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 : 7/11/20082009 1.A SEVERE TROPICAL STORM 11 (IZILDA) 2.A POSITION 2009/03/25 AT 1800 UTC : 23.7S / 42.5E (TWENTY THREE DECIMAL SEVEN DEGREES SOUTH AND FORTY TWO DECIMAL FIVE DEGREES EAST) MOVEMENT : QUASI-STATIONARY 3.A DVORAK ANALYSIS : 4.0/4.0 /D 4.A CENTRAL PRESSURE : 978 HPA 5.A MAX AVERAGE WIND SPEED (10 MN) : 55 KT RADIUS OF MAXIMUM WINDS (RMW) : 30 KM 6.A EXTENSION OF WINDS BY QUADRANTS (KM): 30 KT NE: 200 SE: 130 SO: 340 NO: 200 50 KT NE: 030 SE: 030 SO: 030 NO: 030 7.A FIRST CLOSED ISOBARE (PRESSURE / AVERAGE DIAM): 1006 HPA / 350 KM 8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: DEEP 1.B FORECASTS: 12H: 2009/03/26 06 UTC: 23.8S/42.4E, MAX WIND=065KT, TROPICAL CYCLONE. 24H: 2009/03/26 18 UTC: 23.7S/42.4E, MAX WIND=060KT, SEVERE TROP. STORM. 36H: 2009/03/27 06 UTC: 23.3S/41.8E, MAX WIND=055KT, SEVERE TROP. STORM. 48H: 2009/03/27 18 UTC: 22.9S/40.6E, MAX WIND=050KT, SEVERE TROP. STORM. 60H: 2009/03/28 06 UTC: 22.7S/39.6E, MAX WIND=045KT, MODERATE TROP. STORM. 72H: 2009/03/28 18 UTC: 22.4S/38.6E, MAX WIND=040KT, MODERATE TROP. STORM. 2.B OTHER INFORMATIONS: T=CI=4.0 CONVECTION HAS CLEARLY IMPROVED AROUND THE EYE, AS THE SYSTEM GOES ON INTENSIFYING (CF MICROWAVE IMAGERY F17 AT 1454Z). THE EYE REMAINS QUITE IREEGULAR, AND A WEAK CONSTRAINT IS VISIBLE ON SATELLITE IMAGERY. IZILDA HAS CLEARLY SLOWN DOWN AND IS EXPECTED TO BECOME STATIONNARY WITHIN THE NEXT 24 HOURS BEFORE RECURVING WEST-NORTHWESTWARDS UNDER THE STEERING INFLUENCE OF THE SUBTROPICAL HIGH PRESSURES REBUILDING IN ITS SOUTHWEST. THIS SUBTROPICAL RIDGE IS EXPECTED TO BECOME THE MAIN STEERING FLOW BEYOND TAU36, SYSTEM IS ALSO EXPECTED TO RECURVE WEST-NORTHWESTWARDS. UPPER-LEVEL JET (WELL SHOWED ON INFRARED METEOSAT7 IMAGERY) EXISTING IN THE WEST AND IN THE SOUTH OF THE SYSTEM IS EXPECTED TO KEEP ON IMPROVING THE UPPER LEVEL POLEWARD DIVERGENCE BUT COULD BECOME A LIMITATING FACTOR AS THE SYSTEM RECURVE WEST-NORTHWESTWARDS (BEYOND TAU36) LINKED TO A STRENGTHENING WINDSHEAR. IZILDA COULD BEFORE REACH THE MINIMAL TROPICAL CYCLONE STAGE.