WDPN32 PGTW 261500 MSGID/GENADMIN/NAVPACMETOCCEN PEARL HARBOR HI/JTWC// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 04W WARNING NR 31// RMKS/ 1. FOR METEOROLOGISTS. 2. PROGNOSTIC REASONING FOR 261200Z1 TO 270000Z9 MAY 03. A. TROPICAL STORM (TS) 04W (CHAN-HOM), LOCATED APPROXIMATELY 1060 NM WEST-NORTHWEST OF MIDWAY ISLAND, HAS TRACKED EAST-NORTHEASTWARD AT 21 KNOTS OVER THE PAST 06 HOURS. THE WARNING POSITION IS BASED ON 261130Z3 ENHANCED INFRARED SATELLITE IMAGERY. THE WARNING INTENSITY IS BASED ON SATELLITE CURRENT INTENSITY ESTIMATES OF 55 AND 65 KNOTS. ANIMATED ENHANCED INFRARED IMAGERY INDICATES THAT WHILE TS 04W HAS ALMOST TRANSITIONED INTO AN EXTRATROPICAL SYSTEM, THE TRANSITION IS NOT YET COMPLETE. B. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY REVEALS THAT TS 04W REMAINS VERTICALLY STACKED, WITH TROPICAL BANDING FEATURES STILL EVIDENT, FOR THE SHORT TERM. THE TRANSITION TO AN EXTRATROPICAL SYSTEM SHOULD BE COMPLETE WITHIN THE NEXT 12 HOURS. THE RAPID SPEED OF ADVANCE INTO THE MID-LATITUDES WILL BECOME SLOWED SOMEWHAT AS THE SYSTEM INTERACTS WITH AN UPPER-LEVEL LOW SOUTH OF THE ALEUTIAN ISLANDS. THE AVAILABLE DYNAMIC AIDS CONSISTING OF NOGAPS, GFDN, NCEP (GFS), EGRR, JGSM, JTYM, COAMPS AND MM5 ARE IN REASONABLY CLOSE AGREEMENT. THIS FORECAST IS BASED ON PERSISTENCE AND A CONSENSUS OF THE DYNAMIC AIDS. C. THE SYSTEM WILL CONTINUE TO WEAKEN UNTIL THE TRANSITION TO AN EXTRATROPICAL SYSTEM IS COMPLETED, THEN HOLD A STEADY INTENSITY THROUGH THE NEXT 36 HOURS. D. CURRENT AND FORECAST WIND RADII BASED ON CLIMATOLOGY FOR AN AVERAGE-SIZED SYSTEM. FORECAST TEAM: INGRAM/PIVIN/LAM/ANDERSON// NNNN