WTIO30 FMEE 090708



RSMC / TROPICAL CYCLONE CENTER / LA REUNION

TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)



0.A WARNING NUMBER: 19/13/20142015

1.A TROPICAL CYCLONE  13  (JOALANE)



2.A POSITION 2015/04/09 AT 0600 UTC:

WITHIN 20 NM RADIUS OF POINT 16.5 S / 65.6 E

(SIXTEEN    DECIMAL FIVE   DEGREES SOUTH AND SIXTY FIVE    DECIMAL

SIX   DEGREES EAST)

MOVEMENT : SOUTH-EAST 6 KT



3.A DVORAK ANALYSIS: 4.0/4.5/W 0.5/24 H



4.A CENTRAL PRESSURE: 977 HPA

5.A MAX AVERAGE WIND SPEED (10 MN): 65 KT

RADIUS OF MAXIMUM WINDS (RMW) :19 KM



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

28 KT NE: 330 SE: 500 SW: 280 NW: 260

34 KT NE: 190 SE: 280 SW: 240 NW: 150

48 KT NE: 70 SE: 90 SW: 70 NW: 60

64 KT NE: 30 SE: 30 SW: 30 NW: 0



7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1006 HPA / 1100 KM

8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION : DEEP



1.B FORECASTS:

12H: 2015/04/09 18 UTC: 18.1 S / 66.2 E, MAX WIND=075 KT, TROPICAL

CYCLONE

24H: 2015/04/10 06 UTC: 19.2 S / 67.0 E, MAX WIND=085 KT, TROPICAL

CYCLONE

36H: 2015/04/10 18 UTC: 20.7 S / 68.4 E, MAX WIND=080 KT, TROPICAL

CYCLONE

48H: 2015/04/11 06 UTC: 22.4 S / 69.4 E, MAX WIND=070 KT, TROPICAL

CYCLONE

60H: 2015/04/11 18 UTC: 24.7 S / 69.8 E, MAX WIND=060 KT, SEVERE

TROPICAL STORM

72H: 2015/04/12 06 UTC: 26.9 S / 69.7 E, MAX WIND=050 KT,

POST-TROPICAL DEPRESSION



2.B LONGER-RANGE OUTLOOK :

96H: 2015/04/13 06 UTC: 29.0 S / 69.0 E, MAX WIND=045 KT,

POST-TROPICAL DEPRESSION

120H: 2015/04/14 06 UTC: 31.2 S / 72.4 E, MAX WIND=040 KT,

POST-TROPICAL DEPRESSION



2.C ADDITIONAL INFORMATIONS:

T=4.0- AND CI=4.5-



THE CLOUD PATTERN OF THE SYSTEM ARE STILL FLUCTUATING. AFTER A

DEGENERATIVE PHASES BETWEEN 00Z AND 03Z (ATTESTED BY MW PICS SHOWING

SIGNIFICANT COLLAPSING OF THE INNER-CORE STRUCTURE), DEEP CONVECTION

HAS RESTARTED TO DEVELOP WITHIN THE EYEWALL WITH A TEMPORARILY RAGGED

EYE THAT APPEARED IN EIR BETWEEN 05Z AND 06Z. THE INTENSITY IS HELD

AT 65 KT BUT THIS COULD BE GENEROUS GIVEN THE EVOLUTION OVER THE LAST

6 HOURS. ADT IS AT 60 KT (10 MIN WINDS) AT 06Z.



THE REASON OF THIS INTENSITY FLUCTUATIONS ARE NOT WELL UNDERSTOOD. TO

THE SLIGHT NORTHERLY CONSTRAINT (ANALYZED BY THE CIMSS) AND MENTIONED

PREVIOUSLY, ONE MAY ADD THE NEGATIVE FEED-BACK OF THE SST AS JOALANE

HAS COME-BACK OVER ITS LOCATION THREE DAYS AGO.



AS JOALANE IS NOW EXPECTED TO MOVE AWAY OF THIS AREA AND ATMOSPHERIC

CONDITIONS ARE EXPECTED TO REMAIN FAVORABLE, JOALANE HAS THE

POTENTIAL TO RE-INTENSFY UP TO FRIDAY EVENNING.

FROM SATURDAY, IT COULD WEAKEN CLEARLY, UNDER THE NEGATIVE EFFECT OF

BOTH STRENGTHENING VWS AND LOWERING OF THE OHC.



JOALANE IS CURRENTLY MOVING SOUTH-SOUTH-EASTWARD TOWARDS A BAROMETRIC

COL AND UNDER THE STEERING INFLUENCE OF A MID-TROPOSPHERIC RIDGE IN

ITS EAST. AT THE END OF THE FORECAST PERIOD, IT COULD SLOW UNDER THE

INFLUENCE OF A RIDGE IN ITS SOUTH-WEST.



THERE IS A GOOD CONSENSUS ABOUT THIS TRACK AMONG THE LAST AVALAIBLE

NWP MODELS.=