WTXS31 PGTW 240900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE WARNING// RMKS/ 1. TROPICAL CYCLONE 20S (FAKIR) WARNING NR 004 01 ACTIVE TROPICAL CYCLONE IN SOUTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 240600Z --- NEAR 21.3S 56.2E MOVEMENT PAST SIX HOURS - 150 DEGREES AT 21 KTS POSITION ACCURATE TO WITHIN 020 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 080 NM NORTHEAST QUADRANT 070 NM SOUTHEAST QUADRANT 020 NM SOUTHWEST QUADRANT 035 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 150 NM NORTHEAST QUADRANT 135 NM SOUTHEAST QUADRANT 055 NM SOUTHWEST QUADRANT 080 NM NORTHWEST QUADRANT REPEAT POSIT: 21.3S 56.2E --- FORECASTS: 12 HRS, VALID AT: 241800Z --- 23.7S 57.9E MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 035 NM NORTHEAST QUADRANT 035 NM SOUTHEAST QUADRANT 020 NM SOUTHWEST QUADRANT 025 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 125 NM NORTHEAST QUADRANT 135 NM SOUTHEAST QUADRANT 095 NM SOUTHWEST QUADRANT 075 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 145 DEG/ 10 KTS --- 24 HRS, VALID AT: 250600Z --- 25.3S 59.1E MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 030 NM NORTHEAST QUADRANT 040 NM SOUTHEAST QUADRANT 020 NM SOUTHWEST QUADRANT 020 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 105 NM NORTHEAST QUADRANT 150 NM SOUTHEAST QUADRANT 090 NM SOUTHWEST QUADRANT 070 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 140 DEG/ 09 KTS --- 36 HRS, VALID AT: 251800Z --- 26.7S 60.5E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER RADIUS OF 034 KT WINDS - 075 NM NORTHEAST QUADRANT 125 NM SOUTHEAST QUADRANT 070 NM SOUTHWEST QUADRANT 055 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 110 DEG/ 08 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 260600Z --- 27.2S 62.2E MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 240900Z POSITION NEAR 21.9S 56.6E. TROPICAL CYCLONE 20S (FAKIR), LOCATED APPROXIMATELY 70 NM SOUTHEAST OF ST DENIS, HAS TRACKED SOUTH-SOUTHEASTWARD AT 21 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS A WELL ORGANIZED SYSTEM WITH AN INTERMITTENT RAGGED EYE FEATURE THAT HAS BECOME CLOUD-FILLED AND REPLACED BY A CENTRAL DENSE OVERCAST FEATURE IN THE LAST SEVERAL HOURS. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON A 240229Z SSMIS 91GHZ MICROWAVE IMAGE THAT SHOWS A WELL DEFINED MICROWAVE EYE. THERE IS NO WELL-DEFINED MICROWAVE EYE IN LOWER FREQUENCY MICROWAVE IMAGES, SUGGESTING THAT HIGH VERTICAL WIND SHEAR (VWS) (25-40 KNOTS) IS TILTING THE SYSTEM. THE HIGH VWS IS CURRENTLY BEING OFFSET BY WARM (27-28 CELSIUS) SEA SURFACE TEMPERATURES AND A STRONG POLEWARD OUTFLOW CHANNEL ENHANCED BY A DEEP LAYER TROUGH ANCHORED OVER SOUTHERN MADAGASCAR. THE INITIAL INTENSITY OF 65 KNOTS IS BASED ON DVORAK MULTIAGENCY CURRENT INTENSITY ESTIMATES RANGING FROM T3.5 TO T4.0 (55-65 KNOTS), AND IS HEDGED AT THE HIGHER CI VALUE OF T4.0 DUE TO A 240545Z ADT ESTIMATE OF 77 KTS. TC 20S IS CURRENTLY ACCELERATING SOUTHEASTWARD IN AN ENHANCED STEERING ENVIRONMENT BETWEEN A SUBTROPICAL RIDGE (STR) LOCATED TO THE EAST AND THE TROUGH TO THE WEST OVER MADAGASCAR. THE SYSTEM IS FORECAST TO CONTINUE TRACKING SOUTHEASTWARD FOR THE DURATION OF THE FORECAST PERIOD AS THE STR TO THE EAST RECEDES. TC 20S IS FORECAST TO BEGIN WEAKENING DUE TO THE SEVERE VWS ASSOCIATED WITH THE TROUGH APPROACHING FROM THE WEST AND COOLER SSTS ALONG ITS FORECAST TRACK TO THE SOUTHEAST. THE UNFAVORABLE ENVIRONMENT WILL LEAD TO DISSIPATION BY TAU 48. HOWEVER, AN ALTERNATE SCENARIO IS POSSIBLE WHERE TC 20S INTERACTS WITH THE APPROACHING TROUGH AND UNDERGOES EXTRATROPICAL TRANSITION FROM TAU 36 TO TAU 48. MESOSCALE MODELS FAVOR THIS SCENARIO IN WHICH TC 20S REINTENSIFIES AFTER TAU 48, BUT WINDS AT THIS POINT WILL LIKELY BE EXPANSIVE AND FRONTAL IN NATURE DUE TO THE POSSIBLE EXTRATROPICAL TRANSITION. NUMERICAL MODEL GUIDANCE IS IN GENERAL GOOD AGREEMENT WITH THE SOUTHEASTWARD TRACK DIRECTION FOR THE DURATION OF THE FORECAST PERIOD. SEVERAL OUTLIERS PREDICT TC 20S HOOKING BACK AROUND TO THE NORTHWEST; AS VWS ERODES THE SYSTEM, IT WILL BECOME MORE SUBJECT TO LOWER-LEVEL STEERING FLOW WHICH AT THAT POINT WILL BE SOUTHEASTERLY. HOWEVER, IF TC 20S BECOMES EMBEDDED IN THE UPPER LEVEL TROUGH, IT WOULD ASSUME A MORE EASTWARD, ACCELERATING TRACK. THE SPREAD IN TRACK DIRECTION LENDS OVERALL LOW CONFIDENCE IN THE JTWC TRACK FORECAST. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 240600Z IS 21 FEET. NEXT WARNINGS AT 241500Z, 242100Z, 250300Z AND 250900Z.//