MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 24W (SARIKA) WARNING NR 23// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON 24W (SARIKA), LOCATED APPROXIMATELY 217 NM NORTHEAST OF DA NANG, VIETNAM, HAS TRACKED WEST-NORTHWESTWARD AT 09 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS A RAPIDLY WEAKENING SYSTEM ABOUT TO MAKE LANDFALL NEAR HAINAN. THE INITIAL POSITION IS BASED ON SATELLITE FIXES FROM PGTW AND RJTD WITH FAIR CONFIDENCE. THE CURRENT INTENSITY IS ASSESSED AT 70 KNOTS AND IS BASED ON THE WEAKENING CONVECTIVE STRUCTURE DUE TO THE RECENT LAND INTERACTION COMBINED WITH RECENT DVORAK ESTIMATES RANGING FROM T3.5 TO T4.5 (55 TO 77 KNOTS). UPPER-LEVEL ANALYSIS SHOWS GOOD RADIAL OUTFLOW TAPPING INTO A PASSING SHORTWAVE TROUGH TO THE NORTHWEST AND DOMINANT EASTERLY FLOW ON THE EQUATORWARD SIDE. CURRENTLY TY SARIKA IS TRACKING NORTHWEST ALONG THE PERIPHERY OF A DEEP-LAYERED SUBTROPICAL RIDGE TO THE NORTHEAST.3. FORECAST REASONING. A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING BULLETIN. B. TY SARIKA WILL CONTINUE TO TRACK NORTHWEST GUIDED BY THE CURRENT STEERING RIDGE AS IT MAKES LANDFALL OVER HAINAN AND WEAKENS SIGNIFICANTLY OVER THE NEXT 12 HOURS. THE TRACK WILL CONTINUE OVER THE GULF OF TONKIN MAINTAINING TROPICAL STORM STRENGTH BEFORE MAKING LANDFALL NEAR THE VIETNAM-CHINA BORDER, THEN TURN NORTHWARD AS IT ROUNDS THE STEERING RIDGE AXIS. AVAILABLE MODEL GUIDANCE IS IN VERY GOOD AGREEMENT AS THE SYSTEM TRACKS OVER HAINAN AND INTO VIETNAM, BUT STARTS TO DIVERGE AS IT TRACKS FURTHER INLAND ROUNDING THE RIDGE AXIS. OVERALL THERE IS HIGH CONFIDENCE IN THE FORECAST TRACK.// NNNN NNNN