WTIO30 FMEE 200709 RSMC / TROPICAL CYCLONE CENTER / LA REUNION TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN) 0.A WARNING NUMBER: 37/8/20152016 1.A TROPICAL CYCLONE 8 (FANTALA) 2.A POSITION 2016/04/20 AT 0600 UTC: WITHIN 20 NM RADIUS OF POINT 10.5 S / 52.6 E (TEN DECIMAL FIVE DEGREES SOUTH AND FIFTY TWO DECIMAL SIX DEGREES EAST) MOVEMENT : EAST-SOUTH-EAST 8 KT 3.A DVORAK ANALYSIS: 5.5/5.5/D 0.5/6 H 4.A CENTRAL PRESSURE: 965 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: 180 SE: 100 SW: 140 NW: 220 34 KT NE: 130 SE: 70 SW: 80 NW: 130 48 KT NE: 90 SE: 60 SW: 70 NW: 90 64 KT NE: 60 SE: 60 SW: 60 NW: 60 7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1007 HPA / 300 KM 8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION : DEEP 1.B FORECASTS: 12H: 2016/04/20 18 UTC: 11.5 S / 53.9 E, MAX WIND=085 KT, TROPICAL CYCLONE 24H: 2016/04/21 06 UTC: 12.4 S / 54.8 E, MAX WIND=085 KT, TROPICAL CYCLONE 36H: 2016/04/21 18 UTC: 13.2 S / 55.3 E, MAX WIND=080 KT, TROPICAL CYCLONE 48H: 2016/04/22 06 UTC: 13.3 S / 55.2 E, MAX WIND=060 KT, SEVERE TROPICAL STORM 60H: 2016/04/22 18 UTC: 12.9 S / 54.8 E, MAX WIND=040 KT, MODERATE TROPICAL STORM 72H: 2016/04/23 06 UTC: 12.4 S / 53.6 E, MAX WIND=040 KT, MODERATE TROPICAL STORM 2.B LONGER-RANGE OUTLOOK : 96H: 2016/04/24 06 UTC: 11.2 S / 51.0 E, MAX WIND=050 KT, SEVERE TROPICAL STORM 120H: 2016/04/25 06 UTC: 9.9 S / 48.3 E, MAX WIND=045 KT, MODERATE TROPICAL STORM 2.C ADDITIONAL INFORMATION: T=CI=5.5- FANTALA IS STILL INTENSIFYING. 3HR MEAN RAW DT IS AT 5.3-5.4 SINCE 01Z. THE OVERALL PRESENTATION IS IMPRESSIVE AGAIN SINCE THIS MORNING WITH A GRADUALLY IMPROVING EYE PATTERN (ALTHOUGH SOMEWHAT RAGGED AT TIMES). PRESENT INTENSITY ANALYSIS IS MAINLY BASED ON THIS MANUAL DVORAK ANALYSIS. ADT IS STRONGER AT 5.9 BUT AMSU AND SSMIS ESTIMATES OF THIS MORNING ARE LOWER AT 85 KT 1-MIN (75 KT 10-MIN). 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, THE PREDICTABILITY OF THE EAST-SOUTH-EASTWARD TRACK IS QUITE HIGH AND THE MODEL GUIDANCE IS THUS IN AGREEMENT. FROM THURSDAY EVENING, NONE OF THE AVAILABLE MODELS ALLOW FANTALA TO REACH THE TROUGH, WHICH IS AN EXIT DOOR TOWARDS THE MID-LATITUDES. A NEW HIGH GEOPOTENTIAL CELL FOLLOWING THE TROUGH IS FORECASTED TO SETTLE OVER SOUTH AF MADAGASCAR AND PROGRESSIVELY EXTEND NORTHWARD. FANTALA SHOULD SLOW AGAIN AND FRIDAY, IT COULD TRACK NORTH-WESTWARD, STEERED BY THIS WIDE RIDGE IN ITS SOUTH-WEST. THEN, UNTIL THE END OF THE FORECAST PERIOD, THE SYSTEM IS LIKELY TO BE STEERED BY THE HIGH SUBTROPICAL CELL IN THE LOW AND MID TROPOSPHERE, AND SHOULD KEEP ON A WEST-NORTH-WESTWARD TO NORTH-WESTWARD TRACK. THE CURRENT TRACK FORECAST IS MOSTLY AN UPDATE OF THE PREVIOUS ONE. FANTALA COULD BECOME AN INTENSE TROPICAL CYCLONE LATER TODAY ... THE ONLY LIMITANT FACTOR IS THAT THE SYSTEM IS CURRENTLY PASSING OVER ITS POSITION 3 DAYS AGO AND FANTALA IS EXPECTED TO STAY WITHIN THE POTENTIALLY AFFECTED COOLED AREA ASSOCIATED DURING THE NEXT 24-48 HOURS. SO UNCERTAINTY ON THE EFFECT OF THIS COOLING PATH BRINGS UNCERTAINTY IN THE SHORT RANGE INTENSITY FORECAST. WITH A NE SLOW MOTION EXPECTED FRIDAY AND SOMEWHAT LESS CONDUCIVE ATMOSPHERIC CONDITIONS WITH SOME LIKELY NORTH-EASTERLY CONSTRAINT, A WEAKENING TREND IS ANTICIPATED. AFTER THAT TIME, THE INTENSITY SHOULD STAY MORE OR LESS THE SAME DURING THE NEW NORT-WESTWARDS TRACK.=