WTIO30 FMEE 161836

RSMC / CENTER / LA REUNION TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST )

0.A WARNING NUMBER: 23/8/20152016 1.A INTENSE TROPICAL CYCLONE 8 (FANTALA)

2.A POSITION 2016/04/16 AT 1800 UTC: WITHIN 15 NM RADIUS OF POINT 11.6 S / 54.4 E (ELEVEN DECIMAL SIX DEGREES SOUTH AND FIFTY FOUR DECIMAL FOUR DEGREES EAST) MOVEMENT : WEST-NORTH-WEST 12 KT

3.A DVORAK ANALYSIS: 6.0/6.5/W 0.5/6 H

4.A CENTRAL PRESSURE: 936 HPA 5.A MAX AVERAGE WIND SPEED (10 MN): 110 KT RADIUS OF MAXIMUM WINDS (RMW) :13 KM

6.A EXTENSION OF WIND BY QUADRANTS (KM): 28 KT NE: 120 SE: 300 SW: 370 NW: 120 34 KT NE: 90 SE: 170 SW: 190 NW: 90 48 KT NE: 60 SE: 90 SW: 90 NW: 60 64 KT NE: 50 SE: 60 SW: 60 NW: 50

7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1007 HPA / 300 KM 8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION : DEEP

1.B FORECASTS: 12H: 2016/04/17 06 UTC: 10.9 S / 52.7 E, MAX WIND=105 KT, INTENSE TROPICAL CYCLONE 24H: 2016/04/17 18 UTC: 10.2 S / 51.0 E, MAX WIND=110 KT, INTENSE TROPICAL CYCLONE 36H: 2016/04/18 06 UTC: 9.6 S / 49.8 E, MAX WIND=100 KT, INTENSE TROPICAL CYCLONE 48H: 2016/04/18 18 UTC: 9.5 S / 49.4 E, MAX WIND=085 KT, TROPICAL CYCLONE 60H: 2016/04/19 06 UTC: 9.7 S / 49.4 E, MAX WIND=070 KT, TROPICAL CYCLONE 72H: 2016/04/19 18 UTC: 10.4 S / 50.5 E, MAX WIND=070 KT, TROPICAL CYCLONE

2.B LONGER-RANGE OUTLOOK : 96H: 2016/04/20 18 UTC: 12.4 S / 54.1 E, MAX WIND=085 KT, TROPICAL CYCLONE 120H: 2016/04/21 18 UTC: 13.1 S / 54.7 E, MAX WIND=070 KT, TROPICAL CYCLONE

2.C ADDITIONAL INFORMATION: T=6.0+,CI=6.5-

OVER THE LAST SIX HOURS, FANTAL INTENSITY SEEMS TO STAY SIMILAR OR SLIGHTLY DECAY, ACCORDING TO INFRARED IMAGES. THE GOT WARMER AND SMALLER, EVEN IF THE DEEP CONVECTION RING REMAINED RATHER COLD. THIS ANALYSIS IS IN AGREEMENT WITH OTHER AGENCIES. NEVERTHELESS, TROPICAL CYCLONE FANTALA IS EXTREMELY DANGEROUS, AND HEADING TOWARDS THE FARQUAHR ARCHIPELAGO. AT 18 UTC, THE EYE IS A LITTLE LESS THAN 400 KM TO THE EAST-SOUTH-EAST OF THE SOUTHERNMOST ISLANDS (FARQUAHR ATOLL - ).

THE SYSTEM, AS EXPECTED, HAS BEND NORTHWESTWARDS OVER THE NORTHERN AND NORTHEASTERN SIDE OF A HIGH GEOPOTENTIAL CELL LOCATED SOUTH OF , WITH A RIDGE AXIS OVER MADAGASCAR. THIS RIDGE AXIS SHOULD MAINTAIN TO THE SOUTH-WEST OF FANTALA WITHIN THE NEXT 48 HOURS AND THEREFORE THE TRACK SHOULD CONTINUE TO GRADUALLY BEND NORTHWESTWARDS. ON THIS TRACK, FANTALA IS NOW A SERIOUS THREAT FOR THE SEYCHELLES FARQUAHR ISLANDS (THE SOUTHERN GROUP MAINLY) WITH A POTENTIAL DIRECT HIT WITHIN THE NEXT 24-36 HOURS (RARE EVENT - LAST ONE IS BONDO IN DEC 2006 AND NO OCCURENCE KNOWN BEFORE SINCE THE BEGINNING OF THE SATELLITE ERA). EARLY DATAN SUGGEST, A STORM SURGE AROUND 1 METER, ESPECIALLY IN THE SOUTHERN ISLANDS, CLOSER TO THE CORE.

FROM SUNDAY, THE SOUTHERN HIGH PRESSURE SHOULD WEAKEN. MONDAY, THE STEERING FLOW IS LIKELY TO FAIL. TUESDAY, A NEAR EQUATORIAL RIDGE IN THE NORTH-EAST WILL REBUILT AND FANTALA COULD ADOPT A SOUTH-EASTWARD TRACK. IN THE MDIDLE OF THE NEXT WEEK, THE ARRIVAL OF A NEW SUBTROPICAL RIDGE FROM THE WEST MAY START TO SLOW DOWN THE SYSTEM. THE CURRENT TRACK FORECAST IS BASED ON A CONSENSUS OF THE LAST EURO AND GFS OUTPUT, IN RATHER GOOD AGREEMENT. HOWEVER, THE LOCATION OF THE U-TURN AND THE BEHAVIOUR AFTER TURSADAY, ARE STILL UNCERTAIN.

THE INTENSITY FORECAST IS DIFFICULT DUE TO THE SMALL SIZE OF THE SYSTEM. THE INTENSITY FLUCTUATES RAPIDLY WITH SMALL FLUCTUATIONS OF THE ENVIRONMENTAL CONDITIONS. WITHOUT ANY EARLY INDICATIONS OF THE BEGINNING OF AN ERC AND GIVEN THE EXPECTED RATHER CONDUCIVE UPPER LEVEL CONDITIONS WITHIN THE NEXT 24 HOURS, FANTALA IS LIKELY TO KEEP AN INTENSITY CLOSE TO 110KT. FROM MONDAY, ON THE SOUTH-EASTWARD TRACK, THE SELF INDUCED SST COOLING COULD BECOME THE MAIN FACTOR OF THE WEAKENING OF THE SYSTEM AS ATMOSPHERIC FACTORS ARE EXPECTED TO BE EXCELLENT FOR MOST OF THE FORECAST PERIOD (SLIGHT DETERIORATION POSSIBLE AT THE END OF THE FORECAST)