347
WTIO30 FMEE 060638
RSMC / TROPICAL CYCLONE CENTRE / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)
0.A WARNING NUMBER : 18/8/20082009
1.A TROPICAL CYCLONE 8 (GAEL)
2.A POSITION 2009/02/06 AT 0600 UTC :
WITHIN 20 NM RADIUS OF POINT 18.4S / 53.1E
(EIGHTEEN DECIMAL FOUR DEGREES SOUTH AND FIFTY THREE DECIMAL ONE DEGREES
EAST)
MOVEMENT : WEST 8 KT
3.A DVORAK ANALYSIS : 5.0/5.0 /D 0.5/6 H
4.A CENTRAL PRESSURE : 955 HPA
5.A MAX AVERAGE WIND SPEED (10 MN) : 75 KT
RADIUS OF MAXIMUM WINDS (RMW) : 35 KM
6.A EXTENSION OF WINDS BY QUADRANTS (KM):
30 KT NE: 300 SE: 300 SO: 250 NO: 250
50 KT NE: 050 SE: 070 SO: 070 NO: 050
7.A FIRST CLOSED ISOBARE (PRESSURE / AVERAGE DIAM): 1008 HPA / 900 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: DEEP
1.B FORECASTS:
12H: 2009/02/06 18 UTC: 18.8S/51.8E, MAX WIND=090KT, INTENSE TROP. CYCL..
24H: 2009/02/07 06 UTC: 19.9S/50.9E, MAX WIND=100KT, INTENSE TROP. CYCL..
36H: 2009/02/07 18 UTC: 20.8S/50.8E, MAX WIND=110KT, INTENSE TROP. CYCL..
48H: 2009/02/08 06 UTC: 22.2S/51.2E, MAX WIND=100KT, INTENSE TROP. CYCL..
60H: 2009/02/08 18 UTC: 24.0S/51.9E, MAX WIND=090KT, INTENSE TROP. CYCL..72H: 2009/02/09 06 UTC: 26.1S/53.0E, MAX WIND=080KT, TROPICAL CYCLONE.
2.B OTHER INFORMATIONS:
T=CI=5.0-
GAEL SHOWS AN EYE PATTERN WITH STILL A RAGGED EYE OVER THE LAST EIR
IMAGERY.
CURRENT INTENSITY IS BASED ON AN AVERAGE OF DVORAK ANALYSIS IN EIR
IMAGERY OVER THE LAST 6 HOURS.
MOTION AND SPEED OVER THE LAST 6 HOURS IS ESTIMATED AT : 270/8KT
ENVIRONMENT HAS BECOME FAVOURABLE AS THE WINDSHEAR HAS DECREASED AND DUE
TO THE PRESENCE OF AN EXCELLENT EQUATORWARD OUTFLOW. POLEWARD UPPER LEVEL
DIVERGENCE IS LIMITED.
GAEL TRACKS UNDER THE STEERING FLOW OF A MID TO UPPER LEVEL RIDGE PRESENT
IN THE SOUTH OF THE SYSTEM, WHICH SHOULD THEREFORE KEEP ON TRACKING
WESTSOUTHWESTWARD FOR THE NEXT 12 HOURS. BEYOND, A WEAKNESS IN THE MID TO
HIGH LEVEL RIDGE (DUE TO A MID LAT TROUGH) SHOULD RECURVE THE TRACK
SOUTHWESTWARDS,
AND THEN SOUTHWARDS.
ENVIRONMENTAL CONDITIONS SHOULD KEEP ON IMPROVING: BETTER TRADES INFLOW,
HIGH SST, PRESENCE OF A POLEWARD OUTFLOW DUE TO THE TROUGH.
CURRENT FORECAST TRACK IS CLOSE TO A CONSENSUS OF THE AVAILABLE NWP
MODELS EXCEPT NOGAPS AND GFDN THAT APPEAR TOO MUCH EASTWARDS SINCE A LONG
TIME.
AT THE END OF THE FORECAST PERIOD, COOLER SST SHOULD INDUCE A WEAKENING
TREND.