WTXS31 PGTW 080900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 26S (SEROJA) WARNING NR 016// RMKS/ 1. TROPICAL CYCLONE 26S (SEROJA) WARNING NR 016 02 ACTIVE TROPICAL CYCLONES IN SOUTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 080600Z --- NEAR 17.0S 111.7E MOVEMENT PAST SIX HOURS - 220 DEGREES AT 09 KTS POSITION ACCURATE TO WITHIN 040 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 - 025 NM NORTHEAST QUADRANT 055 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 020 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 075 NM NORTHEAST QUADRANT 110 NM SOUTHEAST QUADRANT 110 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT REPEAT POSIT: 17.0S 111.7E --- FORECASTS: 12 HRS, VALID AT: 081800Z --- 18.2S 110.4E MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 030 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 090 NM NORTHEAST QUADRANT 110 NM SOUTHEAST QUADRANT 100 NM SOUTHWEST QUADRANT 060 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 220 DEG/ 09 KTS --- 24 HRS, VALID AT: 090600Z --- 19.5S 109.2E 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 - 030 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 100 NM NORTHEAST QUADRANT 110 NM SOUTHEAST QUADRANT 110 NM SOUTHWEST QUADRANT 070 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 215 DEG/ 06 KTS --- 36 HRS, VALID AT: 091800Z --- 20.5S 108.4E 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 - 040 NM NORTHEAST QUADRANT 070 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 110 NM NORTHEAST QUADRANT 130 NM SOUTHEAST QUADRANT 120 NM SOUTHWEST QUADRANT 070 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 195 DEG/ 06 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 100600Z --- 21.6S 108.1E MAX SUSTAINED WINDS - 105 KT, GUSTS 130 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 070 NM SOUTHEAST QUADRANT 070 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 120 NM NORTHEAST QUADRANT 140 NM SOUTHEAST QUADRANT 130 NM SOUTHWEST QUADRANT 080 NM NORTHWEST QUADRANT VECTOR TO 72 HR POSIT: 145 DEG/ 10 KTS --- 72 HRS, VALID AT: 110600Z --- 25.0S 110.6E MAX SUSTAINED WINDS - 095 KT, GUSTS 115 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 030 NM NORTHEAST QUADRANT 035 NM SOUTHEAST QUADRANT 030 NM SOUTHWEST QUADRANT 025 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 050 NM NORTHEAST QUADRANT 080 NM SOUTHEAST QUADRANT 070 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 120 NM NORTHEAST QUADRANT 140 NM SOUTHEAST QUADRANT 140 NM SOUTHWEST QUADRANT 090 NM NORTHWEST QUADRANT VECTOR TO 96 HR POSIT: 140 DEG/ 24 KTS --- LONG RANGE OUTLOOK: --- 96 HRS, VALID AT: 120600Z --- 31.9S 118.2E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY BECOMING EXTRATROPICAL RADIUS OF 034 KT WINDS - 130 NM NORTHEAST QUADRANT 140 NM SOUTHEAST QUADRANT 140 NM SOUTHWEST QUADRANT 100 NM NORTHWEST QUADRANT VECTOR TO 120 HR POSIT: 130 DEG/ 28 KTS --- 120 HRS, VALID AT: 130600Z --- 38.8S 129.1E MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY EXTRATROPICAL --- REMARKS: 080900Z POSITION NEAR 17.3S 111.4E. 08APR21. TROPICAL CYCLONE 26S (SEROJA), LOCATED APPROXIMATELY 346 NM NORTH-NORTHWEST OF LEARMONTH, AUSTRALIA, HAS TRACKED SOUTHWESTWARD AT 09 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS THAT THE SYSTEM HAS BEEN SHEARED ON THE EASTERN SIDE PARTIALLY EXPOSING THE LOW LEVEL CIRCULATION (LLC). THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE AIDED BY THE MSI LOOP AND LINED UP WITH A WELL-DEFINED MICROWAVE LLC FEATURE IN THE 080609Z AMSR2 36GHZ. THE INITIAL INTENSITY OF 55KTS IS HEDGED HIGHER THAN THE DVORAK ESTIMATES OF T3.0/45KTS FROM PGTW, KNES, T2.5/35KTS APRF AND THE ADVANCED DVORAK TECHNIQUE (ADT) OF T2.7(41KTS). ANALYSIS INDICATES A MARGINALLY FAVORABLE ENVIRONMENT WITH VERY WARM (30-31C) SEA SURFACE TEMPERATURE (SST) AND FAIR EASTERLY OUTFLOW ALOFT SLIGHTLY OFFSET BY 15-20KTS OF EASTERLY VERTICAL WIND SHEAR. TC 26S IS EXPECTED TO TRACK MORE SOUTHWESTWARD ALONG THE NORTHWEST PERIPHERY OF THE DEEP-LAYERED SUBTROPICAL RIDGE (STR) ANCHORED OVER WESTERN AUSTRALIA. AFTER TAU 12 AND UP TO TAU 24, THE CYCLONE MAY UNDERGO A SLIGHT PULL TO THE RIGHT WITH MINOR WOBBLING AS A RESULT OF BINARY INTERACTION WITH TC 27S THAT WILL APPROACH TC 26S WITHIN 230NM. AFTER TAU 36, A MID-LATITUDE SHORTWAVE TROUGH APPROACHING FROM THE SOUTHWEST WILL WEAKEN THE STR CAUSING THE TC TO BEGIN ROUNDING THE STR AXIS AND TO TRACK MORE SOUTHWARD BEFORE ACCELERATING SOUTHEASTWARD TOWARD THE GREAT AUSTRALIAN BIGHT. THE AFOREMENTIONED FAVORABLE CONDITIONS WILL FUEL RAPID INTENSIFICATION TO A PEAK OF 105KTS BY TAU 48. AFTERWARD, THERE WILL BE AN INCREASE IN VWS, COOLING SST, AND LANDFALL INTERACTION INTO SOUTHWEST AUSTRALIA BETWEEN TAUS 72 AND 96. ONCE OVER LAND, THE SYSTEM WILL RAPIDLY ERODE THE SYSTEM DOWN TO 40KTS BY TAU 96 AND UNDERGO EXTRA- TROPICAL TRANSITION. BY TAU 120, THE SYSTEM WILL HAVE COMPLETELY BECOME A COLD-CORE GALE-FORCE LOW AS IT EXITS INTO THE AUSTRALIAN BIGHT. NUMERICAL MODELS ARE IN FAIR AGREEMENT THROUGH TAU 24, WITH NVGM AND AFUM BEING THE EXTREME LEFT OUTLIERS. NEAR TAUS 36-48, THE EXCESSIVE BINARY INTERACTION (EBI) WITH TC 27S, THE MODELS START SPREADING APART SIGNIFICANTLY AS THE VORTEX BECOMES EMBEDDED IN THE BAROCLINIC ZONE DURING ETT. OVERALL, THERE IS MODERATE CONFIDENCE IN THE JTWC TRACK FORECAST THAT IS LAID SLIGHTLY RIGHT OF THE MODEL CONSENSUS DURING THE MID-PORTION TO OFFSET THE EXTREME LEFT OUTLIERS NVGM AND AFUM. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 080600Z IS 23 FEET. NEXT WARNINGS AT 081500Z, 082100Z, 090300Z AND 090900Z. REFER TO TROPICAL CYCLONE 27S (TWENTYSEVEN) WARNINGS (WTXS32 PGTW) FOR SIX- HOURLY UPDATES.// NNNN