Direction Interrégionale de LA REUNION
B.P.4    97491 Ste Clotilde Cedex
Téléphone                02.62.92.11.00
Fax exploitation      02.62.92.11.48
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RSMC / TROPICAL CYCLONE CENTRE / LA REUNION TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN) 0.A WARNING NUMBER : 6/11/20072008 1.A SEVERE TROPICAL STORM 11 (IVAN) 2.A POSITION 2008/02/08 AT 1200 UTC : WITHIN 20 NM RADIUS OF POINT 16.1S / 63.3E (SIXTEEN DECIMAL ONE DEGREES SOUTH AND SIXTY THREE DECIMAL THREE DEGREES EAST) 3.A DVORAK ANALYSIS : 4.0/4.0 /D 1.0/24 H 4.A CENTRAL PRESSURE : 980 HPA 5.A MAX AVERAGE WIND SPEED (10 MN) : 55 KT 6.A EXTENSION OF WINDS BY QUADRANTS (KM): 30 KT NE: 150 SE: 120 SO: 180 NO: 150 50 KT NE: 050 SE: 050 SO: 050 NO: 050 7.A FIRST CLOSED ISOBARE (PRESSURE / AVERAGE DIAM): 1008 HPA / 1000 KM 8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: DEEP 1.B FORECASTS: 12H: 2008/02/09 00 UTC: 16.4S/63.4E, MAX WIND=065KT, TROPICAL CYCLONE. 24H: 2008/02/09 12 UTC: 16.7S/63.4E, MAX WIND=070KT, TROPICAL CYCLONE. 36H: 2008/02/10 00 UTC: 16.9S/63.3E, MAX WIND=065KT, TROPICAL CYCLONE. 48H: 2008/02/10 12 UTC: 16.8S/63.0E, MAX WIND=060KT, SEVERE TROP. STORM. 60H: 2008/02/11 00 UTC: 16.6S/62.7E, MAX WIND=065KT, TROPICAL CYCLONE. 72H: 2008/02/11 12 UTC: 16.4S/62.3E, MAX WIND=070KT, TROPICAL CYCLONE. 2.B OTHER INFORMATIONS: T=4.0-, CI=4.0- OVERALL STRUCTURE IS STILL IMPROVING WITH THE BEGINNING OF A BANDING EYE ON VIS IMAGERY. HOWEVER, ON IR, CONVECTION REMAINS IS NOT CONSOLIDED IN THE SOUTHEASTERN QUADRANT. AVAILABLE NWP MODELS REMAIN DISAGGREE FOR THE EVOLUTION OF IVAN. SOME (AS NOGAPS, ARPTROP) STILL DRIVE THE SYSTEM EASTWARDS UNDER THE STEERING INFLUENCE OF THE NEAR EQUATORIAL RIDGE. GIVEN THE PRESENT SOUTHWARDS MOTION THAT PUT AWAY THE SYSTEM FROM THIS WESTNORTHWESTWARDS WINDS, IT IS NOT THE SOLUTION REFLECTED BY THE PRESENT FORECAST. AS SUGGESTED BY CEP, GFDN AND UKMO, IVAN SHOULD BEEN IN A VERY WEAK STEERING FLOW WITHIN THE NEXT 24 HOURS AND SHOULD TRACK MORE SLOWLY (ERRATIC MOTION IS POSSIBLE). MONDAY, TRACK SHOULD TURN MORE NORTHWESTWARDS AS THE SUBTROPICAL RIDGE SHOULD BUILT SOUTHWESTWARD. IF ENVIRONMENTALS CONDITIONS REMAINS FAVORABLE FOR FURTHER DEVELOPMENT, SOME FLUCTUATIONS ARE POSSIBLE IN INTENSITY IF THE SYSTEM STAY TOO MUCH TIME OVER THE SAME WATER. GIVEN THE WIDE SPREAD IN NWM SOLUTIONS, IT IS A LOWER THAN AVERAGE DEGREE OF CONFIDENCE IN THIS FORECAST.