WTIO30 FMEE 070031



RSMC / TROPICAL CYCLONE CENTER / LA REUNION

TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)



0.A WARNING NUMBER: 3/2/20172018

1.A MODERATE TROPICAL STORM  2  (IRVING)



2.A POSITION 2018/01/07 AT 0000 UTC:

WITHIN 21 NM RADIUS OF POINT 13.5 S / 87.0 E

(THIRTEEN    DECIMAL FIVE   DEGREES SOUTH AND EIGHTY SEVEN    DECIMAL

ZERO   DEGREES EAST)

MOVEMENT : WEST-SOUTH-WEST 14 KT



3.A DVORAK ANALYSIS: 3.5/3.5/D 0.5/6 H



4.A CENTRAL PRESSURE: 990 HPA

5.A MAX AVERAGE WIND SPEED (10 MN): 45 KT

RADIUS OF MAXIMUM WINDS (RMW) :37 KM



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

28 KT NE: 150 SE: 260 SW: 260 NW: 150

34 KT NE: 110 SE: 70 SW: 70 NW: 70







7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1007 HPA / 1100 KM

8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION : DEEP



1.B FORECASTS:

12H: 2018/01/07 12 UTC: 15.4 S / 84.0 E, MAX WIND=045 KT, MODERATE

TROPICAL STORM

24H: 2018/01/08 00 UTC: 17.2 S / 80.9 E, MAX WIND=050 KT, SEVERE

TROPICAL STORM

36H: 2018/01/08 12 UTC: 19.7 S / 77.9 E, MAX WIND=060 KT, SEVERE

TROPICAL STORM

48H: 2018/01/09 00 UTC: 22.1 S / 75.2 E, MAX WIND=060 KT, SEVERE

TROPICAL STORM

60H: 2018/01/09 12 UTC: 25.0 S / 72.2 E, MAX WIND=050 KT, SEVERE

TROPICAL STORM

72H: 2018/01/10 00 UTC: 28.3 S / 69.9 E, MAX WIND=045 KT, MODERATE

TROPICAL STORM



2.B LONGER-RANGE OUTLOOK :

96H: 2018/01/11 00 UTC: 36.6 S / 71.8 E, MAX WIND=035 KT,

EXTRATROPICAL DEPRESSION

120H: 2018/01/12 00 UTC: 45.1 S / 82.2 E, MAX WIND=035 KT,

EXTRATROPICAL DEPRESSION



2.C ADDITIONAL INFORMATION:

T=CI=3.5-



AFTER STRONG CONVECTION BURSTS DURING THE NIGHT, THE CONVECTION IS

LIGHTLY WEAKENING DURING THE LAST HOURS. AN EYE BEGINS TO APPEAR ON

THE LATEST INFRARED DATA AFTER 00UTC.



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

TOWARDS THE MID-LATITUDES BY A TROUGH ARRIVING FROM THE SOUTH-WEST

WHOSE FORECAST IS ALSO WELL APPREHENDED.



THE UPPER ATMOSPHERIC DYNAMICS IS SUITABLE FOR A SHEAR ENVIRONMENT

NEAR THE SYSTEM. HOWEVER THE SIGNIFICANT SPEED OF DISPLACEMENT OF

IRVING SHOULD ALLOW IT TO COMPENSATE THE NEGATIVE EFFECTS OF THE

SHEAR AND TO INTENSIFY UNTIL THE MAXIMUM STAGE OF SEVERE TROPICAL

STORM, RESTRICTED BY THE OCEANIC POTENTIAL TO THESE LATITUDES AND THE

INFLUENCE OF THE UPPER TROUGH STRONGER. IRVING SHOULD THEN BEGIN TO

WEAKEN WHILE BEGINNING AN EXTRATROPICAL TRANSITION.=