MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 12W (BAILU) WARNING NR 11// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM (TS) 12W (BAILU), LOCATED APPROXIMATELY 200 NM EAST-SOUTHEAST OF KAOHSIUNG, TAIWAN, HAS TRACKED NORTHWESTWARD AT 12 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY SHOWS SLIGHT TIGHTENING OF THE CONVECTIVE BANDS WRAPPING INTO A PARTLY EXPOSED LOW LEVEL CIRCULATION (LLC). THE RAIN BANDS ARE TRAILING FROM THE SOUTHWEST AND ARE VENTILATED BY STRONG EQUATORWARD OUTFLOW. THERE IS ALSO WEAK POLEWARD OUTFLOW INTO A TUTT CELL EAST OF OKINAWA. THE INITIAL POSITION IS PLACED WITH FAIR CONFIDENCE BASED ON A DEFINED CENTER IN THE LLC THAT COINCIDED WITH A CIRCULATION FEATURE ON A COMPOSITE RADAR REFLECTIVITY LOOP FROM TAIWAN. THE INITIAL INTENSITY OF 55KTS IS BASED ON THE DVORAK ESTIMATES OF T3.5/55KTS FROM PGTW AND RCTP AND REFLECTS THE SLIGHT INTENSIFICATION. ENVIRONMENTAL ANALYSIS SHOWS THAT TS 12W IS EXPERIENCING FAVORABLE (5-10KT) VERTICAL WIND SHEAR. THIS, IN ADDITION TO THE AFOREMENTIONED OUTFLOW CHANNELS ARE PARTLY OFFSET BY SUBSIDENCE ALONG THE NORTHWEST QUADRANT OF THE CYCLONE THAT IS CAUSED BY AN INVERTED TROUGH. SEA SURFACE TEMPERATURES AT 29-30C REMAIN FAVORABLE. TS 12W IS TRACKING ALONG THE SOUTHWEST PERIPHERY OF THE SUBTROPICAL RIDGE (STR) TO THE NORTHEAST. 3. FORECAST REASONING. A. THERE IS NO CHANGE TO THE OVERALL FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. THE STR WILL CONTINUE TO STEER TS BAILU NORTHWESTWARD FOR THE REMAINDER OF THE FORECAST, BRUSH THE SOUTHERN TIP OF TAIWAN AROUND TAU 12, CROSS THE TAIWAN STRAIT, THEN MAKE LANDFALL OVER EASTERN CHINA NEAR XIAMEN AFTER TAU 24. THE OVERALL FAVORABLE ENVIRONMENT WILL ENHANCE INTENSIFICATION TO A PEAK OF 60KTS OVER THE NEXT 6HRS. AFTERWARD, INTERACTION WITH THE RUGGED TERRAIN OF TAIWAN AND CHINA WILL GRADUALLY AND THEN RAPIDLY ERODE THE SYSTEM, LEADING TO DISSIPATION BY TAU 48 AS THE CYCLONE DRAGS DEEPER INTO THE CHINESE INTERIOR. DYNAMIC MODEL GUIDANCE REMAINS IN TIGHT GOOD AGREEMENT, LENDING HIGH CONFIDENCE IN THE JTWC FORECAST TRACK.// NNNN NNNN