MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 13W (PODUL) WARNING NR 11// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM (TS) 13W (PODUL), LOCATED APPROXIMATELY 250 NM EAST-NORTHEAST OF HUE, VIETNAM, HAS TRACKED WESTWARD AT 12 KNOTS (KTS) OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS THE CENTRAL CONVECTION DISPLACED APPROXIMATELY 50NM SOUTHWESTWARD OF THE PARTIALLY EXPOSED LOW LEVEL CIRCULATION (LLC). THE INITIAL POSITION IS PLACED WITH FAIR CONFIDENCE BASED ON THE PARTIALLY EXPOSED LLC IN THE MSI LOOP THAT'S SUPERIMPOSED WELL WITH IN AN LLC FEATURE IN A COMPOSITE RADAR REFLECTIVITY LOOP FROM CMA. THE INITIAL INTENSITY OF 35 KNOTS IS BASED ON MULTI-AGENCY DVORAK ESTIMATES OF T2.5/35KTS AND IS CONSISTENT WITH NEARBY SURFACE OBSERVATIONS IN THE SOUTH CHINA SEA. THE ENVIRONMENT IS MARGINAL AT BEST WITH UNFAVORABLY STRONG (25-30 KT) VERTICAL WIND SHEAR OFFSETTING STRONG WESTWARD OUTFLOW, IN-PHASE STORM MOTION, AND WARM SEA SURFACE TEMPERATURES (29-30 CELSIUS). TS 13W IS TRACKING ALONG THE SOUTHERN PERIPHERY OF A SUBTROPICAL RIDGE (STR). 3. FORECAST REASONING. A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TS PODUL WILL CONTINUE TO TRACK WESTWARD UNDER THE STEERING INFLUENCE OF THE STR, CROSS THE GULF OF TONKIN, AND MAKE LANDFALL OVER NORTH CENTRAL VIETNAM AROUND TAU 24. MARGINAL ENVIRONMENTAL CONDITIONS WILL SUSTAIN THE INTENSITY UP TO 12 HOURS THEN GRADUALLY WEAKEN PRIOR TO LANDFALL. AFTERWARD, THE SYSTEM WILL RAPIDLY ERODE AND SHOULD DISSIPATE DUE TO LAND INTERACTION NO LATER THAN TAU 48. THE NUMERICAL MODELS ARE IN TIGHT AGREEMENT LENDING HIGH CONFIDENCE IN THE JTWC TRACK FORECAST WHICH IS LAID CLOSE TO THE MODEL COSENSUS.// NNNN NNNN