WTIO30 FMEE 281810



RSMC / TROPICAL CYCLONE CENTER / LA REUNION

TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)



0.A WARNING NUMBER: 11/7/20142015

1.A MODERATE TROPICAL STORM  7  (DIAMONDRA)



2.A POSITION 2015/01/28 AT 1800 UTC:

WITHIN 20 NM RADIUS OF POINT 20.0 S / 79.9 E

(TWENTY    DECIMAL ZERO   DEGREES SOUTH AND SEVENTY NINE    DECIMAL

NINE   DEGREES EAST)

MOVEMENT : EAST-SOUTH-EAST 6 KT



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



4.A CENTRAL PRESSURE: 986 HPA

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

RADIUS OF MAXIMUM WINDS (RMW) :83 KM



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

28 KT NE: 440 SE: 460 SW: 490 NW: 180

34 KT NE: 290 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 06 UTC: 20.6 S / 80.3 E, MAX WIND=040 KT, MODERATE

TROPICAL STORM

24H: 2015/01/29 18 UTC: 21.4 S / 80.9 E, MAX WIND=035 KT, MODERATE

TROPICAL STORM

36H: 2015/01/30 06 UTC: 22.6 S / 82.0 E, MAX WIND=035 KT, MODERATE

TROPICAL STORM

48H: 2015/01/30 18 UTC: 23.8 S / 83.4 E, MAX WIND=035 KT,

POST-TROPICAL DEPRESSION

60H: 2015/01/31 06 UTC: 24.9 S / 84.5 E, MAX WIND=035 KT,

POST-TROPICAL DEPRESSION

72H: 2015/01/31 18 UTC: 25.9 S / 85.9 E, MAX WIND=035 KT,

POST-TROPICAL DEPRESSION



2.B LONGER-RANGE OUTLOOK :

96H: 2015/02/01 18 UTC: 30.3 S / 89.6 E, MAX WIND=035 KT,

EXTRATROPICAL SYSTEM

120H: 2015/02/02 18 UTC: 37.0 S / 91.4 E, MAX WIND=050 KT,

EXTRATROPICAL SYSTEM



2.C ADDITIONAL INFORMATIONS:

T=3.0 AND CI=3.0



THE GENERAL PATTERN HAS FEX EVOLVED FOR THE LAST 6 HOURS. 0600Z CIMSS

DATA STILL SUGGESTS A WESTERLY VERTICAL WIND-SHEAR AT ABOUT 15KT. THE

POSITION OF THE CENTRE HAS BEEN EXTRAPOLATED THANKS TO 1343Z 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.=