WTIO30 FMEE 161232



RSMC / TROPICAL CYCLONE CENTER / LA REUNION

TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)



0.A WARNING NUMBER: 8/5/20152016

1.A SEVERE TROPICAL STORM  5  (URIAH)



2.A POSITION 2016/02/16 AT 1200 UTC:

WITHIN 20 NM RADIUS OF POINT 18.0 S / 84.3 E

(EIGHTEEN    DECIMAL ZERO   DEGREES SOUTH AND EIGHTY FOUR    DECIMAL

THREE   DEGREES EAST)

MOVEMENT : WEST 10 KT



3.A DVORAK ANALYSIS: 4.0/4.0/D 1.0/12 H



4.A CENTRAL PRESSURE: 981 HPA

5.A MAX AVERAGE WIND SPEED (10 MN): 60 KT

RADIUS OF MAXIMUM WINDS (RMW) :56 KM



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

28 KT NE: 220 SE: 410 SW: 440 NW: 240

34 KT NE: 110 SE: 200 SW: 280 NW: 150

48 KT NE: 80 SE: 120 SW: 110 NW: 90





7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1008 HPA / 800 KM

8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION : DEEP



1.B FORECASTS:

12H: 2016/02/17 00 UTC: 18.1 S / 82.3 E, MAX WIND=070 KT, TROPICAL

CYCLONE

24H: 2016/02/17 12 UTC: 18.7 S / 80.6 E, MAX WIND=080 KT, TROPICAL

CYCLONE

36H: 2016/02/18 00 UTC: 19.8 S / 79.3 E, MAX WIND=080 KT, TROPICAL

CYCLONE

48H: 2016/02/18 12 UTC: 21.2 S / 78.7 E, MAX WIND=070 KT, TROPICAL

CYCLONE

60H: 2016/02/19 00 UTC: 22.3 S / 78.5 E, MAX WIND=060 KT, SEVERE

TROPICAL STORM

72H: 2016/02/19 12 UTC: 22.8 S / 78.2 E, MAX WIND=050 KT, SEVERE

TROPICAL STORM



2.B LONGER-RANGE OUTLOOK :

96H: 2016/02/20 12 UTC: 22.9 S / 77.6 E, MAX WIND=040 KT,

POST-TROPICAL DEPRESSION

120H: 2016/02/21 12 UTC: 24.1 S / 78.0 E, MAX WIND=035 KT,

POST-TROPICAL DEPRESSION



2.C ADDITIONAL INFORMATION:

T=4.0+ CI=4.0+



OVER THE LAST 6 HOURS, CONVECTION HAS GRADUALLY ORGANISED ITSELF AS A

CDO PATTERN. THEN, THE CENTER HAS WARMED  AND NOW, AN EYE IS EVEN

VISIBLE ON THE LAST IR IMAGES. 0933Z SSMI MICROWAVE IMAGES WERE

ALREADY DEPICTING THE BUILDING OF AN EYE PATTERN WITH A CLOSED

CONVECTION RING AT 37GHZ BUT NOT AT 85GHZ YET, WHERE A WEAKNESS WAS

STILL PRESENT IN THE SOUTH-WESTERN QUADRANT. ON THESE IMAGES, A

CONVECTIVE BURST IS ALSO VISIBLE INSIDE THE MAX WINDS RADIUS WHICH

COULD BE AN HARBINGER OF A QUICKER INTENSIFICATION. DVORAK DT AGREES

WITH MET AT 4.0.



URIAH'S TRACK HAS SIGNIFICANTLY BEND WESTWARD SINCE 00Z.THIS EXPECTED

TREND IS DUE TO A BUILDING LOW TO MID-LEVELS SUBTROPICAL RIDGE

LOCATED ON ITS SOUTH IN THE WAKE OF A TROUGH THAT HAS BYPASSED THE

SYSTEM YESTERDAY. FROM WEDNESDAY, THE SYSTEM WILL PROGRESSIVELY MOVE

TOWARDS THE SOUTH-SOUTH-WEST, WITH THE REBUILDING OF A MID-LEVEL

RIDGE IN THE EAST. FOR THE END OF THE WEEK, URIAH IS LIKELY TO SLOW

DOWN BECAUSE OF THE BUILDING OF A SECOND RIDGE IN THE SOUTH. 00Z EURO

ENSEMBLE FORECAST STILL SHOW LARGE SPREAD FROM FRIDAY EVENING,

SUGGESTING AN INCREASED UNCERTAINTY. HOWEVER, THE MAJORITY OF THE

ENSEMBLE MEMBERS AND THE OTHER NWP MODELS FORECAST A SOUTHWARD TO

SOUTHWESTWARD TRACK STEERED BY A BAROCLINIC LOW MOVING TOWARDS THE

MID-LATITUDES AND CAUSING A WEAKNESS IN THE SUBTROPICAL RIDGE.



ON THIS TRACK, UPPER LEVELS CONDITIONS SHOULD REMAIN CONDUCIVE UP TO

THURSDAY WITH A WEAK VERTICAL WINDSHEAR. ON WEDNESDAY, THE BUILDING

OF A NEW OUTFLOW CHANNEL ON THE POLAR SIDE ALONG WITH GOOD OCEANIC

HEAT CONTAIN NEAR 80E, ARE LIKELY TO HELP THE SYSTEM INTENSIFYING

MORE RAPIDLY. AFTER THURSDAY, THE ARRIVAL OF AN UPPER TROUGH WILL

INCREASE THE NORTH-WESTERLY VWS, AND START THE WEAKENING, ACCENTUATED

BY THE MARGINAL OCEAN HEAT CONTENT SOUTH OF 23-24S. MOREOVER, THE

SLOW MOTION FORECAST FROM FRIDAY IS EXPECTED TO SIGNIFICANTLY COOL

THE UNDERLYING SST AND INCREASE THE WEAKENING TREND.=