MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 12W (LIONROCK) WARNING NR 45// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. 290300Z POSITION NEAR 31.1N 142.1E. TYPHOON 12W (LIONROCK), LOCATED APPROXIMATELY 307 NM SOUTH- SOUTHEAST OF YOKOSUKA, JAPAN, HAS TRACKED NORTHEASTWARD AT 16 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS THE BANDING STRUCTURE BECOMING ELONGATED AND EYE FEATURE BECOMING CLOUD-FILLED. A 282139Z SSMIS 91GHZ MICROWAVE IMAGE SHOWS SIGNIFICANT WEAKENING IN THE CONVECTIVE STRUCTURE WITH NOTABLE WEAKENING ON THE WESTERN EYE WALL AND NORTHWESTERN PERIPHERY. THE INITIAL POSITION IS BASED ON SATELLITE EYE FIXES FROM PGTW AND RJTD WITH GOOD CONFIDENCE. THE INITIAL INTENSITY IS ASSESSED AT 95 KNOTS AND IS BASED ON THE DETERIORATING STRUCTURE AND DROPPING DVORAK ESTIMATES FROM ALL AGENCIES WITH THE CURRENT INTENSITY BEING HELD BY CONSTRAINTS AT T5.5 TO T6.0 (102 TO 115 KNOTS). UPPER-LEVEL ANALYSIS INDICATES SIGNIFICANT DISRUPTION TO OUTFLOW OVER THE LAST SIX HOURS. THE DEEPENING TROUGH TO THE NORTHWEST IS CREATING STRONG SOUTHWESTERLY FLOW RESTRICTING THE EQUATORWARD CHANNEL. A TUTT CELL TO THE NORTHEAST IS FURTHER EXACERBATING THE RESTRICTED EXHAUST OVER THE SYSTEM. CURRENTLY TY 12W IS TRACKING NORTHEASTWARD ALONG THE EXTENSION OF A NEAR EQUATORIAL RIDGE (NER) TO THE SOUTHEAST. 3. FORECAST REASONING. A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TY 12W IS EXPECTED TO CONTINUE TO TRACK NORTHEASTWARD UNDER THE INFLUENCE OF THE NER WHILE UNDERGOING SIGNIFICANT WEAKENING IN THE NEXT 24 TO 36 HOURS AS IT TRACKS INTO COOLER WATERS AND UPPER- LEVEL CONDITIONS CONTINUE TO DETERIORATE. BEYOND TAU 24, STEERING WILL BEGIN TO SHIFT TO A NORTHERN DEEP-LAYERED RIDGE ANCHORED NEAR THE KURIL ISLANDS AND TURN TY 12W ON A NORTHWESTERLY TRACK INTO THE DEEPENING TROUGH OVER JAPAN. LANDFALL IS EXPECTED OVER NORTHERN HONSHU JUST BEFORE TAU 36 WITH THE INTENSITY NEAR 60 KNOTS. TY 12W IS EXPECTED TO START EXTRATROPICAL TRANSITION AS IT BEGINS TO INTERACT WITH BAROCLINIC ZONE WITHIN THE TROUGH AROUND THE SAME TIME IT MAKES LANDFALL. THE MOUNTAINOUS TERRAIN OF NORTHERN HONSHU WILL SIGNIFICANTLY DISRUPT THE LOW LEVEL WIND FLOW RESULTING IN A SEVERELY WEAKENED SYSTEM BY TAU 48 AS IT RESURFACES OVER THE SEA OF JAPAN WITH AN INTENSITY OF APPROXIMATELY 45 KNOTS. TY 12W IS EXPECTED TO BECOME FULLY EXTRATROPICAL BY TAU 72 AS IT TRACKS INTO MANCHURIA. DYNAMIC MODEL GUIDANCE IS IN GOOD AGREEMENT AND CONTINUES TO SHOW TIGHTER GROUPING IN THE NORTHWESTERN TURN WITH EACH SUCCESSIVE RUN OVER THE LAST 18 HOURS. COAMPS-TC IS THE ONLY OUTLIER OFF TO THE EAST SHOWING A SLIGHTLY WIDER AND SLOWER TURN WHICH DOESN'T REFLECT THE CURRENT SYNOPTIC SITUATION WELL. THE FORECAST TRACK IS NOW PLACED CLOSE TO THE MULTI-MODEL CONSENSUS. THERE IS GOOD CONFIDENCE IN THE FORECAST TRACK, BUT A DEGREE OF UNCERTAINTY STILL REMAINS AS THE TY 12W BEGINS ACCELERATING INTO THE TROUGH AND STARTS TRANSITIONING INTO AN EXTRATROPICAL SYSTEM.// NNNN NNNN