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 : 3/7/20072008 1.A TROPICAL DISTURBANCE 7 2.A POSITION 2008/01/08 AT 0000 UTC : WITHIN 30 NM RADIUS OF POINT 20.5S / 55.5E (TWENTY DECIMAL FIVE DEGREES SOUTH AND FIFTY FIVE DECIMAL FIVE DEGREES EAST) 3.A DVORAK ANALYSIS : 1.5/1.5 /S 0.0/12 H 4.A CENTRAL PRESSURE : 1003 HPA 5.A MAX AVERAGE WIND SPEED (10 MN) : 20 KT 6.A EXTENSION OF WINDS BY QUADRANTS (KM): 7.A FIRST CLOSED ISOBARE (PRESSURE / AVERAGE DIAM): 1006 HPA / 120 KM 8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: MEDIUM 1.B FORECASTS: 12H: 2008/01/08 12 UTC: 21.6S/55.8E, MAX WIND=020KT, TROP. DISTURBANCE. 24H: 2008/01/09 00 UTC: 23.0S/55.8E, MAX WIND=020KT, TROP. DISTURBANCE. 36H: 2008/01/09 12 UTC: 24.1S/55.1E, MAX WIND=020KT, TROP. DISTURBANCE. 48H: 2008/01/10 00 UTC: 24.7S/54.6E, MAX WIND=020KT, TROP. DISTURBANCE. 60H: 2008/01/10 12 UTC: 25.3S/53.8E, MAX WIND=020KT, TROP. DISTURBANCE. 72H: 2008/01/11 00 UTC: 25.7S/53.3E, MAX WIND=020KT, TROP. DISTURBANCE. 2.B OTHER INFORMATIONS: T=CI=1.5+. THIS WEAK CIRCULATION HAS A POOR POTENTIAL FOR INTENSIFICATION. IT GENERATES NEVERTHELESS VERY BAD WEATHER CONDITIONS NORTH OF MASCAREIGNES ISLANDS AND THIS RAINY WEATHER IS EXPECTED SOON ON REUNION'S ISLAND AND MAURITIUS. BETWEEN 1400Z AND 1700Z , METEOSAT7 INFRARED SATELLITE IMAGERY SHOWED BURSTS OF DEEP CONVECTIVE ACTIVITY NEAR AND OVER THE LLCC, SIGNS OF A WEAKENING WINDSHEAR CONSTRAINT, THIS FACT WAS CONFIRMED BY LA REUNION RADAR. THEN THE WINDSHEAR HAS INFORCED AGAIN AND THE LLCC IS BACK IN THE SOUTH OF THE MAIN CONVECTIVE ACTIVITY BUT ITS LOCATION REMAINS DIFFICULT AS THE SYSTEM IS WEAK AND OF SMALL SIZE. THE MENTIONNED POSITION IN THIS WARNING IS ELABORATED THANKS TO 2111Z AQUA MICROWAVE IMAGERY AND CONVERGENCE OF RAINY CURVED BAND ON OUR RADAR. THIS LOW IS POORLY ANALYZED BY NUMERICAL MODELS, ACTUAL FORECAST LOCATION AND INTENSITY ARE RATHER UNCERTAIN. ONLY THE FRENCH MODEL ALADIN ANALYZES THIS LOW, BUT WITH STRONGER INTENSITY. ENVIRONNEMENTAL CONDITIONS REMAIN UNFAVORABLE, VERTICAL WIND SHEAR REMAIN MODERATE, WITH A GOOD UPPER LEVEL DIVERGENCE, BUT NO LOW LEVEL FLOW IN THE SOUTH. NO INTENSIFICATION IS EXPECTED. HIGH PRESSURES ARE QUASI-STATIONARY AROUND 70E, WITH A PERSISTANT RIDGE EAST TO THE SYSTEM.THE EXTRATROPICAL LOW IS EXPECTED TO TRACK SOUTHWARDS, SOUTH TO THE PERSISTANT HIGH.A RIDGE IS BUILBING SOUTH TO MAURITIUS MORE OR LESS ACCORDING TO EACH MODELE, SPEED AND DIRECTION WILL DEPEND OF THE EVOLUTION OF THIS RIDGE. AT THE END OF THIS FORECAST, SYSTEM SHOULD SLOW DAONS AND RECURVE WESTWARDS UNDERGOING THE REBUILDING HIGH PRESSURES IN ITS SOUTHWEST. THE INTENSITY OF THIS SYSTEM DOES NOT JUSTIFY ISSUANCE OF REGULAR WARNINGS.