MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 09W (VICENTE) WARNING NR 09// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM 09W (VICENTE), LOCATED APPROXIMATELY 175 NM SOUTH OF HONG KONG, HAS TRACKED WEST-NORTHWESTWARD AT 04 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY SHOWS BUILDING CENTRAL CONVECTION WITH FORMATIVE BANDING OVER THE SOUTHERN SEMI-CIRCLE OF THE LOW-LEVEL CIRCULATION CENTER (LLCC). THE CURRENT POSITION IS BASED ON A 221820Z AMSU-B IMAGE WITH HIGH CONFIDENCE. THE CURRENT INTENSITY IS BASED ON A BLEND OF THE SUBJECTIVE DVORAK ESTIMATES OF 45 KNOTS FROM PGTW/RJTD/KNES, AND OBJECTIVE ESTIMATES FROM THE 221800Z SATCON OF 61 KNOTS (COMPRISED OF CIMSS AMSU = 65 KNOTS, ADT = 53 KNOTS). A RE-ANALYSIS OF THE PAST 18 HOUR MICROWAVE AND SCATTEROMETER DATA SUGGESTS THAT TS 09W HAS DEFINITELY SLOWED DOWN AND DIPPED SLIGHTLY SOUTHWESTWARD. HOWEVER, THE DEGREE OF SOUTHWESTWARD DIP IS NOT AS MUCH AS PREVIOUSLY THOUGHT AND RECENT TRACK MOTION SUGGESTS A RETURN TO WEST-NORTHWESTWARD MOTION. UPPER-LEVEL ANALYSIS SHOWS AN ANTICYCLONE TO THE NORTHEAST AND A STRONG POINT SOURCE OF DIVERGENCE TO THE SOUTHEAST OF THE LLCC. THESE FEATURES ARE CAUSING MODERATE (10-15 KNOTS) NORTH-NORTHEASTERLY VERTICAL WIND SHEAR OVER THE LLCC AND GOOD DIVERGENCE TO THE WEST IN AN EQUATORWARD OUTFLOW CHANNEL. ANIMATED WATER VAPOR IMAGERY SHOWS NO SIGNS OF A POLEWARD OUTFLOW CHANNEL. TS 09W IS CURRENTLY BEING STEERED BY THE SOUTHWESTERN PERIPHERY OF THE MID- TO UPPER-LEVEL SUBTROPICAL RIDGE (STR) CENTERED FAR TO THE NORTHEAST. 3. FORECAST REASONING. A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. IT SEEMS AS THOUGH THE TROPICAL UPPER TROPOSPHERIC TROUGH (TUTT) CELL CENTERED NEAR 19N 136E HAS ALTERED THE ORIENTATION OF THE SOUTHWESTERN PERIPHERY OF THE STEERING STR CAUSING TS 09W TO TRACK MORE NORTH THAN PREVIOUSLY THOUGHT. THE SYSTEM SHOULD TRACK TOWARDS THE COASTLINE EAST OF THE LUICHOW PENINSULA AND CONTINUE TO INTENSIFY TO MINIMAL TYPHOON STRENGTH BEFORE MAKING LANDFALL AT TAU 36. DURING TAUS 48-72, TS 09W SHOULD SLOWLY SPIN-DOWN DUE TO LAND INTERACTION. THE MAJORITY OF NUMERICAL MODEL GUIDANCE IS IN EXCELLENT AGREEMENT UP TO THE LANDFALL POINT WITH THE EXCEPTION OF THE MORE POELWARD WBAR. THEREFORE, THE OFFICIAL JTWC TRACK FORECAST IS HELD SLIGHTLY LEFT OF THE MODEL CONSENSUS TO OFFSET THE WBAR AND MAINTAINED SLIGHTLY FASTER DUE TO DIFFERING TRACK SPEEDS IN THE LATER TAUS. HIGH CONFIDENCE STILL REMAINS IN THE FORECAST TRACK.// NNNN NNNN