WDPN31 PGTW 131500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 11W (UTOR) WARNING NR 20// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON (TY) 11W (UTOR), LOCATED APPROXIMATELY 190 NM SOUTH- SOUTHWESTWARD OF HONG KONG, HAS TRACKED WEST-NORTHWESTWARD AT 06 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY (EIR) DEPICTS THE CONVECTIVE STRUCTURE OF THE SYSTEM HAS STARTED TO WANE OVER THE PAST SIX HOURS AS THE CONVECTIVE BANDS HAVE SIGNIFICANTLY SHALLOWED AND THE EYE HAS BECOME RAGGED IN NATURE. ADDITIONALLY, DEEP CONVECTION AROUND THE EYE HAS BECOME LIMITED ACROSS THE NORTHERN SEMI-CIRCLE. RADAR IMAGERY FROM YANGJIANG, CHINA SHOWS THE SYSTEM REMAINS WELL-DEFINED BUT THE CONVECTION AROUND THE NORTHERN PORTION OF THE SYSTEM HAS WEAKENED. THE CURRENT POSITION IS BASED ON THE RAGGED EYE IN THE EIR WITH FAIR CONFIDENCE. THE CURRENT INTENSITY HAS BEEN LOWERED TO 95 KNOTS DUE TO OVERALL WEAKENING SEEN IN THE RADAR IMAGERY AND EIR ALONG WITH FALLING DVORAK INTENSITY ESTIMATES THAT RANGE FROM 90 TO 102 KNOTS. UPPER-LEVEL ANALYSIS INDICATES VERTICAL WIND SHEAR HAS SLIGHTLY INCREASED TO LOW TO MODERATE LEVELS (10-20 KNOTS) WHILE EQUATORWARD OUTFLOW CONTINUES TO REMAIN ROBUST. TY 11W CONTINUES TO TRACK WEST- NORTHWESTWARD ALONG THE SOUTHWESTERN PERIPHERY OF THE SUBTROPICAL STEERING RIDGE (STR) NORTHEAST OF THE SYSTEM. 3. FORECAST REASONING. A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY FROM THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TY 11W IS EXPECTED TO TRACK SLIGHTLY MORE NORTHWESTWARD IN THE NEXT 36 HOURS AS A SLIGHT WEAKNESS IN THE STR DEVELOPS DUE TO THE PASSAGE OF A SHORTWAVE TROUGH ACROSS NORTHERN CHINA. THIS WILL LEAD TO TY 11W MAKING LANDFALL IN THE NEXT 24 HOURS. AFTER LANDFALL, THE STR WILL REBUILD NORTH OF THE SYSTEM AND STEER TY 11W MORE WEST AS IT DRAGS ACROSS SOUTHERN CHINA AND INTO NORTHERN VIETNAM. TY 11W IS EXPECTED TO SLOWLY WEAKEN OVER THE NEXT DAY AS IT CONTINUES TO APPROACH LAND. AFTER LANDFALL, THE FRICTIONAL EFFECTS OF THE LAND WILL ERODE THE SYSTEM LEADING TO ITS DISSIPATION BY TAU 72. NUMERICAL MODEL GUIDANCE CONTINUES TO REMAIN IN GOOD AGREEMENT THROUGH THE FORECAST PERIOD, ALTHOUGH SOME OF THE MODEL GUIDANCE IS LOSING THE VORTEX IN THE LATER TAUS DUE TO THE SYSTEM BECOMING TOO WEAK. DESPITE THIS, HIGH CONFIDENCE REMAINS IN THE FORECAST TRACK WHICH IS SLIGHTLY FASTER THAN MULTI-MODEL CONSENSUS TO OFFSET THE GUIDANCE THAT LOSES THE VORTEX.// NNNN