MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 10W (MAYSAK) WARNING NR 018// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON (TY) 10W (MAYSAK), LOCATED APPROXIMATELY 475 NM SOUTH-SOUTHWEST OF BUSAN, SOUTH KOREA, HAS TRACKED NORTHWARD AT 05 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS SPIRAL BANDING WRAPPING TIGHTLY INTO AN APPROXIMATELY 10 NM DIAMETER EYE. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE EYE PRESENT IN BOTH THE MSI AND COMPOSITE RADAR LOOPS, AS WELL AS IN AN 010501Z AMSR2 36 GHZ IMAGE. THE INITIAL INTENSITY OF 125 KTS IS PLACED WITH HIGH CONFIDENCE AND IS HEDGED BETWEEN MULTIAGENCY DVORAK CURRENT INTENSITY ESTIMATES OF T6.0 (115 KTS, RJTD) AND T6.5 (127 KTS, PGTW), SLIGHTLY ABOVE CONSISTENT CIMSS ADVANCED DVORAK TECHNIQUE CURRENT INTENSITY ESTIMATES OF T6.3 (122 KTS) AND SLIGHTLY UNDER A TIMELY 010450Z SATCON ESTIMATE OF 128 KTS. THE ENVIRONMENT CONTINUES TO BE FAVORABLE WITH ROBUST, RADIAL OUTFLOW ALOFT, LOW (5-10 KTS) VERTICAL WIND SHEAR (VWS), WARM (29-30 CELSIUS) SEA SURFACE TEMPERATURES (SST) AND CONTINUED HIGH OCEAN HEAT CONTENT (50-60 JOULES PER SQUARE CENTIMETER). TY MAYSAK IS TRACKING UNDER THE COMBINED STEERING INFLUENCE OF TWO SUBTROPICAL RIDGES (STR) AND IS CURRENTLY ROUNDING THE PRIMARY STEERING RIDGE AXIS POSITIONED TO THE EAST. A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TY MAYSAK WILL TRACK POLEWARD AFTER ROUNDING THE AXIS OF THE STEERING RIDGE AND WILL BEGIN WEAKENING DUE TO DECREASING SST AND INCREASING VWS THROUGHOUT THE REMAINDER OF THE FORECAST PERIOD. BY TAU 12, THE SYSTEM WILL WEAKEN TO 115 KTS, AND FURTHER TO 100 KTS BY TAU 24 DUE TO THE DEGRADING ENVIRONMENTAL CONDITIONS. FURTHERMORE, ANALYSIS OF THE EYE WALL STRUCTURE IN MICROWAVE IMAGERY SUGGESTS THAT AN EYE WALL REPLACEMENT CYCLE IS LIKELY, WHICH WILL ALSO CONTRIBUTE TO THE WEAKENING TREND OVER THE NEXT 24 TO 48 HOURS. AFTER TRACKING GENERALLY NORTHWARD THROUGH TAU 24, THE SYSTEM WILL MAKE LANDFALL ON THE SOUTHERN COAST OF SOUTH KOREA WEST OF BUSAN. TY MAYSAK WILL THEN CONTINUE TO WEAKEN TO 80 KTS BY TAU 36 AS IT MOVES INLAND DUE TO THE FRICTIONAL EFFECTS OF LAND AND VERY HIGH (> 35 KTS) VWS. THE SYSTEM WILL BEGIN EXTRATROPICAL TRANSITION (ETT) AS IT BECOMES EMBEDDED IN THE BAROCLINIC ZONE AT THAT TIME. AFTER TAU 36 THE SYSTEM WILL CONTINUE TO WEAKEN AND COMPLETE ETT BY TAU 48 AS IT BEGINS TO INTERACT WITH A MIDLATITUDE TROUGH APPROACHING FROM THE NORTHWEST. THERE IS A DISTINCT POSSIBILITY OF DISSIPATION OVER THE RUGGED TAEBAEK MOUNTAIN RANGES PRIOR TO TAU 72. NUMERICAL MODEL SOLUTIONS REMAIN IN TIGHT AGREEMENT, WITH THE JTWC FORECAST TRACK PLACED WEST OF THE MULTI-MODEL CONSENSUS TO OFFSET THE AFUM TRACK, WHICH CONTINUES TO BE THE EXTREME RIGHT- OF-TRACK OUTLIER THAT IS UNREALISTICALLY DRIVING THE VORTEX INTO THE STR. THE TIGHT AGREEMENT OF NUMERICAL MODEL SOLUTIONS THROUGHOUT THE FORECAST PERIOD LENDS OVERALL HIGH CONFIDENCE IN THE JTWC FORECAST TRACK.// NNNN NNNN