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 : 5/11/20082009 1.A MODERATE TROPICAL STORM 11 (IZILDA) 2.A POSITION 2009/03/25 AT 0600 UTC : WITHIN 20 NM RADIUS OF POINT 23.0S / 42.1E (TWENTY THREE DECIMAL ZERO DEGREES SOUTH AND FORTY TWO DECIMAL ONE DEGREES EAST) MOVEMENT : SOUTH-SOUTH-EAST 5 KT 3.A DVORAK ANALYSIS : 3.0/3.0 /D 1.0/24 H 4.A CENTRAL PRESSURE : 991 HPA 5.A MAX AVERAGE WIND SPEED (10 MN) : 40 KT RADIUS OF MAXIMUM WINDS (RMW) : 60 KM 6.A EXTENSION OF WINDS BY QUADRANTS (KM): 30 KT NE: 120 SE: 120 SO: 300 NO: 200 7.A FIRST CLOSED ISOBARE (PRESSURE / AVERAGE DIAM): 1008 HPA / 600 KM 8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: DEEP 1.B FORECASTS: 12H: 2009/03/25 18 UTC: 23.6S/41.9E, MAX WIND=045KT, MODERATE TROP. STORM. 24H: 2009/03/26 06 UTC: 23.7S/41.9E, MAX WIND=050KT, SEVERE TROP. STORM. 36H: 2009/03/26 18 UTC: 23.6S/41.8E, MAX WIND=060KT, SEVERE TROP. STORM. 48H: 2009/03/27 06 UTC: 23.2S/41.3E, MAX WIND=060KT, SEVERE TROP. STORM. 60H: 2009/03/27 18 UTC: 23.2S/40.8E, MAX WIND=040KT, MODERATE TROP. STORM. 72H: 2009/03/28 06 UTC: 23.1S/40.0E, MAX WIND=040KT, MODERATE TROP. STORM. 2.B OTHER INFORMATIONS: T=CI=3.0 IZILDA'S CONVECTIVE ACTIVITY HAS CONCENTRATED WITHIN THE LAST 12 PAST HOURS AND HAS TEMPORARELY SHOWS A LOW DEFINED SATELLITE PATTERN BUT IMPROVING AGAIN WITHIN THE RECENT HOURS. LOW LEVEL PATTERN REMAINS HOWEVER WELL DEFINED (SSMIS-F17 25/0222Z) AND MAXIMUM WINDS 40KT ARE CONFIRMED BY LAST QUIKSCAT SWATH (25/0334Z). SYSTEM KEEPS ON TRACKING SLOWLY SOUTH-SOUTHEASTWARDS UNDER THE STEERING INFLUENCE OF THE MID-LEVEL RIDGE EXISTING IN ITS NORTHEAST THEN BECOMING STATIONNARY WITHIN THE NEXT 24 TO 36 HOURS DUE TO TWO OPPOSITE STEERING FLOWS IN RELATIONSHIP WITH THE REBUILDING MID-LEVEL RIDGE IN THE 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.