WTXS31 PGTW 090900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 26S (SEROJA) WARNING NR 020// RMKS/ 1. TROPICAL CYCLONE 26S (SEROJA) WARNING NR 020 02 ACTIVE TROPICAL CYCLONES IN SOUTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 090600Z --- NEAR 19.7S 109.4E MOVEMENT PAST SIX HOURS - 225 DEGREES AT 10 KTS POSITION ACCURATE TO WITHIN 045 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 085 NM NORTHEAST QUADRANT 090 NM SOUTHEAST QUADRANT 095 NM SOUTHWEST QUADRANT 145 NM NORTHWEST QUADRANT REPEAT POSIT: 19.7S 109.4E --- FORECASTS: 12 HRS, VALID AT: 091800Z --- 20.6S 108.5E 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 - 080 NM NORTHEAST QUADRANT 100 NM SOUTHEAST QUADRANT 100 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 185 DEG/ 04 KTS --- 24 HRS, VALID AT: 100600Z --- 21.4S 108.4E 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: 155 DEG/ 10 KTS --- 36 HRS, VALID AT: 101800Z --- 23.2S 109.3E 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 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/ 18 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 110600Z --- 26.0S 111.8E 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: 135 DEG/ 28 KTS --- 72 HRS, VALID AT: 120600Z --- 33.5S 121.2E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 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: 130 DEG/ 29 KTS --- LONG RANGE OUTLOOK: --- 96 HRS, VALID AT: 130600Z --- 40.0S 133.0E MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY EXTRATROPICAL --- REMARKS: 090900Z POSITION NEAR 19.9S 109.2E. 09APR21. TROPICAL CYCLONE 26S (SEROJA), LOCATED APPROXIMATELY 306 NM WEST-NORTHWEST OF LEARMONTH, AUSTRALIA, HAS TRACKED SOUTHWESTWARD AT 10 KNOTS OVER THE PAST SIX HOURS. MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS DEEP CONVECTION WRAPPING AROUND A LOW LEVEL CIRCULATION CENTER (LLCC). THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE MSI LOOP, MULTIPLE DVORAK AGENCY FIX POSITIONS, AND A TIMELY 090556Z ATMS MICROWAVE IMAGE INDICATING TWO PRIMARY BANDS IN THE NORTHERN AND SOUTHERN SEMICIRCLES WRAPPING ALMOST COMPLETELY AROUND THE LLCC. THE CURRENT INTENSITY OF 50 KNOTS IS ADJUSTED SLIGHTLY HIGHER THAN MULTIPLE DVORAK AGENCY ESTIMATES FROM PGTW AND APRF WITH DVORAK ESTIMATES OF T3.0, THE ADVANCED DVORAK TECHNIQUE (ADT) T2.9(43KTS), A SATELLITE CONSENSUS (SATCON) ESTIMATE OF 48KTS, AND SLIGHTLY LOWER THAN KNES T3.5(55KTS). THE ENVIRONMENT REMAINS FAVORABLE, WITH LOW TO MODERATE (10-15KTS) VERTICAL WIND SHEAR AND DECENT RADIAL OUTFLOW FROM A POINT SOURCE ALOFT. TC26S (SEROJA) AND TC 27S (ODETTE) ARE NOW INTERACTING AS THEY ARE ONLY SEPARATED BY AN ESTIMATED 290NM. ODETTE REMAINS THE SMALLER CYCLONE OF THE TWO AND IS NOT EXPECTED TO PREVENT SEROJA FROM INTENSIFYING AS ODETTE IS NOW DECOUPLING FROM THE UPPER LEVEL OUTFLOW. THE PRESENCE OF TC 27S HAS CAUSED SOME SLIGHT DISRUPTION AND PULLED SEROJA SLIGHTLY TO THE NORTH OF ITS ORIGINAL TRACK. HOWEVER, A PERIOD OF SWIFT INTENSIFICATION REMAINS EXPECTED BETWEEN NOW AND 36 HOURS ONCE SEROJA COMPLETES FORMATION OF AN INNER CORE AND ROUNDS THE RIDGE AXIS TO THE WEST. A LEVELING OFF OF INTENSITY PRIOR TO LANDFALL IN WESTERN AUSTRALIA IS EXPECTED DUE TO INCREASING VERTICAL SHEAR TO 20- 25 KTS AS THE CYCLONE APPROACHES THE JET STREAM, AS WELL AS POSSIBLE ENTRAINMENT OF MID-LATITUDE DRY AIR. THE FORECAST SHOWS THE PEAK INTENSITY BACKING OFF AND IS LOWERED TO 80 KTS AT 48 HOURS, THOUGH SINCE LANDFALL OCCURS BETWEEN THE 48 AND 72 HOUR FORECAST POINTS, THE PEAK INTENSITY PRIOR TO LANDFALL COULD BE HIGHER. THE TRACK FORECAST PHILOSOPHY REMAINS UNCHANGED, WITH A SLOWING OF FORWARD MOTION EXPECTED THROUGH 24 HOURS DUE TO INTERACTION WITH TC ODETTE, BEFORE ACCELERATING SOUTHEASTWARD ALONG THE FLANK OF THE DEEP-LAYER RIDGE OVER WESTERN AUSTRALIA. THIS FORECAST IS SLIGHTLY FASTER THAN THE PREVIOUS ONE THROUGH THE NEXT 12 HOURS DUE TO SEROJA'S SHORT TERM MOTION, AND SHIFTED SLIGHTLY SOUTHWEST BEYOND 24 HOURS, FOLLOWING THE TREND IN THE MODEL GUIDANCE. THE EXACT TIMING OF LANDFALL NEAR GERALDTON, AUSTRALIA BETWEEN 48 AND 72 HOURS HAS ABOVE- AVERAGE UNCERTAINTY DUE TO MODEL SPREAD IN THE SLOW DOWN CAUSED BY INTERACTION WITH TC ODETTE PRIOR TO MAKING ITS SOUTHEASTWARD MOVE TOWARD THE COAST. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 090600Z IS 25 FEET. NEXTWARNINGS AT 091500Z, 092100Z, 100300Z AND 100900Z. REFER TO TROPICAL CYCLONE 27S (ODETTE) WARNINGS (WTXS32 PGTW) FOR SIX- HOURLY UPDATES.// NNNN