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
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RSMC / TROPICAL CYCLONE CENTRE / LA REUNION TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN) 0.A WARNING NUMBER : 15/5/20082009 1.A SEVERE TROPICAL STORM 5 (DONGO) 2.A POSITION 2009/01/11 AT 1800 UTC : WITHIN 30 NM RADIUS OF POINT 24.4S / 69.8E (TWENTY FOUR DECIMAL FOUR DEGREES SOUTH AND SIXTY NINE DECIMAL EIGHT DEGREES EAST) MOVEMENT : SOUTH-SOUTH-EAST 13 KT 3.A DVORAK ANALYSIS : 3.5/3.5 /D 0.5/6 H 4.A CENTRAL PRESSURE : 985 HPA 5.A MAX AVERAGE WIND SPEED (10 MN) : 50 KT RADIUS OF MAXIMUM WINDS (RMW) : 30 KM 6.A EXTENSION OF WINDS BY QUADRANTS (KM): 30 KT NE: 450 SE: 580 SO: 270 NO: 200 50 KT NE: 030 SE: 030 SO: 020 NO: 020 7.A FIRST CLOSED ISOBARE (PRESSURE / AVERAGE DIAM): 1006 HPA / 1100 KM 8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: DEEP 1.B FORECASTS: 12H: 2009/01/12 06 UTC: 26.5S/70.2E, MAX WIND=045KT, MODERATE TROP. STORM. 24H: 2009/01/12 18 UTC: 28.8S/71.0E, MAX WIND=040KT, BECOMING EXTRATROPICAL. 36H: 2009/01/13 06 UTC: 30.9S/72.3E, MAX WIND=040KT, BECOMING EXTRATROPICAL. 48H: 2009/01/13 18 UTC: 33.3S/74.8E, MAX WIND=040KT, EXTRATROPICAL. 60H: 2009/01/14 06 UTC: 36.1S/80.1E, MAX WIND=040KT, EXTRATROPICAL. 72H: 2009/01/14 18 UTC: 41.1S/89.7E, MAX WIND=040KT, EXTRATROPICAL. 2.B OTHER INFORMATIONS: T=3.5-, CI=3.5 DONGO HAS AN ASYMMETRIC WIND STRUCTURE WITH A BIGGER WIND EXTENSION IN THE EAST DUE TO THE GRADIENT EFFECT WITH THE SUBTROPICAL HIGH PRESSURES LOCATED IN THE SOUTHEAST, AN TO ITS OWN MOVEMENT SPEED. THE SYSTEM HAS TEMPORARILY STOPPED TO WEAKEN BUT ENVIRONMENTAL CONDITIONS ARE EXPECTED TO BECOME UNFAVOURABLE AGAIN WITHIN THE NEXT HOURS. IT IS TRACKING OVER A LOWER OCEANIC HEAT CONTENT AND THE NORTHWESTERLY WINDSHEAR CONSTRAINT SHOULD INCREASE OVER THE NEXT HOURS AS THE UPPER LEVEL TROUGH APPROCHES IN THE WEST. THE SYSTEM IS TRACKING SOUTHEASTWARDS UNDER THE STEERING INFLUENCE OF THE MID LEVEL RIDGE LOCATED IN THE EAST. DONGO SHOULD REMAIN UNDER THIS STEERING INFLUENCE DURING THE NEXT DAYS. AVAILABLE DYNAMICAL GUIDANCE IS IN GOOD AGREEMENT SHOWING ONLY SOME SLIGHT DISPERSION FOR THE SPEED. PRESENT FORECAST IS BASED ON A GENERAL CONSENSUS BUT CLOSER TO THE LATEST ECMWF TRACK. THE SYSTEM SHOULD BEGIN ITS EXTRATROPICAL TRANSITION WITHIN THE NEXT 24 HOURS.