MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 04W (MAYSAK) WARNING NR 17// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON (TY) 04W (MAYSAK), LOCATED APPROXIMATELY 260 NM EAST OF YAP, HAS TRACKED WESTWARD AT 12 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY SHOWS THE SYSTEM HAS MAINTAINED AN OVERALL DEEP AND INTENSE CONVECTIVE SIGNATURE WITH TIGHTLY-WRAPPED BANDING INTO A SHARPLY OUTLINED 15-NM EYE, WHICH PROVIDES HIGH CONFIDENCE IN THE INITIAL POSITION. THE EYE FEATURE IS ALSO READILY APPARENT ON A 302351Z 37V GPM COLOR COMPOSITE MICROWAVE PASS. THE INITIAL INTENSITY IS BASED ON AN OVERALL ASSESSMENT OF CLOSELY-SPACED DVORAK ESTIMATES FROM ALL REPORTING AGENCIES. ANIMATED WATER VAPOR IMAGERY CONTINUES TO SHOW EXCELLENT RADIAL OUTFLOW WITH ENHANCED POLEWARD OUTFLOW ASSOCIATED WITH THE MID-LATITUDE WESTERLIES. TY MAYSAK IS TRACKING ALONG THE SOUTHERN PERIPHERY OF THE DEEP-LAYERED SUBTROPICAL RIDGE (STR) TO THE NORTH. 3. FORECAST REASONING. A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TY 04W WILL CONTINUE TRACKING WEST-NORTHWESTWARD UNDER THE INFLUENCE OF THE STEERING STR THROUGH THE ENTIRE FORECAST PERIOD. THE CYCLONE WILL CONTINUE TO INTENSIFY DUE TO FAVORABLE UPPER-LEVEL CONDITIONS AND WARM SST (29 CELSIUS) AND IS FORECAST TO REACH A PEAK INTENSITY OF 140 KNOTS AROUND TAU 24. AFTER TAU 36, TY 04W SHOULD TRACK TOWARD A BREAK IN THE STR ASSOCIATED WITH A PASSING SHORTWAVE TROUGH TO THE NORTH. AS THE TYPHOON GAINS LATITUDE IT WILL GRADUALLY WEAKEN AS IT ENCOUNTERS INCREASED VWS (15-20 KNOT). C. IN THE EXTENDED PERIOD, TY 04W WILL WEAKEN AS IT TRANSITIONS TO THE STEERING INFLUENCE OF THE WESTERN STR AND ENCOUNTERS UPPER-LEVEL CONVERGENCE AND INCREASING VWS. DYNAMIC MODEL GUIDANCE REMAINS IN OVERALL GOOD AGREEMENT, LENDING HIGH CONFIDENCE IN THE JTWC TRACK FORECAST.// NNNN NNNN