MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 15W (TEMBIN) WARNING NR 44// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM (TS) 15W (TEMBIN), LOCATED APPROXIMATELY 230 NM SOUTHWEST OF CHINHAE, SOUTH KOREA, HAS TRACKED NORTH-NORTHEASTWARD AT 20 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY SHOWS ELONGATION ALONG THE NORTHEAST SECTOR, AN INDICATION OF STRONG SOUTHWESTERLY SHEAR. THE CURRENT POSITION IS BASED ON THE ABOVE ANIMATION AND PLACED JUST INSIDE THE DEEPEST CONVECTIVE BANDING WITH FAIR CONFIDENCE. THE INITIAL INTENSITY IS AVERAGED FROM DVORAK ESTIMATES FROM PGTW, KNES, AND RJTD. UPPER-LEVEL ANALYSIS INDICATES THE SYSTEM IS 7 DEGREES POLEWARD OF A RIDGE AXIS ORIENTED NORTHEAST-SOUTHWEST OVER THE JAPANESE ISLAND CHAIN, IN AN AREA OF STRONG (GREATER THAN 25 KNOTS) VERTICAL WIND SHEAR. THE CYCLONE IS TRACKING ALONG THE NORTHWESTERN PERIPHERY OF A MID-LAYERED SUBTROPICAL RIDGE EAST OF JAPAN. 3. FORECAST REASONING. A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TS TEMBIN IS EXPECTED TO ACCELERATE ALONG ITS CURRENT TRACK, MAKE LANDFALL JUST SOUTH OF KUNSAN, SOUTH KOREA, WITHIN SIX HOURS THEN DRAG ACROSS THE RUGGED TAEBAEK MOUNTAIN RANGE. ITS WEAK REMNANTS WILL EXIT INTO THE SEA OF JAPAN AND BECOME AN EXTRA-TROPICAL LOW BY TAU 24. THE ALTERNATE SCENARIO IS THAT TS 15W WILL DISSIPATE OVER LAND AFTER TAU 12. THE AVAILABLE NUMERICAL GUIDANCE IS IN VERY TIGHT AGREEMENT UP TO TAU 12 THEN ERRATICALLY DIVERGE AFTERWARD, A TYPICAL INDICATION OF SIGNIFICANT WEAKENING OF THE STORM VORTEX. THERE IS HIGH CONFIDENCE IN THE FIRST HALF OF THE FORECAST AND LOW CONFIDENCE IN THE LATTER HALF DUE TO THE UNCERTAINTY OF TS 15W'S DISSIPATION OVER LAND. // NNNN NNNN