WDPN31 PGTW 151500 MSGID/GENADMIN/NAVPACMETOCCEN PEARL HARBOR HI/JTWC// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 12W /WARNING NR 10// RMKS/ 1. FOR METEOROLOGISTS. 2. PROGNOSTIC REASONING FOR 151200Z9 TO 171200Z1 JUL 2004. A. TROPICAL STORM (TS) 12W (KOMPASU), LOCATED APPROXIMATELY 220 NM EAST-SOUTHEAST OF HONG KONG, CHINA HAS TRACKED WEST- NORTHWESTWARD AT 09 KNOTS OVER THE PAST 06 HOURS. THE WARNING POSITION IS BASED ON 151130Z1 ENHANCED INFRARED SATELLITE IMAGERY. THE WARNING INTENSITY IS BASED ON SATELLITE CURRENT INTENSITY ESTIMATES OF 45 KNOTS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY REVEALS THE DEEP CONVECTION ASSOCIATED WITH THE SYSTEM HAS WEAKENED OVER THE PAST 06 HOURS. RECENT QUIKSCAT IMAGERY REVEALS A FAIRLY WELL DEFINED AND SMALL, LOW LEVEL CIRCULATION CENTER. B. TS 12W CONTINUES TO TRACK ALONG THE SOUTHWEST EXTENSION OF THE STEERING RIDGE LOCATED NORTHEAST OF THE SYSTEM. AS THE SYSTEM APPROACHES THE CHINESE COASTLINE IT WILL SHIFT TO A MORE POLEWARD TRACK DUE TO THE EFFECTS OF AN ENHANCED GRADIENT CREATED BY THE INTERACTION BETWEEN AN UPPER LEVEL LOW OVER THE CHINESE MAINLAND AND THE STEERING RIDGE NORTHEAST OF THE SYSTEM. THE AVAILABLE DYNAMIC AIDS CONSISTING OF NOGAPS, UKMET, NCEP GFS, JTYM, COAMPS, AFWA MM5 AND WBAR ARE IN GOOD AGREEMENT. THIS FORECAST IS BASED ON A CONSENSUS OF ALL AVAILABLE DYNAMIC AIDS. C. TS 12W IS FORECAST TO INTENSIFY AT A LESS THAN CLIMATOLOGICAL RATE AS THE SYSTEM CONTINUES TO BE DAMPENED DUE TO A LACK OF UPPER LEVEL DIVERGENCE AND DRY AIR ENTRAINMENT IN THE LOWER LEVELS. RECENT MICROWAVE SATELLITE IMAGERY CONFIRMS THE ENTRAINMENT OF DRY AIR ON THE WEST SIDE OF THE SYSTEM. TS 12W IS EXPECTED TO CONTINUE TO SLOWLY INCREASE IN INTENSITY OVER WATER BEFORE MAKING LANDFALL AND THEN DISSIPATE OVER CHINA NEAR TAU 48. D. CURRENT WIND RADII ARE BASED ON A RECENT QUIKSCAT PASS. FORECAST WIND RADII ARE BASED ON CLIMATOLOGY FOR A SMALL SYSTEM. 3. FORECAST TEAM: MOHAMMED/LAM/LEWIN//