MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 25W (HAIMA) WARNING NR 21// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON 25W (HAIMA), LOCATED APPROXIMATELY 200 NM NORTH OF MANILA, PHILIPPINES, HAS TRACKED WEST-NORTHWESTWARD AT 17 KNOTS OVER THE PAST SIX HOURS. THE CURRENT POSITION IS BASED ON ANIMATED INFRARED SATELLITE IMAGERY, RADAR DATA FROM APARRI, PHILIPPINES, AND SYNOPTIC OBSERVATIONS FROM NORTHERN LUZON. THE INTENSITY ESTIMATE OF 100 KNOTS IS CONSISTENT WITH RECENT AUTOMATED SATELLITE INTENSITY ESTIMATES, A 191800Z RTJD SUBJECTIVE DVORAK ESTIMATE, AND OBSERVATIONAL DATA FROM TUGEUGARAO, PHILIPPINES. TY 25W HAS WEAKENED CONSIDERABLY OVER THE PAST SIX HOURS DUE TO AN EYEWALL REPLACEMENT CYCLE AND LAND INTERACTION. UPPER-LEVEL ANALYSIS INDICATES THAT EASTERLY VERTICAL WIND SHEAR HAS ALSO INCREASED OVER THE PAST SIX HOURS. WHILE THE CONVECTIVE STRUCTURE REMAINS IMPRESSIVE, THE EYE HAS BECOME FULLY CLOUD FILLED. THE SYSTEM CONTINUES TO TRACK WEST- NORTHWESTWARD ALONG THE PERIPHERY OF A SUBTROPICAL STEERING RIDGE POSITIONED TO THE NORTH AND EAST. 3. FORECAST REASONING. A. THE MEDIUM-RANGE FORECAST TRACK HAS SHIFTED SLIGHTLY TO THE WEST BASED ON AN ASSESSMENT OF THE LATEST NUMERICAL MODEL GUIDANCE PACKAGE. THE FORECAST PERIOD HAS ALSO BEEN REDUCED TO 72 HOURS BASED ON ANTICIPATED DISSIPATION OVER LAND BY THAT TIME. B. TY 25W IS EXPECTED TO CROSS NORTHERN LUZON AND REEMERGE OVER WATER IN THE NORTHERN PORTION OF THE SOUTH CHINA SEA WITHIN THE NEXT SEVERAL HOURS. STEADY WEAKENING IS ANTICIPATED IN THE NEAR-TERM DUE TO LAND INTERACTION AND MODERATE EASTERLY VERTICAL WIND SHEAR. THE SYSTEM IS EXPECTED TO ROUND THE WESTERN PERIPHERY OF THE STEERING RIDGE DURING THE REMAINDER OF THE FORECAST PERIOD, MAKING LANDFALL TO THE EAST OF HONG KONG AROUND TAU 36. ADDITIONAL WEAKENING IS EXPECTED DUE TO PERSISTENT EASTERLY VERTICAL WIND SHEAR AND DECREASING ALONG-TRACK OCEAN HEAT CONTENT AS THE CIRCULATION TRACKS ACROSS THE NORTHERN PORTION OF THE SOUTH CHINA SEA. TY 25W IS EXPECTED TO DISSIPATE BY TAU 72 AS IT TRACKS INLAND. NUMERICAL MODEL FORECAST TRACK GUIDANCE INDICATES VERY GOOD AGREEMENT, AND THE CURRENT FORECAST TRACK LIES NEAR THE MULTI-MODEL CONSENSUS WITH HIGH CONFIDENCE.// NNNN NNNN