WTIO30 FMEE 210643



RSMC / TROPICAL CYCLONE CENTER / LA REUNION

TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)



0.A WARNING NUMBER: 41/8/20152016

1.A SEVERE TROPICAL STORM  8  (FANTALA)



2.A POSITION 2016/04/21 AT 0600 UTC:

WITHIN 20 NM RADIUS OF POINT 12.3 S / 55.5 E

(TWELVE    DECIMAL THREE   DEGREES SOUTH AND FIFTY FIVE    DECIMAL

FIVE   DEGREES EAST)

MOVEMENT : EAST-SOUTH-EAST 6 KT



3.A DVORAK ANALYSIS: 4.0/4.0/W 1.5/24 H



4.A CENTRAL PRESSURE: 988 HPA

5.A MAX AVERAGE WIND SPEED (10 MN): 60 KT

RADIUS OF MAXIMUM WINDS (RMW) :46 KM



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

28 KT NE: 140 SE: 90 SW: 100 NW: 110

34 KT NE: 120 SE: 90 SW: 90 NW: 100

48 KT NE: 80 SE: 70 SW: 70 NW: 70





7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1011 HPA / 300 KM

8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION : DEEP



1.B FORECASTS:

12H: 2016/04/21 18 UTC: 12.7 S / 56.0 E, MAX WIND=055 KT, SEVERE

TROPICAL STORM

24H: 2016/04/22 06 UTC: 13.2 S / 55.9 E, MAX WIND=045 KT, MODERATE

TROPICAL STORM

36H: 2016/04/22 18 UTC: 13.4 S / 55.0 E, MAX WIND=040 KT, MODERATE

TROPICAL STORM

48H: 2016/04/23 06 UTC: 13.2 S / 53.7 E, MAX WIND=035 KT, MODERATE

TROPICAL STORM

60H: 2016/04/23 18 UTC: 12.6 S / 52.2 E, MAX WIND=035 KT, MODERATE

TROPICAL STORM

72H: 2016/04/24 06 UTC: 11.7 S / 50.8 E, MAX WIND=035 KT, MODERATE

TROPICAL STORM



2.B LONGER-RANGE OUTLOOK :

96H: 2016/04/25 06 UTC: 9.6 S / 47.0 E, MAX WIND=030 KT, TROPICAL

DEPRESSION

120H: 2016/04/26 06 UTC: 8.3 S / 42.8 E, MAX WIND=020 KT, LOW



2.C ADDITIONAL INFORMATION:

T=4.0- CI=4.0+



DURING THE LAST 6 HOURS, FANTALA'S CLOUD PATTERN HAS SLIGHTLY AGAIN

DETERIORATE WITH A CDO WHERE A FADING SPOT CAN STILL BE SPOTTED.

0242Z SSMIS MW IMAGE SHOWS THAT THE CONVECTION RING IS FULLY ERODED

IN THE SOUTH-EASTERN SEMI-CIRCLE.



UNTIL THIS EVENING, FANTALA'S TRACK IS STEERED BY TWO ATMOSPHERIC

PATTERNS : THE NEAR EQUATORIAL RIDGE IN ITS NORTH-EAST AND A WIDE

MID-LATITUDES TROUGH COMING FROM THE SOUTH-WEST. A NEW HIGH

GEOPOTENTIAL CELL FOLLOWING THE TROUGH IS THEN SETTLING OVER THE

SOUTH OF MADAGASCAR AND SHOULD EXTEND NORTHWARD. THIS RIDGE SHOULD

PROGRESSIVELY STEER THE SYSTEM. SO, FANTALA HAS SLOWED DOWN. THIS

NIGHT, THE SYSTEM SHOULD BEGIN TO CURVE SOUTHWARDS THIS NIGHT AND

RESTART A NORTHWESTWARD TRACK FRIDAY NIGHT.

FOR THE FOLLOWING DAYS, THE SYSTEM IS LIKELY TO REMAIN STEERED BY

THIS HIGH SUBTROPICAL CELL IN THE LOW AND MID TROPOSPHERE, AND SHOULD

KEEP ON A NORTH-WESTWARD TRACK. ON THIS PART OF THE TRACK, THE

AGREEMENT BETWEEN THE MODELS IS A BIT LOWER WITH THE GFS TRACK STILL

MORE SOUTHWARD THAN THE ECMWF ONE.



AS IT HEADS BACK ON ITS TRACK, FANTALA IS CURRENTLY PASSING OVER AN

OCEANIC AREA PREVIOUSLY COOLED BY ITSELF 5 DAYS AGO. THIS LACK OF

OCEANIC ENERGY SHOULD GRADUALLY WEAKEN THE SYSTEM.

WITH A NEW SLOW TRACK TURN EXPECTED FRIDAY OVER A LOW OHC AREA AND

SIGNIFICANTLY LESS FAVORABLE ATMOSPHERIC CONDITIONS (WEAKENING OF THE

UPPER LEVEL DIVERGENCE ESPECIALLY EVEN ON THE POLAR SIDE, INCREASE OF

THE NORTHERLY SHEAR MORE SIGNIFICANTLY FROM SATURDAY WHEN IT TURNS

WESTERLY, VERY DRY MID-LEVEL AIR MASS SURROUNDING THE SYSTEM FROM

FRIDAY AND BEYOND), FANTALA'S ENVIRONMENT SHOULD LEAD TO A SUSTAINED

WEAKENING OVER THE WEEK-END AND FURTHER.=