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 : 8/5/20082009 1.A MODERATE TROPICAL STORM 5 (DONGO) 2.A POSITION 2009/01/10 AT 0000 UTC : 18.1S / 67.7E (EIGHTEEN DECIMAL ONE DEGREES SOUTH AND SIXTY SEVEN DECIMAL SEVEN DEGREES EAST) MOVEMENT : SOUTH-SOUTH-WEST 5 KT 3.A DVORAK ANALYSIS : 3.0/3.0 /D 4.A CENTRAL PRESSURE : 993 HPA 5.A MAX AVERAGE WIND SPEED (10 MN) : 36 KT RADIUS OF MAXIMUM WINDS (RMW) : 30 KM 6.A EXTENSION OF WINDS BY QUADRANTS (KM): 30 KT NE: 250 SE: 250 SO: 180 NO: 100 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 12 UTC: 19.4S/67.7E, MAX WIND=045KT, MODERATE TROP. STORM. 24H: 2009/01/11 00 UTC: 21.1S/68.3E, MAX WIND=055KT, SEVERE TROP. STORM. 36H: 2009/01/11 12 UTC: 23.7S/69.0E, MAX WIND=060KT, SEVERE TROP. STORM. 48H: 2009/01/12 00 UTC: 26.1S/69.1E, MAX WIND=060KT, SEVERE TROP. STORM. 60H: 2009/01/12 12 UTC: 28.5S/69.4E, MAX WIND=045KT, MODERATE TROP. STORM. 72H: 2009/01/13 00 UTC: 30.6S/70.2E, MAX WIND=050KT, EXTRATROPICAL. 2.B OTHER INFORMATIONS: T=CI=3.0- OVER THE LAST 6 HOURS, DEEP CONVECTION IS GOING ON ORGANIZING IN CURVED BAND, AND DATA FROM BUOY 16588 CONFIRM THE DEEPENING. DEEP CONVECTION HAS BUILT IN THE SOUTH AS POLAR INFLOW IS INCREASING. NO MAJOR CHANGES WITH THE 12Z RUN. AVAILABLE NWP MODELS ARE IN GOOD AGREEMENT THROUGH THE FORECAST PERIOD. ENVIRONMENT IS RATHER FAVOURABLE AND IS IMPROVING: THE POLEWARD 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 WINDSHEAR. THE SYSTEM IS SLOWING DOWN AND IS EXPECTED TO TRACK SOUTHWARDS TOWARDS A WEAKNESS IN THE SUBTROPICAL PRESSURES, THEN SOUTHEASTWARDS, AHAED OF THE UPPER LEVEL TROUGH AND UNDER THE STEERING FLOW OF AN UPPER LEVEL RIDGE BUILDING IN THE EAST.