WDPN32 PGTW 291500 MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 15W (TALAS) WARNING NR 18// RMKS/ 1. FOR METEOROLOGISTS. 2. 12 HOUR SUMMARY AND ANALYSIS. A. TROPICAL STORM (TS) 15W (TALAS), LOCATED APPROXIMATELY 685 NM SOUTH OF TOKYO, JAPAN, HAS TRACKED NORTH-NORTHWESTWARD AT 04 KNOTS OVER THE PAST SIX HOURS. ANIMATED INFRARED SATELLITE IMAGERY DEPICTS IMPROVING, TIGHTLY-CURVED BANDING (TCB) WRAPPING INTO A WELL-DEFINED LOW-LEVEL CIRCULATION CENTER (LLCC). A 290908Z SSMIS 37 GHZ IMAGE DEPICTS A CONSOLIDATING LLCC WITH A DISTINCT MICROWAVE EYE FEATURE. THEREFORE, THERE IS INCREASED CONFIDENCE IN THE CURRENT POSITION AND MOTION AND GOOD EVIDENCE THAT THE SYSTEM HAS STARTED TO TURN NORTHWESTWARD. ANIMATED WATER VAPOR IMAGERY INDICATES IMPROVING OUTFLOW (NEAR-RADIAL) OVER ALL QUADRANTS EXCEPT THE SOUTHWEST QUADRANT. THE CURRENT INTENSITY IS BASED ON A DVORAK ESTIMATE OF 55 KNOTS FROM PGTW AND ON OBSERVATIONS FROM IWO TO, LOCATED 65 NM EAST- NORTHEAST, INDICATING SURFACE WINDS SUSTAINED AT 30-40 KNOTS GUSTING TO 50-60 KNOTS. 3. FORECAST REASONING. A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY. B. TS 15W IS FORECAST TO ACCELERATE AND TRACK INCREASINGLY POLEWARD ALONG THE WESTERN PERIPHERY OF THE MID-LEVEL SUBTROPICAL RIDGE (STR) THROUGH TAU 72. DYNAMIC MODEL GUIDANCE IS TIGHTLY CLUSTERED WITH THE EXCEPTION OF THE UKMO TRACKER WHICH IS DISPLACED WEST OF THE REMAINDER OF THE OTHER DYNAMIC MODELS (ECMWF, JGSM, GFDN, NOGAPS, WBAR AND GFS). ENSEMBLE MODEL DATA IS ALSO IN TIGHT AGREEMENT AND INDICATES LANDFALL WILL OCCUR NEAR THE KANTO PLAIN. TS 15W IS EXPECTED TO REMAIN WITHIN FAVORABLE CONDITIONS THROUGH TAU 72 AND SHOULD REACH A PEAK INTENSITY NEAR 85 KNOTS BY TAU 72. C. THUS FAR, THERE HAVE BEEN SIGNIFICANT DIFFERENCES IN TRACK SPEED WITH ECMWF AND GFS INDICATING MUCH FASTER TRACK SPEEDS AFTER TAU 72. THE OTHER MODELS HAVE BEEN TRENDING FASTER OVER THE PAST 12 HOURS. THE ECMWF AND GFS APPEAR TO BE EXCESSIVELY FAST AND INDICATE AN UNREALISTIC TRACK INTO THE UPPER-LEVEL JET AFTER TAU 96. BASED ON THIS PROBLEM, THE FORECAST IS SLOWER THAN THE CONSENSUS AT TAU 120. TS 15W WILL WEAKEN DUE TO LAND INTERACTION INITIALLY THEN INCREASING VERTICAL WIND SHEAR AFTER TAU 96. MODELS ARE CONSISTENT IN INDICATING THE STRONG SHEAR ZONE, ASSOCIATED WITH WESTERLY FLOW AND A FRONTAL ZONE, WILL BE LOCATED OVER THE EAST SEA. TS 15W IS EXPECTED TO BEGIN EXTRA-TROPICAL TRANSITION NEAR TAU 96.// NNNN