WTIO30 FMEE 111216



RSMC / TROPICAL CYCLONE CENTER / LA REUNION

TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)



0.A WARNING NUMBER: 9/4/20152016

1.A MODERATE TROPICAL STORM  4  (DAYA)



2.A POSITION 2016/02/11 AT 1200 UTC:

WITHIN 30 NM RADIUS OF POINT 26.5 S / 54.8 E

(TWENTY SIX    DECIMAL FIVE   DEGREES SOUTH AND FIFTY FOUR    DECIMAL

EIGHT   DEGREES EAST)

MOVEMENT : SOUTH-EAST 11 KT



3.A DVORAK ANALYSIS: 2.5/2.5/W 0.5/12 H



4.A CENTRAL PRESSURE: 992 HPA

5.A MAX AVERAGE WIND SPEED (10 MN): 35 KT

RADIUS OF MAXIMUM WINDS (RMW) :46 KM



6.A EXTENSION OF WIND BY QUADRANTS (KM):

28 KT NE: 150 SE: 430 SW: 190 NW: 90

34 KT NE: 60 SE: 60 SW: 60 NW: 60







7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1000 HPA / 400 KM

8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION : DEEP



1.B FORECASTS:

12H: 2016/02/12 00 UTC: 28.6 S / 56.4 E, MAX WIND=030 KT, TROPICAL

DEPRESSION

24H: 2016/02/12 12 UTC: 32.1 S / 57.9 E, MAX WIND=035 KT,

POST-TROPICAL DEPRESSION

36H: 2016/02/13 00 UTC: 36.5 S / 59.7 E, MAX WIND=035 KT,

POST-TROPICAL DEPRESSION

48H: 2016/02/13 12 UTC: 41.0 S / 64.1 E, MAX WIND=035 KT,

EXTRATROPICAL SYSTEM







2.B LONGER-RANGE OUTLOOK :







2.C ADDITIONAL INFORMATION:

T=2.5+ CI=2.5+



OVER THE LAST SIX HOURS, SUMMITS TEMPERATURE INCREASED WITH THE

DIURNAL CYCLE, AND IR IMAGERY SHOW NO SIGN OF A SIGNIFICANT

CURVATURE, IN THE SOUTHERN SEMI-CIRCLE. HOWEVER, LAST MICRO-WAVE DATA

OF 0832Z AND 1052Z SUGGEST THAT A FRAGMENTED CURVED BAND IS

REBUILDING IN THE NORTHERN PARTS OF DAYA. THAT PATTERN MAY INDICATES

THAT THE STORM IS RESISTING TO THE NORTH-WESTERLY CONSTRAINT

GRADUALLY INCREASING (20KT ACCORDING TO THE CIMSS DATA).



THE EVACUATION OF THE SYSTEM TOWARDS THE MID-LATITUDE IS STEERED BY

BOTH A CUT-OFF LOW IN THE SOUTH-WEST AND A HIGH GEOPOTENTIAL AREA IN

THE EAST. UNDER THE JOINED INFLUENCE OF THESE TWO SYNOPTIC

STRUCTURES, THE AVAILABLE NWP MODELS STILL FORECAST SIMILAR

SOUTH-EAST TRACKS WITH MORE SPREAD THIS WEEK-END. THE ENVIRONMENTAL

CONDITIONS BECOME REALLY UNFAVOURABLE FROM THIS NIGHT WITH LOW

ENERGETIC WATERS AND A STRONG VWS UNDER A BRANCH OF THE SUBTROPICAL

WESTERLY JET. IT SHOULD THEN BEGIN A RELATIVELY QUICK EXTRATROPICAL

TRANSITION BEFORE MERGING WITH A BAROCLINIC LOW SATURDAY.=