WTXS31 PGTW 101500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 26S (SEROJA) WARNING NR 025// RMKS/ 1. TROPICAL CYCLONE 26S (SEROJA) WARNING NR 025 02 ACTIVE TROPICAL CYCLONES IN SOUTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 101200Z --- NEAR 21.5S 108.7E MOVEMENT PAST SIX HOURS - 140 DEGREES AT 08 KTS POSITION ACCURATE TO WITHIN 050 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 035 NM NORTHEAST QUADRANT 030 NM SOUTHEAST QUADRANT 035 NM SOUTHWEST QUADRANT 035 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 105 NM NORTHEAST QUADRANT 085 NM SOUTHEAST QUADRANT 085 NM SOUTHWEST QUADRANT 080 NM NORTHWEST QUADRANT REPEAT POSIT: 21.5S 108.7E --- FORECASTS: 12 HRS, VALID AT: 110000Z --- 23.8S 110.7E MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 060 NM NORTHEAST QUADRANT 040 NM SOUTHEAST QUADRANT 030 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 140 NM NORTHEAST QUADRANT 090 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 090 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 140 DEG/ 23 KTS --- 24 HRS, VALID AT: 111200Z --- 27.2S 114.2E MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT WIND RADII VALID OVER OPEN WATER ONLY BECOMING EXTRATROPICAL RADIUS OF 050 KT WINDS - 060 NM NORTHEAST QUADRANT 040 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 140 NM NORTHEAST QUADRANT 100 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 090 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 135 DEG/ 33 KTS --- 36 HRS, VALID AT: 120000Z --- 31.6S 119.7E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY EXTRATROPICAL --- REMARKS: 101500Z POSITION NEAR 22.1S 109.2E. 10APR21. TROPICAL CYCLONE 26S (SEROJA), LOCATED APPROXIMATELY 304 NM WEST OF LEARMONTH, AUSTRALIA, HAS TRACKED SOUTHEASTWARD AT 08 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY OVER THE PAST FEW HOURS INDICATES THAT TC 26S HAS BEEN STRUGGLING TO MAINTAIN AN ORGANIZED CONVECTIVE STRUCTURE IN THE FACE OF MODERATE EASTERLY SHEAR. THE CONVECTIVE SIGNATURE HAS IMPROVED OVER THE LAST HOUR WITH THE RE-EMERGENCE OF SOME WELL DEFINED CURVED BANDING, PARTICULARLY IN THE NORTHEASTERN QUADRANT. DESPITE THE OVERALL DISORGANIZED APPEARANCE, THE INITIAL POSITION WAS PLACED WITH HIGH CONFIDENCE BASED ON A WELL-DEFINED MICROWAVE EYE FEATURE IN A 101059Z SSMIS 37GHZ IMAGE. THE INITIAL INTENSITY IS SET WITH MODERATE CONFIDENCE, HEDGED SLIGHTLY BELOW MULTI-AGENCY DVORAK CURRENT INTENSITY ESTIMATES OF T4.0 (65 KNOTS) FROM PGTW, APRF AND KNES DUE TO A MUCH LOWER ADT ESTIMATE OF T3.0 (45 KTS). TC 26S LIES IN AN OVERALL FAVORABLE ENVIRONMENT, WITH MODERATE (15-20 KT) VWS, ROBUST POLEWARD OUTFLOW AND WARM (27-28C) SSTS. TC 26S HAS ROUNDED THE STR AXIS AND IS NOW ESTABLISHED ON A SOUTHEASTWARD TRACK. THE SYSTEM IS EXPECTED TO CONTINUE ACCELERATING SOUTHEASTWARD THROUGH THE DURATION OF THE FORECAST PERIOD. A SHORT PERIOD OF INTENSIFICATION IS FORECAST OVER THE NEXT 12 HOURS AS THE SYSTEM MOVES INTO A MORE FAVORABLE SHEAR ENVIRONMENT. THEREAFTER, RAPIDLY INCREASING SHEAR AND TERRAIN INTERACTION WILL COLLUDE TO RAPIDLY WEAKEN TC 26S. THE SYSTEM IS EXPECTED TO BEGIN EXTRA-TROPICAL TRANSITION AS IT MAKES LANDFALL AT OR JUST AFTER TAU 24 AS IT BEGINS TO INTERACT WITH THE BAROCLINIC ZONE AND MOVES UNDER THE STRONG WESTERLY FLOW ALOFT. AS THE SYSTEM CONTINUES MOVING OVER SOUTHWEST AUSTRALIA, IT IS EXPECTED TO FULLY TRANSITION TO A STRONG EXTRA- TROPICAL CYCLONE BY TAU 36. DYNAMIC MODEL GUIDANCE IS IN VERY GOOD AGREEMENT THROUGH THE ENTIRE FORECAST PERIOD, LENDING HIGH CONFIDENCE IN THE JTWC FORECAST TRACK. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 101200Z IS 30 FEET. NEXT WARNINGS AT 102100Z, 110300Z, 110900Z AND 111500Z. REFER TO TROPICAL CYCLONE 27S (ODETTE) WARNINGS (WTXS32 PGTW) FOR SIX-HOURLY UPDATES.// NNNN