MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 25W (LAN) WARNING NR 24// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUPER TYPHOON 25W (LAN), LOCATED APPROXIMATELY 337 NM SOUTHEAST OF KADENA AB, HAS TRACKED NORTHEASTWARD AT 11 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY AND A 210553Z 89GHZ AMSU IMAGE DEPICTS DEEP CONVECTION SURROUNDING A 50NM EYE FEATURE WITH WARMING CLOUD TOPS INDICATING THE START OF A WEAKENING TREND. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE EVIDENT EYE FEATURE IN SATELLITE IMAGERY. UPPER-LEVEL ANALYSIS SHOWS DUAL CHANNEL OUTFLOW WITH ENHANCED POLEWARD EXHAUST INTO THE MID-LATITUDE WESTERLIES CURRENTLY OVER JAPAN. SSTS IN THE REGION ARE STILL VERY WARM NEAR 29 CELSIUS, HOWEVER, STY 25W HAS TRACKED INTO AN AREA OF SUBSTANTIALLY LOWER OCEANIC HEAT CONTENT. CURRENTLY STY 25W IS TRACKING POLEWARD ALONG THE WESTERN PERIPHERY OF THE DEEP LAYERED SUBTROPICAL RIDGE. 3. FORECAST REASONING. A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. STY 25W WILL KEEP TRACKING POLEWARD ALONG THE CURRENT STEERING RIDGE FOR THE DURATION OF THE FORECAST PERIOD. A SHORT-WAVE TROUGH IS DEVELOPING JUST NORTHWEST OF THE SYSTEM, AND THE TROUGH WILL BEGIN EXERTING INFLUENCE OVER THE POLEWARD OUTFLOW CHANNEL IN THE NEXT 6 TO 12 HOURS PERPETUATING THE GRADUAL WEAKENING TREND. AS THE SYSTEM CONTINUES ON ITS NORTHWESTWARD TRACK, VERTICAL WIND WILL RISE SUBSTANTIALLY AS IT APPROACHES THE WESTERLIES AND BEGINS INTERACTING WITH THE BAROCLINIC REGION. STY 25W IS FORECAST TO BEGIN EXTRATROPICAL TRANSITION SOMETIME BETWEEN TAU 24 AND 36 AS A FAIRLY LARGE AND INTENSE SYSTEM. GALE FORCE WINDS ARE FORECAST TO EXTEND FAR FROM THE SYSTEM CENTER REACHING WELL INTO THE SEA OF JAPAN DESPITE TAKING A TRACK VERY CLOSE TO YOKOSUKA NAVAL STATION AND SKIRTING THE EASTERN EDGE OF HONSHU. STY 25W WILL BEGIN TO EXHIBIT FRONTAL CHARACTERISTICS SOMETIME AFTER TAU 96 COMPLETING ETT BY TAU 48. DYNAMIC MODEL GUIDANCE IS VERY GOOD AGREEMENT ON BOTH THE TRACK AND SPEED OF THE SYSTEM, THUS LENDING HIGH CONFIDENCE IN THE FORECAST TRACK.// NNNN NNNN