WDPN32 PGTW 300300 MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 18W WARNING NR 12// RMKS/ 1. FOR METEOROLOGISTS. 2. 12 HOUR SUMMARY AND ANALYSIS. A. TROPICAL STORM (TS) 18W (EIGHTEEN) LOCATED APPROXIMATELY 70 NM EAST-SOUTHEAST OF GUAM, HAS TRACKED WEST-NORTHWESTWARD AT 15 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS DEEP CONVECTION HAS SPORADICALLY DEVELOPED OVER THE UNORGANIZED LOW LEVEL CIRCULATION CENTER (LLCC) DURING THE PAST 12 HOURS. POOR UPPER LEVEL SUPPORT ALONG WITH A DISRUPTION OF INFLOW DUE TO THE PROXIMITY OF TY 19W TO THE WEST AND TS 20W TO THE EAST HAS HINDERED SIGNIFICANT DEVELOPMENT OVER THE PAST 12 HOURS. INTENSITY IS BASED ON DVORAK SATELLITE ESTIMATES FROM PGTW AND KNES. THE SYSTEM IS STEERING WESTWARD ALONG THE SOUTHERN PERIPHERY OF THE LOW- TO MID-LEVEL SUBTROPICAL RIDGE (STR) TO THE NORTH. 3. FORECAST REASONING A. THE FORECAST REASONING HAS NOT CHANGED SINCE THE PREVIOUS PROGNOSTIC REASONING BULLETIN. B. TS 18W IS FORECAST TO CONTINUE TRACKING WEST-NORTHWESTWARD UNDER THE INFLUENCE OF THE STR THROUGH TAU 72. THE AVAILABLE MODEL GUIDANCE IS IN POOR AGREEMENT WITH THIS SCENARIO. NOGAPS AND GFDN ARE TRACKING THE SYSTEM NORTHWARD INTO THE STRONG STR TO THE NORTH WITH GFS, ECMWF AND UKMO ALL LOSING THE CIRCULATION CENTER AFTER 12 TO 24 HOURS. THE MODELS ARE LOSING THE SYSTEM AS IT GETS ABSORBED INTO THE OUTER WIND FIELD ASSOCIATED WITH TYPHOON 19W TO THE WEST AFTER TAU 48.// NNNN