****0000004259**** WTIO30 FMEE 310040 RSMC / TROPICAL CYCLONE CENTER / LA REUNION TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN) 0.A WARNING NUMBER: 7/14/20242025 1.A SEVERE TROPICAL STORM 14 (COURTNEY) 2.A POSITION 2025/03/31 AT 0000 UTC: WITHIN 20 NM RADIUS OF POINT 23.2 S / 88.0 E (TWENTY THREE DECIMAL TWO DEGREES SOUTH AND EIGHTY EIGHT DECIMAL ZERO DEGREES EAST) MOVEMENT: SOUTH 6 KT 3.A DVORAK ANALYSIS: 3.0/4.0/W 0.5/6 H 4.A CENTRAL PRESSURE: 980 HPA 5.A MAX AVERAGE WIND SPEED (10 MN): 60 KT RADIUS OF MAXIMUM WINDS (RMW): 48 KM 6.A EXTENSION OF WIND BY QUADRANTS (KM): 28 KT NE: 260 SE: 285 SW: 220 NW: 140 34 KT NE: 155 SE: 215 SW: 155 NW: 100 48 KT NE: 95 SE: 100 SW: 100 NW: 75 7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1010 HPA / 1100 KM 8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: DEEP 1.B FORECASTS (WINDS RADII IN KM): 12H: 2025/03/31 12 UTC: 24.7 S / 88.6 E, VENT MAX= 055 KT, SEVERE TROPICAL STORM 28 KT NE: 260 SE: 315 SW: 250 NW: 165 34 KT NE: 150 SE: 195 SW: 175 NW: 110 48 KT NE: 85 SE: 100 SW: 95 NW: 75 24H: 2025/04/01 00 UTC: 25.6 S / 88.9 E, VENT MAX= 050 KT, POST-TROPICAL DEPRESSION 28 KT NE: 250 SE: 305 SW: 240 NW: 150 34 KT NE: 140 SE: 205 SW: 175 NW: 95 48 KT NE: 0 SE: 100 SW: 95 NW: 0 36H: 2025/04/01 12 UTC: 26.3 S / 88.8 E, VENT MAX= 045 KT, POST-TROPICAL DEPRESSION 28 KT NE: 165 SE: 280 SW: 240 NW: 150 34 KT NE: 0 SE: 155 SW: 140 NW: 85 48H: 2025/04/02 00 UTC: 26.6 S / 87.9 E, VENT MAX= 035 KT, REMNANT LOW 28 KT NE: 130 SE: 230 SW: 260 NW: 120 34 KT NE: 0 SE: 130 SW: 130 NW: 0 60H: 2025/04/02 12 UTC: 26.3 S / 86.0 E, VENT MAX= 030 KT, REMNANT LOW 28 KT NE: 0 SE: 215 SW: 250 NW: 0 72H: 2025/04/03 00 UTC: 25.3 S / 82.9 E, VENT MAX= 025 KT, REMNANT LOW 2.B LONGER-RANGE OUTLOOK: NIL 2.C ADDITIONAL INFORMATION: T=3.0 CI=4.0 OVER THE LAST 6 HOURS, COURTNEY'S CLOUD PATTERN HAS BECOME INCREASINGLY SHEARED BY A STRONG NORTH-WESTERLY SHEAR THAT IS PROBABLY IN EXCESS OF 30 KT. THE SYSTEM'S CENTER IS NOW OUTSIDE THE CONVECTIVE MASS, WHICH IS DISPLACED ABOUT 15-20 NM TO THE SOUTH AND SOUTH-EAST OF THE LLCC. SUBJECTIVE DVORAK ANALYSIS IN SHEARED PATTERN THUS YIELDS A DT OF 3.0. THE 1908Z AMSR2 IMAGE SHOWS THAT DEEP CONVECTION IS NOW MAINLY IN THE SOUTHERN SEMI-CIRCLE AND THAT THE INNER CORE HAS BROADENED. IT ALSO SHOWS THAT THE RECENT SOUTHWARD MOVEMENT HAS BEEN SLIGHTLY SLOWER THAN INITIALLY FORECAST. THE SYSTEM'S INTENSITY IS ESTIMATED AT 60 KT AT 00UTC, DOWNGRADING COURTNEY TO SEVERE TROPICAL STORM STAGE. COURTNEY'S TRACK IS CURVING SOUTHWARDS THEN SOUTH-SOUTHEASTWARDS UNDER THE INFLUENCE OF A RIDGE TO THE EAST/NORTH-EAST AND AN UPPER-LEVEL TROUGH TO THE SOUTH-WEST THEN SOUTH. AS THE SYSTEM WEAKENS, THE STEERING FLOW IS GRADUALLY SHIFTING DOWN TO THE MID-LEVELS 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 RESUME WESTWARDS FROM TUESDAY NIGHT ONWARDS, AS THE REMNANT LOW BECOMES EMBEDDED WITHIN THE TRADE WIND FLOW ALONG THE NORTHERN EDGE OF THE LOW-LEVEL SUBTROPICAL ANTICYCLONE. IT SHOULD BE NOTED THAT FROM MONDAY ONWARDS, THERE IS A RATHER HIGH DISPERSION AMONG AVAILABLE MODELS. COURTNEY'S INTENSITY IS EXPECTED TO CONTINUE TO GRADUALLY WEAKEN UNDER THE EFFECT OF INCREASINGLY HIGH NORTH-WESTERLY WIND SHEAR ALONG THE EDGE OF AN UPPER TROUGH, INJECTING DRY AIR OVER THE SYSTEM'S CENTER. IN ADDITION, THE SYSTEM'S SOUTHWARD MOVEMENT WILL BRING IT OVER SEA SURFACE TEMPERATURES BELOW 26C. FROM MONDAY EVENING ONWARDS, IN AN INCREASINGLY BAROCLINIC ENVIRONMENT, COURTNEY SHOULD LOSE SOME OF ITS TROPICAL FEATURES, CAUSING IT TO EVOLVE INTO A POST-TROPICAL SYSTEM AND THEN INTO A REMNANT LOW WITH A CONVECTION-FREE VORTEX. DRY AIR WILL MASSIVELY SETTLE OVER THE SYSTEM, PREVENTING ANY FURTHER REINTENSIFICATION. GALE-FORCE WINDS AND THEN NEAR-GALE-FORCE WINDS SHOULD PERSIST IN THE SOUTHERN SEMI-CIRCLE DUE TO PRESSURE GRADIENT EFFECT UNTIL WEDNESDAY, BEFORE THE SYSTEM DISSIPATES OVER THE FOLLOWING DAYS. COURTNEY DOES NOT THREATEN ANY INHABITED LAND.=