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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

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RSMC / TROPICAL CYCLONE CENTRE / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)

0.A WARNING NUMBER : 11/5/20082009
1.A MODERATE TROPICAL STORM 5 (DONGO)

2.A POSITION 2009/01/10 AT 1800 UTC :
WITHIN 20 NM RADIUS OF POINT 19.6S / 67.8E
(NINETEEN DECIMAL SIX DEGREES SOUTH AND SIXTY SEVEN DECIMAL EIGHT DEGREES EAST)
MOVEMENT : SOUTH-SOUTH-EAST 8 KT

3.A DVORAK ANALYSIS : 3.0/3.0 /D 0.5/6 H
4.A CENTRAL PRESSURE : 990 HPA
5.A MAX AVERAGE WIND SPEED (10 MN) : 40 KT
RADIUS OF MAXIMUM WINDS (RMW) : 30 KM

6.A EXTENSION OF WINDS BY QUADRANTS (KM):
30 KT NE: 270 SE: 270 SO: 270 NO: 130

7.A FIRST CLOSED ISOBARE (PRESSURE / AVERAGE DIAM): 1008 HPA / 1000 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: DEEP

1.B FORECASTS:
12H: 2009/01/11 06 UTC: 21.7S/68.5E, MAX WIND=050KT, SEVERE TROP. STORM.
24H: 2009/01/11 18 UTC: 24.4S/69.3E, MAX WIND=060KT, SEVERE TROP. STORM.
36H: 2009/01/12 06 UTC: 27.9S/70.0E, MAX WIND=050KT, SEVERE TROP. STORM.
48H: 2009/01/12 18 UTC: 30.3S/71.0E, MAX WIND=050KT, BECOMING EXTRATROPICAL.
60H: 2009/01/13 06 UTC: 32.5S/72.5E, MAX WIND=045KT, EXTRATROPICAL.
72H: 2009/01/13 18 UTC: 34.1S/75.5E, MAX WIND=040KT, EXTRATROPICAL.

2.B OTHER INFORMATIONS:
T=CI=3.0

SINCE AROUND 8 HOURS, DEEP CONVECTION KEEP ON ORGANIZING AROUND THE LLCC. SYSTEM IS INTENSIFYING AND THE QUICKSCAT SWATH OF 13:23Z NOW SHOWS SOME 35 KT WINDS IN THE NORTHEASTERN QUADRANT.

THE EXPECTED SOUTH-SOUTHEASTWARDS RECURVING TRAJECTORY HAS BEGAN (CURRENT MOTION AND SPEED: 150°/8KT) UNDER THE STEERING INFLUENCE OF THE MID-LEVEL RIDGE STRETCHING ALONG AN AXIS
EXTENDING FROM 5S/73E TO 21S/80E (SEE ECMWF NWP 600HPA FLOW) AND THE SYSTEM SHOULD REMAIN UNDER THIS STEERING FLOW WITHIN THE NEXT DAYS.

ENVIRONMENTAL CONDITIONS ARE FAVOURABLE FOR INTENSIFICATION, GOOD LOW LEVEL TRADE WINDS INFLOW (EQUATORWARD INFLOW HAS WEAKENED ON THIS SOUTHWARDS TRACK), WEAKENING VERTICAL WINDSHEAR , STRONG UPPER LEVEL OUTFLOW RELATED TO A WESTERLY POLEWARD JET AND SST UP TO 26.5S DOWN TO 27S.
NORTHWESTERLY VERTICAL WINDSHEAR IS FORECASTED TO STRENGHTEN WITHIN THE NIGHT FROM SUNDAY TO MONDAY, DONGO STILL HAS A WINDOW OF 24 TO 30 HOURS TO REACH THE STRONG TROPICAL STORM STAGE.