WTXS32 PGTW 070300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 27S (TWENTYSEVEN) WARNING NR 009// RMKS/ 1. TROPICAL CYCLONE 27S (TWENTYSEVEN) WARNING NR 009 02 ACTIVE TROPICAL CYCLONES IN SOUTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 070000Z --- NEAR 16.4S 105.7E MOVEMENT PAST SIX HOURS - 270 DEGREES AT 02 KTS POSITION ACCURATE TO WITHIN 040 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 065 NM NORTHEAST QUADRANT 115 NM SOUTHEAST QUADRANT 105 NM SOUTHWEST QUADRANT 070 NM NORTHWEST QUADRANT REPEAT POSIT: 16.4S 105.7E --- FORECASTS: 12 HRS, VALID AT: 071200Z --- 16.1S 105.7E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 085 NM NORTHEAST QUADRANT 110 NM SOUTHEAST QUADRANT 095 NM SOUTHWEST QUADRANT 085 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 015 DEG/ 04 KTS --- 24 HRS, VALID AT: 080000Z --- 15.3S 105.9E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 085 NM NORTHEAST QUADRANT 110 NM SOUTHEAST QUADRANT 095 NM SOUTHWEST QUADRANT 085 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 045 DEG/ 04 KTS --- 36 HRS, VALID AT: 081200Z --- 14.7S 106.5E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 085 NM NORTHEAST QUADRANT 110 NM SOUTHEAST QUADRANT 095 NM SOUTHWEST QUADRANT 085 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 055 DEG/ 09 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 090000Z --- 13.7S 108.1E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 100 NM NORTHEAST QUADRANT 085 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 100 NM NORTHWEST QUADRANT VECTOR TO 72 HR POSIT: 130 DEG/ 14 KTS --- 72 HRS, VALID AT: 100000Z --- 17.3S 112.5E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER RADIUS OF 034 KT WINDS - 100 NM NORTHEAST QUADRANT 070 NM SOUTHEAST QUADRANT 030 NM SOUTHWEST QUADRANT 100 NM NORTHWEST QUADRANT VECTOR TO 96 HR POSIT: 185 DEG/ 19 KTS --- LONG RANGE OUTLOOK: --- 96 HRS, VALID AT: 110000Z --- 25.0S 111.5E MAX SUSTAINED WINDS - 020 KT, GUSTS 030 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 070300Z POSITION NEAR 16.3S 105.7E. 07APR21. TROPICAL CYCLONE 27S (TWENTYSEVEN), LOCATED APPROXIMATELY 593 NM NORTHWEST OF LEARMONTH, AUSTRALIA, HAS TRACKED WESTWARD AT 02 KNOTS OVER THE PAST SIX HOURS. MULTISPECTRAL SATELLITE IMAGERY DEPICTS A SHEARED VORTEX, WITH THE LOW-LEVEL CIRCULATION (LLC) DISPLACED NEAR THE NORTHEASTERN EDGE OF A CIRCULAR MASS OF DEEP CONVECTION IN THE SOUTHERN SEMICIRCLE. THIS SHEAR (15-20 KT) IS BEING INDUCED BY UPPER-LEVEL NORTHEASTERLY OUTFLOW FROM LARGE- SCALE CONVECTION TO THE NORTH OF TC 27S, WHICH INCLUDES OUTFLOW FROM TC 26S. THE CURRENT INTENSITY IS SET AT 40 KT, SLIGHTLY LOWER THAN A SATCON ESTIMATE OF 42 KT AND A 062305Z SMAP PASS SHOWING 42-48 KT UNDER THE CONVECTION. TC 27S IS EMBEDDED IN A MARGINALLY FAVORABLE ENVIRONMENT FOR INTENSIFICATION, WITH THE AFOREMENTIONED MODERATE VERTICAL SHEAR AND A DRY AIR MASS WRAPPING AROUND THE NORTHERN SEMICIRCLE BEING THE PRIMARY LIMITING FACTORS. THIS GENERAL ENVIRONMENT IS EXPECTED TO PERSIST FOR THE NEXT 48 HOURS. NONETHELESS, GIVEN THAT THE CIRCULATION IS COMPACT AND WELL- STRUCTURED, MILD INTENSIFICATION MAY OCCUR IN THE SHORT TERM IF CONVECTION MAINTAINS AT LEAST PARTIAL OVERLAP WITH THE LLC. THE FORECAST IS FOR 27S TO PEAK IN INTENSITY AT 45 KTS IN 36-48 HOURS. THEREAFTER, THE VORTEX IS EXPECTED TO COME IN PROXIMITY TO TC 26S, WHICH SHOULD INCREASE VERTICAL SHEAR MAGNITUDES AND SPEED UP THE CYCLONE'S FORWARD MOTION, BOTH OF WHICH WILL EVENTUALLY LEAD TO AN UNRAVELING OF THE VORTEX. TC 27S IS EXPECTED TO DRIFT SLOWLY NORTHWARD DURING THE NEXT 24 HOURS UNDER WEAK STEERING CURRENTS, AND THEN ACCELERATE EASTWARD AROUND THE NORTHERN SEMICIRCLE OF TC 26S. THE DISTANCE BETWEEN THE TWO CYCLONES CLOSES WITHIN 330 NM BY 48 HOURS, AND THE RESULTING BINARY INTERACTION SHOULD SLING 27S SOUTHEASTWARD AND THEN SOUTHWARD BETWEEN 48 AND 96 HOURS, WITH SIGNIFICANT ACCELERATION IN FORWARD SPEED. BY 72-96 HOURS, TC 27S IS EXPECTED TO BE ABSORBED INTO THE LARGER CIRCULATION OF TC 26S AS IT PASSES WITHIN 100 NM WEST OF LEARMONTH, AUSTRALIA, AND THE FORECAST CALLS FOR DISSIPATION AT THAT TIME. THE TRACK BEYOND 48 HOURS HAS BEEN SHIFTED TO THE LEFT (NORTH AND EAST), FOLLOWING A BLEND OF ECMWF AND GFS. CONFIDENCE IN THIS EXACT TRACK, ESPECIALLY THE TIMING, IS LOWER THAN AVERAGE DUE TO THE UNCERTAINTY POSED BY BINARY INTERACTION WITH TC 26S. NOTE THAT THE INTENSITY FORECAST HERE DOES NOT REFLECT THE POTENTIAL FOR SIGNIFICANT WINDS ASSOCIATED WITH TC 26S THAT MAY OCCUR SIMULTANEOUSLY WHILE THE TWO CYCLONES ARE IN PROXIMITY. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 070000Z IS 18 FEET. NEXT WARNINGS AT 070900Z, 071500Z, 072100Z AND 080300Z. REFER TO TROPICAL CYCLONE 26S (SEROJA) WARNINGS (WTXS31 PGTW) FOR SIX-HOURLY UPDATES.// NNNN