WTIO30 FMEE 231807



RSMC / TROPICAL CYCLONE CENTER / LA REUNION

TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)



0.A WARNING NUMBER: 51/8/20152016

1.A MODERATE TROPICAL STORM  8  (FANTALA)



2.A POSITION 2016/04/23 AT 1800 UTC:

WITHIN 30 NM RADIUS OF POINT 11.6 S / 54.6 E

(ELEVEN    DECIMAL SIX   DEGREES SOUTH AND FIFTY FOUR    DECIMAL SIX

DEGREES EAST)

MOVEMENT : WEST-NORTH-WEST 9 KT



3.A DVORAK ANALYSIS: 2.0/2.5/W 2.0/24 H



4.A CENTRAL PRESSURE: 999 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: 120 SE: 120 SW: 80 NW: 80

34 KT NE: 70 SE: 70 SW: 60 NW: 60







7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1009 HPA / 400 KM

8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION : MEDIUM



1.B FORECASTS:

12H: 2016/04/24 06 UTC: 11.3 S / 53.5 E, MAX WIND=025 KT, TROPICAL

DISTURBANCE

24H: 2016/04/24 18 UTC: 10.9 S / 52.2 E, MAX WIND=025 KT, LOW

36H: 2016/04/25 06 UTC: 10.0 S / 50.6 E, MAX WIND=025 KT, LOW

48H: 2016/04/25 18 UTC: 9.3 S / 48.4 E, MAX WIND=020 KT, LOW

60H: 2016/04/26 06 UTC: 8.8 S / 46.3 E, MAX WIND=020 KT, DISSIPATING

72H: 2016/04/26 18 UTC: 8.1 S / 44.5 E, MAX WIND=020 KT, DISSIPATING



2.B LONGER-RANGE OUTLOOK :







2.C ADDITIONAL INFORMATION:

T=2.0, CI=2.5+



OVER THE PAST 6 HOURS, THE CONVECTION HAS BLOWN UP AND DOWN IN THE

EASTERN SECTOR OF THE SYSTEM. THE VERY LAST IR PICTURES DEPICT A

DECREASING CONVECTIVE ACTIVITY.

THE LAST MW PICTURES DEPICT THE DRY AIR WRAPPING AROUND EX-FANTALA.

THE VERTICAL WIND SHEAR HAS REMAINED WEAK.



A LOW/MID LEVEL SUBTROPICAL RIDGE IS LOCATED IN THE SOUTH OF FANTALA.

THIS SYNOPTIC PATTERN IS GENERATING A LONG-LASTING SOUTH-EASTWARD

STEERING FLOW. THUS, FANTALA IS NOW MOVING TOWARD THE NORTHWEST AND

IS FORECASTED TO KEEP ON TRACKING IN THIS DIRECTION UNTIL THE END OF

THE FORECAST PERIOD. THE MODEL AGREEMENT IS GOOD AND THE AVAILABLE

ENSEMBLE PREDICTION SHOW VERY LITTLE DISPERSION.



ALONG THIS TRACK, FANTALA SHOULD EVOLVE NORTH OF THE UPPER LEVEL

WESTERN WIND BELT WHICH IS EXPECTED TO MOVE NORTHWARD IN THE NEXT FEW

DAYS. THUS VERTICAL WIND SHEAR SHOULD REMAINS RATHER WEAK, AT LEAST

UNTIL TUESDAY. HOWEVER, FANTALA IS CURRENTLY TRACKING OVER LOW

ENERGETIC WATERS, AN AREA THAT IT ALREADY CROSSED TWICE. LAST,

ASSOCIATED TO THE LOW/MID LEVEL SUBTROPICAL RIDGE, THE SOUTHEASTWARD

STEERING FLOW SHOULD CONTINUE TO BRING A DRY AIR MASS FROM THE

MID-LATITUDES, DRYING FANTALA'S ENVIRONMENT. THUS, WITHIN THESE

UNFAVOURABLE ENVIRONMENTAL CONDITIONS (ESPECIALLY FOR A MIDGET

SYSTEM), FANTALA IS LIKELY TO CONTINUE TO WEAKEN VERY RAPIDLY DURING

THE NEXT DAYS. THIS INTENSITY FORECAST IS CONSISTENT WITH THE SHARP

DECREASE OF THE STORM SIGNAL IN THE 00Z ECMWF ENSEMBLE PREDICTION

RUN.=