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 : 9/5/20082009 1.A MODERATE TROPICAL STORM 5 (DONGO) 2.A POSITION 2009/01/10 AT 0600 UTC : WITHIN 30 NM RADIUS OF POINT 17.8S / 66.9E (SEVENTEEN DECIMAL EIGHT DEGREES SOUTH AND SIXTY SIX DECIMAL NINE DEGREES EAST) MOVEMENT : SOUTH-WEST 2 KT 3.A DVORAK ANALYSIS : 2.5/2.5 /W 0.5/12 H 4.A CENTRAL PRESSURE : 995 HPA 5.A MAX AVERAGE WIND SPEED (10 MN) : 35 KT RADIUS OF MAXIMUM WINDS (RMW) : 30 KM 6.A EXTENSION OF WINDS BY QUADRANTS (KM): 30 KT NE: 180 SE: 270 SO: 180 NO: 110 7.A FIRST CLOSED ISOBARE (PRESSURE / AVERAGE DIAM): 1008 HPA / 1000 KM 8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: DEEP 1.B FORECASTS: 12H: 2009/01/10 18 UTC: 19.3S/66.8E, MAX WIND=040KT, MODERATE TROP. STORM. 24H: 2009/01/11 06 UTC: 21.4S/67.7E, MAX WIND=050KT, SEVERE TROP. STORM. 36H: 2009/01/11 18 UTC: 24.1S/68.6E, MAX WIND=060KT, SEVERE TROP. STORM. 48H: 2009/01/12 06 UTC: 27.9S/69.7E, MAX WIND=050KT, SEVERE TROP. STORM. 60H: 2009/01/12 18 UTC: 31.1S/71.1E, MAX WIND=050KT, BECOMING EXTRATROPICAL. 72H: 2009/01/13 06 UTC: 32.1S/72.5E, MAX WIND=050KT, EXTRATROPICAL. 2.B OTHER INFORMATIONS: T=CI=2.5+ LLCC HAS BEEN RELOCATED NORTHWESTWARDS THAN PREVIOULY ANALYSED THANKS TO LAST AVAILABLE MICROWAVE IMAGERY AND WINDS HAS BEEN CALIBRATED THANKS TO LAST ASCAT AND QUIKSCAT SWATHS. DEEP CONVECTION HAS BUILT IN THE SOUTH AS POLAR INFLOW IS INCREASING. AVAILABLE NWP MODELS ARE IN GOOD AGREEMENT THROUGH THE FORECAST PERIOD. ENVIRONMENT IS RATHER FAVOURABLE AND IS IMPROVING: THE POLEWARD LOW LEVEL INFLOW IS TEMPORARILY REBUILD THANKS TO BUILDING SUBTROPICAL HIGH PRESSURES, THE NORTHERLY WINDSHEAR YET MODERATE IS EXPECTED TO DECREASE AND THE UPPER LEVEL DIVERGENCE STRENGTHEN DUE TO AN UPPER LEVEL TROUGH LOCATED IN THE WEST OF THE SYSTEM. IN FACT THE SYSTEM HAS A 36 HOURS PERIOD FOR STRENGTHENING BEFORE A DETERIORATION OF THE ENVIRONMENTALS CONDITIONS AT THE END OF THE FORCAST, WITH COOLER SST AND STRONGER VERTICAL WINDSHEAR. TRAJECTORY IS EXPECTED TO PROGRESSIVELY RECURVE SOUTHWESTWARDS UNDERGOING MID-LEVEL STEERING FLOW IN RELATIONSHIP WITH MID-LEVEL HIGHS IN ITS EAST AND THEN SOUTHEASTWARDS AHAED OF THE UPPER LEVEL TROUGH.