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 : 6/5/20082009 1.A MODERATE TROPICAL STORM 5 (DONGO) 2.A POSITION 2009/01/09 AT 1200 UTC : WITHIN 20 NM RADIUS OF POINT 17.1S / 68.2E (SEVENTEEN DECIMAL ONE DEGREES SOUTH AND SIXTY EIGHT DECIMAL TWO DEGREES EAST) MOVEMENT : SOUTH-SOUTH-WEST 8 KT 3.A DVORAK ANALYSIS : 2.5/2.5 /D 0.5/24 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: 250 SE: 250 SO: 050 NO: 050 7.A FIRST CLOSED ISOBARE (PRESSURE / AVERAGE DIAM): 1008 HPA / 1200 KM 8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: MEDIUM 1.B FORECASTS: 12H: 2009/01/10 00 UTC: 17.7S/68.2E, MAX WIND=040KT , MODERATE TROP. STORM. 24H: 2009/01/10 12 UTC: 18.7S/68.4E, MAX WIND=050KT , SEVERE TROP. STORM. 36H: 2009/01/11 00 UTC: 20.1S/69.1E, MAX WIND=060KT , SEVERE TROP. STORM. 48H: 2009/01/11 12 UTC: 22.8S/69.8E, MAX WIND=060KT , SEVERE TROP. STORM. 60H: 2009/01/12 00 UTC: 25.8S/70.0E, MAX WIND=050KT , SEVERE TROP. STORM. 72H: 2009/01/12 12 UTC: 29.5S/70.0E, MAX WIND=040KT , MODERATE TROP. STORM. 2.B OTHER INFORMATIONS: T=CI=2.5+ OVER THE LAST 6 HOURS, DEEP CONVECTION HAS BUILT NEAR THE CENTER AND AN ASCAT PASS AT 05:22Z HAS SHOWN SOME 30 KT WINDS NEAR THE CENTER. CONSEQUENTLY THE SYSTEM IS UPGRADED TO THE MODERATE TROPICAL STORM STATUS WITH 35 KT WINDS AND HAS BEEN NAMED BY THE MAURITIUS NATIONAL WEATHER SERVICE. DATA FROM BUOY 16588 CONFIRM THE ESTIMATED MSLP. SYSTEM HAS MOVED SOUTHSOUTWESTWARDS DURING THE DAY ALONG AN ESTIMATED 210°/8KT. NO MAJOR CHANGES WITH THE 00Z RUN. AVAILABLE NWP MODELS ARE IN GOOD AGREEMENT THROUGH THE FORECAST PERIOD AND THE PRESENT FORECAST TRACK IS BASED UPON A CONSENSUS BETWEEN ARPEGE, ECMWF, ALADIN AND UKMO. ENVIRONMENT IS RATHER FAVOURABLE AND SHOULD IMPROVE TOMORROW: THE POLEWARD INFLOW SHOULD TEMPORARILY REBUILD THANKS TO BUILDING SUBTROPICAL HIGH PRESSURES, THE WINDSHEAR SHOULD 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 48 HOURS PERIOD FOR STRENGTHENING BEFORE A DETERIORATION OF THE ENVIRONMENTALS CONDITIONS AT THE END OF THE FORCAST, WITH COOLER SST AND STRONGER WINDSHEAR. PRESENT INTENSITY FORECAST FOLLOW A CLIMATOLOGICAL RATES WITHIN THE NEXT 36 HOURS BRINGING THE SYSTEM TO A 60 KT SEVERE TROPICAL STORM. HOWEVER IT IS NOT UNLIKELY THAT THE SYSTEM COULD REACH THE FIRST TROPICAL CYCLONE STAGE. THE SYSTEM IS TRACKING SOUTHSOUTHWESTWARDS TOWARDS A WEAKNESS IN THE SUBTROPICAL PRESSURES, AND ALONG THE NORTHWESTERN TO WESTERN EDGE OF THE MID LEVEL RIDGE LOCATED IN THE SOUTH EAST.