WTXS31 PGTW 060900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 26S (SEROJA) WARNING NR 008// RMKS/ 1. TROPICAL CYCLONE 26S (SEROJA) WARNING NR 008 02 ACTIVE TROPICAL CYCLONES IN SOUTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 060600Z --- NEAR 11.5S 118.9E MOVEMENT PAST SIX HOURS - 255 DEGREES AT 09 KTS POSITION ACCURATE TO WITHIN 060 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 050 KT WINDS - 050 NM NORTHEAST QUADRANT 035 NM SOUTHEAST QUADRANT 045 NM SOUTHWEST QUADRANT 060 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 080 NM NORTHEAST QUADRANT 065 NM SOUTHEAST QUADRANT 085 NM SOUTHWEST QUADRANT 090 NM NORTHWEST QUADRANT REPEAT POSIT: 11.5S 118.9E --- FORECASTS: 12 HRS, VALID AT: 061800Z --- 12.0S 117.8E MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 030 NM NORTHEAST QUADRANT 010 NM SOUTHEAST QUADRANT 000 NM SOUTHWEST QUADRANT 010 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 080 NM NORTHEAST QUADRANT 080 NM SOUTHEAST QUADRANT 100 NM SOUTHWEST QUADRANT 110 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 240 DEG/ 08 KTS --- 24 HRS, VALID AT: 070600Z --- 12.8S 116.3E MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 030 NM NORTHEAST QUADRANT 020 NM SOUTHEAST QUADRANT 000 NM SOUTHWEST QUADRANT 010 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 070 NM NORTHEAST QUADRANT 100 NM SOUTHEAST QUADRANT 100 NM SOUTHWEST QUADRANT 090 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 230 DEG/ 09 KTS --- 36 HRS, VALID AT: 071800Z --- 14.0S 114.8E MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 030 NM NORTHEAST QUADRANT 020 NM SOUTHEAST QUADRANT 010 NM SOUTHWEST QUADRANT 020 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 090 NM NORTHEAST QUADRANT 100 NM SOUTHEAST QUADRANT 090 NM SOUTHWEST QUADRANT 090 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 230 DEG/ 10 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 080600Z --- 15.4S 113.2E MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 010 NM NORTHEAST QUADRANT 015 NM SOUTHEAST QUADRANT 005 NM SOUTHWEST QUADRANT 005 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT 030 NM SOUTHEAST QUADRANT 030 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 120 NM NORTHEAST QUADRANT 130 NM SOUTHEAST QUADRANT 100 NM SOUTHWEST QUADRANT 100 NM NORTHWEST QUADRANT VECTOR TO 72 HR POSIT: 215 DEG/ 10 KTS --- 72 HRS, VALID AT: 090600Z --- 18.5S 110.7E MAX SUSTAINED WINDS - 090 KT, GUSTS 110 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 040 NM NORTHEAST QUADRANT 040 NM SOUTHEAST QUADRANT 035 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 060 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 140 NM NORTHEAST QUADRANT 150 NM SOUTHEAST QUADRANT 130 NM SOUTHWEST QUADRANT 120 NM NORTHWEST QUADRANT VECTOR TO 96 HR POSIT: 205 DEG/ 07 KTS --- LONG RANGE OUTLOOK: --- 96 HRS, VALID AT: 100600Z --- 21.0S 109.4E MAX SUSTAINED WINDS - 105 KT, GUSTS 130 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 045 NM NORTHEAST QUADRANT 050 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 045 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 070 NM NORTHEAST QUADRANT 070 NM SOUTHEAST QUADRANT 070 NM SOUTHWEST QUADRANT 060 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 190 NM NORTHEAST QUADRANT 140 NM SOUTHEAST QUADRANT 120 NM SOUTHWEST QUADRANT 160 NM NORTHWEST QUADRANT VECTOR TO 120 HR POSIT: 165 DEG/ 09 KTS --- 120 HRS, VALID AT: 110600Z --- 24.6S 110.3E MAX SUSTAINED WINDS - 095 KT, GUSTS 115 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 050 NM NORTHEAST QUADRANT 050 NM SOUTHEAST QUADRANT 045 NM SOUTHWEST QUADRANT 055 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 080 NM NORTHEAST QUADRANT 070 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 070 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 150 NM NORTHEAST QUADRANT 140 NM SOUTHEAST QUADRANT 100 NM SOUTHWEST QUADRANT 140 NM NORTHWEST QUADRANT --- REMARKS: 060900Z POSITION NEAR 11.6S 118.6E. 06APR21. TROPICAL CYCLONE 26S (SEROJA), LOCATED APPROXIMATELY 429 NM NORTH-NORTHWEST OF BROOME, AUSTRALIA, HAS TRACKED WEST- SOUTHWESTWARD AT 09 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A DISORGANIZED LOW LEVEL CIRCULATION CENTER (LLCC) WITH PULSING CONVECTION SHEARED TO THE SOUTHWEST OF THE ASSESSED LLCC. DUE TO THE LACK OF RECENT MICROWAVE IMAGERY, THE INITIAL POSITION IS SET WITH ONLY MODERATE CONFIDENCE BASED ON A BLEND OF PGTW, APRF AND KNES FIX POSITIONS AND ANALYSIS OF THE LOW-LEVEL BANDING FEATURES EXPOSED TO THE SOUTH OF THE SYSTEM IN THE ANIMATED VISIBLE IMAGERY. THE INITIAL INTENSITY IS ASSESSED AT 50 KNOTS WITH MODERATE CONFIDENCE BASED ON DVORAK CURRENT INTENSITY ESTIMATES OF T3.5 (55 KTS) FROM PGTW AND APRF, AN ADT ESTIMATE OF T3.2 AND A SATCON ESTIMATE OF 52 KTS. AN EARLIER ASCAT-B AT 060110Z INDICATED A SWATH OF 50-55 KNOT WINDS PRESENT IN THE NORTHEAST AND SOUTHWEST QUADRANTS AND PROVIDED ADDITIONAL SUPPORT TO THE INITIAL INTENSITY ASSESSMENT. ENVIRONMENTAL ANALYSIS REVEALS MARGINAL CONDITIONS, WITH MODERATE TO HIGH (20-25 KTS) EASTERLY VWS AND WEAKLY DIFFLUENT OUTFLOW OFFSET BY VERY WARM (30-31C) SSTS. THE SYSTEM IS CURRENTLY TRACKING WEST-SOUTHWESTWARD ALONG THE NORTHWESTERN PERIPHERY OF A DEEP-LAYER SUBTROPICAL RIDGE (STR) CENTERED OVER WESTERN AUSTRALIA. TC 26S IS FORECAST TO CONTINUE TRACKING SOUTHWESTWARD ALONG THE WESTERN PERIPHERY OF THE STR THROUGH TAU 72. TC 27S WILL APPROACH FROM THE WEST BY ABOUT TAU 48, SWINGING RAPIDLY AROUND THE NORTH THEN NORTHEASTERN PERIPHERY OF TC 26S, IS NOT EXPECTED TO HAVE A SIGNIFICANT IMPACT ON THE OVERALL TRACK FORECAST OF TC 26S AS TC 27S WILL BE THE WEAKER OF THE TWO SYSTEMS AND SHOULD REMAIN FAR ENOUGH DISTANT TO HAVE LITTLE EFFECT. IN THE EXTENDED FORECAST, TC 26S WILL TURN SOUTH THEN SOUTHEASTWARD AFTER TAU 96 IN RESPONSE TO THE APPROACH OF A STRONG MID-LATITUDE TROUGH APPROACHING FROM THE WEST. THE SYSTEM IS EXPECTED TO SLOWLY INTENSIFY THROUGH TAU 48 UNDER MARGINAL ENVIRONMENTAL CONDITIONS. A PERIOD OF MORE RAPID INTENSIFICATION IS EXPECTED BETWEEN TAUS 72 AND 96, PEAKING AT 105 KTS AT TAU 96, AS THE SYSTEM MOVES INTO AN AREA OF DECREASED SHEAR AND TAPS INTO A STRONG POLEWARD OUTFLOW CHANNEL INTO THE BASE OF THE APPROACHING TROUGH. GRADUAL WEAKENING IS EXPECTED THROUGH TAU 120 AS THE SYSTEM MOVES OVER COOLER WATERS AND EXPERIENCES INCREASING SHEAR. NUMERICAL MODEL GUIDANCE IS OVERALL GOOD AGREEMENT WITH 92NM SPREAD AT TAU 48 INCREASING TO 150NM AT TAU 120. HOWEVER THERE IS STILL OVERALL LOW CONFIDENCE IN THE JTWC FORECAST TRACK DUE TO THE UNCERTAINTY SURROUNDING THE IMPACT OF THE BINARY INTERACTION WITH TC 27S. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 060600Z IS 21 FEET. NEXT WARNINGS AT 061500Z, 062100Z, 070300Z AND 070900Z. REFER TO TROPICAL CYCLONE 27S (TWENTYSEVEN) WARNINGS (WTXS32 PGTW) FOR SIX-HOURLY UPDATES.// NNNN