WTXS31 PGTW 091500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 26S (SEROJA) WARNING NR 021// RMKS/ 1. TROPICAL CYCLONE 26S (SEROJA) WARNING NR 021 02 ACTIVE TROPICAL CYCLONES IN SOUTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 091200Z --- NEAR 20.2S 108.9E MOVEMENT PAST SIX HOURS - 225 DEGREES AT 07 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 - 000 NM NORTHEAST QUADRANT 030 NM SOUTHEAST QUADRANT 025 NM SOUTHWEST QUADRANT 000 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 200 NM NORTHEAST QUADRANT 085 NM SOUTHEAST QUADRANT 090 NM SOUTHWEST QUADRANT 180 NM NORTHWEST QUADRANT REPEAT POSIT: 20.2S 108.9E --- FORECASTS: 12 HRS, VALID AT: 100000Z --- 20.8S 108.4E MAX SUSTAINED WINDS - 060 KT, GUSTS 075 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 - 080 NM NORTHEAST QUADRANT 100 NM SOUTHEAST QUADRANT 100 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 165 DEG/ 07 KTS --- 24 HRS, VALID AT: 101200Z --- 22.2S 108.8E MAX SUSTAINED WINDS - 065 KT, GUSTS 080 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 - 080 NM NORTHEAST QUADRANT 100 NM SOUTHEAST QUADRANT 100 NM SOUTHWEST QUADRANT 060 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 140 DEG/ 14 KTS --- 36 HRS, VALID AT: 110000Z --- 24.4S 110.7E 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 040 NM SOUTHWEST QUADRANT 000 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 090 NM NORTHEAST QUADRANT 110 NM SOUTHEAST QUADRANT 110 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 140 DEG/ 22 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 111200Z --- 27.8S 113.8E 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 020 NM SOUTHWEST QUADRANT 015 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT 040 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 090 NM NORTHEAST QUADRANT 120 NM SOUTHEAST QUADRANT 120 NM SOUTHWEST QUADRANT 060 NM NORTHWEST QUADRANT VECTOR TO 72 HR POSIT: 130 DEG/ 30 KTS --- 72 HRS, VALID AT: 121200Z --- 35.5S 124.9E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY BECOMING EXTRATROPICAL RADIUS OF 034 KT WINDS - 120 NM NORTHEAST QUADRANT 130 NM SOUTHEAST QUADRANT 110 NM SOUTHWEST QUADRANT 090 NM NORTHWEST QUADRANT VECTOR TO 96 HR POSIT: 125 DEG/ 27 KTS --- LONG RANGE OUTLOOK: --- 96 HRS, VALID AT: 131200Z --- 40.8S 137.1E MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY EXTRATROPICAL --- REMARKS: 09APR21. TROPICAL CYCLONE 26S (SEROJA), LOCATED APPROXIMATELY 317 NM WEST-NORTHWEST OF LEARMONTH, AUSTRALIA, HAS TRACKED SOUTHWESTWARD AT 07 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY(EIR) SHOWS DEEP CONVECTION COMPLETELY WRAPPING AROUND A COMPACT LOW LEVEL CIRCULATION (LLC). THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED UPON THE EIR LOOP AND MULTIPLE DVORAK AGENCY FIX POSITIONS AND A MICROWAVE EYE OBSERVED ON THE 091113Z SSMIS 37GHZ IMAGE. THE CURRENT INTENSITY OF 55 KNOTS IS SUPPORTED WITH MULTIPLE DVORAK AGENCY ESTIMATES FROM PGTW AND APRF WITH DVORAK ESTIMATES OF T3.5(55KTS). KNES IS MARKED SLIGHTLY HIGHER AT T4.0(65KTS), WHILE THE ADVANCED DVORAK TECHNIQUE(ADT) IS LOWER AT T3.0(45KTS). THE ENVIRONMENT REMAINS FAVORABLE, WITH LOW TO MODERATE (10-15KTS) VERTICAL WIND SHEAR AND STRONG POLEWARD OUTFLOW ALOFT. TC26S (SEROJA) AND TC 27S (ODETTE) ARE CONTINUING TO INTERACT AS THEY ARE ONLY SEPARATED BY AN ESTIMATED 295NM. ODETTE REMAINS THE SMALLER CYCLONE OF THE TWO AND IS NOT EXPECTED TO PREVENT SEROJA FROM INTENSIFYING AS ODETTE HAS DECOUPLED AND BECOME PARTLY EXPOSED. A PERIOD OF SWIFT INTENSIFICATION REMAINS POSSIBLE AS SEROJA COMPLETES FORMATION OF AN INNER CORE AND ROUNDS THE RIDGE AXIS TO THE WEST THROUGH TAU 36. THE INTENSITY IS EXPECTED TO INCREASE UP TO TAU 48 JUST PRIOR TO LANDFALL IN WESTERN AUSTRALIA AS VERTICAL SHEAR IS EXPECTED TO INCREASE TO 20-25 KTS AND THE CYCLONE APPROACHES THE JET STREAM, AS WELL AS POSSIBLE ENTRAINMENT OF A MID-LATITUDE DRY AIR MASS. THE FORECAST SHOWS THE PEAK INTENSITY BACKING OFF TO 80KTS AT TAU 48. LANDFALL OF THE SYSTEM IS EXPECTED TO OCCUR SHORTLY AFTER TAU 48 WITH THE PEAK INTENSITY HAPPENING JUST PRIOR TO LANDFALL. THE TRACK FORECAST PHILOSOPHY REMAINS UNCHANGED, WITH A SLOWING OF FORWARD MOTION EXPECTED THROUGH 24 HOURS DUE TO INTERACTION WITH TC ODETTE, AND THEN ACCELERATION SOUTHEASTWARD ALONG THE FLANK OF THE DEEP-LAYER RIDGE OVER WESTERN AUSTRALIA. THE EXACT TIMING OF LANDFALL NEAR GERALDTON, AUSTRALIA JUST AFTER TAU 48 HAS ABOVE- AVERAGE UNCERTAINTY DUE TO UNCERTAINTY IN HOW MUCH TC SEROJA WILL BE SLOWED DOWN BY INTERACTION WITH TC ODETTE PRIOR TO MAKING ITS SOUTHEASTWARD MOVE TOWARD THE COAST. AFTER LANDFALL THE SYSTEM IS EXPECTED TO DECREASE IN INTENSITY AND RAPIDLY TRANSITION AS AN EXTRA- TROPICAL LOW AS IT MOVES OVER THE AUSTRALIAN BITE BY TAU 72 AND COMPLETE TRANSITION PROCESS OVER THE MUCH COOLER WATER BEFORE TAU 96. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 091200Z IS 27 FEET. NEXT WARNINGS AT 092100Z, 100300Z, 100900Z AND 101500Z. REFER TO TROPICAL CYCLONE 27S (ODETTE) WARNINGS (WTXS32 PGTW) FOR SIX-HOURLY UPDATES.// NNNN