240900Z POSITION NEAR 41.2N 139.1E. TROPICAL STORM 23W (CIMARON), LOCATED APPROXIMATELY 161 NM WEST OF MISAWA, JAPAN, HAS TRACKED NORTH-NORTHEASTWARD AT 21 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTI-SPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A WEAKENING SYSTEM, WITH A DECOUPLED AND FULLY EXPOSED LLCC AND EXPANDING ASYMMETRIC CLOUD SHIELD. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE EXPOSED LLCC. THE INITIAL INTENSITY OF 45 KNOTS IS BASED ON A 240111Z ASCAT PASS SHOWING 40-44 KT WIND BARBS TO THE SOUTHEAST OF THE CENTER, AND ABOVE A PGTW SUBTROPICAL FIX OF 35 KTS. ENVIRONMENTAL ANALYSIS SHOWS THAT THE SYSTEM LIES IN AN AREA OF HIGH (30+ KNOTS) VWS UNDER THE MIDLATITUDE JET AND COOL (24-25 DEG CELSIUS) SSTS. THE CYCLONE CONTINUES TO TRACK RAPIDLY TOWARDS THE NORTHEAST CARRIED ALONG BY THE WESTERLY JET. DUE TO THE POSITION UNDER THE WESTERLY JET AND COOL SSTS, 23W HAS BEGUN EXTRATROPICAL TRANSITION, WITH A 232200Z AMSU CORE TEMPERATURE CROSS-SECTION SHOWING A BUILDING COLD-CORE ANOMALY AT MID-LEVELS. 23W WILL CONTINUE TO ACCELERATE TOWARDS THE EAST- NORTHEAST UNDER THE WESTERLY JET, AND TRANSITION INTO A COLD-CORE SYSTEM WITH EXPANSIVE WIND FIELDS AND ASYMMETRIC CONVECTION. MODELS SHOW THAT 23W AND 22W WILL REMAIN DISTINCT SYSTEMS. 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 240600Z IS 18 FEET. REFER TO TROPICAL STORM 22W (SOULIK) WARNINGS (WTPN35 PGTW) FOR SIX-HOURLY UPDATES. REFER TO TROPICAL DEPRESSION 24W (TWENTYFOUR) WARNINGS (WTPN32 PGTW) FOR SIX-HOURLY UPDATES.