WDPN32 PGTW 101500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 17W (SEVENTEEN) WARNING NR 003// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM (TS) 17W (SEVENTEEN), LOCATED APPROXIMATELY 239 NM EAST-SOUTHEAST OF DA NANG, VIETNAM, HAS TRACKED WEST-NORTHWESTWARD AT 11 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY DEPICTS A CONSOLIDATING SYSTEM WITH DEEP CONVECTION EXPANDING OVER THE LOW-LEVEL CIRCULATION CENTER (LLCC) AND IMPROVED CONVECTIVE BANDING. A 101119Z SSMIS 91GHZ MICROWAVE IMAGE REVEALS IMPROVED DEEP CONVECTIVE BANDING WRAPPING INTO THE WESTERN QUADRANT OF A DEFINED LLCC, WHICH SUPPORTS THE INITIAL POSITION WITH FAIR CONFIDENCE. THE INITIAL INTENSITY IS ASSESSED AT 35 KNOTS BASED ON A 101332Z ASCAT-B IMAGE SHOWING NUMEROUS 30-35 KNOT WINDS OVER THE NORTHERN SEMICIRCLE. UPPER-LEVEL ANALYSIS INDICATES A FAVORABLE ENVIRONMENT WITH DIFFLUENT FLOW AND LOW VERTICAL WIND SHEAR. SST VALUES ARE CONDUCIVE FOR FURTHER DEVELOPMENT AT 29-30C. TS 17W IS TRACKING NORTHWESTWARD UNDER THE STEERING INFLUENCE OF A SUBTROPICAL RIDGE (STR) POSITIONED TO THE NORTH. 3. FORECAST REASONING. A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TS 17W WILL TRACK GENERALLY WESTWARD THROUGH THE REMAINDER OF THE FORECAST PERIOD ALONG THE SOUTHERN PERIPHERY OF THE AFOREMENTIONED LOW-LEVEL STR. TS 17W WILL STEADILY INTENSIFY TO A PEAK INTENSITY OF 45 KTS BY TAU 24. THE SYSTEM SHOULD MAKE LANDFALL NEAR TAU 24 SOUTH OF DANANG, VIETNAM. AFTERWARDS, INCREASING VWS AND THE RUGGED TERRAIN OF VIETNAM WILL STEADILY WEAKEN THE SYSTEM UNTIL DISSIPATION BY TAU 48. WITH THE EXCEPTION OF UEMI, NUMERICAL MODEL GUIDANCE REMAINS IN GOOD AGREEMENT THROUGHOUT THE FORECAST PERIOD WITH A 70 NM SPREAD AT TAU 24. THE JTWC FORECAST TRACK LIES NEAR THE MULTI-MODEL CONSENSUS AND THE ECMWF MODEL SOLUTION WITH FAIR CONFIDENCE.// NNNN