WDPN32 PGTW 270300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 19W (EWINIAR) WARNING NR 13// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM 19W (EWINIAR), LOCATED APPROXIMATELY 345 NM SOUTH- SOUTHEAST OF YOKOSUKA, JAPAN, HAS TRACKED NORTHWARD AT 12 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY REVEALS A PARTIALLY EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC) WITH WEAKENING CONVECTION WRAPPING INTO THE LLCC. A 262118Z 37GHZ CORIOLIS 37GHZ MICROWAVE IMAGE REVEALS A TIGHTLY WRAPPED SYSTEM WITH A SMALL EYE FEATURE BEGINNING TO APPEAR. CURRENT POSITION IS BASED ON THE PARTIALLY EXPOSED LLCC IN THE MSI WITH HIGH CONFIDENCE. THE CURRENT INTENSITY OF 55 KNOTS IS CONSISTENT WITH RECENT AUTOMATED INTENSITY ESTIMATES, AND LOW-LEVEL STRUCTURE EVIDENT IN THE CORIOLIS MICROWAVE IMAGE. RECENT ANIMATED WATER VAPOR IMAGERY SHOWS DEEP CONVECTION CONTINUES TO WEAKEN AS TS 19W BEGINS TO INTERACT WITH A CLOSED UPPER-LEVEL LOW NOW LOCATED OVER THE SYSTEM. 3. FORECAST REASONING. A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS FORECAST PROGNOSTIC REASONING MESSAGE. B. TS 19W IS FORECAST TO TURN TOWARD THE NORTH-NORTHWEST AND SLOW SIGNIFICANTLY OVER THE NEXT 24 HOURS AS IT INTERACTS WITH THE UPPER- LEVEL LOW OVER IT. TS 19W WILL LIKELY HOLD ITS INTENSITY DESPITE THIS INTERACTION DUE TO STRONG DIFFLUENCE ALOFT CURRENTLY IN PLACE. AFTER TAU 24, TS 19W WILL TURN NORTHEASTWARD AHEAD OF A DEVELOPING MIDLATITUDE TROUGH AND BEGIN TO ACCELERATE AFTER TAU 36 UPON A REBUILDING SUBTROPICAL RIDGE EAST OF THE SYSTEM. EXTRATROPICAL TRANSITION WILL COMMENCE BY TAU 48 AND THE SYSTEM WILL BECOME FULLY EXTRATROPICAL BY TAU 72. THE CURRENT FORECAST LIES SLIGHTLY INSIDE AND AHEAD OF THE MULTI-MODEL CONSENSUS TO ACCOUNT FOR HISTORICAL TRENDS IN MODEL GUIDANCE DURING RECURVATURE SCENARIOS AND TO OFFSET GFDN WHICH TAKES AN ERRONEOUS POLEWARD TRACK. DUE TO GOOD MODEL AGREEMENT, FORECAST CONFIDENCE IS HIGH.// NNNN