MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 10W (MATMO) WARNING NR 22// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON (TY) 10W (MATMO), LOCATED APPROXIMATELY 106 NM SOUTH- SOUTHWEST OF TAIPEI, TAIWAN, HAS TRACKED NORTHWESTWARD AT 13 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY (EIR) SHOWS TY 10W HAS MADE LANDFALL WITH TAIWAN IN THE PAST FEW HOURS. DUE TO THE TERRAIN OF TAIWAN THERE HAS BEEN A SLIGHT EXPANSION IN THE CENTRAL CONVECTION, BUT CONVECTION ALONG THE BOUNDARY OF THE SYSTEM HAS DIMINISHED FROM THE PREVIOUS FORECAST. CURRENT INTENSITY HAS BEEN DECREASED TO 80 KNOTS IN RESPONSE TO THE OVERALL WEAKENING OBSERVED IN EIR, AND OBSERVATIONS ACROSS TAIWAN. TY 10W IS TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF A DEEP-LAYERED SUBTROPICAL RIDGE (STR) ANCHORED TO THE NORTHEAST. 3. FORECAST REASONING. A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TY 10W IS FORECAST TO REMAIN ON A NORTHWESTWARD TRACK UNDER THE STEERING INFLUENCE OF THE STR THROUGH TAU 24, AFTER WHICH A MID- LATITUDE TROUGH APPROACHING FROM THE NORTHWEST WILL WEAKEN THE STR AND CAUSE TY MATMO TO TURN POLEWARD. AS THE SYSTEM CROSSES TAIWAN INTO THE TAIWAN STRAIT, LOW LEVEL INFLOW AND FRICTIONAL EFFECTS WILL CAUSE TY 10W TO WEAKEN QUICKLY. DUE TO THE QUICK TRACK OVER THE TAIWAN STRAIT, THE SYSTEM WILL NOT HAVE SUFFICIENT TIME TO RE- STRENGTHEN. INCREASING FRICTIONAL EFFECTS AROUND TAU 12, WITH LANDFALL INTO CHINA, WILL FURTHER WEAKEN TY 10W, WITH FULL DISSIPATION EXPECTED BY TAU 48. THE REMNANTS OF TY 10W WILL INTERACT WITH THE SEMI-STATIONARY MID-LATITUDE BOUNDARY THAT EXTENDS FROM EASTERN CHINA THROUGH SOUTHERN KOREA AND WILL EVENTUALLY BE ABSORBED WITHIN THE MID-LATITUDE WESTERLY FLOW. MODEL GUIDANCE SUPPORTS THE ABSORPTION OF THE SYSTEM INTO THE BOUNDARY BEYOND TAU 48. BASED ON THE TIGHT GROUPING OF MODEL GUIDANCE, THERE IS HIGH CONFIDENCE IN THE FORECAST TRACK.// NNNN NNNN