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

*************** CORRECTIVE ************** RSMC / TROPICAL CYCLONE CENTRE / LA REUNION TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN) 0.A WARNING NUMBER : 1/6/20082009 1.A ZONE OF DISTURBED WEATHER 6 2.A POSITION 2009/01/17 AT 1200 UTC : WITHIN 30 NM RADIUS OF POINT 15.3S / 55.2E (FIFTEEN DECIMAL THREE DEGREES SOUTH AND FIFTY FIVE DECIMAL TWO DEGREES EAST) MOVEMENT : WEST-SOUTH-WEST 6 KT 3.A DVORAK ANALYSIS : 1.5/1.5 /D 1.5/24 H 4.A CENTRAL PRESSURE : 1005 HPA 5.A MAX AVERAGE WIND SPEED (10 MN) : 20 KT RADIUS OF MAXIMUM WINDS (RMW) : NIL 6.A EXTENSION OF WINDS BY QUADRANTS (KM): 7.A FIRST CLOSED ISOBARE (PRESSURE / AVERAGE DIAM): 1010 HPA / 700 KM 8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: MEDIUM 1.B FORECASTS: 12H: 2009/01/18 00 UTC: 16.5S/53.8E, MAX WIND=025KT, TROP. DISTURBANCE. 24H: 2009/01/18 12 UTC: 17.9S/51.9E, MAX WIND=030KT, TROP. DEPRESSION. 36H: 2009/01/19 00 UTC: 19.3S/50.5E, MAX WIND=035KT, MODERATE TROP. STORM. 48H: 2009/01/19 12 UTC: 21.0S/49.6E, MAX WIND=040KT, MODERATE TROP. STORM. 60H: 2009/01/20 00 UTC: 22.3S/49.3E, MAX WIND=050KT, SEVERE TROP. STORM. 72H: 2009/01/20 12 UTC: 23.7S/49.8E, MAX WIND=050KT, SEVERE TROP. STORM. 2.B OTHER INFORMATIONS: T=CI=1.5+ SURFACE OBSERVATIONS AND CLASSICAL SATELLITE IMAGERY SHOW THAT THE SYSTEM, THAT IS CURRENTLY LOCATED NORTH OF THE MASCAREGNAS ISLANDS AT ABOUT 330 NM NORTH OF LA REUNION, HAS PROGRESSIVELY BECOME BETTER ORGANISED TODAY. 24 HOURS VARIATION OF PRESSURE AT TROMELIN (61976) ARE IN THE RANGE OF -2.5/-3 HPA SINCE 09 TU. MSLP AT THE CENTER IS ESTIMATED FROM SURFACE PRESSURE RECORDED AT TROMELIN CORRECTED FROM THE BAROMETRIC TIDE. MOTION AND SPEED ARE AN UNCERTAIN: 250/06KT. SYSTEM IS FED BY A GOOD TRADEWINDS INFLOW, BUT MONSOON FLOW APPEARS WEAKER AND LESS EFFICIENT (POSSIBLY DISTURB BY THE NORTHERN TIP OF MADAGASCAR). WINDSHEAR HAS DECREASED OVER THE LAST 24 HOURS AND UPPER LEVEL DIVERGENCE IS GOOD, SPECIALLY IN THE NORTHERN PART WITH SOME NICE CIRRUS EXPENSION (MORE LIMITED IN THE SOUTHERN PART). AS THE SYSTEM IS OVER WARM SST IN THE RANGE OF 29°C, CONDITIONS APPEAR FAVORABLE FOR FURTHER DEVELOPMENT. MOST OF THE NWP GUIDANCE ARE NOT IN GOOD AGREEMENT ABOUT THE DEVELOPMENT OF THIS SYSTEM. ON THE 17/00Z RUN, ECMWF AND ALADIN DEVELOP STRONGLY THE SYSTEM, NOGAPS AND ARPEGE (GLOBAL FRENCH MODEL) MAINTAIN A WEAK LOW AND GFS AND UKMO DO NOT MAINTAIN THE INITIAL CIRCULATION. HOWEVER GIVEN THE CURRENT TREND, THE PRESENT FORECAST IS BASED ON AN ECMWF/ ALADIN CONSENSUS, BUT IT IS IMPORTANT TO NOTICE THAT THERE IS A LOWER THAN USUAL CONFIDENCE FOR THE INTENSITY FORECAST. THE PHILOSOPHY OF THE TRACK IS THAT THE SYSTEM SHOULD TRACK ON THE NORTHWESTERN SIDE OF THE SUBTROPICAL RIDGE TOWARDS A WEAKNESS IN THE PRESSURE FIELD LOCATED SOUTH OF MADAGASCAR. CURRENT INTENSITY OF THIS SYSTEM DOES NOT JUSTIFY THE ISSUANCE OF REGULAR ADVISORY AT THIS TIME