WTXS31 PGTW 110900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 26S (SEROJA) WARNING NR 028// RMKS/ 1. TROPICAL CYCLONE 26S (SEROJA) WARNING NR 028 01 ACTIVE TROPICAL CYCLONE IN SOUTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 110600Z --- NEAR 26.1S 112.0E MOVEMENT PAST SIX HOURS - 145 DEGREES AT 23 KTS POSITION ACCURATE TO WITHIN 030 NM POSITION BASED ON EYE FIXED BY A COMBINATION OF SATELLITE AND RADAR PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 030 NM NORTHEAST QUADRANT 030 NM SOUTHEAST QUADRANT 020 NM SOUTHWEST QUADRANT 020 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 050 NM NORTHEAST QUADRANT 045 NM SOUTHEAST QUADRANT 030 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 125 NM NORTHEAST QUADRANT 110 NM SOUTHEAST QUADRANT 055 NM SOUTHWEST QUADRANT 090 NM NORTHWEST QUADRANT REPEAT POSIT: 26.1S 112.0E --- FORECASTS: 12 HRS, VALID AT: 111800Z --- 30.2S 116.5E MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT WIND RADII VALID OVER OPEN WATER ONLY BECOMING EXTRATROPICAL RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT 030 NM SOUTHEAST QUADRANT 020 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 110 NM NORTHEAST QUADRANT 080 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 090 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 130 DEG/ 36 KTS --- 24 HRS, VALID AT: 120600Z --- 34.7S 123.3E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY EXTRATROPICAL RADIUS OF 034 KT WINDS - 100 NM NORTHEAST QUADRANT 070 NM SOUTHEAST QUADRANT 000 NM SOUTHWEST QUADRANT 070 NM NORTHWEST QUADRANT --- REMARKS: 110900Z POSITION NEAR 27.1S 113.1E. 11APR21. TROPICAL CYCLONE 26S (SEROJA), LOCATED APPROXIMATELY 255 NM SOUTH-SOUTHWEST OF LEARMONTH, AUSTRALIA, HAS TRACKED SOUTHEASTWARD AT 23 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY INDICATES TIGHTLY CURVED CONVECTIVE BANDING WRAPPING INTO A WEAK EYE FEATURE. A 110630Z GMI 89GHZ MICROWAVE IMAGE REVEALS A COMPACT CORE WITH DEEP CONVECTION WRAPPING AROUND THREE QUARTERS OF THE CIRCULATION AND A WELL DEFINED 7NM WIDE MICROWAVE EYE FEATURE. THE EYE FEATURE WAS ALSO EVIDENT IN ANIMATED RADAR DATA FROM THE CARNARVON AIRPORT RADAR SITE. THE COMBINATION OF THE DATA CONFIRMING THE EYE FEATURE SEEN IN THE RADAR, VISIBLE AND MICROWAVE IMAGERY LENT HIGH CONFIDENCE TO THE INITIAL POSITION. THE INITIAL INTENSITY IS SET AT 70 KNOTS WITH MODERATE CONFIDENCE, SLIGHTLY LOWER THAN THE MULTI-AGENCY DVORAK INTENSITY ESTIMATES OF T4.5 (77 KTS) FROM BOTH PGTW AND APRF, AND KNES AT T5.0 (90 KTS). ADT WAS SIGNIFICANTLY LOWER AT T3.1, BUT THE PRESENCE OF THE MICROWAVE AND RADAR EYE PROVIDED STRONG SUPPORT FOR AN INCREASE IN THE INTENSITY OVER THE PREVIOUS SIX HOUR ANALYSIS. TC 26S IS CONTINUING TO ACCELERATE SOUTHEASTWARD ALONG THE WESTERN PERIPHERY OF A DEEP STR LOCATED TO THE EAST AND WILL CONTINUE THIS MOTION THROUGH THE DURATION OF THE FORECAST PERIOD. TC 26S IS EXPECTED TO MAKE LANDFALL NEAR GERALDTON, AUSTRALIA WITHIN THE NEXT 6-8 HOURS BEFORE CONTINUING SOUTHEAST INTO THE GREAT AUSTRALIAN BIGHT. WHILE STILL A TROPICAL CYCLONE, TC 26S IS BEGINNING TO SHOW SOME SIGNS OF INTERACTION WITH THE DRIER, COOLER AIR MASS ENTRENCHED TO THE SOUTHWEST AND IS EXPECTED TO BEGIN EXTRA-TROPICAL TRANSITION (ETT) IMMINENTLY. AS IT MOVES OVER LAND THROUGH TAU 12, THE SYSTEM WILL COMPLETE ETT NO LATER THAN TAU 24 AS IT BECOMES EMBEDDED WITHIN THE DEEP WESTERLIES AND DEVELOPS FRONTAL CHARACTERISTICS. THE SYSTEM HAS LIKELY REACHED PEAK INTENSITY AND WILL SLOWLY WEAKEN PRIOR TO LANDFALL DUE TO RAPIDLY INCREASING VWS AND DECREASING SSTS. ONCE OVER LAND, THE INFLUENCE OF TERRAIN AND VERY HIGH SHEAR VALUES WILL RAPIDLY WEAKEN THE SYSTEM AS IT UNDERGOES ETT. DYNAMIC MODEL GUIDANCE IS IN VERY GOOD AGREEMENT LENDING HIGH CONFIDENCE TO THE JTWC FORECAST TRACK. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 110600Z IS 30 FEET. NEXT WARNINGS AT 111500Z, 112100Z AND 120300Z.// NNNN