MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 09W (BAVI) WARNING NR 018// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON (TY) 09W (BAVI), LOCATED APPROXIMATELY 290 NM SOUTH- SOUTHWEST OF KUNSAN AB, SOUTH KOREA, HAS TRACKED NORTH- NORTHWESTWARD AT 08 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY DEPICTS GRADUAL WEAKENING OF THE OUTER SPIRAL BANDING, HOWEVER, THE SYSTEM RETAINS A COMPACT EYEWALL SURROUNDING A SMALL 10NM EYE, WHICH SUPPORTS THE INITIAL POSITION WITH HIGH CONFIDENCE. A 251700Z AMSR2 89GHZ COMPOSITE IMAGE INDICATES AN EYEWALL REPLACEMENT CYCLE (ERC) WITH THE INNER EYEWALL BEGINNING TO ERODE AND AN OUTER EYEWALL FORMING. THE UW-CIMSS M-PERC PRODUCT ALSO DEPICTS THE TWO EYEWALLS, HOWEVER, THE PROBABILITIES REMAIN LOW AT ABOUT 10%. THE INITIAL WIND RADII HAVE BEEN ADJUSTED BASED ON A DETAILED ANALYSIS OF THE 251134Z ASCAT-A IMAGE. UPPER- LEVEL CONDITIONS ARE FAVORABLE FOR DEVELOPMENT WITH ROBUST POLEWARD OUTFLOW AND LOW TO MODERATE VERTICAL WIND SHEAR (VWS). SST VALUES (29 TO 30C) REMAIN CONDUCIVE. THE INITIAL INTENSITY REMAINS ASSSESSED AT 95 KNOTS BASED ON AN AVERAGE OF SUBJECTIVE DVORAK INTENSITY ESTIMATES OF T5.0 (90 KNOTS) AND A 251800Z ADT ESTIMATE OF 5.3/5.7 (ROUGHLY 95 TO 105 KNOTS). TY 09W IS TRACKING POLEWARD ALONG THE WESTERN PERIPHERY OF A DEEP-LAYERED SUBTROPICAL RIDGE (STR) POSITIONED TO THE EAST. 3. FORECAST REASONING. A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TY 09W WILL CONTINUE TO TRACK POLEWARD OVER THE NEXT 48 HOURS ALONG THE WESTERN PERIPHERY OF THE BUILDING STR TO THE EAST. WITH THE EXCEPTION OF THE SOLE OUTLIER AFUI, NUMERICAL MODEL GUIDANCE IS IN TIGHT AGREEMENT THROUGH TAU 36 WITH A 47NM SPREAD IN SOLUTIONS AT TAU 36. ADDITIONALLY, THE ECMWF ENSEMBLE SOLUTIONS ARE ALSO IN GOOD AGREEMENT REFLECTING A HIGH CONFIDENCE (LOW UNCERTAINTY) FORECAST TRACK. THERE IS SOME POTENTIAL FOR SLIGHT INTENSIFICATION OVER THE NEXT 12 HOURS AS THE ERC COMPLETES AND THE OUTER EYEWALL CONTRACTS. NEAR TAU 24, THE SYSTEM WILL BEGIN EXTRA- TROPICAL TRANSITION AS IT INTERACTS THE MIDLATITUDE SOUTHWESTERLY FLOW. TY 09W WILL GRADUALLY WEAKEN AS THE SYSTEM ENCOUNTERS COOLER SST (28-25C) OVER THE NORTHERN YELLOW SEA AND STRONG VWS AFTER TAU 24. TY 09W SHOULD COMPLETE EXTRA-TROPICAL TRANSITION BY TAU 48 AS IT GAINS FRONTAL CHARACTERISTICS AND NEARS THE JET. OVERALL, THERE IS HIGH CONFIDENCE IN THE JTWC FORECAST TRACK WHICH IS POSITIONED NEAR THE MULTI-MODEL CONSENSUS.// NNNN NNNN