MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 02W (WUTIP) WARNING NR 21// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON (TY) 02W (WUTIP), LOCATED APPROXIMATELY 172 NM WEST OF NAVSTA GUAM, HAS TRACKED WEST-NORTHWESTWARD AT 04 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY DEPICTS ASYMMETRIC CORE CONVECTION SURROUNDING A 16NM EYE, WHICH SUPPORTS THE INITIAL POSITION WITH HIGH CONFIDENCE. A 240545Z SSMI 85GHZ MICROWAVE IMAGE INDICATES DEEP CONVECTIVE BANDING WRAPPING TIGHTLY INTO A MICROWAVE EYE FEATURE WITH SHALLOW BANDING EXPOSED OVER THE WESTERN AND SOUTHERN SEMICIRCLES DUE TO DRY AIR ENTRAINMENT AS INDICATED IN THE ANIMATED TOTAL PRECIPITABLE WATER IMAGERY. THE INITIAL INTENSITY IS ASSESSED AT 115 KNOTS BASED ON DVORAK INTENSITY ESTIMATES OF 5.5/6.5 (102/115 KNOTS) FROM ALL AGENCIES AND A UW- CIMSS SATCON ESTIMATE OF 110 KNOTS. UPPER-LEVEL CONDITIONS REMAIN FAVORABLE WITH LOW (5 TO 10 KNOTS) SOUTHEASTERLY VERTICAL WIND SHEAR (VWS), A ROBUST POLEWARD OUTFLOW CHANNEL AND GOOD EQUATORWARD OUTFLOW. SST VALUES REMAIN FAVORABLE AT 27C, ALTHOUGH OCEAN HEAT CONTENT IS LOW. TY 02W IS TRACKING WEST-NORTHWESTWARD UNDER THE STEERING INFLUENCE OF A DEEP-LAYERED SUBTROPICAL RIDGE (STR) POSITIONED TO THE NORTHEAST. 3. FORECAST REASONING. A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. THROUGH TAU 36, TY 02W IS FORECAST TO TRACK NORTHWESTWARD TO NORTH-NORTHWESTWARD ALONG THE SOUTHWESTERN PERIPHERY OF THE DEEP- LAYERED STR TOWARD A BREAK IN THE STR ASSOCIATED WITH A SHORTWAVE TROUGH PROPAGATING TO THE NORTH. GRADUAL WEAKENING IS EXPECTED DUE TO DRY AIR ENTRAINMENT. AFTER TAU 36, THE SHORTWAVE TROUGH IS FORECAST TO SHIFT NORTHEAST ALLOWING AN EXTENSION OF THE LOW- TO MID- LEVEL STR TO BUILD TO THE NORTH. CONSEQUENTLY, 02W WILL TURN WEST- NORTHWESTWARD AND ACCELERATE. MORE SIGNIFICANT WEAKENING IS EXPECTED AS VWS INCREASES AND SST VALUES DECREASE SLIGHTLY TO 26C. NUMERICAL MODEL GUIDANCE IS IN FAIR AGREEMENT WITH SOME UNCERTAINTY IN THE TIMING OF THE TURN TO THE WEST-NORTHWEST. C. AFTER TAU 72, INCREASING VWS (OVER 30 KTS) AND CONVERGENCE ASSOCIATED WITH INCREASING UPPER-LEVEL (200MB) WESTERLIES OVER THE SYSTEM AS WELL AS DRY AIR ENTRAINMENT ASSOCIATED WITH A NORTHEAST SURGE EVENT WILL SERVE TO RAPIDLY WEAKEN THE SYSTEM LEADING TO DISSIPATION BY TAU 96. WITH THE EXCEPTION OF THE SOLE OUTLIER, GFS, NUMERICAL MODEL GUIDANCE REMAINS IN FAIR AGREEMENT. OVERALL, THERE IS LOW CONFIDENCE (HIGH UNCERTAINTY) IN THE JTWC FORECAST TRACK DUE TO THE RAPIDLY EVOLVING SYNOPTIC ENVIRONMENT.// NNNN NNNN