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 : 12/11/20072008 1.A SEVERE TROPICAL STORM 11 (IVAN) 2.A POSITION 2008/02/10 AT 0000 UTC : WITHIN 30 NM RADIUS OF POINT 15.4S / 64.0E (FIFTEEN DECIMAL FOUR DEGREES SOUTH AND SIXTY FOUR DECIMAL ZERO DEGREES EAST) 3.A DVORAK ANALYSIS : 3.0/3.5 /W 1.0/24 H 4.A CENTRAL PRESSURE : 984 HPA 5.A MAX AVERAGE WIND SPEED (10 MN) : 50 KT 6.A EXTENSION OF WINDS BY QUADRANTS (KM): 30 KT NE: 150 SE: 100 SO: 160 NO: 200 50 KT NE: 030 SE: 030 SO: 030 NO: 030 7.A FIRST CLOSED ISOBARE (PRESSURE / AVERAGE DIAM): 1006 HPA / 800 KM 8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: DEEP 1.B FORECASTS: 12H: 2008/02/10 12 UTC: 15.3S/64.4E, MAX WIND=050KT, SEVERE TROP. STORM. 24H: 2008/02/11 00 UTC: 15.3S/64.6E, MAX WIND=045KT, MODERATE TROP. STORM. 36H: 2008/02/11 12 UTC: 15.2S/64.8E, MAX WIND=040KT, MODERATE TROP. STORM. 48H: 2008/02/12 00 UTC: 15.0S/64.7E, MAX WIND=040KT, MODERATE TROP. STORM. 60H: 2008/02/12 12 UTC: 14.8S/64.4E, MAX WIND=045KT, MODERATE TROP. STORM. 72H: 2008/02/13 00 UTC: 14.5S/63.9E, MAX WIND=050KT, SEVERE TROP. STORM. 2.B OTHER INFORMATIONS: T=3.0+ CI=3.5 REVEALED BY THE LATEST AVAILABLE MICROWAVE IMAGERY, DEEP CONVECTION HAS WEAKEN WITHIN THE SYSTEM. CI HAS BEEN LOWERED CONSEQUENTLY. IVAN STILL DRIFTING IN AN EASTERLY MOTION DURING LAST HOURS. THIS DRIFT SHOULD CONTINUE FOR THE NEXT 24 HOURS IN MORE OR LESS THE SAME DIRECTION AS IVAN IS IN A VERY WEAK STEERING ENVIRONEMENT AND THE SOUTHERN EDGE OF NEAR EQUATORIAL WESTERLIES. DURING MONDAY 11, TRACK SHOULD PROGRESSIVELY TURN NORTHWESTWARDS AS THE SUBTROPICAL RIDGE BUILDS IN THE SOUTHWEST, BUT STILL AT LOW SPEED AS WESTERLIES THAT WILL STILL PREVAILED AROUND 10S SHOULD HAVE A COMPETITIVE INFLUENCE ON THE STEERING FLOW. SYSTEM IS CURRENTLY EXPERIENCING SOME EASTERLY SHEAR. IF THOSE ENVIRONMENTAL CONDITIONS SHOULD IMPROVE TOMORROW, INTENSIFICATION IS EMPEDED AS THE SYSTEM HAS A VERY LOW MOTION (INDUCED COOLER SST). FORECAST INTENSITY HAS BEEN ADJUSTED LOWER. NWP MODELS CONTINUE TO SHOW VERY POOR AGREEMENT ON THIS SYSTEM. PRESENT GUIDANCE IS CLOSE TO THE ECMWF, ITS ENSEMBLE PREDICTION SYSTEM AND LATEST NOGAPS SOLUTIONS.