WTIO30 FMEE 190640 RSMC / TROPICAL CYCLONE CENTER / LA REUNION TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN) 0.A WARNING NUMBER: 33/8/20152016 1.A TROPICAL CYCLONE 8 (FANTALA) 2.A POSITION 2016/04/19 AT 0600 UTC: WITHIN 20 NM RADIUS OF POINT 9.3 S / 50.0 E (NINE DECIMAL THREE DEGREES SOUTH AND FIFTY DECIMAL ZERO DEGREES EAST) MOVEMENT : EAST-SOUTH-EAST 6 KT 3.A DVORAK ANALYSIS: 4.5/5.5/W 0.5/6 H 4.A CENTRAL PRESSURE: 960 HPA 5.A MAX AVERAGE WIND SPEED (10 MN): 85 KT RADIUS OF MAXIMUM WINDS (RMW) :33 KM 6.A EXTENSION OF WIND BY QUADRANTS (KM): 28 KT NE: 240 SE: 280 SW: 220 NW: 220 34 KT NE: 190 SE: 190 SW: 180 NW: 180 48 KT NE: 120 SE: 120 SW: 110 NW: 110 64 KT NE: 70 SE: 70 SW: 70 NW: 70 7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1009 HPA / 500 KM 8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION : DEEP 1.B FORECASTS: 12H: 2016/04/19 18 UTC: 9.6 S / 50.9 E, MAX WIND=080 KT, TROPICAL CYCLONE 24H: 2016/04/20 06 UTC: 10.2 S / 52.5 E, MAX WIND=070 KT, TROPICAL CYCLONE 36H: 2016/04/20 18 UTC: 11.3 S / 54.0 E, MAX WIND=065 KT, TROPICAL CYCLONE 48H: 2016/04/21 06 UTC: 12.4 S / 54.9 E, MAX WIND=060 KT, SEVERE TROPICAL STORM 60H: 2016/04/21 18 UTC: 13.3 S / 55.7 E, MAX WIND=055 KT, SEVERE TROPICAL STORM 72H: 2016/04/22 06 UTC: 13.7 S / 55.6 E, MAX WIND=050 KT, SEVERE TROPICAL STORM 2.B LONGER-RANGE OUTLOOK : 96H: 2016/04/23 06 UTC: 13.1 S / 54.2 E, MAX WIND=050 KT, SEVERE TROPICAL STORM 120H: 2016/04/24 06 UTC: 11.2 S / 51.9 E, MAX WIND=045 KT, MODERATE TROPICAL STORM 2.C ADDITIONAL INFORMATION: T=4.5- CI=5.5- DURING THE PAST 6 HOURS, THE EYE HAS DISAPPEARED AND THE CLOUD TOPS HAVE WARMED, AS THE UNDERLYING WATYERS ARE COOLING AND THE OHC IS SIGNIFICANTLY WEAKENING. THE INFLUENCE OF THE LIGHT NORTH-EASTERLY CONSTRAINT ALOFT REMAINS WEAK AND THE UPPER DIVERGENCE STILL APPEARS VERY CONDUCIVE, ESPECIALLY ON THE POLAR SIDE. 0319Z SSMIS MW DATA REVEAL THAT FANTALA'S CORE STRUCURE REMAINS WELL ORGANISED, BUT A WEAKNESS BEGINS TO EMERGE IN THE NORTH-EASTERN QUADRANT. FROM TODAY AND UNTIL THURSDAY, FANTALA'S TRACK WILL BE STEERED BY TWO ATMOSPHERIC PATTERNS : THE NEAR EQUATORIAL RIDGE BUILDING IN ITS NORTH-EAST AND A WIDE MID-LATITUDES TROUGH COMING FROM THE SOUTH-WEST. UNDER THIS DOUBLE INFLUENCE, FATALA ALREADY BEGAN TO TRACK FASTER AGAIN EAST-SOUTH-EASTWARDS. FROM FRIDAY, THE LAST ENSEMBLE AND DETERMINISTIC RUNS CONFIRM THAT FANTALA SHOULD NOT REACH THE TROUGH AND THUS NOT SHIFT TOWARDS THE MID-LATITUDES. ONCE THE THALWEG HAS SHIFTED EASTWARD, A NEW HIGH GEOPOTENTIAL CELL IS FORECASTED TO ARRIVE OVER THE SOUTHERN MOZAMBIQUE CHANNEL AND PROGRESSIVELY EXTEND NORTHWARD. FANTALA SHOULD THEN TRACK NORTH-WESTWARD AGAIN STEERED BY THIS WIDE RIDGE. THE AVAILABLE NWP MODELS ARE IN RATHER GOOD AGREEMENT FOR THIS NEW TURN FROM THURSDAY NIGHT NORTH OF 15S. THEN, DISPERSION INCREASES AGAIN, AND THE UNCERTAINTY REMAINS HIGH ON THE TRACK DIRECTION. ECMWF MODEL FORECAST A TRACK OFF THE COAST OF THE AMBER CAPE, WHILE GFS TRACK IS A LITTLE BIT MORE SOUTHWARD AND LEAVES A POSSIBILITY FOR FANTALA TO MAKE LANDFALL ON THE NORTHERN REGION OF MADAGASCAR. TODAY, WITH THE ACCELERATION TOWARD THE EAST-SOUTH-EAST, HELPED BY A GOOD UPPER LEVEL DIVERGENCE, THE CLOUD PATTERN COULD REMAIN QUITE GOOD. HOWEVER, THE OCEAN HEAT CONTENT IS BEGINNING TO LACK AS THE SYSTEM IS TURNING BACK OVER WATERS IT ALREADY COOLED. FROM THURSDAY, THE UPPER LEVEL CONDITIONS ARE LIKELY TO BECOME LESS FAVORABLE WITH A POORER DIVERGENCE AND A NORTHERLY TO NORTHEASTERLY CONSTRAINT. THUS, FANTALA INTENSITY IS LIKELY TO DECREASE SLOWLY FROM WEDNESDAY AND NOT MUCH EVOLVE FROM WEDNESDAY, AS FANTALA TRACKS OVER WARMER WATERS AGAIN.=