WTIO30 FMEE 080617



RSMC / TROPICAL CYCLONE CENTER / LA REUNION

TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)



0.A WARNING NUMBER: 15/13/20142015

1.A TROPICAL CYCLONE  13  (JOALANE)



2.A POSITION 2015/04/08 AT 0600 UTC:

WITHIN 10 NM RADIUS OF POINT 14.6 S / 64.0 E

(FOURTEEN    DECIMAL SIX   DEGREES SOUTH AND SIXTY FOUR    DECIMAL

ZERO   DEGREES EAST)

MOVEMENT : EAST 5 KT



3.A DVORAK ANALYSIS: 4.5/4.5/D 0.5/6 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: 2015/04/08 18 UTC: 15.6 S / 64.6 E, MAX WIND=075 KT, TROPICAL

CYCLONE

24H: 2015/04/09 06 UTC: 16.9 S / 65.1 E, MAX WIND=080 KT, TROPICAL

CYCLONE

36H: 2015/04/09 18 UTC: 18.2 S / 65.8 E, MAX WIND=085 KT, TROPICAL

CYCLONE

48H: 2015/04/10 06 UTC: 19.1 S / 66.6 E, MAX WIND=095 KT, INTENSE

TROPICAL CYCLONE

60H: 2015/04/10 18 UTC: 20.3 S / 67.9 E, MAX WIND=105 KT, INTENSE

TROPICAL CYCLONE

72H: 2015/04/11 06 UTC: 21.8 S / 69.0 E, MAX WIND=110 KT, INTENSE

TROPICAL CYCLONE



2.B LONGER-RANGE OUTLOOK :

96H: 2015/04/12 06 UTC: 25.4 S / 69.2 E, MAX WIND=070 KT, TROPICAL

CYCLONE

120H: 2015/04/13 06 UTC: 28.2 S / 68.8 E, MAX WIND=060 KT,

POST-TROPICAL DEPRESSION



2.C ADDITIONAL INFORMATIONS:

T=4.5- AND CI=4.5+



JOALANE HAS RESTARTED A ESATERN MOTION. AN EYE IS AGAIN VISIBLE ON

CLASSICAL IMAGERY, BUT LAST MICRO-WAVES DATA SHOW A WEAKNESS IN THE

SOUTHEASTERN PART OF THE CDO, AND A BREAK WITH THE LARGE BAND OF DEEP

CONVECTION EAST OF THE SYSTEM.

AFTER THE WEAKENING OF LAST NIGHT, THE SYSTEM HAVE TROUBLE FOR THE

MOMENT TO FIND AGAIN A GOOD  OCEANIC CONDITIONS, DESPITE VERY

FAVOURABLE UPPER LEVEL ENVIRONMENTAL CONDITIONS.



SOUTHWARD MID-LEVEL RIDGE IS EXPECTED TO DISSIPATE WITHIN THE NEXT

HOURS AND 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 SERIOUS THREAT FOR RODRIGUES

ISLAND.=