UNCLAS//N03144// MSGID/GENADMIN/NAVPACMETOCCEN PEARL HARBOR HI/JTWC// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 01W WARNING NR 10// RMKS/ WDPN31 PGTW 180300 1. FOR METEOROLOGISTS. 2. PROGNOSTIC REASONING FOR 180000Z9 TO 210000Z3 JAN 03. A. TROPICAL STORM (TS) 01W, LOCATED APPROXIMATELY 130 NM EAST OF GUAM, HAS TRACKED NORTHWESTWARD AT 16 KNOTS OVER THE PAST 06 HOURS. THE WARNING POSITION IS BASED ON 172330Z6 VISIBLE AND ENHANCED INFRARED SATELLITE IMAGERY. THE WARNING INTENSITY IS BASED ON SATELLITE CURRENT INTENSITY ESTIMATES OF 30, 35 AND 45 KNOTS. ANIMATED MULTISPECTRAL IMAGERY INDICATES INCREASED OUTFLOW OVER THE PAST SIX HOURS. B. TS 01W IS FORECAST TO TRACK NORTHWESTWARD OVER THE NEXT 12 TO 24 HOURS UNDER THE INFLUENCE OF THE LOW TO MID-LEVEL SUBTROPICAL RIDGE NORTHEAST OF THE SYSTEM. A MID-LATITUDE SYSTEM LOCATED OVER THE SEA OF JAPAN IS EXPECTED TO DEEPEN AND PROPAGATE EASTWARD, WEAKENING THE SUBTROPICAL RIDGE BY MID PERIOD, RESULTING IN A NORTHWARD AND THEN NORTHEASTWARD TRACK BY 72 HOURS. THE AVAILABLE DYNAMIC AIDS, CONSISTING OF NOGAPS, GFDN, THE JAPANESE GLOBAL SPECTRAL (JGSM) AND TYPHOON (JTYM) MODELS, UKMET GLOBAL SPECTRAL MODEL (EGRR), NCEP AVIATION (AVN), COAMPS, AND AFWA MM5, ARE IN FAIR AGREEMENT. THE AIDS DEPICT A WEAKER SUBTROPICAL RIDGE THAN IMAGERY SUGGESTS, RESULTING IN A SLOWER TRACK THROUGH 24 HOURS. OUR FORECAST IS BASED ON PERSISTENCE AND A BLEND OF THE AVAILABLE DYNAMIC AIDS AND THE MEDIUM BETA ADVECTION MODEL. C. TS 01W IS EXPECTED TO INTENSIFY AT A NEAR CLIMATOLOGICAL OVER THE NEXT 24 HOURS AS IT TRACKS TOWARD THE UPPER LEVEL RIDGE AXIS. THE INTENSITY WILL THEN BEGIN TO WEAKEN AS IT TRACKS ABOVE THE RIDGE AXIS AND ENCOUNTERS INCREASING VERTICAL WIND SHEAR. D. INITIAL AND FORECAST WIND RADII ARE BASED ON CLIMATOLOGY FOR AN AVERAGE SIZED SYSTEM. FORECAST TEAM: WINGEART/GRUBER/LAM/STATEN/SHERRY// NNNN