WTIO30 FMEE 141238
RSMC / TROPICAL CYCLONE CENTER / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)

0.A WARNING NUMBER: 9/1/20202021
1.A SEVERE TROPICAL STORM 1 (ALICIA)

2.A POSITION 2020/11/14 AT 1200 UTC:
WITHIN 20 NM RADIUS OF POINT 9.6 S / 77.4 E
(NINE DECIMAL SIX DEGREES SOUTH AND
SEVENTY SEVEN DECIMAL FOUR DEGREES EAST)
MOVEMENT: SOUTH-WEST 15 KT

3.A DVORAK ANALYSIS: 3.5/3.5/D 1.0/24 H

4.A CENTRAL PRESSURE: 992 HPA
5.A MAX AVERAGE WIND SPEED (10 MN): 50 KT
RADIUS OF MAXIMUM WINDS (RMW): 50 KM

6.A EXTENSION OF WIND BY QUADRANTS (KM):
28 KT NE: 190 SE: 240 SW: 170 NW: 160
34 KT NE: 120 SE: 120 SW: 120 NW: 60
48 KT NE: 60 SE: 60 SW: 0 NW: 0


7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): NIL
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: DEEP

1.B FORECASTS:
12H: 2020/11/15 00 UTC: 11.8 S / 74.9 E, VENT MAX= 060 KT, SEVERE
TROPICAL STORM
24H: 2020/11/15 12 UTC: 14.2 S / 73.6 E, VENT MAX= 070 KT, TROPICAL
CYCLONE
36H: 2020/11/16 00 UTC: 16.2 S / 73.4 E, VENT MAX= 080 KT, TROPICAL
CYCLONE
48H: 2020/11/16 12 UTC: 17.4 S / 73.3 E, VENT MAX= 060 KT, SEVERE
TROPICAL STORM
60H: 2020/11/17 00 UTC: 18.6 S / 73.2 E, VENT MAX= 040 KT, MODERATE
TROPICAL STORM
72H: 2020/11/17 12 UTC: 19.9 S / 73.1 E, VENT MAX= 030 KT, FILLING UP

2.B LONGER-RANGE OUTLOOK:
96H: 2020/11/18 12 UTC: 22.9 S / 72.6 E, VENT MAX= 025 KT, FILLING UP

2.C ADDITIONAL INFORMATION:
T=CI=3.5+

THE CLOUD PATTERN HAS EVOLVED IN A CDO PATTERN SINCE LATE MORNING
WITH OCCASIONAL EYE-LIKE FEATURES ON VISIBLE IMAGERY AROUND MIDDAY.
THE MICROWAVE IMAGERY OF 0845Z AND 1101Z SHOW HOWEVER THAT THE INNER
CORE IS STRUGGLING TO ORGANIZE ITSELF IN THE MID-LEVELS IN POSSIBLE
CONNECTION WITH A MODERATE EASTERLY CONSTRAINT. THE WATER VAPOR
IMAGING CLEARLY MATERIALIZES A POOR OUTFLOW IN THE EASTERN SEMICIRCLE
WHILE IT IS EXCELLENT IN THE WESTERN SEMICIRCLE. THE INTENSITY
ESTIMATE REMAINS AT 50 KT IN GOOD AGREEMENT BETWEEN THE HIGHEST
SUBJECTIVE DVORAK ESTIMATES AND THE ADT.

ALICIA HAS WELL RESUMED A RAPID SOUTHWESTWARD MOVEMENT STEERED BY THE
STEERING FLOW GENERATED BY THE SUBTROPICAL RIDGE. WITH THE ARRIVAL OF
A DEEP LAYERS TROUGH FROM THE SOUTHWEST, THE RIDGE IS GRADUALLY
SHIFTING EASTWARD AND WILL LEAVE A NORTHERLY FLOW FROM SUNDAY
ONWARDS. THE NUMERICAL MODELS ARE IN GOOD AGREEMENT ON THIS GLOBAL
TRAJECTORY. AT THE END OF THE FORECAST PERIOD, THE UNCERTAINTY
INCREASES IN RELATION TO THE WEAK STEERING FLOW AND THE EXISTENCE OF
TWO POSSIBLE SCENARIOS: THE PERSISTENCE OF A SOUTHWARDS TO
SOUTHEASTWARDS TRACK OR A SOUTHWESTWARDS OR WESTWARDS DRIFT OF A
REMNANT LOW IN THE TRADE WIND FLOW.

ON THIS TRAJECTORY, THE ENVIRONMENTAL CONDITIONS ARE VERY FAVORABLE
UNTIL MONDAY MORNING. WITH THE HELP OF THE STRENGTHENING EQUATORIAL
WESTERLY WINDS, A VERY GOOD DIVERGENCE, LITTLE SHEAR AND A VERY
STRONG OCEANIC POTENTIAL, THE SYSTEM SHOULD REACH THE TROPICAL
CYCLONE STAGE TOMORROW. BY EARLY NEXT WEEK, HOWEVER, CONDITIONS ARE
EXPECTED TO DETERIORATE SIGNIFICANTLY WITH INSUFFICIENT OCEANIC
POTENTIAL SOUTH OF 17S, INCREASING SHEAR, GRADUALLY ASSOCIATED WITH
INTRUSIONS OF DRY MID-TROPICAL AIR.=
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