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 : 35/11/20072008 1.A TROPICAL CYCLONE 11 (IVAN) 2.A POSITION 2008/02/15 AT 1800 UTC : 16.2S / 54.1E (SIXTEEN DECIMAL TWO DEGREES SOUTH AND FIFTY FOUR DECIMAL ONE DEGREES EAST) 3.A DVORAK ANALYSIS : 4.5/4.5 /D 1.0/24 H 4.A CENTRAL PRESSURE : 966 HPA 5.A MAX AVERAGE WIND SPEED (10 MN) : 65 KT 6.A EXTENSION OF WINDS BY QUADRANTS (KM): 30 KT NE: 320 SE: 280 SO: 260 NO: 320 50 KT NE: 070 SE: 070 SO: 070 NO: 070 7.A FIRST CLOSED ISOBARE (PRESSURE / AVERAGE DIAM): 1006 HPA / 1000 KM 8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: DEEP 1.B FORECASTS: 12H: 2008/02/16 06 UTC: 16.7S/52.5E, MAX WIND=070KT, TROPICAL CYCLONE. 24H: 2008/02/16 18 UTC: 17.3S/51.3E, MAX WIND=080KT, TROPICAL CYCLONE. 36H: 2008/02/17 06 UTC: 17.9S/50.2E, MAX WIND=090KT, INTENSE TROP. CYCL.. 48H: 2008/02/17 18 UTC: 18.4S/49.3E, MAX WIND=100KT, INTENSE TROP. CYCL.. 60H: 2008/02/18 06 UTC: 18.8S/48.6E OVERLAND. 72H: 2008/02/18 18 UTC: 19.6S/47.8E OVERLAND. 2.B OTHER INFORMATIONS: T AND CI=4.5 IVAN HAS BEEN TRACKING SOUTHWESTWARDS AT 9 KT DURING THE 6 LAST HOURS. THE SYSTEM IS INTESIFYING, WITH A WELL DEFINED EYE IN LOW AND MID-LEVEL (SEE WINDSAT AT 1431Z), WHICH EXTENDS PROGRESSIVLY TO UPPER LEVEL (SEE IR METEOSAT IMAGERY AT 1800Z). THE LOW LEVEL CIRCULATION CENTER HAS TRACKED OVER TROMELIN ISLAND (LOCATED EXACTLY BY 15.88S.54.52E) NEAR BY 1500Z, WHERE IT HAS BEEN RECORDED 969,2HPA AT 1500Z (WHAT JUSTIFIES ESTIMATED PRESSURE). MAX SURFACE WINDS (10 MIN AVERAGE) HAVE BEEN MEASURED DURING THE FIRST PASS OF THE EYE WALL AT 1300Z AT 52KT (GUSTS 80KT, FROM THE SOUTHEAST, 150 DEGREES DIRECTION). THE ISLAND HAS REMAINED LESS THAN 3 HOURS IN A RATHER QUITE WINDS AREA (WITH WEAKER RAINFALLS). WE DON'T HAVE WINDS DATA ANYMORE AFTER 1530 UTC (MOMENT OF THE CHANGE OF DIRECTION, WITH THE SECOND EYEWALL PASS). 0000Z NWP MODEL RUNS ARE IN GOOD AGREEMENT FOR A WEST-SOUTHWESTWARDS TRACK WITHIN THE NEXT 48 HOURS. SUBTROPICAL RIDGE APPEARS NOW TO HOLD THE SYSTEM ON A GENERALLY WESTSOUTHWARDS TRACK ALONG THE NORTHERN EDGE OF THE SUBTROPICAL RIDGE. IT SHOULD KEEP ON REGULARY INTENSIFYING WITHIN A FAVORABLE ENVIRONMENT (HIGH OCEAN HEAT CONTAIN AND DECREASING SHEAR). SPREAD ON THE ECMWF ENSEMBLE FORECAST IS RATHER NARROW. SO THIS FORECAST IS CLOSE TO THE ECMWF AND ITS ENSEMBLE PREDICTION SYSTEM SOLUTIONS. IVAN IS A SERIOUS THREAT FOR THE CENTRAL EAST COAST OF MADAGASCAR. WINDS EXTENSION HAS BEEN ESTIMATED THANKS TO 1431Z QUIKSCAT SWATH.