AFTERNOON ASCAT PASSES).

TODAY THE SHEAR SHOULD DECREASE WITH A SYSTEM EVOLVING ALMOST IN
PHASE WITH THE UPPER LEVELS RIDGE. THE ENVIRONMENT REMAINS DRY ON THE
OTHER HAND IN MID-TROPOSPHERE, ESPECIALLY IN THE NORTH OF THE SYSTEM
AND THIS SHOULD CONTINUE FOR THE NEXT 24 HOURS. THEREAFTER, THE
SYSTEM IS STILL EXPECTED TO EVOLVE IN A MOISTER AND LESS SHEARED
ENVIRONMENT WITH AN EXCELLENT UPPER LEVELS DIVERGENCE ON THE
EQUATORWARDS AS IT IS EXPECTED TO NEAR THE MALAGASY COAST. THE
DYNAMICAL GUIDANCES DO NOT ANALYZE WELL THE CURRENT INTENSIFICATION
TREND AND STILL DO NOT PROPOSE A CLEAR INTENSIFICATION DURING THIS
PERIOD. THE PRESENT INTENSITY FORECAST REMAINS THEREFORE RATHER
UNCERTAIN.

IN TERMS OF TRACK, NO CHANGE: THE SYSTEM IS MOVING ON THE NORTH TO
NORTH-WESTERN EDGE OF THE SUBTROPICAL HIGH PRESSURES FROM LOW TO MID
TROPOSPHERE. A SLOWDOWN IS POSSIBLE NEXT NIGHT AS A BAROMETRIC COL
TEMPORARILY CIRCULATES FAR TO THE SOUTH.

THE INHABITANTS OF THE NORTHERN HALF OF THE EAST COAST OF MADAGASCAR
(NORTH OF 20S MAINLY, NOTABLY BETWEEN THE CITIES OF TOAMASINA IN THE
SOUTH AND SAMBAVA IN THE NORTH) ARE INVITED TO FOLLOW THE EVOLUTION
OF THIS SYSTEM DURING THE NEXT FEW DAYS WITH THE LOCAL AUTHORITIES.
THE DEGRADATION OF THE METEOROLOGICAL CONDITIONS IN THE SECTOR COULD
BEGIN IN THE NIGHT OF FRIDAY TO SATURDAY WITH A POSSIBLE LANDFALL
SATURDAY NIGHT OR SUNDAY MORNING.=

>

Original Message :

WTIO22 FMEE 250011
SECURITE
GALE WARNING FOR METAREA VII AND METAREA VIII (S)
ISSUED BY METEO-FRANCE/TROPICAL CYCLONE CENTER/LA REUNION 25/12/2020
AT 0000 UTC.
WARNING NUMBER: 011/4 (SOUTH-WEST INDIAN OCEAN)
10 MINUTES AVERAGE WIND SPEED IN KNOTS (KT)
(WIND GUSTS AT SEA MAY BE ABOUT 40% STRONGER THAN THE AVERAGED WIND)
MINIMUM SEA LEVEL PRESSURE IN HECTOPASCAL (HPA)
(INDICATIVE FIGURE).

GALE WARNING
BEGINNING OF VALIDITY: FRIDAY 25/12/2020 AT 0000 UTC.

PHENOMENON: MODERATE TROPICAL STORM 4 (CHALANE) 995 HPA
POSITION: WITHIN 20 NM RADIUS OF POINT 15.7 S / 56.5 E
(FIFTEEN DECIMAL SEVEN DEGREES SOUTH AND
FIFTY SIX DECIMAL FIVE DEGREES EAST) AT 0000 UTC
MOVEMENT: WEST-SOUTH-WEST 8 KT

THREAT AREAS:
SQUALLY WEATHER EXTENDING UP TO 200 NM FROM THE CENTER IN THE
SOUTHERN SEMI-CIRCLE.

GALE FORCE WINDS 35/40 KT AND VERY ROUGH TO HIGH SEAS EXTENDING UP TO
110 NM IN THE SOUTHERN SEMI-CIRCLE.
NEAR GALE FORCE WINDS 30 KT AND ROUGH TO VERY ROUGH SEAS EXTENDING UP
TO 155 NM IN THE SOUTH-WESTERN QUADRANT AND UP TO 160 NM IN THE
SOUTH-EASTERN QUADRANT.
STRONG GUSTS UNDER SQUALLS.

FORECAST POSITION AND INTENSITY:
12H, VALID 2020/12/25 AT 12 UTC:
15.7 S / 54.6 E, MAX WIND = 40 KT, MODERATE TROPICAL STORM
28 KT NE: 45 NM SE: 205 NM SW: 180 NM NW: 45 NM
34 KT NE: 40 NM SE: 105 NM SW: 80 NM NW: 40 NM

24H, VALID 2020/12/26 AT 00 UTC:
15.6 S / 53.1 E, MAX WIND = 45 KT, MODERATE TROPICAL STORM
28 KT NE: 55 NM SE: 205 NM SW: 180 NM NW: 45 NM
34 KT NE: 50 NM SE: 110 NM SW: 80 NM NW: 40 NM

OTHER INFORMATION:
NIL.=

>

Original Message :

WTIO31 FMEE 241806
CMRS / CENTRE DES CYCLONES TROPICAUX DE LA REUNION
BULLETIN D'ANALYSE ET DE PREVISION CYCLONIQUE (SUD-OUEST OCEAN
INDIEN)

0.A NUMERO DU BULLETIN : 10/4/20202021
1.A TEMPETE TROPICALE MODEREE 4 (CHALANE)

2.A POSITION A 1800 UTC LE 24/12/2020 :
DANS UN RAYON DE 20 MN AUTOUR DU POINT 15.5 S / 57.4 E
(QUINZE DEGRES CINQ SUD ET CINQUANTE SEPT DEGRES QUATRE EST)
DEPLACEMENT: OUEST 9 KT

3.A ANALYSE DE DVORAK: 2.5/2.5/D 0.5/24 H

4.A PRESSION AU CENTRE: 996 HPA
5.A VENT MAX (MOYEN/10 MN): 40 KT
RAYON DES VENTS MAXIMAUX (RVM): NON RENSEIGNE

6.A EXTENSION DES VENTS PAR QUADRANTS (KM):
28 KT NE: 0 SE: 295 SO: 285 NO: 0
34 KT NE: 0 SE: 205 SO: 205 NO: 0

7.A COTE/DIAM PREMIERE ISOBARE FERMEE: 1007 HPA / 1100 KM
8.A EXTENSION VERTICALE DE LA CIRCULATION CYCLONIQUE: PROFONDE

1.B PREVISIONS (EXTENSIONS DES VENTS FORTS EN KM):
12H: 25/12/2020 06 UTC: 15.6 S / 55.2 E, VENT MAX= 040 KT, TEMPETE
TROPICALE MODEREE
28 KT NE: 0 SE: 380 SO: 335 NO: 0
34 KT NE: 0 SE: 195 SO: 150 NO: 0

24H: 25/12/2020 18 UTC: 15.7 S / 53.7 E, VENT MAX= 045 KT, TEMPETE
TROPICALE MODEREE
28 KT NE: 100 SE: 380 SO: 335 NO: 85
34 KT NE: 95 SE: 205 SO: 150 NO: 75

36H: 26/12/2020 06 UTC: 15.9 S / 52.5 E, VENT MAX= 045 KT, TEMPETE
TROPICALE MODEREE
28 KT NE: 120 SE: 380 SO: 335 NO: 85
34 KT NE: 110 SE: 215 SO: 150 NO: 75

48H: 26/12/2020 18 UTC: 16.4 S / 50.9 E, VENT MAX= 045 KT, TEMPETE
TROPICALE MODEREE
28 KT NE: 140 SE: 380 SO: 335 NO: 85
34 KT NE: 130 SE: 220 SO: 150 NO: 75

60H: 27/12/2020 06 UTC: 16.7 S / 49.1 E, VENT MAX= 030 KT, DEPRESSION
SUR TERRE
28 KT NE: 140 SE: 380 SO: 335 NO: 75

72H: 27/12/2020 18 UTC: 17.3 S / 46.9 E, VENT MAX= 025 KT, DEPRESSION
SUR TERRE

2.B TENDANCE ULTERIEURE:
96H: 28/12/2020 18 UTC: 19.4 S / 43.6 E, VENT MAX= 030 KT, DEPRESSION
SUR TERRE
28 KT NE: 185 SE: 380 SO: 335 NO: 95

120H: 29/12/2020 18 UTC: 19.3 S / 40.5 E, VENT MAX= 050 KT, FORTE
TEMPETE TROPICALE
28 KT NE: 260 SE: 380 SO: 335 NO: 110
34 KT NE: 250 SE: 280 SO: 150 NO: 100
48 KT NE: 100 SE: 140 SO: 110 NO: 90

2.C COMMENTAIRES:
T=CI=2.5

LA CONFIGURATION NUAGEUSE DU SYSTEME A PEU CHANGE DEPUIS CE MATIN ET
RESTE CELLE D'UN SYSTEME CISAILLE AVEC LE CENTRE LOCALISE EN BORDURE
NORD DES BOUFFEES REGULIERES DE CONVECTION ORAGEUSE. LA DISTANCE
ENTRE LE CENTRE ESTIME ET LA BORDURE DE LA CONVECTION EST RESTEE EN
MOYENNE INFERIEURE A 0.75AO (ASSOCIE A UN DT DE 2.5). SANS EVOLUTION
NOTABLE DE LA CONFIGURATION, L'ESTIMATION FINALE D'INTENSITE EST
LAISSEE A 40 KT (CONFIRME SUR LES PASS ASCAT DE CET APRES-MIDI).

AUJOURD'HUI LE CISAILLEMENT DEVRAIT BAISSER AVEC UN SYSTEME EVOLUANT
PRESQU'EN PHASE AVEC LA DORSALE D'ALTITUDE. L'ENVIRONNEMENT RESTE PAR
CONTRE BIEN SEC EN MOYENNE TROPOSPHERE NOTAMMENT AU NORD DU SYSTEME
ET CELA DEVRAIT SE MAINTENIR POUR LES PROCHAINES 24H. PAR LA SUITE,
LE SYSTEME EST TOUJOURS PREVU EVOLUER DANS UN ENVIRONNEMENT PLUS
HUMIDE ET MOINS CISAILLE AVEC UNE EXCELLENTE DIVERGENCE D'ALTITUDE
COTE EQUATORIAL A L'APPROCHE DES COTES MALGACHES. LES GUIDANCES
DYNAMIQUES ANALYSENT MAL LA TENDANCE EN COURS A L'INTENSIFICATION ET
NE PROPOSENT TOUJOURS PEU OU PAS D'INTENSIFICATION FRANCHE SUR CETTE
PERIODE. LA PRESENTE PREVISION D'INTENSITE RESTE DONC ASSEZ
INCERTAINE.

EN TERME DE TRAJECTOIRE, PAS DE CHANGEMENT : LE SYSTEME SE DEPLACE
SUR LA FACADE NORD A NORD-OUEST DES HAUTES PRESSIONS SUBTROPICALES DE
BASSE A MOYENNE TROPOSPHERE. UN RALENTISSEMENT EST POSSIBLE DEMAIN
SOIR ALORS QU'UN COL BAROMETRIQUE CIRCULE TEMPORAIREMENT LOIN AU SUD.

EN PREMIERE PARTIE DE SEMAINE PROCHAINE, LE SYSTEME DEVRAIT SORTIR
DANS LE CANAL DU MOZAMBIQUE OU LES CONDITIONS APPARAISSENT FAVORABLES
A UNE INTENSIFICATION (CISAILLEMENT FAIBLE, BONNE DIVERGENCE
D'ALTITUDE COTE NORD, BONNE ALIMENTATION DE BASSES COUCHES COTE NORD
ET POTENTIEL OCEANIQUE FAVORABLE). UN DEPLACEMENT EN DIRECTION
GENERALE DE L'OUEST RESTE ENVISAGEE.

LES HABITANTS DE LA MOITIE NORD DE LA COTE EST DE MADAGASCAR (AU NORD
DE 20S PRINCIPALEMENT,NOTAMMENT ENTRE LES VILLES DE TAMATAVE AU SUD
ET DE SAMBAVA AU NORD) SONT INVITES A SUIVRE L'EVOLUTION DE CE
SYSTEME AU COURS DES PROCHAINS JOURS AUPRES DES AUTORITES LOCALES. LA
DEGRADATION DES CONDITIONS METEOROLOGIQUES DANS LE SECTEUR POURRAIT
COMMENCER DANS LA NUIT DE VENDREDI A SAMEDI AVEC UN ATTERRISSAGE
POSSIBLE DANS LA NUIT DE SAMEDI A DIMANCHE OU DIMANCHE MATIN.CONFIRME=

>

Original Message :

WTIO30 FMEE 241806
RSMC / TROPICAL CYCLONE CENTER / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)

0.A WARNING NUMBER: 10/4/20202021
1.A MODERATE TROPICAL STORM 4 (CHALANE)

2.A POSITION 2020/12/24 AT 1800 UTC:
WITHIN 20 NM RADIUS OF POINT 15.5 S / 57.4 E
(FIFTEEN DECIMAL FIVE DEGREES SOUTH AND
FIFTY SEVEN DECIMAL FOUR DEGREES EAST)
MOVEMENT: WEST 9 KT

3.A DVORAK ANALYSIS: 2.5/2.5/D 0.5/24 H

4.A CENTRAL PRESSURE: 996 HPA
5.A MAX AVERAGE WIND SPEED (10 MN): 40 KT
RADIUS OF MAXIMUM WINDS (RMW): NIL

6.A EXTENSION OF WIND BY QUADRANTS (KM):
28 KT NE: 0 SE: 295 SW: 285 NW: 0
34 KT NE: 0 SE: 205 SW: 205 NW: 0

7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1007 HPA / 1100 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: DEEP

1.B FORECASTS (WINDS RADII IN KM):
12H: 2020/12/25 06 UTC: 15.6 S / 55.2 E, VENT MAX= 040 KT, MODERATE
TROPICAL STORM
28 KT NE: 0 SE: 380 SW: 335 NW: 0
34 KT NE: 0 SE: 195 SW: 150 NW: 0

24H: 2020/12/25 18 UTC: 15.7 S / 53.7 E, VENT MAX= 045 KT, MODERATE
TROPICAL STORM
28 KT NE: 100 SE: 380 SW: 335 NW: 85
34 KT NE: 95 SE: 205 SW: 150 NW: 75

36H: 2020/12/26 06 UTC: 15.9 S / 52.5 E, VENT MAX= 045 KT, MODERATE
TROPICAL STORM
28 KT NE: 120 SE: 380 SW: 335 NW: 85
34 KT NE: 110 SE: 215 SW: 150 NW: 75

48H: 2020/12/26 18 UTC: 16.4 S / 50.9 E, VENT MAX= 045 KT, MODERATE
TROPICAL STORM
28 KT NE: 140 SE: 380 SW: 335 NW: 85
34 KT NE: 130 SE: 220 SW: 150 NW: 75

60H: 2020/12/27 06 UTC: 16.7 S / 49.1 E, VENT MAX= 030 KT, OVERLAND
DEPRESSION
28 KT NE: 140 SE: 380 SW: 335 NW: 75

72H: 2020/12/27 18 UTC: 17.3 S / 46.9 E, VENT MAX= 025 KT, OVERLAND
DEPRESSION

2.B LONGER-RANGE OUTLOOK:
96H: 2020/12/28 18 UTC: 19.4 S / 43.6 E, VENT MAX= 030 KT, OVERLAND
DEPRESSION
28 KT NE: 185 SE: 380 SW: 335 NW: 95

120H: 2020/12/29 18 UTC: 19.3 S / 40.5 E, VENT MAX= 050 KT, SEVERE
TROPICAL STORM
28 KT NE: 260 SE: 380 SW: 335 NW: 110
34 KT NE: 250 SE: 280 SW: 150 NW: 100
48 KT NE: 100 SE: 140 SW: 110 NW: 90

2.C ADDITIONAL INFORMATION:
T=CI=2.5

THE CLOUD PATTERN HAS CHANGED LITTLE SINCE THIS MORNING AND REMAINS
THAT OF A SHEAR SYSTEM WITH THE CENTER LOCATED AT THE NORTHERN EDGE
OF THE REGULAR THUNDERSTORM CONVECTION GUSTS. THE DISTANCE BETWEEN
THE ESTIMATED CENTER AND THE EDGE OF THE CONVECTION HAS REMAINED ON
AVERAGE LESS THAN 0.75AO (ASSOCIATED WITH A DT OF 2.5). WITHOUT ANY
NOTABLE EVOLUTION OF THE CONFIGURATION, THE FINAL INTENSITY ESTIMATE
IS LEFT AT 40 KT (BASED ON THIS AFTERNOON ASCAT PASSES).

TODAY THE SHEAR SHOULD DECREASE WITH A SYSTEM EVOLVING ALMOST IN
PHASE WITH THE UPPER LEVELS RIDGE. THE ENVIRONMENT REMAINS DRY ON THE
OTHER HAND IN MID-TROPOSPHERE, ESPECIALLY IN THE NORTH OF THE SYSTEM
AND THIS SHOULD CONTINUE FOR THE NEXT 24 HOURS. THEREAFTER, THE
SYSTEM IS STILL EXPECTED TO EVOLVE IN A MOISTER AND LESS SHEARED
ENVIRONMENT WITH AN EXCELLENT UPPER LEVELS DIVERGENCE ON THE
EQUATORWARDS AS IT IS EXPECTED TO NEAR THE MALAGASY COAST. THE
DYNAMICAL GUIDANCES DO NOT ANALYZE WELL THE CURRENT INTENSIFICATION
TREND AND STILL DO NOT PROPOSE A CLEAR INTENSIFICATION DURING THIS
PERIOD. THE PRESENT INTENSITY FORECAST REMAINS THEREFORE RATHER
UNCERTAIN.

IN TERMS OF TRACK, NO CHANGE: THE SYSTEM IS MOVING ON THE NORTH TO
NORTH-WESTERN EDGE OF THE SUBTROPICAL HIGH PRESSURES FROM LOW TO MID
TROPOSPHERE. A SLOWDOWN IS POSSIBLE TOMORROW EVENING AS A BAROMETRIC
COL TEMPORARILY CIRCULATES FAR TO THE SOUTH.

THE INHABITANTS OF THE NORTHERN HALF OF THE EAST COAST OF MADAGASCAR
(NORTH OF 20S MAINLY, NOTABLY BETWEEN THE CITIES OF TAMATAVE IN THE
SOUTH AND SAMBAVA IN THE NORTH) ARE INVITED TO FOLLOW THE EVOLUTION
OF THIS SYSTEM DURING THE NEXT FEW DAYS WITH THE LOCAL AUTHORITIES.
THE DEGRADATION OF THE METEOROLOGICAL CONDITIONS IN THE SECTOR COULD
BEGIN IN THE NIGHT OF FRIDAY TO SATURDAY WITH A POSSIBLE LANDFALL
SATURDAY NIGHT OR SUNDAY MORNING.=

>

Original Message :

WTIO22 FMEE 241805
SECURITE
GALE WARNING FOR METAREA VII AND METAREA VIII (S)
ISSUED BY METEO-FRANCE/TROPICAL CYCLONE CENTER/LA REUNION 24/12/2020
AT 1800 UTC.
WARNING NUMBER: 010/4 (SOUTH-WEST INDIAN OCEAN)
10 MINUTES AVERAGE WIND SPEED IN KNOTS (KT)
(WIND GUSTS AT SEA MAY BE ABOUT 40% STRONGER THAN THE AVERAGED WIND)
MINIMUM SEA LEVEL PRESSURE IN HECTOPASCAL (HPA)
(INDICATIVE FIGURE).

GALE WARNING
BEGINNING OF VALIDITY: THURSDAY 24/12/2020 AT 1800 UTC.

PHENOMENON: MODERATE TROPICAL STORM 4 (CHALANE) 996 HPA
POSITION: WITHIN 20 NM RADIUS OF POINT 15.5 S / 57.4 E
(FIFTEEN DECIMAL FIVE DEGREES SOUTH AND
FIFTY SEVEN DECIMAL FOUR DEGREES EAST) AT 1800 UTC
MOVEMENT: WEST 9 KT

THREAT AREAS:
SQUALLY WEATHER EXTENDING UP TO 250 NM FROM THE CENTER IN THE
SOUTHERN SEMI-CIRCLE.

GALE FORCE WINDS 35/40 KT AND VERY ROUGH TO HIGH SEAS EXTENDING UP TO
110 NM IN THE SOUTHERN SEMI-CIRCLE.
NEAR GALE FORCE WINDS 30 KT AND ROUGH TO VERY ROUGH SEAS EXTENDING UP
TO 155 NM IN THE SOUTH-WESTERN QUADRANT AND UP TO 160 NM IN THE
SOUTH-EASTERN QUADRANT.
STRONG GUSTS UNDER SQUALLS.

FORECAST POSITION AND INTENSITY:
12H, VALID 2020/12/25 AT 06 UTC:
15.6 S / 55.2 E, MAX WIND = 40 KT, MODERATE TROPICAL STORM
28 KT NE: 0 NM SE: 205 NM SW: 180 NM NW: 0 NM
34 KT NE: 0 NM SE: 105 NM SW: 80 NM NW: 0 NM

24H, VALID 2020/12/25 AT 18 UTC:
15.7 S / 53.7 E, MAX WIND = 45 KT, MODERATE TROPICAL STORM
28 KT NE: 55 NM SE: 205 NM SW: 180 NM NW: 45 NM
34 KT NE: 50 NM SE: 110 NM SW: 80 NM NW: 40 NM

OTHER INFORMATION:
NIL.=

>

Disclaimer
While we try everything to ensure accuracy, this information is purely indicative and should not be used for any decision making without alternate sources of information.
The JRC is not responsible for any damage or loss resulting from the use of the information presented on this website.
The designations employed and the presentation of material on the map do not imply the expression of any opinion whatsoever on the part of the European Union concerning the legal status of any country, territory or area or of its authorities, or concerning the delimitation of its frontiers or boundaries.