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 : 10/11/20082009 1.A MODERATE TROPICAL STORM 11 (IZILDA) 2.A POSITION 2009/03/26 AT 1200 UTC : 23.8S / 42.3E (TWENTY THREE DECIMAL EIGHT DEGREES SOUTH AND FORTY TWO DECIMAL THREE DEGREES EAST) MOVEMENT : WEST 4 KT 3.A DVORAK ANALYSIS : 2.5/3.0 /W 0.5/6 H 4.A CENTRAL PRESSURE : 993 HPA 5.A MAX AVERAGE WIND SPEED (10 MN) : 40 KT RADIUS OF MAXIMUM WINDS (RMW) : 30 KM 6.A EXTENSION OF WINDS BY QUADRANTS (KM): 30 KT NE: 040 SE: 180 SO: 180 NO: 040 7.A FIRST CLOSED ISOBARE (PRESSURE / AVERAGE DIAM): 1009 HPA / 500 KM 8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: SHALLOW 1.B FORECASTS: 12H: 2009/03/27 00 UTC: 23.6S/41.6E, MAX WIND=030KT, TROP. DEPRESSION. 24H: 2009/03/27 12 UTC: 23.3S/40.9E, MAX WIND=025KT, TROP. DISTURBANCE. 36H: 2009/03/28 00 UTC: 23.0S/39.6E, MAX WIND=020KT, TROP. DISTURBANCE. 48H: 2009/03/28 12 UTC: 23.1S/38.4E, MAX WIND=015KT, FILLING UP. 60H: 2009/03/29 00 UTC: 23.2S/37.3E, MAX WIND=015KT, FILLING UP. 72H: 2009/03/29 12 UTC: 23.7S/36.4E, MAX WIND=015KT, FILLING UP. 2.B OTHER INFORMATIONS: T=2.5- CI=3.0 INERTIA BETWEEN SYSTEM PATTERN AND TRUE WEAKENING IS LESS FOR SMALL SIZES SYSTEMS (6H). THE SYSTEM HAS DRASTICALLY AND QUICKLY WEAKENED WITHIN AN UNFAVORABLE ENVIRONMENT. NORTHWESTERLY VERTICAL WINDSHEAR IS OBVIOUS ON THE IMAGERY. LLCC IS NOW FULLY EXPOSED WEST OF THE RESIDUAL CONVECTION, WHICH IS EASTWARDS AWAY OVER THE SOUTHWESTERN PART OF MADAGASCAR. MICROWAVE (AMSU 0631Z) AND WATER VAPOR IMAGERIES SHOW A DRIER AIR INTRUSION IN THE WEST. IZILDA HAS TRACKED ERRATICALLY BUT IS NOW TRACKING WESTWARDS UNDER THE STEERING INFLUENCE OF THE SUBTROPICAL HIGH PRESSURES. UPPER-LEVEL JET PRESENT IN THE SOUTHWEST OF THE SYSTEM SHOULD CONTINUE TO BE A LIMITATING FACTOR. THEN THE STRENGTHENING NORTHERLY WINDSHEAR (BEYOND TAU 24 TO 36) SHOULD WEAKEN THIS SMALL SIZE SYSTEM.