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
Fax direction           02.62.92.11.47

RSMC / TROPICAL CYCLONE CENTRE / LA REUNION TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN) 0.A WARNING NUMBER : 21/11/20072008 1.A SEVERE TROPICAL STORM 11 (IVAN) 2.A POSITION 2008/02/12 AT 0600 UTC : 14.1S / 64.6E (FOURTEEN DECIMAL ONE DEGREES SOUTH AND SIXTY FOUR DECIMAL SIX DEGREES EAST) 3.A DVORAK ANALYSIS : 4.0/4.0 /W 0.5/12 H 4.A CENTRAL PRESSURE : 975 HPA 5.A MAX AVERAGE WIND SPEED (10 MN) : 60 KT 6.A EXTENSION OF WINDS BY QUADRANTS (KM): 30 KT NE: 300 SE: 250 SO: 250 NO: 250 50 KT NE: 050 SE: 050 SO: 050 NO: 050 7.A FIRST CLOSED ISOBARE (PRESSURE / AVERAGE DIAM): 1005 HPA / 1000 KM 8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: DEEP 1.B FORECASTS: 12H: 2008/02/12 18 UTC: 14.0S/63.7E, MAX WIND=060KT, SEVERE TROP. STORM. 24H: 2008/02/13 06 UTC: 14.0S/62.6E, MAX WIND=070KT, TROPICAL CYCLONE. 36H: 2008/02/13 18 UTC: 14.0S/61.3E, MAX WIND=075KT, TROPICAL CYCLONE. 48H: 2008/02/14 06 UTC: 14.4S/59.9E, MAX WIND=080KT, TROPICAL CYCLONE. 60H: 2008/02/14 18 UTC: 15.2S/58.4E, MAX WIND=085KT, TROPICAL CYCLONE. 72H: 2008/02/15 06 UTC: 16.1S/56.9E, MAX WIND=090KT, INTENSE TROP. CYCL.. 2.B OTHER INFORMATIONS: T=4.0- AND CI=4.5+ DEEP CONVECTION ASSOCIATED TO THE SYSTEM BARELY CONSOLIDATES IN THE SOUTHERN PART AS SHOWED ON THE MICROWAVE IMAGERY (TRMM 11/2237Z, F14 12/0018Z, F16 12/0311Z) ; BEING QUASISTATIONARY OVER THE LAST 36 HOURS, THE OCEANIC HEAT POTENTIAL HAS WEAKENED. IVAN REMAINS UNDER THE INFLUENCE OF TWO COMPETING STEERING FLOWS; SUBTROPICAL HIGH PRESSURES REBUILDING IN THE SOUTH AND EQUATORIAL UPPER LEVEL RIGDE. THE SYSTEM SEEMS HOWEVER TO TRACK SLOWLY WESTWARDS OVER THE LAST HOURS. IT SHOULD THEN ACCELERATE BEYOND 24 HOURS ON THE NORTHERN EDGE OF THE SUBTROPICAL RIDGE BECOMING THE PRIMARY STEERING FLOW, AND INTENSIFY REGULARLY WITHIN A FAVORABLE ENVIRONEMENT UNDER THE UPPER LEVEL RIDGE. BEYOND 48 HOURS, IVAN IS FORECASTED TO RECURVE PROGRESSIVELY SOUTHWESTWARDS AS THIS SUBTROPICAL RIDGE WEAKENS.