WTIO30 FMEE 081841



RSMC / TROPICAL CYCLONE CENTER / LA REUNION

TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)



0.A WARNING NUMBER: 17/13/20142015

1.A TROPICAL CYCLONE  13  (JOALANE)



2.A POSITION 2015/04/08 AT 1800 UTC:

WITHIN 30 NM RADIUS OF POINT 15.9 S / 65.0 E

(FIFTEEN    DECIMAL NINE   DEGREES SOUTH AND SIXTY FIVE    DECIMAL

ZERO   DEGREES EAST)

MOVEMENT : SOUTH-SOUTH-EAST 8 KT



3.A DVORAK ANALYSIS: 4.5/4.5/S 0.0/6 H



4.A CENTRAL PRESSURE: 972 HPA

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

RADIUS OF MAXIMUM WINDS (RMW) :19 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: 60 SE: 60 SW: 60 NW: 60

64 KT NE: 30 SE: 30 SW: 30 NW: 30



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 06 UTC: 17.5 S / 65.4 E, MAX WIND=075 KT, TROPICAL

CYCLONE

24H: 2015/04/09 18 UTC: 18.8 S / 65.8 E, MAX WIND=080 KT, TROPICAL

CYCLONE

36H: 2015/04/10 06 UTC: 19.8 S / 66.7 E, MAX WIND=090 KT, INTENSE

TROPICAL CYCLONE

48H: 2015/04/10 18 UTC: 21.3 S / 68.2 E, MAX WIND=095 KT, INTENSE

TROPICAL CYCLONE

60H: 2015/04/11 06 UTC: 22.9 S / 68.8 E, MAX WIND=095 KT, INTENSE

TROPICAL CYCLONE

72H: 2015/04/11 18 UTC: 24.9 S / 69.2 E, MAX WIND=085 KT, TROPICAL

CYCLONE



2.B LONGER-RANGE OUTLOOK :

96H: 2015/04/12 18 UTC: 28.2 S / 69.7 E, MAX WIND=050 KT,

POST-TROPICAL DEPRESSION

120H: 2015/04/13 18 UTC: 31.4 S / 71.7 E, MAX WIND=040 KT,

POST-TROPICAL DEPRESSION



2.C ADDITIONAL INFORMATIONS:

T=CI=4.5

SINCE 15Z, THE SATELLITE PICTURES DEPICT THE EYE SHRINKING THEN

DISAPPEARING.



JOALANE SEEMS TO INITIATE A SOUTH-SOUTH-EASTWARD MOTION TOWARDS A

BAROMETRIC 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.

BUT, ACCORDING TO THE FLUCTUATING INTENSITY OBSERVED BY NOW, THE

INTENSITY FORECAST HAS BEEN LOWERED.



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.=