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 : 5/12/20082009 1.A MODERATE TROPICAL STORM 12 (JADE) 2.A POSITION 2009/04/05 AT 0600 UTC : 13.4S / 52.7E (THIRTEEN DECIMAL FOUR DEGREES SOUTH AND FIFTY TWO DECIMAL SEVEN DEGREES EAST) MOVEMENT : WEST-SOUTH-WEST 10 KT 3.A DVORAK ANALYSIS : 2.5/2.5 /D 1.0/24 H 4.A CENTRAL PRESSURE : 995 HPA 5.A MAX AVERAGE WIND SPEED (10 MN) : 35 KT RADIUS OF MAXIMUM WINDS (RMW) : 40 KM 6.A EXTENSION OF WINDS BY QUADRANTS (KM): 30 KT NE: 030 SE: 060 SO: 060 NO: 030 7.A FIRST CLOSED ISOBARE (PRESSURE / AVERAGE DIAM): 1008 HPA / 700 KM 8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: DEEP 1.B FORECASTS: 12H: 2009/04/05 18 UTC: 15.0S/51.1E, MAX WIND=045KT , MODERATE TROP. STORM. 24H: 2009/04/06 06 UTC: 16.3S/50.3E, MAX WIND=045KT , MODERATE TROP. STORM. 36H: 2009/04/06 18 UTC: 18.0S/49.6E, MAX WIND=045KT , MODERATE TROP. STORM. 48H: 2009/04/07 06 UTC: 19.2S/49.3E, MAX WIND=040KT , MODERATE TROP. STORM. 60H: 2009/04/07 18 UTC: 20.7S/49.2E, MAX WIND=040KT , MODERATE TROP. STORM. 72H: 2009/04/08 06 UTC: 21.6S/49.3E, MAX WIND=030KT , TROP. DEPRESSION. 2.B OTHER INFORMATIONS: T AND CI=2.5+ SYSTEM NAMED BY MADAGASCAR. CENTRE RELOCATED 60 NM IN THE WEST-NORTH-WEST, THANKS TO RECENT MMICROWAVE DATA F17/0141Z, WINDSAT 0225Z, TRMM/0313Z. THSES IMAGERIES SHOW A NICE ORGANIZATION IN 37 GHZ, BUT STILL ASCATTERED DEEP CONVECTION AT 85 GHZ. ENVIRONMENTAL CONDITIONS ARE FAVOURABLE FOR INTENSIFICATION WITH A EFFICIENT POLEWARD LOW LEVEL INFLOW ON THE NORTHERN EDGE OF THE SUBTROPICAL HIGH PRESSURES REBUILDING IN THE SOUTHWEST. UPPER LEVEL ENVIRONMENT IS FAVOURABLE WITH A WEAK VERTICAL WINDSHEAR IN THE AREA AND A GOOD POLEWARD UPPER LEVEL OUTFLOW AND A BUILDING EQUATORWARD ONE. HOWEVER WITH THE FORECASTED TRACK, THE SYSTEM GETS CLOSER TO MADAGASCAR. THE VICINITY OF COASTS SHOULD HAMPER THE INTENSIFICATION. SYSTEM IS EXPECTED TO BE DRIVEN BY THE NORTHEASTERLY STEERING FLOW GENERATED BY THE MID LEVEL RIDGE EXISTING EAST OF THE SYSTEM. AVAILABLE NWP MODELS ARE NOT IN AGREEMENT WITH THE EXPECTED TRACK. SOME OF THEM FORECAST A DIRECT SOUTHWESTWARDS TRACK TOWARDS THE NORTHEASTERN MALAGASY COASTLINE (LANDFALL WITHIN TAU 24) BUT MOST OF THEM FORECAST NOW A SOUTHWARDS RECURVE TRACK ON AND AFTER TAU 24 BETWEEN MADAGASCAR AND LA REUNION. THIS SCENARIO IS STABLE SINCE SEVERAL ECMWF MODEL RUNS. THIS IS THE ONE CHOSEN BY LA REUNION RSMC. ON AND AFTER TAU 60, SYSTEM SHOULD BE CONSTRAINTED BY NORTHWESTERLY VERTICAL WINDSHEAR.