WTPN31 PGTW 150300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TYPHOON 15W (MERBOK) WARNING NR 018 // RMKS/ 1. TYPHOON 15W (MERBOK) WARNING NR 018 03 ACTIVE TROPICAL CYCLONES IN NORTHWESTPAC MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 150000Z --- NEAR 36.7N 164.5E MOVEMENT PAST SIX HOURS - 030 DEGREES AT 33 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT WIND RADII VALID OVER OPEN WATER ONLY BECOMING EXTRATROPICAL RADIUS OF 064 KT WINDS - 065 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 045 NM SOUTHWEST QUADRANT 045 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 110 NM NORTHEAST QUADRANT 090 NM SOUTHEAST QUADRANT 090 NM SOUTHWEST QUADRANT 075 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 175 NM NORTHEAST QUADRANT 155 NM SOUTHEAST QUADRANT 115 NM SOUTHWEST QUADRANT 125 NM NORTHWEST QUADRANT REPEAT POSIT: 36.7N 164.5E --- FORECASTS: 12 HRS, VALID AT: 151200Z --- 43.2N 168.6E MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT WIND RADII VALID OVER OPEN WATER ONLY EXTRATROPICAL RADIUS OF 064 KT WINDS - 040 NM NORTHEAST QUADRANT 050 NM SOUTHEAST QUADRANT 020 NM SOUTHWEST QUADRANT 020 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 100 NM NORTHEAST QUADRANT 130 NM SOUTHEAST QUADRANT 090 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 280 NM NORTHEAST QUADRANT 320 NM SOUTHEAST QUADRANT 250 NM SOUTHWEST QUADRANT 210 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 025 DEG/ 42 KTS --- 24 HRS, VALID AT: 160000Z --- 50.5N 174.6E MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT WIND RADII VALID OVER OPEN WATER ONLY EXTRATROPICAL RADIUS OF 050 KT WINDS - 070 NM NORTHEAST QUADRANT 160 NM SOUTHEAST QUADRANT 130 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 330 NM NORTHEAST QUADRANT 340 NM SOUTHEAST QUADRANT 260 NM SOUTHWEST QUADRANT 240 NM NORTHWEST QUADRANT --- REMARKS: 150300Z POSITION NEAR 38.3N 165.5E. 15SEP22. TYPHOON 15W (MERBOK), LOCATED APPROXIMATELY 1050 NM NORTH OF WAKE ISLAND, HAS TRACKED NORTH-NORTHEASTWARD AT 33 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) AND WATER VAPOR IMAGERY SHOW THAT WHILE TY 15W RETAINS A WELL DEFINED LOW LEVEL CIRCULATION CENTER (LLCC), THE CONVECTIVE SIGNATURE IS BEGINNING TO ELONGATE AND ERODE AS THE SYSTEM INTERACTS WITH A FRONT BEARING DOWN FROM THE NORTHWEST AND STRONG UPPER-LEVEL FLOW FROM THE SOUTHWEST. THE IMAGERY ALSO SHOWS A STRONG UPPER-LEVEL LOW AND ACCOMPANYING SURFACE FEATURE, LOCATED APPROXIMATELY 450NM TO THE NORTHWEST, MOVING RAPIDLY SOUTHEASTWARD TOWARDS A RENDEZVOUS WITH TY 15W. THE SYSTEM HAS STARTED EXTRATROPICAL TRANSITION (ETT) AS IT HAS NOW MOVED UNDER THE RIGHT REAR REGION OF A STRONG 100-PLUS KNOT JET MAX AND IS QUICKLY DEVELOPING FRONTAL CHARACTERISTICS DUE TO STRONG LOW-LEVEL TEMPERATURE ADVECTION. THE INITIAL POSITION IS ASSESSED WITH HIGH CONFIDENCE, WHILE THE INITIAL INTENSITY IS ASSESSED WITH MEDIUM CONFIDENCE, IN LINE WITH THE SUBJECTIVE AND OBJECTIVE FIX DATA. EVEN WHILE THE SYSTEM HAS BEGUN ETT, THE VERY STRONG BAROCLINIC FORCING AND PRESENCE OF A STING JET IN THE LOWER LEVELS, MEANS THAT IT WILL MAINTAIN INTENSITY AS A MINIMAL TYPHOON, WITH GUSTS UP TO OR EXCEEDING 80 KNOTS, PARTICULARLY IN THE REGION OF THE STING JET, THROUGH AT LEAST THE NEXT 12 TO 18 HOURS BEFORE FINALLY BEGINNING TO WEAKEN SLIGHTLY AS IT APPROACHES THE WESTERN ALEUTIANS. ETT WILL BE VERY RAPID IN THIS SCENARIO, AS THE SYSTEM IS SCREAMING TO THE NORTH AT OVER 35 KNOTS AND THE SYSTEM WILL TRANSITION TO A HURRICANE FORCE EXTRATROPICAL LOW, WITH A DRAMATICALLY EXPANDING WIND FIELD, WITHIN THE NEXT 12 HOURS. THIS IS THE FINAL WARNING ON THIS SYSTEM BY THE JOINT TYPHOON WRNCEN PEARL HARBOR HI. THE SYSTEM WILL BE CLOSELY MONITORED FOR SIGNS OF REGENERATION. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 150000Z IS 35 FEET. REFER TO TROPICAL STORM 14W (MUIFA) WARNINGS (WTPN32 PGTW) FOR SIX-HOURLY UPDATES. REFER TO TROPICAL STORM 16W (NANMADOL) WARNINGS (WTPN33 PGTW) FOR SIX-HOURLY UPDATES.// NNNN