MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 36W (THIRTYSIX) WARNING NR 002// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL DEPRESSION (TD) 36W (THIRTYSIX), LOCATED APPROXIMATELY 325 NM SOUTHEAST OF HO CHI MINH CITY, VIETNAM, HAS TRACKED WEST-SOUTHWESTWARD AT 16 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS THE SYSTEM CONTINUED TO CONSOLIDATE. THE CENTRAL CONVECTION, ALTHOUGH SHEARED NORTHWESTWARD OF THE LOW LEVEL CIRCULATION (LLC), HAS DEEPENED. THE INITIAL POSITION IS PLACED WITH FAIR CONFIDENCE BASED ON THE EIR LOOP AND LINED UP TO A NOTCH FEATURE IN THE 311057Z SSMIS MICROWAVE IMAGE. THE INITIAL INTENSITY OF 30 KNOTS IS BASED ON THE DVORAK ESTIMATE OF T2.0/30KTS FROM PGTW. UPPER LEVEL ANALYSIS INDICATES THE SYSTEM IS IN AN AREA OF MODERATE (20-25 KNOTS) SOUTHEASTERLY VERTICAL WIND SHEAR (VWS) OFFSET BY EXCELLENT POLEWARD OUTFLOW. SEA SURFACE TEMPERATURES IN THE SOUTH CHINA SEA AND INTO THE GULF OF THAILAND ARE VERY CONDUCIVE AT 28-29 CELSIUS. THE CYCLONE IS TRACKING ALONG THE SOUTHEASTERN PERIPHERY OF A SUBTROPICAL RIDGE (STR) ANCHORED TO THE NORTHWEST. 3. FORECAST REASONING. A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY FROM THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TD 36W IS EXPECTED TO TRACK WEST-SOUTHWESTWARD THEN NORTHWESTWARD TOWARD THE GULF OF THAILAND AROUND THE SOUTHERN PERIPHERY OF THE STR. THE VWS IS EXPECTED TO DECREASE AND ALLOW A MODEST INTENSIFICATION TO A PEAK OF 45 KNOTS BY TAU 72 AS IT ENTERS THE GULF OF THAILAND. C. AFTER TAU 72, VWS WILL ONCE AGAIN PICK UP. THIS, IN ADDITION TO LAND INTERACTION AS TD 36W CROSSES THE MALAY PENINSULA AFTER TAU 96 WILL CAUSE A STEADY WEAKENING DOWN TO 30 KNOTS BY TAU 120. THE AVAILABLE NUMERICAL GUIDANCE IS IN OVERALL AGREEMENT WITH GRADUAL SPREADING TO OVER 300 NM BY TAU 120 WITH HWRF ON THE LEFT AND NAVGEM ON THE RIGHT MARGIN OF THE MODEL ENVELOPE. THIS, IN ADDITION TO THE FORMATIVE NATURE OF THE SYSTEM, LENDS LOW CONFIDENCE TO THE JTWC TRACK FORECAST.// NNNN NNNN