WTXS31 PGTW 081500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 26S (SEROJA) WARNING NR 017// RMKS/ 1. TROPICAL CYCLONE 26S (SEROJA) WARNING NR 017 02 ACTIVE TROPICAL CYCLONES IN SOUTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 081200Z --- NEAR 17.7S 111.4E MOVEMENT PAST SIX HOURS - 210 DEGREES AT 09 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT 080 NM SOUTHEAST QUADRANT 080 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 100 NM NORTHEAST QUADRANT 100 NM SOUTHEAST QUADRANT 095 NM SOUTHWEST QUADRANT 070 NM NORTHWEST QUADRANT REPEAT POSIT: 17.7S 111.4E --- FORECASTS: 12 HRS, VALID AT: 090000Z --- 18.9S 110.3E MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT 080 NM SOUTHEAST QUADRANT 080 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 110 NM NORTHEAST QUADRANT 100 NM SOUTHEAST QUADRANT 090 NM SOUTHWEST QUADRANT 080 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 225 DEG/ 07 KTS --- 24 HRS, VALID AT: 091200Z --- 19.9S 109.3E MAX SUSTAINED WINDS - 080 KT, GUSTS 100 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 020 NM NORTHEAST QUADRANT 020 NM SOUTHEAST QUADRANT 015 NM SOUTHWEST QUADRANT 015 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT 080 NM SOUTHEAST QUADRANT 080 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 110 NM NORTHEAST QUADRANT 100 NM SOUTHEAST QUADRANT 100 NM SOUTHWEST QUADRANT 080 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 215 DEG/ 05 KTS --- 36 HRS, VALID AT: 100000Z --- 20.7S 108.7E MAX SUSTAINED WINDS - 090 KT, GUSTS 110 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 020 NM NORTHEAST QUADRANT 020 NM SOUTHEAST QUADRANT 015 NM SOUTHWEST QUADRANT 015 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 050 NM NORTHEAST QUADRANT 090 NM SOUTHEAST QUADRANT 090 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 110 NM NORTHEAST QUADRANT 100 NM SOUTHEAST QUADRANT 100 NM SOUTHWEST QUADRANT 080 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 180 DEG/ 06 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 101200Z --- 22.0S 108.7E MAX SUSTAINED WINDS - 100 KT, GUSTS 125 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 020 NM NORTHEAST QUADRANT 020 NM SOUTHEAST QUADRANT 020 NM SOUTHWEST QUADRANT 015 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 050 NM NORTHEAST QUADRANT 090 NM SOUTHEAST QUADRANT 090 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 110 NM NORTHEAST QUADRANT 100 NM SOUTHEAST QUADRANT 100 NM SOUTHWEST QUADRANT 090 NM NORTHWEST QUADRANT VECTOR TO 72 HR POSIT: 145 DEG/ 14 KTS --- 72 HRS, VALID AT: 111200Z --- 26.4S 112.3E MAX SUSTAINED WINDS - 080 KT, GUSTS 100 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 020 NM NORTHEAST QUADRANT 040 NM SOUTHEAST QUADRANT 030 NM SOUTHWEST QUADRANT 000 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 050 NM NORTHEAST QUADRANT 090 NM SOUTHEAST QUADRANT 090 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 120 NM NORTHEAST QUADRANT 110 NM SOUTHEAST QUADRANT 110 NM SOUTHWEST QUADRANT 090 NM NORTHWEST QUADRANT VECTOR TO 96 HR POSIT: 135 DEG/ 28 KTS --- LONG RANGE OUTLOOK: --- 96 HRS, VALID AT: 121200Z --- 33.6S 122.0E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY BECOMING EXTRATROPICAL RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT 070 NM SOUTHEAST QUADRANT 080 NM SOUTHWEST QUADRANT 060 NM NORTHWEST QUADRANT VECTOR TO 120 HR POSIT: 130 DEG/ 23 KTS --- 120 HRS, VALID AT: 131200Z --- 39.2S 131.1E MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY EXTRATROPICAL --- REMARKS: 081500Z POSITION NEAR 18.0S 111.1E. 08APR21. TROPICAL CYCLONE 26S (SEROJA), LOCATED APPROXIMATELY 315 NM NORTH-NORTHWEST OF LEARMONTH, AUSTRALIA, HAS TRACKED SOUTH- SOUTHWESTWARD AT 09 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY (EIR) INDICATES THE SYSTEM HAS CONTINUED TO BE BATTERED BY EASTERLY SHEAR. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED UPON A 081127Z SSMIS 37GHZ IMAGE. THE INITIAL INTENSITY OF 55KTS IS HEDGED HIGHER THAN THE DVORAK ESTIMATES OF T2.5/35KTS FROM MULTIPLE DVORAK INTENSITY ESTIMATES FROM PGTW, KNES, AND APRF, AND HEDGED ABOVE SATELLITE CONSENSUS (SATCON) 44KTS AND THE ADVANCED DVORAK TECHNIQUE (ADT) OF T2.7 (41KTS). ANALYSIS INDICATES AN IMPROVING ENVIRONMENT WITH VERY WARM (30-31C) SEA SURFACE TEMPERATURE (SST), SLIGHT RADIAL OUTFLOW ALOFT, AND IMPROVING LIGHT TO MODERATE (10-15 KTS) EASTERLY VERTICAL WIND SHEAR. TC 26S IS EXPECTED TO TRACK SOUTHWESTWARD ALONG THE NORTHWEST PERIPHERY OF THE DEEP-LAYERED SUBTROPICAL RIDGE (STR) ANCHORED OVER WESTERN AUSTRALIA. THE CYCLONE IS EXPECTED TO SLIGHTLY WOBBLE AND PULL TO THE RIGHT AS A RESULT OF BINARY INTERACTION WITH TC 27S THAT WILL APPROACH TC 26S TO WITHIN 250NM. BETWEEN TAU 24 AND 36, A MID- LATITUDE SHORTWAVE TROUGH APPROACHING FROM THE SOUTHWEST WILL WEAKEN THE STR. IN RESPONSE, THE TC WILL BEGIN TO ROUND THE STR AXIS AND TRACK MORE SOUTHWARD THEN ACCELERATE SOUTHEASTWARD TOWARD THE AUSTRALIAN BIGHT. THE AFOREMENTIONED FAVORABLE CONDITIONS WILL POTENTIALLY FUEL A RAPID INTENSIFICATION TO A PEAK OF 100KTS BY TAU 48. AFTERWARD, THERE WILL BE AN INCREASE IN VWS, COOLING SST, AND LANDFALL INTO SOUTHWEST AUSTRALIA JUST AFTER TAU 72. ONCE OVER LAND, THE SYSTEM WILL RAPIDLY ERODE DOWN TO 40KTS BY TAU 96 AND UNDERGO EXTRA-TROPICAL TRANSITION. JUST BEYOND TAU 96, THE SYSTEM IS EXPECTED TO COMPLETELY BECOME A COLD-CORE GALE-FORCE LOW EXITING INTO THE AUSTRALIAN BIGHT, BECOMING FULLY EXTRA-TROPICAL BEFORE TAU 120. NUMERICAL MODELS ARE IN TIGHT AGREEMENT THROUGH TAU 36 WITH ONLY A 90NM DISPARITY. THE EXCESSIVE BINARY INTERACTION WITH TC 27S INCREASES THE ALONG/CROSS TRACK ERROR THROUGH THE REMAINDER OF THE FORECAST. OVERALL, THERE IS MODERATE CONFIDENCE IN THE JTWC TRACK FORECAST THAT IS LAID SLIGHTLY RIGHT OF THE MODEL CONSENSUS UNTIL THE COMPLETION OF THE TURN ALONG THE RIDGE AXIS. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 081200Z IS 24 FEET. NEXT WARNINGS AT 082100Z, 090300Z, 090900Z AND 091500Z. REFER TO TROPICAL CYCLONE 27S (TWENTYSEVEN) WARNINGS (WTXS32 PGTW) FOR SIX-HOURLY UPDATES.// NNNN