013
WTIO30 FMEE 110026

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

0.A WARNING NUMBER : 12/5/20082009
1.A SEVERE TROPICAL STORM 5 (DONGO)

2.A POSITION 2009/01/11 AT 0000 UTC :
WITHIN 30 NM RADIUS OF POINT 20.7S / 68.3E
(TWENTY DECIMAL SEVEN DEGREES SOUTH AND SIXTY EIGHT DECIMAL THREE DEGREES
EAST)
MOVEMENT : SOUTH-SOUTH-EAST 11 KT

3.A DVORAK ANALYSIS : 3.5/3.5 /D 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) : 30 KM

6.A EXTENSION OF WINDS BY QUADRANTS (KM):
30 KT NE: 330 SE: 270 SO: 270 NO: 130
50 KT NE: 035 SE: 035 SO: 035 NO: 035

7.A FIRST CLOSED ISOBARE (PRESSURE / AVERAGE DIAM): 1008 HPA / 1200 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: DEEP

1.B FORECASTS:
12H: 2009/01/11 12 UTC: 23.3S/69.2E, MAX WIND=060KT, SEVERE TROP. STORM.
24H: 2009/01/12 00 UTC: 25.9S/70.3E, MAX WIND=050KT, SEVERE TROP. STORM.
36H: 2009/01/12 12 UTC: 29.6S/71.3E, MAX WIND=050KT, BECOMING
EXTRATROPICAL.
48H: 2009/01/13 00 UTC: 31.8S/72.6E, MAX WIND=040KT, BECOMING
EXTRATROPICAL.
60H: 2009/01/13 12 UTC: 32.9S/74.1E, MAX WIND=040KT, EXTRATROPICAL.
72H: 2009/01/14 00 UTC: 34.6S/77.5E, MAX WIND=040KT, EXTRATROPICAL.

2.B OTHER INFORMATIONS:
T=CI=3.5

OVERALL PATTERN HAS IMPROVED DURING THE WHOLE NIGHT WITH AN ONGOING
CURVED BAND PATTERN. LATEST ANALYSIS IN EIR IMAGERY SHOWS CONVECTION WRAP
OF .90 ON LOG 10 SPIRAL THAT YIELDS TO A DT OF 3.5. ANALYSIS FROM PGTW
AND KNES CONFIRM THIS INTENSITY.

NO MAJOR CHANGE HAS CAME FROM THE 12Z RUN. AVAILABLE DYNAMICAL GUIDANCE
ARE IN GOOD AGREEMENT SHOWING ONLY SOME SLIGHT DISPERSION FOR THE SPEED.
PRESENT FORECAST IS BASED ON A GENERAL GENERAL BUT CLOSER TO THE LATEST
ECMWF TRACK. IT IS JUST SLIGHTLY EASTWARDS OF THE PREVIOUS FORECAST TRACK
..

SYSTEM IS STILL TRACKING SOUTHSOUTHEASTWARDS (CURRENT MOTION AND SPEED:
155o/11KT) UNDER THE STEERING INFLUENCE OF THE MID-LEVEL RIDGE LOCATED TO
THE NORTH EAST OF THE SYSTEM. IT SHOULD REMAIN UNDER THIS STEERING FLOW
WITHIN THE NEXT DAYS.

ENVIRONMENTAL CONDITIONS ARE STILL FAVOURABLE FOR INTENSIFICATION BUT ARE
STILL FORECAST TO DETERIORATE SUNDAY NIGHT WITH A STRONGER NORTHWESTERLY
SHEAR AND PROGRESSIVELY COOLER SST. DONGO HAS STILL A WINDOW OF 18 TO 24
HOURS TO REACH ITS MAXIMAL INTENSITY.