WTIO30 FMEE 171905



RSMC / TROPICAL CYCLONE CENTER / LA REUNION

TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)



0.A WARNING NUMBER: 15/6/20142015

1.A MODERATE TROPICAL STORM  6  (CHEDZA)



2.A POSITION 2015/01/17 AT 1800 UTC:

WITHIN 30 NM RADIUS OF POINT 22.1 S / 50.3 E

(TWENTY TWO    DECIMAL ONE   DEGREES SOUTH AND FIFTY    DECIMAL THREE

DEGREES EAST)

MOVEMENT : EAST-SOUTH-EAST 10 KT



3.A DVORAK ANALYSIS: 2.5/2.5/D 1.0/12 H



4.A CENTRAL PRESSURE: 990 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: 200 SE: 460 SW: 330 NW: 200

34 KT NE: 170 SE: 300 SW: 190 NW: 150







7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1000 HPA / 800 KM

8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION : MEDIUM



1.B FORECASTS:

12H: 2015/01/18 06 UTC: 22.5 S / 51.5 E, MAX WIND=040 KT, MODERATE

TROPICAL STORM

24H: 2015/01/18 18 UTC: 22.9 S / 52.2 E, MAX WIND=045 KT, MODERATE

TROPICAL STORM

36H: 2015/01/19 06 UTC: 23.7 S / 52.7 E, MAX WIND=045 KT, MODERATE

TROPICAL STORM

48H: 2015/01/19 18 UTC: 24.7 S / 53.1 E, MAX WIND=050 KT, SEVERE

TROPICAL STORM

60H: 2015/01/20 06 UTC: 25.8 S / 53.6 E, MAX WIND=050 KT, SEVERE

TROPICAL STORM

72H: 2015/01/20 18 UTC: 27.1 S / 54.6 E, MAX WIND=050 KT,

POST-TROPICAL DEPRESSION



2.B LONGER-RANGE OUTLOOK :

96H: 2015/01/21 18 UTC: 29.2 S / 57.1 E, MAX WIND=040 KT,

POST-TROPICAL DEPRESSION

120H: 2015/01/22 18 UTC: 31.9 S / 61.7 E, MAX WIND=040 KT,

EXTRATROPICAL SYSTEM



2.C ADDITIONAL INFORMATIONS:

T=CI=2.5



THE CURRENT POSITION IS EXTRAPOLATED FROM MW FIX FROM THIS EVENING

AND ON MET7 IMAGERY.



THE CURRENT INTENSITY ASSESSMENT IS HIGHER THAN ALL AVAILABLE DVORAK

ESTIMATES (RANGING FROM 25-35 KT) BASED ON IMPROVING ORGANISATION

SEEN ON MW IMAGERY AND ON 30-35 KT WINDS READ ON ASCAT PASS OF 1737Z

FAR FROM THE CENTER WITHIN THE EASTERN SECTOR THAT MAKE BELIEVABLE

THAT 35-40 KT WINDS EXIST AT LEAST OVER A LARGE PORTIONS OF THE

SOUTHERN SECTOR.



THE SYSTEM IS ON A TRACK GLOBALLY EASTWARD ON THE SOUTHERN EDGE OF

THE NEAR-EQUATORIAL RIDGE. FROM TOMORROW, IT WILL SLOW DOWN AND TURN

SOUTH-SOUTH-EASTWARD TOWARDS A MID-LATITUDES TROUGH .



ON THIS PATH, FOR THE NEXT 24HOURS, THE UPPER LEVEL

WEST-NORTH-WESTERLY  WINDSHEAR WILL REMAIN MODERATE ALOFT, AND WILL

HINDER THE DEEPENING OF THE SYSTEM, DESPITE A GOOD LOW LEVELS

CONVERGENCE, AND A GOOD OCEANIC HEAT POTENTIAL.

FOR THE FOLLOWING 24H TO 36H (FROM SUNDAY 12Z TO TUESDAY 00Z) , THE

UPPER LEVEL WINDSHEAR IS LIKELY TO DECREASE AND A GOOD OUTFLOW

CHANNEL IS LIKELY TO BUILT POLEWARD, ALLOWING THE SYSTEM TO DEEPEN

MORE SIGNIFICANTLY.

FROM TUESDAY, THE INCREASING UPPER LEVEL WINDSHEAR IS LIKELY TO LIMIT

FURTHER INTENSIFICATION.

AT THE END OF THE FORECAST RANGE (THURSDAY) THE OCEANIC HEAT

POTENTIAL SHOULD DECREASE AND THE SYSTEM SHOULD ADOPT POST-TROPICAL

FEATURES.=