MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 05W (FIVE) WARNING NR 09// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM (TS) 05W (HAISHEN), LOCATED APPROXIMATELY 99 NM NORTH-NORTHWEST OF CHUUK, FSM HAS TRACKED WESTWARD AT 03 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS THE SYSTEM HAS MAINTAINED CONVECTIVE WRAP INTO THE LOW LEVEL CIRCULATION CENTER (LLCC) THAT HAS NOW BECOME FULLY EXPOSED. THE INITIAL POSITION IS BASED ON THE MSI LOOP WITH HIGH CONFIDENCE. THE INITIAL INTENSITY OF 45 KNOTS IS BASED ON AN OVERALL ASSESSMENT OF DVORAK ESTIMATES FROM ALL REPORTING AGENCIES. UPPER-LEVEL ANALYSIS INDICATES A MARGINALLY-FAVORABLE ENVIRONMENT WITH MODERATE (15 TO 20 KNOT) VERTICAL WIND SHEAR (VWS). TS 05W IS CURRENTLY TRACKING WESTWARD ALONG THE SOUTHERN PERIPHERY OF A WEAKENING EXTENSION OF THE SUBTROPICAL RIDGE (STR) TO THE NORTH. 3. FORECAST REASONING. A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. THE STEERING STR IS EXPECTED TO CONTINUE TO WEAKEN AS A MID- LATITUDE TROUGH DIGS IN FROM THE NORTHEAST. THIS WILL CAUSE TS 05W TO REMAIN IN A SLOW OR QUASI-STATIONARY MOTION. CONCURRENTLY, THE VWS IS EXPECTED TO INCREASE AND GRADUALLY ERODE THE SYSTEM, WITH DISSIPATION BY TAU 48. THERE REMAINS A SIGNIFICANT VARIATION IN THE DYNAMIC MODEL GUIDANCE LEADING TO LOW CONFIDENCE IN THE JTWC FORECAST TRACK.// NNNN NNNN