MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 24W (SARIKA) WARNING NR 26// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM 24W (SARIKA), LOCATED APPROXIMATELY 138 NM EAST- SOUTHEAST OF HANOI, VIETNAM, HAS TRACKED NORTHWESTWARD AT 10 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY AND A 181437Z MHS IMAGE DEPICTS A RAPIDLY DETERIORATING SYSTEM BECOMING SLIGHTLY ELONGATED WITH ONLY A SHALLOW BAND OF CONVECTION ON THE NORTHERN PERIPHERY. THE SYSTEM HAS EMERGED BACK OVER WATER IN THE GULF OF TONKIN EXHIBITING SIGNS OF SOME WIND SHEAR PRESENT. THE POSITION IS BASED ON SATELLITE FIXES FROM RJTD AND PGTW WITH FAIR CONFIDENCE. THE INITIAL INTENSITY IS ASSESSED AT 45 KNOTS AND IS BASED ON DVORAK ESTIMATES RANGING FROM T2.5 TO T3.5 (35 TO 55 KNOTS) AND A PARTIAL 181438Z METOP-B ASCAT IMAGE SHOWING AT LEAST 40 KNOTS ON THE WESTERN SIDE OF THE LOW LEVEL CIRCULATION CENTER. CURRENTLY TS SARIKA IS TRACKING NORTHWESTWARD ALONG THE SOUTHERN PERIPHERY OF A DEEP-LAYERED SUBTROPICAL RIDGE. 3. FORECAST REASONING. A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING BULLETIN. B. TS SARIKA WILL CONTINUE ON ITS CURRENT TRACK NORTHWESTWARD MAINTAINING TROPICAL STORM INTENSITY. LANDFALL OVER NORTHERN VIETNAM IS EXPECTED IN THE NEXT SIX TO TWELVE HOURS WHERE THE INTENSITY IS EXPECTED TO DROP CONSIDERABLY. TS SARIKA IS EXPECTED TO FULLY DISSIPATE BY TAU 36. DYNAMIC MODEL GUIDANCE IS IN FAIRLY GOOD AGREEMENT TO THE STORM TRACK OVER THE NEXT TWELVE HOURS AS IT TRACKS OVER WATER. HOWEVER, AS THE SYSTEM WEAKENS OVER LAND, MODEL SOLUTIONS SHOW CONSIDERABLE SPREAD IN THE DIRECTION OF THE VORTEX MOVEMENT. OVERALL THERE IS HIGH CONFIDENCE IN THE FORECAST TRACK.// NNNN NNNN