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 : 9/8/20082009 1.A MODERATE TROPICAL STORM 8 (GAEL) 2.A POSITION 2009/02/04 AT 0000 UTC : WITHIN 30 NM RADIUS OF POINT 17.8S / 61.9E (SEVENTEEN DECIMAL EIGHT DEGREES SOUTH AND SIXTY ONE DECIMAL NINE DEGREES EAST) MOVEMENT : WEST-SOUTH-WEST 8 KT 3.A DVORAK ANALYSIS : 2.5/2.5 /S 4.A CENTRAL PRESSURE : 995 HPA 5.A MAX AVERAGE WIND SPEED (10 MN) : 35 KT RADIUS OF MAXIMUM WINDS (RMW) : 50 KM 6.A EXTENSION OF WINDS BY QUADRANTS (KM): 30 KT NE: 280 SE: 150 SO: 150 NO: 280 7.A FIRST CLOSED ISOBARE (PRESSURE / AVERAGE DIAM): 1009 HPA / 1000 KM 8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: DEEP 1.B FORECASTS: 12H: 2009/02/04 12 UTC: 18.0S/59.7E, MAX WIND=040KT, MODERATE TROP. STORM. 24H: 2009/02/05 00 UTC: 18.0S/57.6E, MAX WIND=050KT, SEVERE TROP. STORM. 36H: 2009/02/05 12 UTC: 18.1S/55.8E, MAX WIND=060KT, SEVERE TROP. STORM. 48H: 2009/02/06 00 UTC: 18.4S/53.9E, MAX WIND=070KT, TROPICAL CYCLONE. 60H: 2009/02/06 12 UTC: 18.9S/52.6E, MAX WIND=080KT, TROPICAL CYCLONE. 72H: 2009/02/07 00 UTC: 19.6S/51.0E, MAX WIND=090KT, INTENSE TROP. CYCL.. 2.B OTHER INFORMATIONS: T=2.5+ AND CI=2.5+ DEEP CONVECTIVE ACTIVITY HAS BUILT NEAR THE CENTER AND OVER THE NORTHERN SEMI CIRCLE DURING THE NIGHT. UPPER LEVEL DIVERGENCE HAS IMPROVED JUDGED BY THE CIRRUS EXPENSION EVEN IF A SLIGHT SOUTHEASTERLY SHEAR REMAINS (LIGHT ARC OF CIRRUS IN THE SOUTHEASTERN QUADRANT) CENTER BECOMES DIFFICULT TO LOCALIZE ON IR IMAGERY AND CURRENT POSITION IS BASED ON EXTRAPOLATION OF 21:09Z FIX ON AQUA (FIX NEAR 17.7S/62.3E). UNCERTAINTY IS CONSEQUENTLY STRONGER THAN USUAL. SYSTEM IS NOW CLOSER OF THE UPPER LEVEL RIDGE AXIS WITH A DECREASING WINDSHEAR (SUGGEST BY THE CIMSS DATA AT 21:00Z) A MID-LEVEL RIDGE IS BUILDING SOUTH OF THE SYSTEM AND SHOULD PROGRESSIVELY TURN THE TRACK ON A MORE WESTWARD COMPONENT. CURRENT FORCAST TRACK, BASED ON 12Z NWP MODELS IS A LITTLE BIT MORE TO THE NORTH THAN THE PREVIOUS ONE AND IS CLOSER TO THE GENERAL CONSENSUS. IT IS MORE AND MORE LIKELY THAT MAURITIUS AND LA REUNION ISLANDS SHOULD NOT BE CONCERNED BY THE ACTIVE PART OF THE SYSTEM AS IT PASSES NORTH OF THE ISLANDS THIS ISLAND SHOULD HOWEVER CLOSELY MONITOR THE PROGRESS OF THE SYSTEM. AT THE END OF THE PERIOD, A WEAKNESS IN THE MID-LEVEL RIDGE COULD ALLOW A MORE SOUTHWESTWARDS TRACK. BY THIS TIME, SYSTEM SHOULD BE ON A VERY FAVORABLE ENVIRONMENT WITH GOOD LOW LEVEL INFLOW, HIGH SST, GOOD UPPER LEVEL DIVERGENCE AND A WEAK WINDSHEAR. FOR SATURDAY, SOME NWP MODELS (ECMWF, ALADIN FRENCH MODEL) DEEP SIGNIFICATIVELY THE SYSTEM AND IT IS LIKELY THAT GAEL COULD BECOME A DANGEROUS HURRICANE BY THIS TIME. CONSEQUENTLY, INTEREST ALONG THE EASTERN COAST OF MADAGASCAR SHOULD CLOSELY MONITOR THE PROGRESS OF THIS SYSTEM TOO.