WTIO30 FMEE 211221



RSMC / TROPICAL CYCLONE CENTER / LA REUNION

TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)



0.A WARNING NUMBER: 8/1/20152016

1.A MODERATE TROPICAL STORM  1  (ANNABELLE)



2.A POSITION 2015/11/21 AT 1200 UTC:

WITHIN 20 NM RADIUS OF POINT 10.7 S / 71.4 E

(TEN    DECIMAL SEVEN   DEGREES SOUTH AND SEVENTY ONE    DECIMAL FOUR

DEGREES EAST)

MOVEMENT : SOUTH 3 KT



3.A DVORAK ANALYSIS: 3.0/3.0/S 0.0/6 H



4.A CENTRAL PRESSURE: 993 HPA

5.A MAX AVERAGE WIND SPEED (10 MN): 40 KT

RADIUS OF MAXIMUM WINDS (RMW) :46 KM



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

28 KT NE: 190 SE: 190 SW: 190 NW: 150

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







7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1007 HPA / 700 KM

8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION : DEEP



1.B FORECASTS:

12H: 2015/11/22 00 UTC: 11.7 S / 71.6 E, MAX WIND=045 KT, MODERATE

TROPICAL STORM

24H: 2015/11/22 12 UTC: 13.2 S / 71.9 E, MAX WIND=045 KT, MODERATE

TROPICAL STORM

36H: 2015/11/23 00 UTC: 14.5 S / 72.8 E, MAX WIND=035 KT, MODERATE

TROPICAL STORM

48H: 2015/11/23 12 UTC: 15.9 S / 73.7 E, MAX WIND=030 KT, TROPICAL

DEPRESSION

60H: 2015/11/24 00 UTC: 17.1 S / 75.0 E, MAX WIND=030 KT, TROPICAL

DEPRESSION

72H: 2015/11/24 12 UTC: 18.1 S / 75.7 E, MAX WIND=025 KT, LOW



2.B LONGER-RANGE OUTLOOK :

96H: 2015/11/25 12 UTC: 19.6 S / 74.1 E, MAX WIND=020 KT, REMNANT LOW

120H: 2015/11/26 12 UTC: 20.1 S / 69.4 E, MAX WIND=020 KT, REMNANT

LOW



2.C ADDITIONAL INFORMATION:

FT=CI=3.0+



DURING THE LAST 6 HOURS, DEEP CONVECTION REACH A THRESHIOLD WITH A

SLIGHT WARMING OF THE SUMMITS NEAR THE CENTER. ON THE LAST PICTURES,

A BURST OF DEEP CONVECTION IS OBSERVED ON THE CENTRAL PARTS. THE

STRUCTURE IS HARDLY CONSOLIDATING TO A CURVED BAND.



THE CURRENT SOUTHESTWARDS TRACK IS SLOW DURING THE NEXT HOURS.

AVAILABLE NWP ARE IN GOOD AGREEMENT TO FORECAST A SIMILAR MOVEMENT

TOWARDS A WEAKNESS IN THE PRESSURE FIELD TO THE SOUTH OF THE SYSTEM.

THIS TRACK IS SUPPORTED BY THE PRESENCE OF AN EQUATORIAL MID LEVEL

RIDGE EXPECTED TO BUILD IN THE EAST-NORTH-EAST OF THE SYSTEM.



ALONG THIS TRACK, ENVIRONMENTAL CONDITIONS REMAIN FAVOURABLE WITH A

GOOD UPPER LEVEL DIVERGENCE, WEAK VERTICAL WINDSHEAR AND ONE POLAR

OUTFLOW CHANNEL. THIS WINDOW FOR INTENSIFICATION SHOULD ALLOW THE

SYSTEM TO KEEP ITS CURRENT INTENSITY OR SLIGHTLY STRENGTHEN.



BUT ON SUNDAY AFTERNOON, NORTHERLY VERTICAL WINDSHEAR SHOULD INCREASE

AHEAD OF A UPPER LEVEL TROUGH AND THE SYSTEM SHOULD WEAKEN. MOREOVER,

THE HEAT CONTENT WILL BECOME MARGINAL SOUTH OF 13S. FROM TUESDAY,

THERE IS STILL SOME UNCERTAINTY. THE LOW LEVEL CIRCULATION COULD

INTERACT WITH THE UPPER TROUGH AND CONTINUE SOUTHEASTWARD OR TRACK

EASTWARDS IN THE TRADES FLOW FILLING UP PROGRESSIVELY.=