MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 18W (PHANFONE) WARNING NR 27// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON (TY) 18W (PHANFONE), LOCATED APPROXIMATELY 502 NM SOUTHWEST OF YOKOSUKA, JAPAN, HAS TRACKED NORTH-NORTHEASTWARD AT 13 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS A 30-NM RAGGED EYE WITH WEAKENED SPIRAL BANDING. THE INITIAL POSITION IS BASED ON THE EYE FEATURE ON THE MSI LOOP WITH HIGH CONFIDENCE. THE INITIAL INTENSITY OF 90 KNOTS IS BASED ON AN OVERALL ASSESSMENT OF DVORAK CURRENT INTENSITY ESTIMATES FROM ALL REPORTING AGENCIES AND REFLECTS THE WEAKENING TREND. UPPER-LEVEL ANALYSIS INDICATES TY 18W IS LOCATED IN AN AREA OF STRONG (GREATER THAN 30 KNOTS) VERTICAL WIND SHEAR (VWS) OFFSET BY VIGOROUS OUTFLOW, ESPECIALLY ON THE POLEWARD SIDE THAT IS SUSTAINING THE REMNANT CONVECTION. TY 18W HAS ROUNDED THE WESTERN EDGE OF THE DEEP-LAYERED SUBTROPICAL RIDGE (STR) TO THE EAST AND HAS BEGUN TO ACCELERATE NORTHEASTWARD INTO THE COLD MID-LATITUDE BAROCLINIC ZONE. 3. FORECAST REASONING. A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TY 18W WILL CONTINUE TO ACCELERATE NORTHEASTWARD AND BE QUICKLY ABSORBED INTO THE BAROCLINIC ZONE AS IT UNDERGOES EXTRA-TROPICAL TRANSITION. INCREASING VWS AND COOLING SEA SURFACE TEMPERATURES WILL RAPIDLY ERODE THE SYSTEM BUT WILL STILL BE A VERY INTENSE STORM FORCE COLD-CORE LOW BY TAU 24. THE AVAILABLE NUMERIC GUIDANCE REMAINS IN TIGHT AGREEMENT LENDING HIGH CONFIDENCE TO THE JTWC TRACK FORECAST THAT IS LAID SLIGHTLY TO THE RIGHT OF AND FASTER THAN MULTI-MODEL CONSENSUS.// NNNN NNNN