WTIO30 FMEE 151226



RSMC / TROPICAL CYCLONE CENTER / LA REUNION

TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)



0.A WARNING NUMBER: 18/8/20152016

1.A INTENSE TROPICAL CYCLONE  8  (FANTALA)



2.A POSITION 2016/04/15 AT 1200 UTC:

WITHIN 15 NM RADIUS OF POINT 12.5 S / 58.8 E

(TWELVE    DECIMAL FIVE   DEGREES SOUTH AND FIFTY EIGHT    DECIMAL

EIGHT   DEGREES EAST)

MOVEMENT : WEST 9 KT



3.A DVORAK ANALYSIS: 6.5/6.5/D 1.5/12 H



4.A CENTRAL PRESSURE: 938 HPA

5.A MAX AVERAGE WIND SPEED (10 MN): 110 KT

RADIUS OF MAXIMUM WINDS (RMW) :19 KM



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

28 KT NE: 130 SE: 220 SW: 200 NW: 130

34 KT NE: 110 SE: 170 SW: 150 NW: 90

48 KT NE: 70 SE: 100 SW: 90 NW: 70

64 KT NE: 60 SE: 60 SW: 60 NW: 60



7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1007 HPA / 400 KM

8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION : DEEP



1.B FORECASTS:

12H: 2016/04/16 00 UTC: 12.4 S / 57.2 E, MAX WIND=115 KT, INTENSE

TROPICAL CYCLONE

24H: 2016/04/16 12 UTC: 12.1 S / 55.5 E, MAX WIND=110 KT, INTENSE

TROPICAL CYCLONE

36H: 2016/04/17 00 UTC: 11.5 S / 54.0 E, MAX WIND=105 KT, INTENSE

TROPICAL CYCLONE

48H: 2016/04/17 12 UTC: 10.7 S / 52.6 E, MAX WIND=100 KT, INTENSE

TROPICAL CYCLONE

60H: 2016/04/18 00 UTC: 10.1 S / 51.7 E, MAX WIND=095 KT, INTENSE

TROPICAL CYCLONE

72H: 2016/04/18 12 UTC: 9.7 S / 51.3 E, MAX WIND=080 KT, TROPICAL

CYCLONE



2.B LONGER-RANGE OUTLOOK :

96H: 2016/04/19 12 UTC: 10.7 S / 53.0 E, MAX WIND=070 KT, TROPICAL

CYCLONE

120H: 2016/04/20 12 UTC: 13.2 S / 56.4 E, MAX WIND=080 KT, TROPICAL

CYCLONE



2.C ADDITIONAL INFORMATION:

T=CI=6.5-



DURING THE LAST 24 HOURS, CYCLONE FANTALA UNDERWENT A RAPID

INTENSIFICATION EVENT. THE DEEPENING WAS PARTICULARLY STRONG  DURING

THE LAST HOURS, WITH THE WARMING OF THE EYE AND COOLING OF THE

CONVECTIVE RING TOPS. NORTHERLY VERTICAL WIND SHEAR DECAY AS

SUGGESTED BY THE CLOUD PATTERN (ANALYSED AT 06Z AROUND 7KT).



THE SYSTEM KEEPS ON TRACKING WESTWARD ON THE NORTHERN SIDE OF A HIGH

GEOPOTENTIAL CELL LOCATED BETWEEN MADAGASCAR AND THE MASCAREIGNES

ISLANDS. TOMORROW, WITH THE GRADUAL STRENGTHENING OF THIS HIGH, IT

SHOULD ORIENTATE A BIT MORE NORTHWESTWARD. ON SATURDAY, FANTALA IS

FORECASTED TO TRANSIT A LITTLE MORE THAN 100 NM SOUTH OF AGALEGA AT

THE STAGE OF INTENSE TROPICAL CYCLONE.

FROM SUNDAY AND ESPECIALLY MONDAY, THE NEAR EQUATORIAL RIDGE IN THE

NORTH-EAST WILL TAKE OVER THE STEERING FLOW AND DRIVE A SHARP

SOUTH-EASTWARD U-TURN OF THE SYSTEM. THE MOST RELIABLE NWP MODELS ARE

IN AGREEMENT AND STILL FORECAST A NARROW CLOCKWISE LOOP. HOWEVER, THE

EXACT LOCATION OF THE TURN REMAINS UNCERTAIN : LAST AVAILABLE

GUIDANCE FROM THE EURO AND THE AMERICAN MODEL TEND TO BRING THE

CENTER CLOSER TO THE FARQHAR ARCHIPELAGO.



UP TO TUESDAY, FANTALA IS LIKELY TO UNDERGO RATHER CONDUCIVE UPPER

LEVEL ENVIRONMENT. THE NORTHERLY CONSTRAINT SHOULD REMAIN MARGINAL

WHILE POLAR SIDE DIVERGENCE IS EXPECTED TO INCREASE SUNDAY AFTER A

TEMPORARY DECAY SATURDAY. BUT, WEST OF 55E, THE LESSER OCEAN HEAT

CONTENT SHOULD BECOME THE LIMITING FACTOR FOR THE INTENSITY OF THE

SYSTEM. ITS INFLUENCE WILL BE ALL THE MORE IMPORTANT IF FANTALA SLOWS

DOWN AND RETURN ON ITS PREVIOUS TRACK WHERE WATERS ARE COLDER.

WEDNESDAY, A UPPER AND MID LEVELS TROUGH ARRIVES FROM THE SOUTH-WEST

AND MAY INDUCE A MODERATE NORTH-WESTERLY UPPER LEVEL CONSTRAINT.

AFTER A TEMPORARY NEW DEEPENING, IT IS LIKELY TO BEGIN TO WEAKEN

SIGNIFICANTLY.=