MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 20W (HAGIBIS) WARNING NR 023// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON 20W (HAGIBIS), LOCATED APPROXIMATELY 543 NM SOUTH OF YOKOSUKA, JAPAN, HAS TRACKED NORTH-NORTHWESTWARD AT 10 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY REVEALS A MORE RAGGED 32 NM EYE THAN PREVIOUSLY OBSERVED IN THE PAST 6-12 HOURS. ADDITIONALLY, THE CONVECTIVE STRUCTURE AROUND THE EYE HAS DECREASED SLIGHTLY OVER THE PAST 6 HOURS WITH A BREAK IN THE EYEWALL TO THE SOUTHWEST, INDICATING WEAKENING. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE EYE VISIBLE ON EIR AND EXTRAPOLATION FROM A 101701Z AMSR2 36 GHZ MICROWAVE IMAGE. THE INITIAL INTENSITY IS BASED ON DVORAK INTENSITY ESTIMATES OF 6.5 BY PGTW AND 6.0 BY RJTD AND REFLECTS THE WEAKENING TREND THAT IS EXPECTED TO PERSIST. UPPER LEVEL ANALYSIS INDICATED LOW TO MODERATE (10-20 KNOTS) VERTICAL WIND SHEAR (VWS) OFFSET BY DECENT EQUATORWARD OUTFLOW AND STRONG POLEWARD OUTFLOW ENHANCED BY A SHORTWAVE TROUGH TO THE NORTHWEST. CURRENT SSTS (28-29C)REMAIN FAVORABLE TO SUSTAIN TY 20W. HOWEVER, THE CIMSS TOTAL PRECIPITABLE WATER (TPW) LOOP REVEALS DRY AIR BEGINNING TO ENTRAIN IN THE OUTER BANDS AND WRAPPING TOWARD THE CENTER OF TY 20W PARTIALLY OFFSETTING THE PREVIOUSLY STATED FAVORABLE CONDITIONS. HAGIBIS IS CURRENTLY TRACKING ALONG THE WESTERN PERIPHERY OF A DEEP-LAYERED SUBTROPICAL RIDGE (STR) TO THE EAST. 3. FORECAST REASONING. A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM THE PREVIOUS PROGNOSTIC REASONING MESSAGE. THE EASTERN WIND RADII HAVE BEEN ADJUSTED BASED ON THE 101127Z ASCAT-B AND WESTERN WIND RADII HAVE BEEN ADJUSTED BY THE 101152Z ASCAT-A PASSES. B. STEERED BY THE STR LOCATED TO THE EAST, TY HAGIBIS WILL CONTINUE ON ITS CURRENT TRACK THROUGH TAU 12. AFTERWARD, IT WILL TRACK ALMOST DUE NORTH ROUNDING THE STR AXIS AT TAU 24 AND BEGIN ACCELERATING NORTHEASTWARD ON THE POLEWARD SIDE, MAKING A QUICK LANDFALL NEAR YOKOSUKA AT ABOUT TAU 42. THE SYSTEM WILL CONTINUE TO GRADUALLY WEAKEN DUE TO INCREASING VWS, SUBSIDENCE ASSOCIATED WITH THE APPROACHING SHORTWAVE TROUGH, AND COLD DRY AIR ADVECTION NEAR THE SURFACE. TY 20W WILL BEGIN INTERACTING WITH THE UPPER LEVEL JET BY TAU 48 AND WILL COMPLETE EXTRATROPICAL TRANSITION BY TAU 60 AT WHICH POINT IT WILL BE COMPLETELY ENCOMPASSED BY THE JET AND WILL HAVE GAINED FRONTAL CHARACTERISTICS. THE NUMERICAL MODELS ARE IN TIGHT AGREEMENT WITH A SPREAD OF ONLY 25 NM AT TAU 48, LENDING HIGH CONFIDENCE IN THE JTWC TRACK FORECAST THAT IS PLACED JUST SLIGHTLY FASTER THAN THE MULTI-MODEL CONSENSUS AFTER TAU 48.// NNNN NNNN