WTIO30 FMEE 091816



RSMC / TROPICAL CYCLONE CENTER / LA REUNION

TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)



0.A WARNING NUMBER: 14/2/20172018

1.A SEVERE TROPICAL STORM  2  (IRVING)



2.A POSITION 2018/01/09 AT 1800 UTC:

WITHIN 30 NM RADIUS OF POINT 24.3 S / 70.8 E

(TWENTY FOUR    DECIMAL THREE   DEGREES SOUTH AND SEVENTY    DECIMAL

EIGHT   DEGREES EAST)

MOVEMENT : SOUTH-SOUTH-WEST 26 KT



3.A DVORAK ANALYSIS: NIL



4.A CENTRAL PRESSURE: 978 HPA

5.A MAX AVERAGE WIND SPEED (10 MN): 50 KT

RADIUS OF MAXIMUM WINDS (RMW) :74 KM



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

28 KT NE: 260 SE: 460 SW: 460 NW: 170

34 KT NE: 190 SE: 350 SW: 350 NW: 130

48 KT NE:  SE: 110 SW: 130 NW:





7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1008 HPA / 700 KM

8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION : DEEP



1.B FORECASTS:

12H: 2018/01/10 06 UTC: 28.9 S / 68.5 E, MAX WIND=050 KT,

POST-TROPICAL DEPRESSION

24H: 2018/01/10 18 UTC: 34.4 S / 68.6 E, MAX WIND=055 KT,

POST-TROPICAL DEPRESSION

36H: 2018/01/11 06 UTC: 40.2 S / 75.0 E, MAX WIND=055 KT,

POST-TROPICAL DEPRESSION









2.B LONGER-RANGE OUTLOOK :







2.C ADDITIONAL INFORMATION:

IRVING SUFFERS FROM THE MODERATE NORTHWESTWARD VERTICAL WINDSHEAR

(ANALYSED AT 1200Z NEAR 20KT BY CIMSS). 1317Z SSMIS MICROWAVE DATA

SHOW CLEARLY THE CONVECTION DISPLACE OVER THE SOUTHERN SEMI-CIRCLE.

THE LAST INFRARED IMAGERIES SHOW A CONVECTION LESS AND LESS INTENSE

WITH CLOUD TOPS WARMER AND WARMER LINKED TO A VERY WEAK OCEANIC HEAT

CONTENT. CURRENT INTENSITY ESTIMATION IS IN A GOOD AGREEMENT WITH

1637Z ASCAT SWATH THAT INDICATED STORM WINDS OVER THE SOUTHERN

SEMI-CIRCLE.



IRVING TRACKS QUICKLY SOUTHWESTWARD OVER THE NORTHWESTERN EDGE OF THE

MID-TROPOSPHERIC RIDGE LOCATED ON ITS SOUTHEAST. TOMORROW, AS THE

SYSTEM MOVES TOWARD THE MID-LATITUDES, IT SHOULD CURVE PROGRESSIVELY

SOUTHWARD AND THEN SOUTHEASTWARD AHEAD A WIDE AND DEEP TROUGH.



ON THIS TRACK, THE OCEANIC HEAT CONTENT IS NOW INSUFFICIENT AND THE

NORTHWESTERN VERTICAL WINDSHEAR IS FORECASTED TO STRENGTHENED. FROM

TOMORROW, THE SYSTEM SHOULD EVOLVE LIKE A WARM CORE SECLUSION WITH A

SHALLOW WARM CORE BEFORE MERGE WITH THE LOW LEVEL TROUGH ASSOCIATED

TO EX-AVA DEPRESSION.=