WDPN32 PGTW 220300 MSGID/GENADMIN/NAVPACMETOCCEN PEARL HARBOR HI/JTWC// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 04W WARNING NR 13// RMKS/ 1. FOR METEOROLOGISTS. 2. PROGNOSTIC REASONING FOR 220000Z4 TO 250000Z7 MAY 03. A. TYPHOON (TY) 04W (CHAN-HOM), LOCATED APPROXIMATELY 380 NM EAST-SOUTHEAST OF GUAM, HAS TRACKED NORTHWARD AT 07 KNOTS OVER THE PAST 06 HOURS. THE WARNING POSITION IS BASED ON 212330Z1 VISIBLE AND ENHANCED INFRARED SATELLITE IMAGERY. THE WARNING INTENSITY IS BASED ON SATELLITE CURRENT INTENSITY ESTIMATES OF 55 AND 65 KNOTS. A 212204Z1 SPECIAL SENSOR MICROWAVE IMAGER PASS INDICATES THE DEVELOPMENT OF A BANDING EYE FEATURE. B. TY 04W IS FORECAST TO CONTINUE TRACKING POLEWARD ALONG THE WESTERN PERIPHERY OF THE MID-LEVEL SUBTROPICAL RIDGE TO THE NORTHEAST TOWARDS A WEAKNESS IN THE RIDGE. THIS WEAKNESS IS BEING ENHANCED BY A SHORTWAVE TROUGH MOVING OFF THE EAST COAST OF JAPAN. THE AVAILABLE DYNAMIC AIDS CONSISTING OF NOGAPS, NCEP (GFS), JGSM, JTYM, GFDN, UKMET GLOBAL (EGRR), AND AFWA MM5 REMAIN IN GOOD AGREEMENT. THIS FORECAST IS BASED ON PERSISTENCE AND A CONSENSUS OF THE DYNAMIC AIDS. C. THE SYSTEM IS EXPECTED TO INTENSIFY STEADILY THROUGH 48 HOURS IN A FAVORABLE UPPER LEVEL ENVIRONMENT WITH GOOD POLEWARD OUTFLOW BEING PROVIDED BY A DEVELOPING TROPICAL UPPER TROPOSPHERIC TROUGH (TUTT) TO THE NORTHEAST. AFTER 48 HOURS, TY 04W IS EXPECTED TO MOVE POLEWARD OF THE UPPER LEVEL RIDGE AXIS AND WEAKEN SLIGHTLY IN A LESS FAVORABLE ENVIRONMENT. D. CURRENT AND FORECAST WIND RADII ARE BASED ON CLIMATOLOGY FOR AN INTENSIFYING AVERAGE-SIZED SYSTEM. FORECAST TEAM: KENDALL/KLINZMANN/MECHANIC/SHERRY/BIRD// NNNN