MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 20W (HAGIBIS) WARNING NR 028// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON (TY) 20W (HAGIBIS), LOCATED APPROXIMATELY 224 NM SOUTH-SOUTHWEST OF YOKOSUKA, JAPAN, HAS TRACKED NORTHWARD AT 13 KNOTS (KTS) OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS CONVECTIVE BANDING WRAPPING INTO A LOW LEVEL CIRCULATION CENTER (LLCC). THE UPPER LEVEL CONVECTION HAS BECOME SHEARED TO THE NORTHEAST AS TY 20W HAS INTERACTED WITH THE MID-LATITUDE TROUGH. THE INITIAL POSITION IS PLACED WITH GOOD CONFIDENCE BASED ON MULTI-AGENCY SATELLITE FIXES AND CENTRALIZED ON THE EYE OBSERVED IN MSI. SET WITH GOOD CONFIDENCE, THE INITIAL INTENSITY OF 90 KTS IS BASED ON DVORAK CURRENT INTENSITY ESTIMATES OF T5.0/90 KTS FROM PGTW AND RJTD. THE SYSTEM IS STEADILY WEAKENING AS IT TRANSITS TOWARD THE ISLAND OF HONSHU. DESPITE STRONG POLEWARD OUTFLOW, THE SURROUNDING ENVIRONMENT IS BECOMING UNFAVORABLE AS MODERATE TO HIGH (20-30 KTS) VERTICAL WIND SHEAR (VWS) FROM THE MID-LATITUDE TROUGH DISRUPTS THE OUTFLOW CHANNEL. SEA SURFACE TEMPERATURES (SST) ARE NEUTRALLY FAVORABLE AT 27-28 CELSIUS. TRACKING NORTHEASTWARD, TY 20W IS ROUNDING THE AXIS OF THE SUBTROPICAL RIDGE (STR) SERVING AS THE PRIMARY STEERING MECHANISM. 3. FORECAST REASONING. A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TY 20W WILL TRACK NORTHEASTWARD UNDER THE STEERING INFLUENCE OF THE AFOREMENTIONED STR UNTIL IT MAKES LANDFALL AROUND TAU 12 IN THE TOKYO AREA. THE SYSTEM WILL CONTINUALLY WEAKEN AS THE UPPER LEVEL OUTFLOW CONTINUES TO BE SHEARED BY THE MID-LATITUDE TROUGH AND FRICTIONAL TERRAIN EFFECTS ERODE THE SYSTEM. FOLLOWING LANDFALL, THE SYSTEM WILL BECOME FULLY EMBEDDED WITHIN THE TROUGH AND ACCELERATE NORTHEASTWARD AS IT UNDERGOES EXTRATROPICAL TRANSITION EAST OF HONSHU. TY 20W IS EXPECTED TO BE A STRONG EXTRATROPICAL LOW PRESSURE SYSTEM BY TAU 36. NUMERICAL MODELS ARE IN STRONG AGREEMENT THROUGHOUT THE DURATION OF THE FORECAST PERIOD. THE JTWC FORECAST TRACK IS LAID CLOSE TO MODEL CONSENSUS, LENDING HIGH CONFIDENCE TO THE FORECAST TRACK.// NNNN NNNN