WTIO30 FMEE 282335



RSMC / TROPICAL CYCLONE CENTER / LA REUNION

TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)



0.A WARNING NUMBER: 12/7/20142015

1.A MODERATE TROPICAL STORM  7  (DIAMONDRA)



2.A POSITION 2015/01/29 AT 0000 UTC:

WITHIN 25 NM RADIUS OF POINT 20.2 S / 80.1 E

(TWENTY    DECIMAL TWO   DEGREES SOUTH AND EIGHTY    DECIMAL ONE

DEGREES EAST)

MOVEMENT : SOUTH-EAST 5 KT



3.A DVORAK ANALYSIS: 3.0/3.0/S 0.0/6 H



4.A CENTRAL PRESSURE: 989 HPA

5.A MAX AVERAGE WIND SPEED (10 MN): 40 KT

RADIUS OF MAXIMUM WINDS (RMW) :102 KM



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

28 KT NE: 300 SE: 460 SW: 490 NW: 170

34 KT NE: 190 SE: 290 SW: 260 NW: 110







7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1007 HPA / 1000 KM

8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION : MEDIUM



1.B FORECASTS:

12H: 2015/01/29 12 UTC: 21.1 S / 80.9 E, MAX WIND=040 KT, MODERATE

TROPICAL STORM

24H: 2015/01/30 00 UTC: 22.2 S / 81.8 E, MAX WIND=040 KT, MODERATE

TROPICAL STORM

36H: 2015/01/30 12 UTC: 24.0 S / 82.9 E, MAX WIND=035 KT, MODERATE

TROPICAL STORM

48H: 2015/01/31 00 UTC: 25.4 S / 84.3 E, MAX WIND=035 KT,

POST-TROPICAL DEPRESSION

60H: 2015/01/31 12 UTC: 26.7 S / 85.6 E, MAX WIND=035 KT,

POST-TROPICAL DEPRESSION

72H: 2015/02/01 00 UTC: 28.4 S / 87.4 E, MAX WIND=035 KT,

POST-TROPICAL DEPRESSION



2.B LONGER-RANGE OUTLOOK :

96H: 2015/02/02 00 UTC: 31.4 S / 89.8 E, MAX WIND=040 KT,

EXTRATROPICAL SYSTEM

120H: 2015/02/03 00 UTC: 43.8 S / 97.5 E, MAX WIND=050 KT,

EXTRATROPICAL SYSTEM



2.C ADDITIONAL INFORMATIONS:

T=3.0 AND CI=3.0



DEEP CONVECTION REMAIN ONLY IN THE SOUTHERN PART OF CIRCULATION.

1800Z CIMSS DATA STILL SUGGESTS A INCREASING WESTERLY VERTICAL

WIND-SHEAR AT ABOUT 25KT. THE POSITION OF THE CENTRE HAS BEEN

EXTRAPOLATED THANKS TO 2231Z MW PICTURE.



UNTIL SATURDAY, DIAMONDRA IS EXPECTED TO TRACK GENERALLY

SOUTH-EASTWARDS UNDER THE STEERING INFLUENCE OF THE AFOREMENTIONED

NEAR-EQUATORIAL RIDGE AND A TRANSIENT MID-LEVEL TROUGH IN ITS SOUTH.

IT SHOULD SLOWLY WEAKEN WITH THE INFLUENCE OF THE WEST-SOUTHWESTERLY

VERTICAL WIND-SHEAR AND OF THE DECREASING OCEAN HEAT POTENTIAL.



FROM SATURDAY, DIAMONDRA SHOULD BEGIN ITS EXTRA-TROPICALIZATION ON A

SOUTHWARD TRACK. THE WINDS ARE THEN EXPECTED TO STRENGTHEN IN THE

MID-LATITUDES GENERAL CIRCULATION.=