WTIO30 FMEE 081231



RSMC / TROPICAL CYCLONE CENTER / LA REUNION

TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)



0.A WARNING NUMBER: 16/13/20142015

1.A TROPICAL CYCLONE  13  (JOALANE)



2.A POSITION 2015/04/08 AT 1200 UTC:

WITHIN 15 NM RADIUS OF POINT 15.1 S / 64.7 E

(FIFTEEN    DECIMAL ONE   DEGREES SOUTH AND SIXTY FOUR    DECIMAL

SEVEN   DEGREES EAST)

MOVEMENT : SOUTH-EAST 8 KT



3.A DVORAK ANALYSIS: 4.5/4.5/D 0.5/12 H



4.A CENTRAL PRESSURE: 972 HPA

5.A MAX AVERAGE WIND SPEED (10 MN): 70 KT

RADIUS OF MAXIMUM WINDS (RMW) :28 KM



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

28 KT NE: 280 SE: 460 SW: 200 NW: 150

34 KT NE: 180 SE: 200 SW: 170 NW: 110

48 KT NE: 90 SE: 100 SW: 90 NW: 80

64 KT NE: 50 SE: 50 SW: 50 NW: 50



7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1005 HPA / 2000 KM

8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION : DEEP



1.B FORECASTS:

12H: 2015/04/09 00 UTC: 16.4 S / 65.2 E, MAX WIND=075 KT, TROPICAL

CYCLONE

24H: 2015/04/09 12 UTC: 17.7 S / 65.6 E, MAX WIND=085 KT, TROPICAL

CYCLONE

36H: 2015/04/10 00 UTC: 18.9 S / 66.2 E, MAX WIND=095 KT, INTENSE

TROPICAL CYCLONE

48H: 2015/04/10 12 UTC: 20.1 S / 67.4 E, MAX WIND=105 KT, INTENSE

TROPICAL CYCLONE

60H: 2015/04/11 00 UTC: 21.8 S / 68.5 E, MAX WIND=110 KT, INTENSE

TROPICAL CYCLONE

72H: 2015/04/11 12 UTC: 23.9 S / 69.0 E, MAX WIND=095 KT, INTENSE

TROPICAL CYCLONE



2.B LONGER-RANGE OUTLOOK :

96H: 2015/04/12 12 UTC: 28.4 S / 69.0 E, MAX WIND=065 KT, TROPICAL

CYCLONE

120H: 2015/04/13 12 UTC: 29.9 S / 68.2 E, MAX WIND=045 KT,

POST-TROPICAL DEPRESSION



2.C ADDITIONAL INFORMATIONS:

T=4.5 AND CI=4.5+



JOALANE HAS RESTARTED A ESATERN, THEN SOUTHEASTERN MOTION. AN EYE IS

AGAIN VISIBLE ON CLASSICAL IMAGERY, AND LAST MICRO-WAVES DATA OF

10H36Z SHOW AN ISOLATED CDO SURROUNDED BY A FRAGMENTED NEW BAND WHICH

SEEM TO  CLOSE INTO A SECONDARY WALL



AFTER THE WEAKENING OF LAST NIGHT, THE SYSTEM WHICH HAS TROUBLE FOR

THE MOMENT TO RE-INTENSIFY, DESPITE OF  VERY FAVOURABLE UPPER LEVEL

ENVIRONMENTAL CONDITIONS, SHOULD AS IT GOES ON ITS MOTION A GOOD

SPEED FIND AN AREA OF FAVOURABLE ENERGETICAL POTENTIAL.



AS SOUTHWARD MID-LEVEL RIDGE IS GOING TO DISSIPATE, THE SYSTEM SHOULD

THEREFORE SHIFT SOUTH-SOUTH-EASTWARDS BACK TOWARDS A COL.

A NEW SUBTROPICAL RIDGE IS REBUILDING IN ITS SOUTHWEST ON SATURDAY

AND SHOULD STEERED JOALANE SOUTHWARDS THEN SOUTH-SOUTH-WESTWARDS.



BACK IN MOTION, JOALANE IS EXPECTED TO RE-INTENSIFY.

ATMOSPHERICS ENVIRONMENTAL CONDITIONS SHOULD KEEP FAVOURABLE UNTIL

FRIDAY UNDER THE UPPER LEVEL RIDGE AXIS WITH WEAK VWS AND AN UPPER

LEVEL OUTFLOW CHANNEL POLEWARD.



FROM FRIDAY LATE OR SATURDAY EARLY, SYSTEM IS EXPECTED TO WEAKEN AS

IT EXPERIENCES THE DOUBLE CONSTRAINTS OF STRENGTHENING

NORTH-WESTERLY UPPER LEVEL WINDS AND MARGINAL HEAT OCEANIC CONTENT

SOUTH OF 21S.



LAST DETERMINISTIC'S NWP MODELS (ECMWF, GFS, UKMO) ARE IN GOOD

AGREEMENT ABOUT THIS SCENARIO.



JOALANE KEEPS HOWEVER ON REPRESENTING A THREAT FOR RODRIGUES ISLAND.=