WDPN32 PGTW 261500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 19W (EWINIAR) WARNING NR 11// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM (TS) TROPICAL STORM 19W (EWINIAR), LOCATED APPROXIMATELY 485 NM SOUTH-SOUTHEAST OF YOKOSUKA, JAPAN, HAS TRACKED NORTH-NORTHEASTWARD AT 13 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY SHOWS CENTRAL DEEP CONVECTION HAS BECOME MORE SHALLOW AS IT CONTINUES TO BE SHEARED NORTHEASTWARD. THIS IS EVIDENT ON A 260801Z SSSMI-S MICROWAVE IMAGE THAT ALSO LENDS FAIR CONFIDENCE IN THE INITIAL POSITION. THE INITIAL INTENSITY OF 45 KNOTS IS ON THE HIGH END OF DVORAK ESTIMATES FROM PGTW, KNES, AND RJTD. TS 19W IS MOVING ALONG THE NORTHWESTERN PERIPHERY OF A SUBTROPICAL RIDGE (STR) TO THE EAST THAT WAS WEAKENED BY A TRANSITING MID-LATITUDE TROUGH THAT HAS DEEPENED INTO A CLOSED LOW SOUTHEAST OF JAPAN. 3. FORECAST REASONING. A. NO CHANGE IN THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TS 19W IS FORECAST TO TURN MORE NORTHWARD OVER THE NEXT 24 HOURS AS THE STR REBUILDS WITH THE FILLING AND EVENTUAL PASSAGE OF THE AFOREMENTIONED UPPER LEVEL LOW. THE SYSTEM IS ALSO EXPECTED TO SLOW DOWN IN RESPONSE TO THIS EVENT. AFTER THE LOW PASSES, 19W WILL ACCELERATE NORTHEASTWARD AHEAD OF A SECONDARY MID-LATITUDE TROUGH. THE SYSTEM IS EXPECTED TO INTENSIFY SLIGHTLY OVER THE NEXT 24 HOURS DUE TO STRONG DIFFLUENCE ALOFT AND PASSAGE OVER WARM WATERS. AS THE CYCLONE ENCOUNTERS THE BAROCLINIC ZONE AFTER TAU 48 IT WILL GRADUALLY WEAKEN AND BEGIN EXTRATROPICAL TRANSITION (ET), COMPLETING ET BY TAU 72. THE NUMERICAL MODEL GUIDANCE IS IN GOOD OVERALL AGREEMENT AND THE CURRENT TRACK FORECAST LIES SLIGHTLY AHEAD OF THE CONSENSUS IN THE EXTENDED PERIOD. THERE IS HIGH CONFIDENCE IN THE FORECAST TRACK. // NNNN