WDPN34 PGTW 291500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 11W (NESAT) WARNING NR 015// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON 11W (NESAT), LOCATED APPROXIMATELY 32 NM SOUTH-SOUTHEAST OF TAIPEI, TAIWAN, HAS TRACKED NORTHWESTWARD AT 16 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY DEPICTS FLARING CENTRAL CONVECTION AS THE SYSTEM MADE LANDFALL NEAR YILAN COUNTY TAIWAN. THERE IS HIGH CONFIDENCE IN THE INITIAL POSITION WHICH IS BASED ON ANIMATED RADAR IMAGERY FROM TAIWAN SHOWING THE SYSTEM CENTER PENETRATE INLAND. THE INITIAL INTENSITY ASSESSMENT OF 70 KNOTS IS BASED ON WEAKENING FROM LAND INTERACTION, ALTHOUGH LOCAL SURFACE OBSERVATIONS HAVE NOT CONFIRMED THE CURRENT INTENSITY. UPPER- LEVEL ANALYSIS SHOWS A FAVORABLE ENVIRONMENT WITH RADIAL OUTFLOW HOWEVER THE SYSTEM IS EXPECTED TO WEAKEN WHILE TRACKING OVER THE MOUNTAINOUS TERRAIN. TY 11W IS TRACKING NORTHWESTWARD ALONG A SUBTROPICAL RIDGE ANCHORED OVER THE EAST CHINA SEA. 3. FORECAST REASONING. A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TY 11W IS FORECAST TO CONTINUE TRACKING NORTHWESTWARD GUIDED BY THE NORTHERN STEERING RIDGE. TY NESAT IS EXPECTED TO REEMERGE OVER THE TAIWAN STRAIT SOMETIME IN THE NEXT SIX HOURS AND REORGANIZE AS A TROPICAL STORM MAINTAINING AN INTENSITY OF 50 KNOTS. AROUND TAU 24 TY NESAT WILL MAKE LANDFALL AGAIN OVER CHINA. DURING THIS TIME THE STEERING RIDGE WILL REORIENT ON A NORTH-SOUTH AXIS CAUSING TY NESAT TO ABRUPTLY TURN NORTH AND ACCELERATE. TS HAITANG WILL ALSO INTERACT WITH TY NESAT AROUND THIS TIME. TS HAITANG WILL APPROACH FROM THE SOUTHEAST AND THE TWO SYSTEMS WILL MERGE WHILE OVER CHINA AROUND TAU 48. DYNAMIC MODEL GUIDANCE SHOWS FAIRLY GOOD AGREEMENT, BUT THERE IS A DEGREE OF UNCERTAINTY IN WHERE THE SYSTEM WILL TRACK AS IS DISSIPATES AND MERGES WITH TS HAITANG OVER CHINA. OVERALL THERE IS LOW CONFIDENCE IN THE FORECAST TRACK. NNNN