WTXS31 PGTW 080300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 26S (SEROJA) WARNING NR 015// RMKS/ 1. TROPICAL CYCLONE 26S (SEROJA) WARNING NR 015 02 ACTIVE TROPICAL CYCLONES IN SOUTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 080000Z --- NEAR 15.9S 113.8E MOVEMENT PAST SIX HOURS - 240 DEGREES AT 07 KTS POSITION ACCURATE TO WITHIN 025 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 025 NM SOUTHEAST QUADRANT 015 NM SOUTHWEST QUADRANT 015 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT 065 NM SOUTHEAST QUADRANT 095 NM SOUTHWEST QUADRANT 055 NM NORTHWEST QUADRANT REPEAT POSIT: 15.9S 113.8E --- FORECASTS: 12 HRS, VALID AT: 081200Z --- 17.1S 112.4E MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 025 NM NORTHEAST QUADRANT 025 NM SOUTHEAST QUADRANT 025 NM SOUTHWEST QUADRANT 025 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 040 NM NORTHEAST QUADRANT 040 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 070 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 220 DEG/ 08 KTS --- 24 HRS, VALID AT: 090000Z --- 18.3S 111.3E MAX SUSTAINED WINDS - 075 KT, GUSTS 090 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 030 NM SOUTHEAST QUADRANT 025 NM SOUTHWEST QUADRANT 025 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT 070 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 220 DEG/ 07 KTS --- 36 HRS, VALID AT: 091200Z --- 19.4S 110.3E 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 - 035 NM NORTHEAST QUADRANT 035 NM SOUTHEAST QUADRANT 030 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 075 NM NORTHEAST QUADRANT 080 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 205 DEG/ 06 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 100000Z --- 20.5S 109.7E 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 - 035 NM NORTHEAST QUADRANT 035 NM SOUTHEAST QUADRANT 030 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 105 NM NORTHEAST QUADRANT 105 NM SOUTHEAST QUADRANT 090 NM SOUTHWEST QUADRANT 080 NM NORTHWEST QUADRANT VECTOR TO 72 HR POSIT: 165 DEG/ 08 KTS --- 72 HRS, VALID AT: 110000Z --- 23.5S 110.7E MAX SUSTAINED WINDS - 110 KT, GUSTS 135 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 - 045 NM NORTHEAST QUADRANT 050 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 110 NM NORTHEAST QUADRANT 120 NM SOUTHEAST QUADRANT 090 NM SOUTHWEST QUADRANT 080 NM NORTHWEST QUADRANT VECTOR TO 96 HR POSIT: 140 DEG/ 21 KTS --- LONG RANGE OUTLOOK: --- 96 HRS, VALID AT: 120000Z --- 29.6S 117.2E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY BECOMING EXTRATROPICAL --- 120 HRS, VALID AT: 130000Z --- 34.5S 126.3E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY EXTRATROPICAL RADIUS OF 034 KT WINDS - 120 NM NORTHEAST QUADRANT 070 NM SOUTHEAST QUADRANT 000 NM SOUTHWEST QUADRANT 130 NM NORTHWEST QUADRANT --- REMARKS: 080300Z POSITION NEAR 16.2S 113.4E. 08APR21. TROPICAL CYCLONE (TC) 26S (SEROJA), LOCATED APPROXIMATELY 384 NM NORTH OF LEARMONTH, AUSTRALIA, HAS TRACKED WEST-SOUTHWESTWARD AT 07 KNOTS OVER THE PAST SIX HOURS. ANIMATED 6-HOUR MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS THE SYSTEM HAS FURTHER CONSOLIDATED WITH A DEEPENED CENTRAL CONVECTION, ALBEIT REMAINING SHEARED SOUTHWESTWARD FROM THE LOW LEVEL CIRCULATION (LLC). THE INITIAL POSITION IS PLACED WITH FAIR CONFIDENCE AIDED BY LOW-CLOUD TRACING IN THE MSI LOOP INTO THE OBSCURED LLC AND LINED UP WITH A DEFINED MICROWAVE LLC FEATURE IN THE 072005Z SSMIS 37GHZ. THE INITIAL INTENSITY OF 55KTS IS BASED ON THE DVORAK ESTIMATES OF T3.5/55KTS FROM PGTW AND KNES AND REFLECTS THE IMPROVED STATE OF THE SYSTEM. ANALYSIS INDICATES A FAVORABLE ENVIRONMENT WITH VERY WARM (30-31C) SEA SURFACE TEMPERATURE (SST) AND GOOD RADIAL OUTFLOW ALOFT SLIGHTLY OFFSET BY 10-15KT NORTHEASTERLY 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 24 AND UP TO TAU 48, THE CYCLONE MAY UNDERGO A SLIGHT PULL TO THE RIGHT AND/OR MINOR WOBBLING AS A RESULT OF BINARY INTERACTION WITH TC 27S THAT WILL APPROACH TC 26S TO WITHIN 250NM. AFTER TAU 48, 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 GREAT AUSTRALIAN BIGHT. THE AFOREMENTIONED FAVORABLE CONDITIONS WILL FUEL RAPID INTENSIFICATION TO A PEAK OF 110KTS BY TAU 72. AFTERWARD, INCREASING VWS, COOLING SST, AND LANDFALL INTO SOUTHWEST AUSTRALIA BY TAU 84 WILL IN TURN RAPIDLY ERODE THE SYSTEM DOWN TO 40KTS BY TAU 120. CONCURRENTLY, BY TAU 96, TC SEROJA WILL UNDERGO EXTRA-TROPICAL TRANSITION AND BY TAU 12O, WILL BECOME A COLD CORE GALE-FORCE LOW AS IT EXITS INTO THE AUSTRALIAN BIGHT. NUMERICAL MODELS ARE IN TIGHT AGREEMENT WITH SEVERAL MODELS INCLUDING NVGM, ECMF, AND EEMN INVARIABLY JUTTING OUT TO THE RIGHT OF THE PACK FROM TAU 24-48, AN INDICATION OF EXCESSIVE BINARY INTERACTION (EBI) WITH TC 27S. AFTER TAU 96, THE MODELS SPREAD OUT 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 LEFT OF THE MODEL CONSENSUS DURING THE MID-PORTION TO OFFSET THE EBI MODELS. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 080000Z IS 22 FEET. NEXT WARNINGS AT 080900Z, 081500Z, 082100Z AND 090300Z. REFER TO TROPICAL CYCLONE 27S (TWENTYSEVEN) WARNINGS (WTXS32 PGTW) FOR SIX-HOURLY UPDATES.// NNNN