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 : 14/5/20082009 1.A SEVERE TROPICAL STORM 5 (DONGO) 2.A POSITION 2009/01/11 AT 1200 UTC : WITHIN 20 NM RADIUS OF POINT 22.8S / 69.7E (TWENTY TWO DECIMAL EIGHT DEGREES SOUTH AND SIXTY NINE DECIMAL SEVEN DEGREES EAST) MOVEMENT : SOUTH-EAST 13 KT 3.A DVORAK ANALYSIS : 3.0/3.5 /W 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) : 40 KM 6.A EXTENSION OF WINDS BY QUADRANTS (KM): 30 KT NE: 300 SE: 300 SO: 170 NO: 170 50 KT NE: 030 SE: 030 SO: 030 NO: 030 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 00 UTC: 25.6S/70.1E, MAX WIND=040KT, MODERATE TROP. STORM. 24H: 2009/01/12 12 UTC: 28.0S/70.7E, MAX WIND=040KT, BECOMING EXTRATROPICAL. 36H: 2009/01/13 00 UTC: 30.0S/71.9E, MAX WIND=040KT, BECOMING EXTRATROPICAL. 48H: 2009/01/13 12 UTC: 32.0S/73.6E, MAX WIND=040KT, EXTRATROPICAL. 60H: 2009/01/14 00 UTC: 34.2S/76.7E, MAX WIND=030KT, EXTRATROPICAL. 72H: 2009/01/14 12 UTC: 38.7S/85.4E, MAX WIND=030KT, EXTRATROPICAL. 2.B OTHER INFORMATIONS: T=3.0, 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 PESSURES LOCATED IN THE SOUTHEAST, AN TO ITS OWN MOVEMENT SPEED. THE SYSTEM SHOWS SIGNS OF WEAKENING ON THE LAST SATELLITE IMAGERY. IT IS TRACKING OVER A LOWER OCEANIC HEAT CONTENT AND THE NORTHWESTERLY WINDSHEAR CONSTRAINT CAN BE DEPICTED ON THE IMAGERY. THIS WINDSHEAR 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.