WDPN31 PGTW 161500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 03W (BAVI) WARNING NR 21// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM (TS) 03W (BAVI), LOCATED APPROXIMATELY 254 NM NORTH OF ULITHI, HAS TRACKED WEST-NORTHWESTWARD AT 08 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED IR SATELLITE IMAGERY DEPICTS A SLIGHTLY EXPOSED LOW-LEVEL CIRCULATION CENTER WITH PERSISTENT DEEP CONVECTION DISPLACED OVER THE NORTHWESTERN QUADRANT DUE TO MODERATE SOUTHEASTERLY VERTICAL WIND SHEAR (VWS). THE INITIAL POSITION AND INTENSITY IS BASED ON A 160854Z WINDSAT IMAGE WITH FAIR CONFIDENCE. TS BAVI IS TRACKING ALONG THE SOUTHERN PERIPHERY OF A STRONG SUBTROPICAL RIDGE (STR) TO THE NORTH. 3. FORECAST REASONING. A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TS BAVI IS EXPECTED TO CONTINUE TO KEEP A GENERALLY WESTWARD TRACK UNDER THE INFLUENCE OF THE STR TO THE NORTH FOR THE REMAINDER OF THE FORECAST PERIOD. DUE TO MARGINAL UPPER-LEVEL CONDITIONS, THE SYSTEM IS EXPECTED TO WEAKEN THROUGHOUT THE FORECAST PERIOD. C. IN THE EXTENDED PERIOD, TS BAVI WILL MAINTAIN THIS WESTWARD MOTION UNDER THE STEERING INFLUENCE OF THE STR AND A BUILDING STR FROM THE WEST. AS VWS AND UPPER- LEVEL CONVERGENCE INCREASE, TS 03W WILL CONTINUE TO WEAKEN WITH DISSIPATION EXPECTED BY TAU 120 AS THE SYSTEM IS AFFECTED BY SOUTH CENTRAL LUZON. DYNAMIC MODEL GUIDANCE REMAINS IN VERY TIGHT AGREEMENT LENDING HIGH CONFIDENCE TO THE JTWC TRACK FORECAST, WHICH IS POSITIONED CLOSE TO THE MULTI-MODEL CONSENSUS.// NNNN