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 : 2/2/20072008 1.A SEVERE TROPICAL STORM 2 (ARIEL EX-LEE) 2.A POSITION 2007/11/15 AT 1800 UTC : WITHIN 30 NM RADIUS OF POINT 11.6S / 88.9E (ELEVEN DECIMAL SIX DEGREES SOUTH AND EIGHTY EIGHT DECIMAL NINE DEGREES EAST) 3.A DVORAK ANALYSIS : 3.5/3.5 /S 0.0/24 H 4.A CENTRAL PRESSURE : 984 HPA 5.A MAX AVERAGE WIND SPEED (10 MN) : 50 KT 6.A EXTENSION OF WINDS BY QUADRANTS (KM): 30 KT NE: 110 SE: 250 SO: 250 NO: 080 50 KT NE: 025 SE: 025 SO: 025 NO: 025 7.A FIRST CLOSED ISOBARE (PRESSURE / AVERAGE DIAM): 1008 HPA / 500 KM 8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: MEDIUM 1.B FORECASTS: 12H: 2007/11/16 06 UTC: 11.9S/87.5E, MAX WIND=050KT, SEVERE TROP. STORM. 24H: 2007/11/16 18 UTC: 12.0S/86.0E, MAX WIND=050KT, SEVERE TROP. STORM. 36H: 2007/11/17 06 UTC: 12.2S/85.1E, MAX WIND=050KT, SEVERE TROP. STORM. 48H: 2007/11/17 18 UTC: 12.4S/84.6E, MAX WIND=050KT, SEVERE TROP. STORM. 60H: 2007/11/18 06 UTC: 12.8S/84.2E, MAX WIND=045KT, MODERATE TROP. STORM. 72H: 2007/11/18 18 UTC: 13.2S/83.9E, MAX WIND=040KT, MODERATE TROP. STORM. 2.B OTHER INFORMATIONS: T AND CI = 3.5. TWO MICROWAVE PASSES (SSMI AT 1423Z AND AMSUB AT 1558Z) GIVE A FAIRLY GOOD FIX. THOSE DATA SEEMS TO CONFIRM A BEGINNING OF RECURVATURE WESTSOUTHWESTWARDS. SYSTEM IS SHOWING SIGNS OF NORTHWESTERLY VERTICAL WINDSHEAR DUE TO HIGH LEVEL WINDS SOUTH OF 15S. LAST METEOSAT7 SATELLITE IMAGERY SHOWS HOWEVER A STILL HOMOGENOUS AND COLD CONVECTION. POTENTIAL FOR INTENSIFICATION REMAINS LIMITED DUE TO LESS FAVOURABLE ENVIRONMENTAL CONDITIONS WITH A NARROW WINDOW OF WEAK VERTICAL WINDSHEAR BETWEEN 5S AND 13/14S. ARIEL SHOULD BE STEERED WESTWARDS FOR THE NEXT TWO DAYS BY THE SUBTROPICAL RIDGE SOUTHWARDS BEFORE SLOWING DOWN DUE TO A WEAKNESS IN THE RIDGE.