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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 : 10/5/20082009
1.A MODERATE TROPICAL STORM 5 (DONGO)

2.A POSITION 2009/01/10 AT 1200 UTC :
WITHIN 30 NM RADIUS OF POINT 18.8S / 67.6E
(EIGHTEEN DECIMAL EIGHT DEGREES SOUTH AND SIXTY SEVEN DECIMAL SIX DEGREES EAST)
MOVEMENT : SOUTH-SOUTH-EAST 8 KT

3.A DVORAK ANALYSIS : 2.5/2.5 /S 0.0/24 H
4.A CENTRAL PRESSURE : 994 HPA
5.A MAX AVERAGE WIND SPEED (10 MN) : 35 KT
RADIUS OF MAXIMUM WINDS (RMW) : 30 KM

6.A EXTENSION OF WINDS BY QUADRANTS (KM):
30 KT NE: 180 SE: 270 SO: 180 NO: 110

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 00 UTC: 20.5S/68.2E, MAX WIND=040KT, MODERATE TROP. STORM.
24H: 2009/01/11 12 UTC: 22.7S/68.8E, MAX WIND=050KT, SEVERE TROP. STORM.
36H: 2009/01/12 00 UTC: 25.4S/69.4E, MAX WIND=060KT, SEVERE TROP. STORM.
48H: 2009/01/12 12 UTC: 28.3S/70.0E, MAX WIND=050KT, BECOMING EXTRATROPICAL.
60H: 2009/01/13 00 UTC: 30.6S/71.4E, MAX WIND=050KT, EXTRATROPICAL.
72H: 2009/01/13 12 UTC: 32.5S/73.3E, MAX WIND=050KT, EXTRATROPICAL.

2.B OTHER INFORMATIONS:
T=CI=2.5+
AT 0730Z VISIBLE METEOSAT7 IMAGERY SHOWS A PARTIALLY EXPOSED VORTEX CENTERED NEAR 18.1S/67.4E, SIGN THAT THE EXPECTED SOUTH-SOUTHEASTWARDS RECURVING TRAJECTORY HAS BEGAN 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.
CONVECTIVE ACTIVITY DOESN'T SHOW SIGNIFICATIVE IMPROVMENT SINCE 10/0000Z.
ACCORDING TO LAST NIGHT 10/0216Z QUIKSCAT SWATH (NO WINDS MORE THAN 30KT) AND THE BUOY 16588 (995.2HPA AT 10/0800Z AND 993.6HPA AT 10/0400Z) , CURRENT INTENSITY IS ESTIMATED AT T=CI=2.5+ WITH MAXIMUM WINDS AT 35KT AND MSLP AT 994HPA.
AS NEW LIGHT ON THIS ELEMENT (CLOUD PATTERN, SCATTEROMETRY AND BUOY), DONGO STILL SHOWS CHARACTERISTICS OF AN HYBRID LOW BETWEEN CLASSICAL TROPICAL LOW AND MONSSON ONE
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 36 HOURS TO REACH THE STRONG TROPICAL STORM STAGE.