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 : 31/11/20072008 1.A SEVERE TROPICAL STORM 11 (IVAN) 2.A POSITION 2008/02/14 AT 1800 UTC : WITHIN 30 NM RADIUS OF POINT 14.1S / 57.6E (FOURTEEN DECIMAL ONE DEGREES SOUTH AND FIFTY SEVEN DECIMAL SIX DEGREES EAST) 3.A DVORAK ANALYSIS : 4.0/4.0 /D 0.5/24 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: 250 SE: 250 SO: 250 NO: 200 50 KT NE: 050 SE: 050 SO: 050 NO: 050 7.A FIRST CLOSED ISOBARE (PRESSURE / AVERAGE DIAM): 1007 HPA / 1100 KM 8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: DEEP 1.B FORECASTS: 12H: 2008/02/15 06 UTC: 14.9S/55.9E, MAX WIND=060KT, SEVERE TROP. STORM. 24H: 2008/02/15 18 UTC: 15.6S/54.6E, MAX WIND=065KT, TROPICAL CYCLONE. 36H: 2008/02/16 06 UTC: 16.1S/53.8E, MAX WIND=070KT, TROPICAL CYCLONE. 48H: 2008/02/16 18 UTC: 16.6S/53.1E, MAX WIND=075KT, TROPICAL CYCLONE. 60H: 2008/02/17 06 UTC: 17.1S/52.5E, MAX WIND=080KT, TROPICAL CYCLONE. 72H: 2008/02/17 18 UTC: 17.7S/51.7E, MAX WIND=085KT, TROPICAL CYCLONE. 2.B OTHER INFORMATIONS: T=4.0- AND CI=4.0- LATEST MICROWAVE IMAGERY (SSMI, 1450Z) DEPICT AN IMPROVING ORGANISATION OF DEEP CONVECTION ACTIVITY CLOSE TO THE CENTER (COMPARE TO AQUA PASS OF 0942Z) EVEN IF A SLIGHT TILT OF THE VORTEX STILL EXIST. THE SYSTEM SHOULD GENERALLY CONTINUE TO TRACK WESTSOUTHWARDS ALONG THE NORTHERN EDGE OF THE SUBTROPICAL RIDGE AS IT BECOME THE PRIMARY STEERING FLOW. IT SHOULD THEN KEEP ON REGULARLY INTENSIFYING WITHIN A MORE FAVORABLE ENVIRONMENT, UNDER THE UPPER LEVEL RIDGE (WEAKER EASTERLY SHEAR IS EXPECTED ON THE FORECAST TRACK- CF. CIMSS DATA) 14/00Z ECMWF RUN DOESN'T FORECAST ANYMORE THE TRACK MORE SOUTHSOUTHWESWARDS BEYOND THE 17, ONLY A MORE SOUTHWASTWARDS COMPONENT. MOREOVER, FOR THE FIRST TIME SINCE THE BEGINNING OF IVAN'S LIFE, SPREAD ON THE ECMWF ENSEMBLE FORECAST SYSTEM HAS REDUCED SENSITIVELY ... GIVEN A LITTLE MORE CONFIDENCE ON THE GUIDANCE. SO THIS FORECAST IS CLOSE TO THE ECMWF AND ECMWF ENSEMBLE PREDICTION SYSTEM SOLUTIONS.