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 : 23/11/20062007 1.A SEVERE TROPICAL STORM 11 (HUMBA) 2.A POSITION 2007/02/26 AT 1800 UTC : 24.4S / 78.0E (TWENTY FOUR DECIMAL FOUR DEGREES SOUTH AND SEVENTY EIGHT DECIMAL ZERO DEGREES EAST) 3.A DVORAK ANALYSIS : 3.0/3.5 /W 0.5/24 H 4.A CENTRAL PRESSURE : 985 HPA 5.A MAX AVERAGE WIND SPEED (10 MN) : 50 KT 6.A EXTENSION OF WINDS BY QUADRANTS (KM): 30 KT NE: 200 SE: 600 SO: 800 NO: 200 50 KT NE: 050 SE: 080 SO: 100 NO: 050 7.A FIRST CLOSED ISOBARE (PRESSURE / AVERAGE DIAM): 1004 HPA / 1000 KM 8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: DEEP 1.B FORECASTS: 12H: 2007/02/27 06 UTC: 26.3S/78.3E, MAX WIND=050KT, SEVERE TROP. STORM. 24H: 2007/02/27 18 UTC: 28.0S/78.0E, MAX WIND=050KT, SEVERE TROP. STORM. 36H: 2007/02/28 06 UTC: 29.2S/77.5E, MAX WIND=050KT, EXTRATROPICAL. 48H: 2007/02/28 18 UTC: 30.5S/78.5E, MAX WIND=050KT, EXTRATROPICAL. 60H: 2007/03/01 06 UTC: 31.5S/80.5E, MAX WIND=050KT, EXTRATROPICAL. 72H: 2007/03/01 18 UTC: 33.0S/84.0E, MAX WIND=050KT, EXTRATROPICAL. 2.B OTHER INFORMATIONS: T=3.0, CI=3.5 UNDERGOING AN INCREASING NORTHWESTERLY VERTICAL WINDSHEAR, DEEP CONVECTION IS SOUTHEASTWARDS AWAY FROM THE CENTRE. LOW LEVEL CIRCULATION REMAINS RATHER BROAD, AND STRONG WINDS EXTEND FAR IN THE SOUTH DUE TO THE GRADIENT EFFECT WITH SUBTROPICAL HIGH PRESSURES, CENTRED IN THE SOUTH OF THE SYSTEM. HUMBA IS EXPECTED TO KEEP ON TRACKING MAINLY SOUTHWARDS BECOMING EXTRATROPICAL OVER SEAS SOUTH OF 25 SOUTH WHERE SST ARE UNDER 26 DEGRES CELSIUS. UNDER THE OPPOSITE STEERING FLOWS OF A MIDLEVEL RIDGE LOCATED EAST OF THE SYSTEM (SOUTHWARDS STEERING FLOW FOR A WELL STRUCTURED SYSTEM), AND LOW LEVEL SUBTROPICAL HIGH PRESSURES DRIFTING IN THE SOUTH DURING THE NEXT 36 HOURS (AND SHOULD MAKE THE LOW LEVEL VORTEX TRACK SOUTHWESTWARDS IN CASE OF SHEARING), THE LLCC SHOULD TRACK SOUTHWARDS, THEN TEMPORARILLY SOUTHWESTWARDS AT MEDIUM RANGE, BEFORE EVACUATE SOUTHEASTWARDS IN THE WESTERLIES.