MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 20W (HAGIBIS) WARNING NR 029// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON (TY) 20W (HAGIBIS), LOCATED APPROXIMATELY 121 NM SOUTHWEST OF YOKOSUKA, JAPAN, HAS TRACKED NORTH-NORTHEASTWARD AT 18 KNOTS (KTS) OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (AMSI) DEPICTS AN ASYMMETRIC CLOUD PATTERN WITH DEEPER CONVECTION TO THE NORTH AND SHALLOWER RAIN BANDS TO THE SOUTH OF THE OBSCURED LOW LEVEL CIRCULATION CENTER. THERE IS GOOD CONFIDENCE IN THE INITIAL POSITION BASED ON THE AMSI AND RADAR FIXES FROM RJTD. THE INITIAL INTENSITY OF 85 KTS IS CONSISTENT WITH PGTW/RJTD DVORAK INTENSITY ESTIMATES OF T4.5/5.0 (77-90 KTS). HIGH (25-30 KT) VERTICAL WIND SHEAR (VWS) IS OFFSETTING EXCELLENT POLEWARD OUTFLOW TO MAKE THE ENVIRONMENT UNFAVORABLE. SEA SURFACE TEMPERATURES (SST) AROUND 25-26 CELSIUS ARE MARGINALLY SUPPORTIVE. TY 20W IS TRACKING ALONG THE PERIPHERY OF A SUBTROPICAL RIDGE (STR) TO THE SOUTHEAST, JUST POLEWARD OF THE STR AXIS. 3. FORECAST REASONING. A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. FOR THE DURATION OF THE FORECAST, TY 20W WILL SHIFT ONTO A NORTHEASTWARD TRACK AS IT BECOMES EMBEDDED IN THE MID-LATITUDE WESTERLIES AND UNDERGOES EXTRATROPICAL TRANSITION (ETT). LANDFALL OVER HONSHU SHOULD OCCUR PRIOR TO TAU 6. SHORTLY AFTER LANDFALL, ETT SHOULD BEGIN AND COMPLETION IS EXPECTED BY TAU 36. THE INTENSITY SHOULD BE 75-80 KTS AT LANDFALL. HIGH VWS, LAND INTERACTION, AND COOL SST SHOULD CONTRIBUTE TO STEADY WEAKENING FOR THE DURATION OF THE FORECAST. WITH THE EXCEPTION OF NAVGEM, NUMERICAL MODEL GUIDANCE IS IN STRONG AGREEMENT, LENDING TO HIGH CONFIDENCE IN THE JTWC FORECAST TRACK.// NNNN NNNN