MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 12W (BAILU) WARNING NR 12// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM (TS) 12W (BAILU), LOCATED APPROXIMATELY 125 NM SOUTHEAST OF KAOHSIUNG, TAIWAN, HAS TRACKED WEST-NORTHWESTWARD AT 13 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY SHOWS THE SYSTEM HAS MAINTAINED OVERALL CONVECTIVE SIGNATURE PUNCTUATED BY THE APPEARANCE OF A LARGE, RAGGED EYE-LIKE FEATURE. EXPANSIVE 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 THE EYE-LIKE FEATURE 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 CONSISTENT WITH NEARBY SURFACE OBSERVATIONS. ENVIRONMENTAL ANALYSIS SHOWS THAT TS 12W IS UNDER 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 WEST-NORTHWESTWARD FOR THE REMAINDER OF THE FORECAST, CLIP THE SOUTHERN TIP OF TAIWAN AROUND TAU 06, CROSS THE TAIWAN STRAIT, THEN MAKE LANDFALL OVER EASTERN CHINA NEAR XIAMEN JUST BEFORE TAU 24. INTERACTION WITH THE RUGGED TERRAIN OF TAIWAN AND CHINA WILL GRADUALLY AND THEN RAPIDLY ERODE THE SYSTEM, LEADING TO DISSIPATION BY TAU 36 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