WDPN32 PGTW 191500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 06W (TALIM) WARNING NR 08// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM (TS) 06W (TALIM), LOCATED APPROXIMATELY 360 NM SOUTHWEST OF TAIPEI, TAIWAN, HAS TRACKED NORTHEASTWARD AT 11 KNOTS OVER THE PAST SIX HOURS. ANIMATED INFRARED SATELLITE IMAGERY (MSI) SHOWS CENTRAL CONVECTION HAS SLIGHTLY DEEPENED AND EXPANDED OVER THE LOW LEVEL CIRCULATION CENTER (LLCC), ALTHOUGH THE DEEP, CURVED, CONVECTIVE BANDING REMAINS SHEARED TO THE SOUTHWEST, AS SHOWN ON ANIMATED WATER VAPOR IMAGERY. THE INITIAL POSITION WAS EXTRAPOLATED FROM A 190947Z CORIOLIS MICROWAVE IMAGE WITH POOR CONFIDENCE. THE INITIAL INTENSITY IS SLIGHTLY HIGHER THAN SUBJECTIVE DVORAK ESTIMATES TO REFLECT THE DEEPENING CENTRAL CONVECTION. UPPER LEVEL ANALYSIS INDICATES THE CYCLONE IS TO THE NORTHEAST OF A RIDGE AXIS IN AN AREA OF HIGH (25-30 KNOT) NORTHEASTERLY VERTICAL WIND SHEAR (VWS). THE SYSTEM IS CURRENTLY TRACKING ALONG THE NORTHWEST PERIPHERY OF A SUBTROPICAL RIDGE (STR) ANCHORED TO THE EAST-SOUTHEAST. 3. FORECAST REASONING. A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TS 06W WILL CONTINUE TO TRACK ALONG THE NORTHWEST PERIPHERY OF THE STEERING STR THROUGHOUT THE FORECAST PERIOD AND THE VWS IS EXPECTED TO REMAIN HIGH. ADDITIONALLY, SEA SURFACE TEMPERATURES (SST) IN THE TAIWAN STRAIT ARE RELATIVELY COOLER. THESE TWO FACTORS WILL WEAKEN THE SYSTEM OVER THE NEXT 24 HOURS. AS TS 06W EMERGES IN THE EAST CHINA SEA, THE SST WILL BE WARMER AND VWS WILL SLIGHTLY RELAX AS THE UPPER LEVEL WINDS BECOME MORE IN PHASE WITH THE STORM MOTION. THESE WILL CAUSE THE SYSTEM TO MOMENTARILY INTENSIFY BEFORE MAKING LANDFALL INTO KYUSHU AFTER TAU 48. AFTER TAU 48, TS 06W WILL UNDERGO EXTRA-TROPICAL TRANSITION (ETT), AND TRAVERSE ACROSS THE RUGGED TERRAIN OF KYUSHU AND HONSHU AND WILL COMPLETE ETT BY TAU 72. DYNAMIC MODEL GUIDANCE IS IN GOOD AGREEMENT UP TO TAU 72, THEREFORE, THERE IS GOOD CONFIDENCE IN THIS PORTION OF THE TRACK FORECAST. C. AFTER TAU 72, REMNANTS OF A COLD-CORE 06W WILL EXIT INTO THE COLD PACIFIC OCEAN SOUTH OF HOKKAIDO. DUE TO THE WEAK NATURE OF THE VORTEX AT THE EXTENDED TAUS, THERE IS VERY POOR CONFIDENCE IN THIS PORTION OF THE FORECAST TRACK. // NNNN