WTIO30 FMEE 091807



RSMC / TROPICAL CYCLONE CENTER / LA REUNION

TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)



0.A WARNING NUMBER: 21/13/20142015

1.A TROPICAL CYCLONE  13  (JOALANE)



2.A POSITION 2015/04/09 AT 1800 UTC:

WITHIN 21 NM RADIUS OF POINT 17.6 S / 66.0 E

(SEVENTEEN    DECIMAL SIX   DEGREES SOUTH AND SIXTY SIX    DECIMAL

ZERO   DEGREES EAST)

MOVEMENT : SOUTH-SOUTH-EAST 6 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) :24 KM



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

28 KT NE: 310 SE: 460 SW: 310 NW: 300

34 KT NE: 200 SE: 280 SW: 240 NW: 200

48 KT NE: 70 SE: 110 SW: 100 NW: 100

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



7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1006 HPA / 1000 KM

8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION : DEEP



1.B FORECASTS:

12H: 2015/04/10 06 UTC: 18.3 S / 66.5 E, MAX WIND=075 KT, TROPICAL

CYCLONE

24H: 2015/04/10 18 UTC: 20.3 S / 68.1 E, MAX WIND=085 KT, TROPICAL

CYCLONE

36H: 2015/04/11 06 UTC: 22.0 S / 69.1 E, MAX WIND=075 KT, TROPICAL

CYCLONE

48H: 2015/04/11 18 UTC: 24.3 S / 69.5 E, MAX WIND=065 KT, TROPICAL

CYCLONE

60H: 2015/04/12 06 UTC: 27.1 S / 69.7 E, MAX WIND=055 KT,

POST-TROPICAL DEPRESSION

72H: 2015/04/12 18 UTC: 28.1 S / 69.3 E, MAX WIND=050 KT,

POST-TROPICAL DEPRESSION



2.B LONGER-RANGE OUTLOOK :

96H: 2015/04/13 18 UTC: 30.1 S / 69.5 E, MAX WIND=045 KT,

POST-TROPICAL DEPRESSION

120H: 2015/04/14 18 UTC: 31.8 S / 71.6 E, MAX WIND=045 KT,

POST-TROPICAL DEPRESSION



2.C ADDITIONAL INFORMATIONS:

T=CI=4.5+



DURING THE LAST 6 HOURS, THE CLOUD PATTERN HAS PROGRESSIVELY

IMPROVED, WITH A COLDER CDO AND AGAIN AN EYE TEMPORALY HOT.



JOALANE IS STRUGGLING TO INTENSIFY AND AS THE REASON OF THIS

INTENSITY FLUCTUATIONS ARE NOT WELL UNDERSTOOD, IT PUTS STRONG

UNCERTAINTY OVER THE EXPECTED RE-INTENSIFICATION SHOWN ON THE

OFFICIAL TRACK. TO THE SLIGHT NORTHERLY CONSTRAINT (ANALYZED BY THE

CIMSS) AND MENTIONED PREVIOUSLY, ONE MAY ADD THE NEGATIVE FEED-BACK

OF THE SST AS JOALANE HAS COME-BACK, THIS MORNING, OVER ITS LOCATION

THREE DAYS AGO.



AS JOALANE IS NOW EXPECTED TO MOVE AWAY OF THIS AREA AND ATMOSPHERIC

CONDITIONS ARE EXPECTED TO REMAIN FAVORABLE, WITH A PERSISTENT GOOD

POLAR OUTFLOW, JOALANE HAS STILL THE POTENTIAL TO RE-INTENSIFY UP TO

FRIDAY EVENING OR SATURDAY MORNING.

AFTER THAT TIME, IT SHOULD WEAKEN CLEARLY, UNDER THE NEGATIVE EFFECT

OF BOTH STRENGTHENING VWS AND LOWERING OF THE OHC.



JOALANE IS CURRENTLY MOVING SOUTH-SOUTH-EASTWARD TOWARDS A BAROMETRIC

COL AND UNDER THE STEERING INFLUENCE OF A MID-TROPOSPHERIC RIDGE IN

ITS EAST. AT THE END OF THE FORECAST PERIOD, IT COULD SLOW UNDER THE

INFLUENCE OF A RIDGE IN ITS SOUTH-WEST.



THERE IS A GOOD CONSENSUS ABOUT THIS TRACK AMONG THE LAST AVAILABLE

NWP MODELS.=