WTIO30 FMEE 161239
RSMC / TROPICAL CYCLONE CENTRE / LA REUNION
TROPICAL CYCLONE TECHNICAL BULLETIN (SOUTH-WEST INDIAN OCEAN)
0.A WARNING NUMBER : 6/12/20092010
1.A MODERATE TROPICAL STORM 12 (GELANE)
2.A POSITION 2010/02/16 AT 1200 UTC :
WITHIN 20 NM RADIUS OF POINT 12.6S / 60.2E
(TWELVE DECIMAL SIX DEGREES SOUTH AND SIXTY DECIMAL TWO DEGREES EAST)
MOVEMENT : SOUTH 4 KT
3.A DVORAK ANALYSIS : 3.0/3.0 /D 1.0/24 H
4.A CENTRAL PRESSURE : 990 HPA
5.A MAX AVERAGE WIND SPEED (10 MN) : 40 KT
RADIUS OF MAXIMUM WINDS (RMW) : 15 KM
6.A EXTENSION OF WINDS BY QUADRANTS (KM):
30 KT NE: 170 SE: 170 SO: 075 NO: 075
7.A FIRST CLOSED ISOBARE (PRESSURE / AVERAGE DIAM): 1008 HPA / 850 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: DEEP
1.B FORECASTS:
12H: 2010/02/17 00 UTC: 13.3S/60.5E, MAX WIND=050KT, SEVERE TROP.
STORM.
24H: 2010/02/17 12 UTC: 14.1S/60.7E, MAX WIND=060KT, SEVERE TROP.
STORM.
36H: 2010/02/18 00 UTC: 14.5S/60.8E, MAX WIND=070KT, TROPICAL
CYCLONE.
48H: 2010/02/18 12 UTC: 15.0S/60.7E, MAX WIND=080KT, TROPICAL
CYCLONE.
60H: 2010/02/19 00 UTC: 15.4S/60.6E, MAX WIND=080KT, TROPICAL
CYCLONE.
72H: 2010/02/19 12 UTC: 15.9S/60.5E, MAX WIND=070KT, TROPICAL
CYCLONE.
2.B OTHER INFORMATIONS:
T=CI=3.0+
SYSTEM HAS BEEN NAMED GELANE AT 0900Z BY THE MAURITIUS METEOROLOGICAL
SERVICES.
NOAA 19 MICROWAVE PASS AT 0916Z DEPICTS A WELL DEFINED CENTER WITH
FORMATION OF AN OEIL FEATURE ON 85 GHZ. OVER THE LAST SATELLITE
PICTURES,
CURVED BAND STRUCTURE SEEMS TO EVOLVE TOWARDS CDO PATTERN WITH
BULDING
CONVECTION NEAR THE CENTER.
SYSTEM HAS MOVED SOUTHWARDS OVER THE LAST 6 HOURS AND SLOWED DOWN.
IT SHOUD CONTINU ON ITS SLOW SOUTHERLY TO SOUTHSOUTHEASTERLY MOTION
FOR
THE NEXT 48 HOURS AS STEERING FLOW ASSOCIATED TO THE NEAR EQUATORIAL
RIDGE IS BALANCED BY THE SUBTROPICAL RIDGE LOCATED TO THE SOUTH.
BEYOND, AVAILABLE NWP MODELS SHOW STRONG DISAGREEMENT AS THEY SPLIT
INTO
2 ENSEMBLES OF TRACKS. GFDN, UKMO AND AVNO HAVE THE MOST EASTERLY
SCENRIO
WITH SOUTHEASTWARDS TRACKS ALONG THE WHOLE FORECAST PERIOD. ON THE
OTHER
HAND, ECMWF, ALADIN-REUNION, AND ARPEGE SHOW A GRADUAL TURN TOWARDS
THE
SOUTHWES
T. PRESENT FORECAST REMAINS IN THE PHILOSOPHY OF PREVIOUS ADVISORY
AND IS
CLOSE TO THE TRACKS FOLLOWED BY THE EUROPEAN MODELS. THEREFORE,
THERE IS
A LOWER THAN USUAL CONFIDENCE IN THE FORECAST TRACK.
CONDITIONS REMAIN FAVOURABLE FOR REGULAR INTENSIFICATION FOR THE NEXT
2
TO 3 DAYS. BEYOND, AN UPPER LEVEL TROUGHS HOULD TAKE PLACE BETWEEN
MADAGASCAR AND LA REUNION AND ACCORDING TO THE PRESENT FORCAST TRACK
SHOULD INDUCE INCREASING NORTHWESTERLY SHEAR
FORECASTS BEYOND TAU 72H (CAUTION, ERROR MAY BE LARGE):
096H: 2010/02/20 12 UTC: 17.0S/60E, MAX WIND=050KT , SEVERE TROP.
STORM.
120H: 2010/02/21 12 UTC: 18.6S/58.7E, MAX WIND=040KT , MODERATE TROP.
STORM.=
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