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 : 5/4/20072008 1.A TROPICAL DISTURBANCE 4 (0420072008) 2.A POSITION 2007/12/13 AT 1200 UTC : WITHIN 20 NM RADIUS OF POINT 13.7S / 69.8E (THIRTEEN DECIMAL SEVEN DEGREES SOUTH AND SIXTY NINE DECIMAL EIGHT DEGREES EAST) 3.A DVORAK ANALYSIS : 2.0/2.0 /S 0.0/24 H 4.A CENTRAL PRESSURE : 1000 HPA 5.A MAX AVERAGE WIND SPEED (10 MN) : 25 KT 6.A EXTENSION OF WINDS BY QUADRANTS (KM): 7.A FIRST CLOSED ISOBARE (PRESSURE / AVERAGE DIAM): 1008 HPA / 800 KM 8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: MEDIUM 1.B FORECASTS: 12H: 2007/12/14 00 UTC: 13.8S/69.7E, MAX WIND=025KT, TROP. DISTURBANCE. 24H: 2007/12/14 12 UTC: 13.9S/69.5E, MAX WIND=030KT, TROP. DEPRESSION. 36H: 2007/12/15 00 UTC: 14.2S/69.0E, MAX WIND=030KT, TROP. DEPRESSION. 48H: 2007/12/15 12 UTC: 14.6S/68.0E, MAX WIND=030KT, TROP. DEPRESSION. 60H: 2007/12/16 00 UTC: 14.9S/66.4E, MAX WIND=040KT, MODERATE TROP. STORM. 72H: 2007/12/16 12 UTC: 15.5S/65.3E, MAX WIND=040KT, MODERATE TROP. STORM. 2.B OTHER INFORMATIONS: T AND CI=2.0 WITHIN THE ELONGATED CLOCKWISE CIRCULATION MENTIONNED IN THE 0600Z WARNING AND SHOWED BY 0106UTC QUIKSCAT SWATH, THE SECONDARY CENTER MONITORED NORTHEASTWARD OF THE DEEP CONVECTIVE ACTIVITY IS BECOMED THE MAIN. IT IS TOTALLY EXPOSED WITH A BETTER DEFINED VORTEX. ENVIRONMENTAL CONDITIONS IS POORLY FAVORABLE. IN LOW LEVELS, EQUATORWARD CONVERGENCE IS GOOD BUT IS WEAKER ON THE TRADEWIND SIDE. A MID-LAT TROUGH THAT SHOULD PASS SOUTH OF THE SYSTEM WITHIN THE NEXT 48 HOURS SHOULD MAINTAIN POOR INFLOW ON THIS SIDE. IN HIGH LEVEL, POLEWARD OUTFLOW IS WELL DEFINED ASSOCIATED WITH A NORTHWESTWARDS SUBTROPICAL JET. EQUATORWARD, EAST-NORTHEASTERLY VERTICAL WHINDSHEAR REMAINS MODERATE BUT SEEMS TO DECREASE SINCE THE RECENT PAST HOURS (SEE THE CIRRUS EXPANSION NORTHWARDS) . NWP MODELS ARE IN AGREEMENT TO LET THE SYSTEM IN THE SAME AREA DURING THE NEXT 24 HOURS UNDERGOING OPPOSITE STEERING FLOWS IN THE MID-LEVELS (WESTERLIES IN THE NORTH, SOUTHEASTERLIES IN THE EAST AND NORTHWESTERLIES IN THE SOUTH). THE SYSTEM SHOULD TRACK SLOWLY GLOBALLY SOUTHWESTWARDS DURING THE NEXT 48 HOURS WITHOUT INTENSIFYING SIGNIFICANTLY AND THEN PROGRESSIVELY ACCELERATING TOWARDS A LESS SHEARED ENVIRONMENT.