MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 02W (WUTIP) WARNING NR 17// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON (TY) 02W (WUTIP), LOCATED APPROXIMATELY 170 NM SOUTHWEST OF ANDERSEN AFB, GUAM, HAS TRACKED NORTHWESTWARD AT 09 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY AND A 230654Z AMSU 89GHZ IMAGE DEPICT A CONSOLIDATING SYSTEM WITH IMPROVED EYEWALL CONVECTION AND A CONTRACTING, ROUND 12-15NM EYE. ANIMATED RADAR IMAGERY SHOWS EXTENSIVE, HEAVY RAINFALL ASSOCIATED WITH THE NORTHERN SPIRAL RAINBANDS ADVECTING OVER GUAM, AND A WELL- DEFINED EYEWALL, WHICH SUPPORTS THE INITIAL POSITION WITH HIGH CONFIDENCE. THE SPIRAL BANDS HAVE CONTINUED TO PRODUCE PERSISTENT GALE-FORCE SURFACE WINDS OVER GUAM WITH GUSTS CLOSE TO 50 KNOTS. BASED ON THE IMPROVED CONVECTIVE STRUCTURE AND DVORAK INTENSITY ESTIMATES OF T6.0 (115 KNOTS) FROM BOTH KNES AND PGTW, THE INITIAL INTENSITY IS INCREASED TO 115 KNOTS. UPPER-LEVEL CONDITIONS REMAIN FAVORABLE WITH LOW TO MODERATE (15 TO 20 KNOTS) SOUTHEASTERLY VERTICAL WIND SHEAR (VWS) OFFSET BY A ROBUST POLEWARD OUTFLOW CHANNEL AND GOOD EQUATORWARD OUTFLOW. SST VALUES HAVE DECREASED TO 27C BUT REMAIN FAVORABLE. TY 02W IS TRACKING 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. TY 02W SHOULD CONTINUE TO TRACK NORTHWESTWARD TO NORTH- NORTHWESTWARD UNDER THE STEERING INFLUENCE OF THE AFOREMENTIONED STR TO THE NORTHEAST THROUGH TAU 72. NUMERICAL MODEL GUIDANCE REMAINS IN TIGHT AGREEMENT THROUGH THIS PHASE OF THE FORECAST WITH A 65NM SPREAD IN THE MODEL SOLUTIONS AT TAU 72. IN GENERAL, THERE IS SOME UNCERTAINTY IN THE INTENSITY FORECAST, HOWEVER, THE SYSTEM IS EXPECTED TO MAINTAIN AT 115 KNOTS THROUGH TAU 12 DUE TO THE STRONG OUTFLOW WITH A STEADY, SLOW WEAKENING TREND FROM TAU 24 THROUGH TAU 72 AS SST VALUES DECREASE SLIGHTLY TO 26C AND VWS BEGINS TO NEGATIVELY AFFECT THE SYSTEM. C. AFTER TAU 72, AN UPPER-LEVEL SHORTWAVE TROUGH IS FORECAST TO DEEPEN TO THE NORTH, WHICH WILL SERVE TO WEAKEN THE STEERING RIDGE AND LEAD TO A SLOWER NORTHWARD TO NORTHWESTWARD DRIFT. AFTER TAU 84, INCREASING VWS (20 TO 40 KNOTS) AND CONVERGENCE ASSOCIATED WITH THE SHORTWAVE TROUGH WILL RAPIDLY WEAKEN THE SYSTEM. AFTER TAU 96, THE WEAKENED SYSTEM WILL ACCELERATE WEST-NORTHWESTWARD UNDER THE STEERING INFLUENCE OF A STRONG LOW-LEVEL RIDGE AND NORTHEASTERLY SURGE FORECAST TO BUILD SOUTH AND SOUTHEAST OF JAPAN. DUE TO THE COMPLEX AND RAPIDLY-EVOLVING SYNOPTIC PATTERN, THERE IS INCREASING UNCERTAINTY IN THE EXACT TRACK WITH A 570NM SPREAD IN SOLUTIONS AT TAU 120. THEREFORE, THERE IS LOW CONFIDENCE IN THIS PORTION OF THE JTWC TRACK AND INTENSITY FORECAST.// NNNN NNNN