WTIO30 FMEE 151909 RSMC / TROPICAL CYCLONE CENTER / LA REUNION TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN) 0.A WARNING NUMBER: 7/7/20172018 1.A SEVERE TROPICAL STORM 7 (ELIAKIM) 2.A POSITION 2018/03/15 AT 1800 UTC: WITHIN 25 NM RADIUS OF POINT 16.0 S / 51.8 E (SIXTEEN DECIMAL ZERO DEGREES SOUTH AND FIFTY ONE DECIMAL EIGHT DEGREES EAST) MOVEMENT : WEST-SOUTH-WEST 12 KT 3.A DVORAK ANALYSIS: 3.0/3.0/D 0.5/24 H 4.A CENTRAL PRESSURE: 983 HPA 5.A MAX AVERAGE WIND SPEED (10 MN): 50 KT RADIUS OF MAXIMUM WINDS (RMW) :74 KM 6.A EXTENSION OF WIND BY QUADRANTS (KM): 28 KT NE: 370 SE: 330 SW: 370 NW: 330 34 KT NE: 280 SE: 240 SW: 220 NW: 240 48 KT NE: 0 SE: 130 SW: 0 NW: 0 7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1006 HPA / 900 KM 8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION : DEEP 1.B FORECASTS: 12H: 2018/03/16 06 UTC: 16.1 S / 50.2 E, MAX WIND=060 KT, SEVERE TROPICAL STORM 24H: 2018/03/16 18 UTC: 16.3 S / 49.0 E, MAX WIND=045 KT, OVERLAND DEPRESSION 36H: 2018/03/17 06 UTC: 16.9 S / 47.5 E, MAX WIND=035 KT, OVERLAND DEPRESSION 48H: 2018/03/17 18 UTC: 17.8 S / 47.6 E, MAX WIND=030 KT, OVERLAND DEPRESSION 60H: 2018/03/18 06 UTC: 19.8 S / 48.6 E, MAX WIND=040 KT, OVERLAND DEPRESSION 72H: 2018/03/18 18 UTC: 21.4 S / 49.1 E, MAX WIND=045 KT, MODERATE TROPICAL STORM 2.B LONGER-RANGE OUTLOOK : 96H: 2018/03/19 18 UTC: 25.2 S / 51.6 E, MAX WIND=045 KT, MODERATE TROPICAL STORM 120H: 2018/03/20 18 UTC: 30.0 S / 54.0 E, MAX WIND=040 KT, POST-TROPICAL DEPRESSION 2.C ADDITIONAL INFORMATION: T=CI=3.0 OVER THE LAST SIX HOURS, AFTER AN IMPROVEMENT, WITH A BAND WRAPPING IN THE SOUTHERN SEMI-CIRCLE, THE SYSTEM LOST ORGANIZATION IN INFRARED IMAGERY. MICROWAVE DATA (SSMIS 1456Z) CONFIRM THE FIRST IMPRESSION WITH A BROAD CORE SURROUNDED BY HALF A RING OF CONVECTION. ELIAKIM WAS SO UPGRADED TO SEVERE TROPICAL STORM. DVORAK ESTIMATE DO NOT REFLECT THE SYSTEM INTENSITY BECAUSE OF ITS LARGE STRUCTURE. FOR THE TRACK FORECAST, ELIAKIM REMAINS STEERED BY A MID-LEVEL RIDGE IN THE SOUTH-EAST AND CONTINUES TO TRACK WEST-SOUTH-WESTWARD UNTIL ITS LANDING ON MADAGASCAR FRIDAY BETWEEN MASOALA PENINSULA AND STE MARIE ISLAND. ON SATURDAY, ELIAKIM SHOULD EVOLVE OVERLAND, THE FORECAST POSITIONS ARE THEREFORE UNCERTAIN DUE TO THE POTENTIAL DISAPPEARING OF THE LOW LEVEL CIRCULATION. SUNDAY, THE WEAKENED SYSTEM SHOULD COME BACK OVER SEA AND TRACK GENERALLY SOUTH-EASTWARD, STEERED BY THE RIDGE AT EAST AND THE ARRIVING UPPER TROUGH IN THE SOUTH-WEST. THE AVAILABLE GUIDANCE REMAINS IN RATHER GOOD AGREEMENT OVER THIS SCENARIO, EVEN IF THE LOCALISATION AND TIMING OF THE RETURN OVER SEA REMAIN RELATIVELY UNCERTAIN. THE ENVIRONMENT IS CONDUCIVE FOR FURTHER INTENSIFICATION OF THE SYSTEM UNTIL ITS LANDING ON THE MALAGASY NORTH-EASTERN COASTS FRIDAY, THANKS TO A GREAT UPPER DIVERGENCE. HOWEVER THE WIDE INNER CORE STRUCTURE SHOULD PREVENT A RAPID DEEPENING. THE SYSTEM COULD BE CLOSE TO THE MINIMAL TROPICAL CYCLONE STAGE JUST BEFORE LANDING. ONCE OVERLAND, THE SYSTEM WILL WEAKEN. SUNDAY EVENING, AS ELIAKIM SHOULD HAVE JUST CAME BACK OVER SEA, THE STRENGTHENING OF A NORTH-WESTERLY SHEAR AHEAD OF AN UPPER TROUGH SHOULD STRONGLY LIMIT THE CHANCES FOR RE-INTENSIFICATION. AT LONG RANGE, ELIAKIM MAY BEGIN ITS EXTRATROPICALISATION UNDER A GROWING BAROCLINIC INFLUENCE. THE SYSTEM BROAD CORE IS COMING CLOSER TO THE MASOALA PENINSULA. THE WEATHER CONDITIONS WILL CONTINUE TO WORSEN, AND WILL BECOME DANGEROUS. THE STORM SURGE COULD REACH 1M ON THE COAST AND LOCALLY 2M IN THE BOTTOM OF ANTONGIL BAY NEAR MAROANTSETRA. BEWARE THAT THIS VALUE DOES NOT TAKE INTO ACCOUNT THE TIDE NOR THE WAVE SET-UP.=