MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 04W (MAYSAK) WARNING NR 21// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUPER TYPHOON (STY) 04W (MAYSAK), LOCATED APPROXIMATELY 76 NM NORTH- NORTHWEST OF YAP, HAS TRACKED WEST-NORTHWESTWARD AT 11 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY SHOWS THE SYSTEM HAS MAINTAINED A 20-NM AXIS-SYMMETRIC EYE THAT IS UNDERGOING AN ANNULAR CYCLE: THE EYE IS SURROUNDED BY A UNIFORM RING OF DEEP CONVECTION WITH A LACK OF CONVECTION OUTSIDE THE RING. THIS IS READILY APPARENT ON A 312213Z 91 GHZ SSMIS COLOR COMPOSITE MICROWAVE IMAGE. THE INITIAL POSITION IS BASED ON THE EYE FEATURE WITH HIGH CONFIDENCE. THE INITIAL INTENSITY IS BASED ON AN OVERALL ASSESSMENT OF CONCENTRIC DVORAK FIXES FROM PGTW, KNES, AND RJTD. UPPER LEVEL ANALYSIS SHOWS THE SYSTEM IS IN AN AREA OF LOW (05 TO 10 KNOT) VERTICAL WIND SHEAR (VWS). ADDITIONALLY, THE SYSTEM SUSTAINS ITS OWN DIVERGENT POINT SOURCE ALOFT THAT IS PROVIDING EXCELLENT RADIAL OUTFLOW. STY 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. STY 04W WILL CONTINUE TRACKING WEST-NORTHWESTWARD UNDER THE INFLUENCE OF THE STEERING STR THROUGHOUT THE FORECAST PERIOD. AS FAVORABLE ENVIRONMENTAL CONDITIONS PERSIST IN THE NEAR TERM, STY 04W WILL LIKELY CONTINUE TO INTENSIFY OVER THE NEXT 12 HOURS, PEAKING AT 150 KNOTS. AFTERWARDS, EXPECT A WEAKENING TREND AS VWS INCREASES WITH THE APPROACH OF A MID-LATITUDE TROUGH FROM THE NORTHWEST. C. IN THE EXTENDED TAUS, STY MAYSAK WILL CONTINUE TO WEAKEN AS IT ENCOUNTERS UPPER-LEVEL CONVERGENCE AND INCREASING VWS ASSOCIATED WITH THE AFOREMENTIONED TROUGH. HOWEVER, WHEN THE CYCLONE MAKES LANDFALL SHORTLY NEAR TAU 96 OVER NORTHERN LUZON, PHILIPPINES, NEAR PALANAN, ISABELA, IT WILL BE AN INTENSE 90-KNOT TYPHOON. MAYSAK WILL THEN EMERGE IN THE SOUTH CHINA SEA WEAKENED BY THE ROUGH TERRAIN BUT STILL AT A STRONG TROPICAL STORM INTENSITY. DYNAMIC NUMERICAL MODEL GUIDANCE REMAINS IN OVERALL TIGHT AGREEMENT, LENDING HIGH CONFIDENCE IN THE JTWC TRACK FORECAST WHICH IS LAID CLOSE TO THE MULTI-MODEL CONSENSUS.// NNNN NNNN