WTIO30 FMEE 071309



RSMC / TROPICAL CYCLONE CENTER / LA REUNION

TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)



0.A WARNING NUMBER: 5/2/20172018

1.A SEVERE TROPICAL STORM  2  (IRVING)



2.A POSITION 2018/01/07 AT 1200 UTC:

WITHIN 30 NM RADIUS OF POINT 14.5 S / 84.5 E

(FOURTEEN    DECIMAL FIVE   DEGREES SOUTH AND EIGHTY FOUR    DECIMAL

FIVE   DEGREES EAST)

MOVEMENT : WEST-SOUTH-WEST 14 KT



3.A DVORAK ANALYSIS: 4.0/4.0/D 0.5/12 H



4.A CENTRAL PRESSURE: 983 HPA

5.A MAX AVERAGE WIND SPEED (10 MN): 55 KT

RADIUS OF MAXIMUM WINDS (RMW) :46 KM



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

28 KT NE: 220 SE: 330 SW: 330 NW: 220

34 KT NE: 150 SE: 190 SW: 190 NW: 110

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





7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1006 HPA / 800 KM

8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION : DEEP



1.B FORECASTS:

12H: 2018/01/08 00 UTC: 16.7 S / 80.9 E, MAX WIND=065 KT, TROPICAL

CYCLONE

24H: 2018/01/08 12 UTC: 19.1 S / 78.0 E, MAX WIND=070 KT, TROPICAL

CYCLONE

36H: 2018/01/09 00 UTC: 21.5 S / 75.0 E, MAX WIND=070 KT, TROPICAL

CYCLONE

48H: 2018/01/09 12 UTC: 23.9 S / 72.3 E, MAX WIND=060 KT, SEVERE

TROPICAL STORM

60H: 2018/01/10 00 UTC: 26.9 S / 69.8 E, MAX WIND=050 KT, SEVERE

TROPICAL STORM

72H: 2018/01/10 12 UTC: 31.4 S / 68.8 E, MAX WIND=045 KT,

POST-TROPICAL DEPRESSION



2.B LONGER-RANGE OUTLOOK :

96H: 2018/01/11 12 UTC: 41.6 S / 74.8 E, MAX WIND=045 KT,

POST-TROPICAL DEPRESSION





2.C ADDITIONAL INFORMATION:

T=CI=4.0-



DURING THE LAST HOURS, DEEP CONVECTION GOT STRONGER NEAR THE CENTER

IN A CURVED BAND PATTERN. MICROWAVE DATA CONFIRMED THE STRENGTHENING

OF THE INNER CORE. IN AGREEMENT WITH THIS MORNING ADDITIONAL ASCAT

DATA, THE INTENSITY IS UPGRADED TO 55KT.



NO CHANGE IN TERMS OF FORECAST ON THE IRVING SYSTEM, ALL NUMERICAL

MODELS ARE WELL IN AGREEMENT ON ITS EVOLUTION, DEFINING THEN A GOOD

CONFIDENCE IN THE FORECAST. IRVING'S TRACK IS STEERED BY A STRONG

RIDGE IN THE SOUTH-EAST. FROM WEDNESDAY, IRVING SHOULD BE ATTRACTED

SOUTH-EASTWARDS TOWARD THE MID-LATITUDES BY A TROUGH ARRIVING FROM

THE SOUTH-WEST.



THE SYSTEM IS LIKELY TO KEEP CONDUCIVE ENVIRONMENTAL CONDITIONS UP TO

TOMORROW EVENING WITH A VERY GOOD UPPER DIVERGENCE. IT SHOULD REACH

TROPICAL CYCLONE STATUS IN THE NEXT MORNING. THEN, AHEAD OF THE UPPER

ATMOSPHERIC DYNAMICS DESPITE ITS SIGNIFICANT SPEED, SHEAR NEGATIVE

IMPACTS ARE LIKELY TO LIMIT ITS DEEPENING POTENTIAL AND THEN WEAKEN

IRVING FROM TUESDAY. ON THURSDAY, THE OCEANIC POTENTIAL AS WELL WILL

DECAY SOUTH OF 27S. IRVING SHOULD THEN BEGIN ITS EXTRATROPICAL

TRANSITION.=