MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 10W (MAYSAK) WARNING NR 021// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON (TY) 10W (MAYSAK), LOCATED APPROXIMATELY 301 NM SOUTH- SOUTHWEST OF BUSAN, SOUTH KOREA, HAS TRACKED NORTH-NORTHEASTWARD AT 10 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS THE SYSTEM CONTINUED TO WEAKEN AS EVIDENCED BY FRAGMENTATION ALONG THE EYEWALL AND COOLING OF CONVECTIVE CLOUD TOPS ALONG THE MAIN FEEDER BANDS WRAPPING IN FROM SOUTHEAST TO NORTHWEST. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE 20-NM RAGGED, FRAGMENTED, BUT DEFINED EYE THAT LINED UP WELL WITH THE CIRCULATION CENTER IN A COMPOSITE RADAR LOOP FROM JMA. THE INITIAL INTENSITY OF 105 KTS IS BASED ON THE LOW END OF CONSTRAINED AGENCY DVORAK ESTIMATES RANGING FROM T5.5/102KTS TO T6.0/115KTS AND REFLECTS THE WEAKENING STAGE. SSTS REMAIN WARM AT 29C, UPPER LEVEL RADIAL OUTFLOW ALSO REMAINS STRONG, AND VWS AT 15-20 KTS IS MITIGATED BY THE STORM MOTION THAT IS IN-PHASE WITH THE UPPER LEVEL WIND FLOW. HOWEVER, CONVECTIVE BANDS DESCRIBED ABOVE ARE NOW ERODING AS THEY MAKE CONTACT WITH THE SOUTHERN TIP OF SOUTH KOREA AND THE ISLAND OF KYUSHU, JAPAN. TY MAYSAK IS NOW TRACKING ALONG THE WESTERN EDGE OF THE SUBTROPICAL RIDGES (STR) TO THE EAST. A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TY MAYSAK WILL TRACK GENERALLY NORTHWARD ALONG THE WESTERN PERIPHERY OF THE STEERING STR, MAKING LANDFALL WEST OF BUSAN NEAR TAU 18, DRAG OVER THE KOREAN PENINSULA WITH A BRIEF SPLASH OVER THE SEA OF JAPAN JUST AFTER TAU 24 BEFORE CROSSING INTO MANCHURIA NEAR TAU 30. IT WILL CONTINUE WEAKENING DUE TO DECREASING SSTS AND INTERACTION WITH THE SOUTH KOREAN COAST. HOWEVER, IT WILL STILL BE A MODERATE TYPHOON AT 85 KTS PRIOR TO LANDFALL. AFTER LANDFALL, THE SYSTEM WILL RAPIDLY ERODE WITH THE ADDITION OF FRICTIONAL EFFECTS OVER THE RUGGED MOUNTAIN RANGES OF THE KOREAN PENINSULA. CONCURRENTLY AT TAU 12, THE SYSTEM WILL BEGIN EXTRATROPICAL TRANSITION (ETT) AS IT ENTERS THE BAROCLINIC ZONE BECOMING A COLD CORE LOW BY TAU 24. THERE IS A DISTINCT POSSIBILITY OF DISSIPATION OVER THE RUGGED TAEBAEK MOUNTAIN RANGES PRIOR TO TAU 36. NUMERICAL MODEL SOLUTIONS REMAIN IN TIGHT AGREEMENT, WITH THE JTWC FORECAST TRACK PLACED JUST LEFT OF THE MULTI-MODEL CONSENSUS TO OFFSET THE AFUM TRACK, WHICH IS THE SOLE EXTREME RIGHT OF TRACK OUTLIER. THERE IS OVERALL HIGH CONFIDENCE IN THE JTWC FORECAST TRACK.// NNNN NNNN