****0000004303**** WTIO30 FMEE 310627 RSMC / TROPICAL CYCLONE CENTER / LA REUNION TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN) 0.A WARNING NUMBER: 8/14/20242025 1.A SEVERE TROPICAL STORM 14 (COURTNEY) 2.A POSITION 2025/03/31 AT 0600 UTC: WITHIN 20 NM RADIUS OF POINT 23.9 S / 88.5 E (TWENTY THREE DECIMAL NINE DEGREES SOUTH AND EIGHTY EIGHT DECIMAL FIVE DEGREES EAST) MOVEMENT: SOUTH-SOUTH-EAST 8 KT 3.A DVORAK ANALYSIS: 3.0/4.0/S 0.0/6 H 4.A CENTRAL PRESSURE: 981 HPA 5.A MAX AVERAGE WIND SPEED (10 MN): 60 KT RADIUS OF MAXIMUM WINDS (RMW): 54 KM 6.A EXTENSION OF WIND BY QUADRANTS (KM): 28 KT NE: 280 SE: 325 SW: 230 NW: 215 34 KT NE: 150 SE: 220 SW: 185 NW: 95 48 KT NE: 95 SE: 110 SW: 80 NW: 55 7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1010 HPA / 900 KM 8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: MEDIUM 1.B FORECASTS (WINDS RADII IN KM): 12H: 2025/03/31 18 UTC: 25.0 S / 88.8 E, VENT MAX= 050 KT, POST-TROPICAL DEPRESSION 28 KT NE: 270 SE: 315 SW: 270 NW: 130 34 KT NE: 0 SE: 185 SW: 175 NW: 0 48 KT NE: 0 SE: 85 SW: 65 NW: 0 24H: 2025/04/01 06 UTC: 25.8 S / 88.8 E, VENT MAX= 045 KT, POST-TROPICAL DEPRESSION 28 KT NE: 0 SE: 315 SW: 270 NW: 0 34 KT NE: 0 SE: 185 SW: 165 NW: 0 36H: 2025/04/01 18 UTC: 26.5 S / 88.5 E, VENT MAX= 040 KT, POST-TROPICAL DEPRESSION 28 KT NE: 0 SE: 240 SW: 280 NW: 0 34 KT NE: 0 SE: 140 SW: 120 NW: 0 48H: 2025/04/02 06 UTC: 26.4 S / 87.0 E, VENT MAX= 035 KT, REMNANT LOW 28 KT NE: 0 SE: 215 SW: 220 NW: 0 34 KT NE: 0 SE: 130 SW: 95 NW: 0 60H: 2025/04/02 18 UTC: 25.9 S / 85.0 E, VENT MAX= 030 KT, FILLING UP 28 KT NE: 0 SE: 140 SW: 140 NW: 0 72H: 2025/04/03 06 UTC: 25.2 S / 81.6 E, VENT MAX= 030 KT, FILLING UP 28 KT NE: 0 SE: 140 SW: 140 NW: 0 2.B LONGER-RANGE OUTLOOK: NIL 2.C ADDITIONAL INFORMATION: T=3.0 CI=4.0+ LITTLE CHANGE OVER THE LAST 6 HOURS: COURTNEY'S CLOUD PATTERN REMAIN SHEARED, WITH DEEP CONVECTION DETACHED FROM THE LOW-LEVEL CENTER IN THE SOUTHEAST QUADRANT OF THE SYSTEM. THE DEEP VERTICAL WINDSHEAR ESTIMATED BY CIMSS IS NORTH-WESTERLY FOR 30KT, WHICH IS FULLY CONSISTENT WITH THE LARGE-SCALE SITUATION THAT CURRENTLY PLACES THE SYSTEM ON THE EASTERN FLANK OF A UPPER TROUGH CIRCULATING FURTHER WEST. THE PRESENCE OF CONVECTION STILL ALLOWS A SUBJECTIVE DVORAK ANALYSIS, GIVING A DT OF 3.0. DUE TO INERTIA, AND ALSO TAKING INTO ACCOUNT DATA FROM THE RCM1-VH SAR AT 2326Z AND THE 0342Z ASCAT-C SWATH, THE CI REMAINS AT 4.0+, CLASSIFYING THE SYSTEM AT THE UPPER STAGE OF A SEVERE TROPICAL STORM FOR 60KT. COURTNEY'S TRACK CURVES SOUTH-SOUTHEAST UNDER THE INFLUENCE OF A RIDGE TO THE NORTHEAST AND AN UPPER TROUGH TO THE SOUTHWEST AND SOUTH. WITH THE PROGRESSIVE WEAKENING OF THE SYSTEM, THE STEERING FLOW DROPS BACK INTO THE MID-TROPOSPHERE AND THEN INTO THE LOWER LAYERS. BETWEEN MONDAY EVENING AND TUESDAY, COURTNEY SHOULD MOVE SLOWLY WITHIN A BAROMETRIC COL AT 700HPA, THEN THE MOVEMENT SHOULD ACCELERATE WESTWARDS FROM TUESDAY EVENING, AS THE REMNANT LOW IS TAKEN UP IN THE TRADE WINDS ON THE NORTH FACE OF THE SUBTROPICAL LOW LAYER. THE RSMC FORECAST IS BASED ON A COMPROMISE BETWEEN THE BEST AVAILABLE GUIDANCE, WHOSE DISPERSION IS INCREASING FROM MONDAY ONWARDS, INDUCING LOW CONFIDENCE IN THE SYSTEM'S TRACK BEYOND. COURTNEY'S INTENSITY WILL CONTINUE TO GRADUALLY DECREASE AS A RESULT OF INCREASINGLY STRONG NORTHWESTERLY WINDSHEAR ALONG THE UPPER TROUGH, INJECTING DRY AIR OVER THE LOW LEVEL CENTER. IN ADDITION, COURTNEY'S SOUTHWARD MOVEMENT MEANS THAT IT IS CIRCULATING OVER MUCH COOLER SURFACE WATERS, WITH VIRTUALLY NO OCEAN HEAT POTENTIAL. FROM MONDAY EVENING, IN AN INCREASINGLY BAROCLINIC ENVIRONMENT, COURTNEY SHOULD LOSE ITS TROPICAL CHARACTERISTICS, EVOLVING INTO A POST-TROPICAL SYSTEM AND THEN INTO A REMNANT LOW IN THE FORM OF A VORTEX DEVOID OF DEEP CONVECTION. DRY AIR WILL SETTLE PERMANENTLY OVER THE LLC, WITH NO POSSIBILITY OF REINTENSIFYING. GALE-FORCE WINDS, THEN NEAR GALE FORCE WINDS, MAY PERSIST IN THE SOUTHERN SEMICIRCLE DUE TO THE PRESSURE GRADIENT EFFECT UNTIL WEDNESDAY, BEFORE THE SYSTEM DISSIPATES OVER THE FOLLOWING DAYS. COURTNEY DOES NOT THREATEN ANY INHABITED LAND.=