WTIO30 FMEE 300016 CCA

***************CORRECTIVE**************



RSMC / TROPICAL CYCLONE CENTER / LA REUNION

TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)



0.A WARNING NUMBER: 6/9/20172018

1.A SEVERE TROPICAL STORM  9  (FLAMBOYAN)



2.A POSITION 2018/04/30 AT 0000 UTC:

WITHIN 30 NM RADIUS OF POINT 14.1 S / 85.0 E

(FOURTEEN    DECIMAL ONE   DEGREES SOUTH AND EIGHTY FIVE    DECIMAL

ZERO   DEGREES EAST)

MOVEMENT : SOUTH-SOUTH-WEST 9 KT



3.A DVORAK ANALYSIS: 3.5/3.5/W 0.5/6 H



4.A CENTRAL PRESSURE: 990 HPA

5.A MAX AVERAGE WIND SPEED (10 MN): 50 KT

RADIUS OF MAXIMUM WINDS (RMW) :37 KM



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

28 KT NE: 150 SE: 410 SW: 410 NW: 110

34 KT NE: 70 SE: 150 SW: 150 NW:

48 KT NE: 40 SE: 60 SW: 40 NW:





7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1007 HPA / 1500 KM

8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION : DEEP



1.B FORECASTS:

12H: 2018/04/30 12 UTC: 15.6 S / 84.1 E, MAX WIND=045 KT, MODERATE

TROPICAL STORM

24H: 2018/05/01 00 UTC: 16.9 S / 83.6 E, MAX WIND=035 KT, MODERATE

TROPICAL STORM

36H: 2018/05/01 12 UTC: 18.3 S / 83.4 E, MAX WIND=035 KT,

POST-TROPICAL DEPRESSION

48H: 2018/05/02 00 UTC: 19.8 S / 83.6 E, MAX WIND=035 KT,

POST-TROPICAL DEPRESSION

60H: 2018/05/02 12 UTC: 20.8 S / 84.2 E, MAX WIND=035 KT,

EXTRATROPICAL DEPRESSION

72H: 2018/05/03 00 UTC: 22.2 S / 85.4 E, MAX WIND=030 KT,

EXTRATROPICAL DEPRESSION



2.B LONGER-RANGE OUTLOOK :

96H: 2018/05/04 00 UTC: 28.5 S / 91.5 E, MAX WIND=035 KT,

EXTRATROPICAL DEPRESSION





2.C ADDITIONAL INFORMATION:

T=3.5- CI=3.5



ENVIRONMENTAL DRY AIR HAS REDUCED THE SIZE OF FLAMBOYAN THAT CONSISTS

OF A SMALL VERY COLD CDO. 2055Z SSMI 85 GHZ MICROWAVE SHOWS THAT THE

INTERNAL CORE HAS SUFFERED DURING THE LAST HOURS WITH THE EROSION OF

THE MICROWAVE EYE FEATURE. DATA FROM 1604Z ASCAT SHOWED THAT STORM

FORCE WINDS ARE LOCATED ESSENTIALLY WITHIN THE SOUTHEASTERN QUADRANT.

SO THE INTENSITY IS ESTIMATED AT 50 KT.



DURING THE NIGHT, WITH THE WEAKENING OF THE MID TROPOSPHERE RIDGE AT

SOUTH, THE SYSTEM HAS BENDED SOUTHWESWARD. FROM TUESDAY, FLAMBOYAN IS

EXPECTED TO CURVE SOUTH THEN ACCELERATING SOUTHEASTWARD FROM

WEDNESDAY AHEAD A MID/UPPER LEVEL TOUGH BEFORE EVACUATE TOWARD THE

MID-LATITUDE. THE RSMC TRACK FORECAST IS BASED ON A MODEL CONSENSUS.



TODAY, ENVIRONMENTAL CONDITIONS BEGIN TO DETERIORATE. EQUATORWARD

UPPER LEVEL DIVERGENCE BECOMES POOR BUT POLERWARD DIVERGENCE REMAINS

VERY GOOD AHEAD AN UPPER LEVEL TROUGH. BUT, PROGRESSIVELY,

NORTHWESTWARD VERTICAL WINDSHEAR ASSOCIATED TO THE TROUGH IS

FORECASTED TO NOTICEABLY INCREASE LEADING TO A QUICK WEAKENING OF THE

SYSTEM FROM MONDAY NIGHT. FROM WEDNESDAY, INTERACTING WITH THE

SUBTROPICAL JETSTREAM AND EVOLVING OVER COOLER SST, THE SYSTEM SHOULD

START ITS EXTRAPOLISATION PHASE AND GAIN QUICKLY FRONTAL

CHARACTERISTICS.=