WDPN31 PGTW 240300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 27W (IN-FA) WARNING NR 29// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON TY) 27W (IN-FA), LOCATED APPROXIMATELY 530 NM SOUTH- SOUTHEAST OF KADENA AB, HAS TRACKED NORTHEASTWARD AT 11 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS TIGHTLY-CURVED CONVECTIVE BANDING WRAPPING INTO THE WELL-DEFINED LOW- LEVEL CIRCULATION CENTER (LLCC). A 232218Z SSMIS 37GHZ IMAGE ALSO SHOWS AN WELL-ORGANIZED LLCC WITH PERSISTENT CORE CONVECTION AND A SMALL MICROWAVE EYE FEATURE, WHICH SUPPORTS THE CURRENT POSITION WITH GOOD CONFIDENCE. ANIMATED WATER VAPOR IMAGERY DEPICTS AN UPPER- LEVEL TROUGH POSITIONED OVER THE WESTERN PERIPHERY OF THE SYSTEM PRODUCING MODERATE SOUTHWESTERLY VERTICAL WIND SHEAR (VWS) AND DIFFLUENT FLOW. THE CURRENT INTENSITY IS ASSESSED AT 85 KNOTS BASED ON DVORAK INTENSITY ESTIMATES RANGING FROM 77 TO 90 KNOTS. TY 27W HAS ACCELERATED SLIGHTLY AS IT BEGINS TO ROUND THE WESTERN PERIPHERY OF THE SUBTROPICAL RIDGE (STR). 3. FORECAST REASONING. A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TY 27W WILL CONTINUE TO ROUND THE STR AXIS OVER THE NEXT 12 TO 24 HOURS AND IS FORECAST TO ACCELERATE NORTHEASTWARD AS IT INTERACTS WITH THE APPROACHING MIDLATITUDE TROUGH. TY IN-FA WILL BEGIN EXTRA- TROPICAL TRANSITION (ETT) NEAR TAU 48 AS IT BEGINS TO INTERACT WITH THE BAROCLINIC ZONE AND ENCOUNTER STRONGER VWS. TY 27W WILL CONTINUE TO ACCELERATE NORTHEASTWARD ALONG THE NORTHWESTERN PERIPHERY OF THE STEERING STR AND IS FORECAST TO COMPLETE ETT BY TAU 72 AS IT EMBEDS DEEPER INTO THE MIDLATITUDE WESTERLY FLOW. DYNAMIC MODEL GUIDANCE IS IN FAIR AGREEMENT WITH THE BULK OF THE GUIDANCE SUPPORTING A RE- CURVE SCENARIO. HOWEVER, JGSM AND JENS NOW INDICATE A RAPID WEAKENING PHASE AND STALL AS THE SYSTEM REMNANTS STEER UNDER THE BUILDING LOW-LEVEL RIDGE TO THE NORTH. ECMWF AND EGRR ALSO RAPIDLY WEAKEN THE SYSTEM WITH THE REMNANTS TRACKING MORE EAST- NORTHEASTWARD. CURRENTLY, THE RE-CURVE SCENARIO IS ASSESSED AS THE MOST PROBABLE TRACK AND, OVERALL, THERE IS HIGH CONFIDENCE IN THE JTWC TRACK FORECAST.// NNNN