WTIO30 FMEE 280107



RSMC / TROPICAL CYCLONE CENTER / LA REUNION

TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)



0.A WARNING NUMBER: 8/7/20142015

1.A MODERATE TROPICAL STORM  7  (DIAMONDRA)



2.A POSITION 2015/01/28 AT 0000 UTC:

WITHIN 30 NM RADIUS OF POINT 18.1 S / 77.7 E

(EIGHTEEN    DECIMAL ONE   DEGREES SOUTH AND SEVENTY SEVEN    DECIMAL

SEVEN   DEGREES EAST)

MOVEMENT :   QUASI-STATIONARY



3.A DVORAK ANALYSIS: 2.5/3.0/W 0.5/12 H



4.A CENTRAL PRESSURE: 990 HPA

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

RADIUS OF MAXIMUM WINDS (RMW) :56 KM



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

28 KT NE: 440 SE: 460 SW: 350 NW: 490

34 KT NE: 290 SE: 290 SW: 220 NW: 310







7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1006 HPA / 700 KM

8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION : MEDIUM



1.B FORECASTS:

12H: 2015/01/28 12 UTC: 18.4 S / 78.2 E, MAX WIND=040 KT, MODERATE

TROPICAL STORM

24H: 2015/01/29 00 UTC: 18.8 S / 79.0 E, MAX WIND=040 KT, MODERATE

TROPICAL STORM

36H: 2015/01/29 12 UTC: 19.8 S / 80.1 E, MAX WIND=035 KT, MODERATE

TROPICAL STORM

48H: 2015/01/30 00 UTC: 21.1 S / 81.4 E, MAX WIND=030 KT, TROPICAL

DEPRESSION

60H: 2015/01/30 12 UTC: 22.6 S / 82.9 E, MAX WIND=030 KT, TROPICAL

DEPRESSION

72H: 2015/01/31 00 UTC: 23.9 S / 84.2 E, MAX WIND=035 KT,

POST-TROPICAL DEPRESSION



2.B LONGER-RANGE OUTLOOK :

96H: 2015/02/01 00 UTC: 26.3 S / 87.0 E, MAX WIND=050 KT,

EXTRATROPICAL SYSTEM

120H: 2015/02/02 00 UTC: 31.7 S / 91.2 E, MAX WIND=050 KT,

EXTRATROPICAL SYSTEM



2.C ADDITIONAL INFORMATIONS:

T=2.5 AND CI=3.0

EXPERIENCING TWO COMPETING MID-LEVELS STEERING FLOWS, ONE GENERATED

BY THE NEAR-EQUATORIAL RIDGE AND THE OTHER BY THE SUBTROPICAL RIDGE,

DIAMONDRA IS QUASI-STATIONARY.

CURRENT POSITION IS HOWEVER DIFFICULT TO PRECISELY LOCATE AND IS

MAINLY BASED ON 1942Z (GCOM) AND 1402Z (TRMM) MICRO-WAVES FIXES.

THIS ESTIMATED LOCATION IS HOWEVER CONSISTENT WITH THE 2321Z GPM

SWATH THAT HAS BEEN AVAILABLE TOO LATE TO BE USED.

SYSTEM KEEPS ON EXPERIENCING NORTH-WESTERLY VERTICAL WINDSHEAR.

DIAMONDRA IS EXPECTED TO TRACK GLOBALLY SOUTH-EASTWARDS UNDER THE

STEERING INFLUENCE OF THE AFOREMENTIONED NEAR-EQUATORIAL RIDGE AND A

TRANSIENT MID-LEVEL TROUGH IN ITS SOUTH.

AS DIAMONDRA TRACKS SOUTH-EASTWARDS IN THE SAME DIRECTION THAN THE

WINDSHEAR, IT IS NOT EXPECTED TO WEAKEN RAPIDLY AND IT IS NOT

EXCLUDED THAT A TEMPORARILY STRENGTHENING SHOULD OCCUR WITHIN THE

NEXT 24 HOURS.

FROM SATURDAY, DIAMONDRA SHOULD BEGIN ITS EXTRA-TROPICALIZATION,

WINDS ARE THEN EXPECTED TO STRENGTHEN IN THE MID-LATITUDES GENERAL

CIRCULATION.=