WDPN31 PGTW 191500 MSGID/GENADMIN/NAVPACMETOCCEN PEARL HARBOR HI/JTWC// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 18W /WARNING NR 23// RMKS/ 1. FOR METEOROLOGISTS. 2. PROGNOSTIC REASONING FOR 191200Z3 TO 210000Z3 AUG 2004. A. TROPICAL STORM (TS) 18W (MEGI), LOCATED APPROXIMATELY 240 NM WEST OF MISAWA, JAPAN, HAS TRACKED NORTHEASTWARD AT 36 KNOTS OVER THE PAST 06 HOURS AND COMPLETED TRANSITION INTO AN EXTRATROPICAL SYSTEM. THE WARNING POSITION IS BASED ON 191130Z5 ENHANCED INFRARED SATELLITE IMAGERY. THE WARNING INTENSITY IS BASED ON SATELLITE CURRENT INTENSITY ESTIMATES OF 45, 55 AND 65 KNOTS. B. TS 18W IS FORECAST TO CONTINUE TRACKING RAPIDLY NORTHEASTWARD ALONG THE NORTHWESTERN PERIPHERY OF THE STEERING RIDGE SOUTHEAST OF THE SYSTEM. TS 18W WILL CONTINUE TO MERGE WITH THE MID-LATITUDE WESTERLIES AND ACCELERATE NORTHEASTWARDS. TS 18W WILL BECOME COMPLETELY EMBEDDED IN THE BAROCLINIC ZONE BY THE COMPLETION OF THE FORECAST PERIOD. THE AVAILABLE DYNAMIC AIDS CONSISTING OF NOGAPS, UKMET EGRR, NCEP GFS, GFDN, WBAR, JGSM, JTYM AND COAMPS ARE IN GOOD AGREEMENT WITH THIS SCENARIO. THIS FORECAST IS BASED ON A CONSENSUS OF ALL AVAILABLE DYNAMIC AIDS. C. THE INTENSITY OF TS 18W WILL CONTINUE TO STEADILY DECREASE AS IT BECOMES EMBEDDED IN THE BAROCLINIC ZONE, TRACKS OVER COOLER WATERS AND INTERACTS WITH LAND. D. CURRENT AND FORECAST WIND RADII ARE BASED ON CLIMATOLOGY FOR AN AVERAGE SIZED SYSTEM. 3. FORECAST TEAM: DIXON/BOWER/HEATH/FUNK// NNNN