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 : 19/4/20082009 1.A TROPICAL DEPRESSION 4 (EX-CINDA) 2.A POSITION 2008/12/20 AT 1200 UTC : WITHIN 20 NM RADIUS OF POINT 14.1S / 62.6E (FOURTEEN DECIMAL ONE DEGREES SOUTH AND SIXTY TWO DECIMAL SIX DEGREES EAST) MOVEMENT : SOUTH-WEST 4 KT 3.A DVORAK ANALYSIS : 1.5/2.5 /W 1.5/24 H 4.A CENTRAL PRESSURE : 998 HPA 5.A MAX AVERAGE WIND SPEED (10 MN) : 30 KT RADIUS OF MAXIMUM WINDS (RMW) : NIL 6.A EXTENSION OF WINDS BY QUADRANTS (KM): 30 KT NE: SE: 200 SO: 200 NO: 7.A FIRST CLOSED ISOBARE (PRESSURE / AVERAGE DIAM): 1010 HPA / 950 KM 8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: SHALLOW 1.B FORECASTS: 12H: 2008/12/21 00 UTC: 14.7S/61.3E, MAX WIND=020KT, TROP. DISTURBANCE. 24H: 2008/12/21 12 UTC: 15.2S/60.3E, MAX WIND=025KT, TROP. DISTURBANCE. 36H: 2008/12/22 00 UTC: 15.9S/59.7E, MAX WIND=030KT, TROP. DEPRESSION. 48H: 2008/12/22 12 UTC: 16.4S/59.6E, MAX WIND=030KT, TROP. DEPRESSION. 60H: 2008/12/23 00 UTC: 16.8S/59.0E, MAX WIND=025KT, TROP. DISTURBANCE. 72H: 2008/12/23 12 UTC: 17.2S/58.4E, MAX WIND=025KT, TROP. DISTURBANCE. 2.B OTHER INFORMATIONS: T=1.5- CI=2.5- INTENSITY ANALYSIS: BASED ON SATELLITE IMAGERY AND AN ASCAT PASS AT 05:19Z THAT SUGGEST THAT IT STILL EXIST 30 KT WINDS IN THE SOUTHERN SEMI CIRCLE. FORECAST PHILOSOPHY: SYSTEM IS SUFFERING FROM STRONG NORTHWESTLY SHEAR ON THE SOUTHWESTERN EDGE OF AN UPPER LEVEL ANTICYCLONE LOCATED TO THE NORTHEAST. TOMORROW THIS SYSTEM COMES CLOSER TO "EX-CINDA" AND SHOULD ALLOW A WEAKENING IN THE VERTICAL WINDSHEAR AND A POTENTIAL REINTENSIFICATION . AVAILABLE NWP MODELS ARE DISAGREE ABOUT THAT: SOME OF THEM LIKE UKMO KEEP A WEAK AND SHALLOW SYSTEM AND MAKE IT TOWARDS THE WESTWOUTHWEST. OTHER ONE LIKE THE ECMWF, STRENGTHEN A LITTLE BIT THE CIRCULATION AND MAKE IT STEERED BY THE MID LEVEL FLOW. SO TRACKS FROM THIS KIND OF NWP STOP NEAR 60E AND AVEN HAVE A TEMPORARY RECURVATURE TOWARDS THE SOUTHEAST. PRESENT FORECAST IS BASED ON A CONSENSUS OF ALL AVAILABLE DYNAMICAL GUIDANCE AND MAKE ONLY A SMALL INTENSIFICATION BECAUSE IT SEEMS HARD TO BELIEVE THAT IT COULD BE A SIGNIFICENT INTENSIFICATION IN SUCH A MARGINAL ENVIRONEMENT (NO MONSOON INFLOW AND DRY ENVIRONEMENT) IT IS IMPORTANT TO NOTICE THAT THERE IS A STRONGER THAN USUAL UNCERTAINTY FOR BOTH TRACK AND INTENSITY FORCAST.