MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 30W (KONG-REY) WARNING NR 24// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON (TY) 30W (KONG-REY), LOCATED APPROXIMATELY 247 NM SOUTH OF KADENA AB, OKINAWA, JAPAN, HAS TRACKED NORTHWESTWARD AT 10 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY SHOWS THE SYSTEM CONTINUED TO WEAKEN AS CENTRAL CONVECTIVE TOPS WARMED UP AND FEEDER BANDS UNRAVELED. THE PINHOLE EYE HAS BECOME CLOUD-COVERED BUT STILL DISCERNIBLE. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE CLOUD-FILLED EYE THAT LINED UP WELL WITH A MICROWAVE EYE FEATURE IN THE 031724Z ATMS IMAGE. THE INITIAL INTENSITY OF 90 KNOTS IS BASED ON EQUIVALENT DVORAK ESTIMATES OF T5.0 FROM PGTW AND RJTD AND IS REFLECTIVE OF THE WEAKENING TREND. UPPER LEVEL ANALYSIS INDICATES TY 30W IS STILL IN AN AREA OF LOW (05-10 KNOT) VERTICAL WIND SHEAR (VWS) AND EXCELLENT DUAL OUTFLOW CHANNELS WITH A VERY STRONG POLEWARD BIAS. ALONG TRACK SEA SURFACE TEMPERATURES (SSTS) REMAIN WARM AT (28-29 CELSIUS). HOWEVER, THE CYCLONE IS NOW TRACKING ALONG A SWATH OF LOW OCEAN HEAT CONTENT CAUSED BY THE PREVIOUS PASSAGE OF TY TRAMI SEVERAL DAYS AGO. PLUS, COLD DRY AIR IS NOW ADVECTING FROM THE NORTHWEST. THESE SURFACE DYNAMICS ARE THE PRIMARY CAUSES FOR THE SIGNIFICANT WEAKENING OF THE SYSTEM. THE CYCLONE IS TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF THE DEEP-LAYERED SUBTROPICAL RIDGE (STR) TO THE NORTHEAST. 3. FORECAST REASONING. A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TY 30W WILL ROUND THE WESTERN EDGE OF THE STR AND TURN MORE POLEWARD, CRESTING THE RIDGE AXIS NEAR TAU 36. AFTERWARD, IT WILL RECURVE AND ACCELERATE NORTHEASTWARD AHEAD OF THE MID-LATITUDE TROUGH APPROACHING FROM THE NORTHWEST. BY TAU 72, TY 30W WILL BE IN THE MIDDLE OF THE SEA OF JAPAN (SOJ). NEAR TAU 36, THE SYSTEM WILL BEGIN EXTRA TROPICAL TRANSITION AND BY TAU 48 WILL BECOME A COLD-CORE LOW OVER THE COLD WATERS OF THE SOJ. INCREASING VWS AND DECREASING SSTS WILL CONTRIBUTE TO THE WEAKENING TREND DOWN TO 65 KNOTS BY TAU 72. C. AFTER TAU 72, TY KONG-REY WILL CONTINUE TO ACCELERATE NORTHEASTWARD AND BY TAU 96, AT A TRACK SPEED EXCEEDING 30 KNOTS, WILL HAVE CROSSED NORTHERN JAPAN AND EMERGED BACK IN THE PACIFIC OCEAN EAST OF HOKKAIDO AS A STORM-FORCE 45-KNOT COLD CORE LOW, FULLY EMBEDDED IN THE BAROCLINIC ZONE WITH AN EXPANSIVE WIND FIELD. DYNAMIC MODEL GUIDANCE IS IN GOOD AGREEMENT WITH A SMALL ACROSS-TRACK SPREAD; HOWEVER, THERE IS POOR AGREEMENT IN THE ALONG-TRACK FORECAST SPEEDS AFTER TAU 36. THEREFORE, THERE IS HIGH CONFIDENCE IN THE JTWC NNNN NNNN