MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 31W (YUTU) WARNING NR 15// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUPER TYPHOON (STY) 31W (YUTU), LOCATED APPROXIMATELY 99 NM WEST-NORTHWEST OF SAIPAN, HAS TRACKED WEST-NORTHWESTWARD AT 12 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY SHOWS STY 31W HAS MAINTAINED A WELL DEFINED EYE WITH DEEP CONVECTION SURROUNDING IT. THE INITIAL POSITION IS BASED ON A 250000Z HIMAWARI VISIBLE SATELLITE IMAGE WHICH SHOWS THE 20NM WIDE EYE. THE INITIAL INTENSITY OF 145 KNOTS IS BASED ON A SLIGHT WEAKENING TREND DUE TO AN EYEWALL REPLACEMENT CYCLE AND IS HEDGED BETWEEN DVORAK CURRENT INTENSITY (CI) ESTIMATES OF T7.5 (155 KNOTS) FROM PGTW, RJTD, AND KNES, AND AN ADT CI OF T7.0 (140 KNOTS). ENVIRONMENTAL ANALYSIS SHOWS STY 31W IS EXPERIENCING MODERATE VERTICAL WIND SHEAR (15 TO 20 KNOTS) AND HAS NEAR RADIAL OUTFLOW. SEA SURFACE TEMPERATURES ALSO REMAIN FAVORABLE, NEAR 30 DEGREES CELSIUS. STY 31W IS TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF A SUBTROPICAL RIDGE (STR) LOCATED TO THE NORTHEAST AND THE SOUTHEASTERN PERIPHERY OF AN STR LOCATED TO THE NORTHWEST. 3. FORECAST REASONING. A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. THROUGH TAU 72, STY 31W WILL CONTINUE TO TRACK TO THE WEST-NORTHWEST WHILE POSITIONED BETWEEN THE AFOREMENTIONED STRS. MODEL GUIDANCE REMAINS IN FAIRLY GOOD AGREEMENT THOUGH TAU 24, INDICATING A WEST-NORTHWESTWARD TRACK, BUT QUICKLY DIVERGES AFTER THAT WITH A SPREAD OF 470 NM BY TAU 72. AT TAU 72, JGSM IS THE OUTLIER TO THE SOUTHWEST INDICATING A WESTWARD TRACK WITH NVGM THE OUTLIER TO THE NORTHEAST INDICATING A RECURVE SCENARIO. THE JTWC FORECAST TRACK IS PLACED NEAR THE MULTI-MODEL CONSENSUS IN THE MIDDLE GROUP OF A TRIFURCATION, FAVORING THE ECMWF, HWRF, AND GFS TRACKERS. DUE TO THE WIDE SPREAD IN MODEL GUIDANCE THERE IS LOW CONFIDENCE IN THIS PORTION OF THE JTWC FORECAST TRACK. C. BEYOND TAU 72, THE TRIFURCATION IN THE MODELS BECOMES EVEN MORE PRONOUNCED. JGSM, EGRR, AND AFUM INDICATE A WEST-SOUTHWESTWARD TRACK WITH NVGM AND CTCX INDICATING A NORTHEASTWARD TRACK. ECMWF, GFS, AND HWRF INDICATE A WEST-NORTHWESTWARD TRACK AND A DECREASE IN FORWARD SPEED NEAR TAU 96. NVGM AND JGSM REMAIN AT THE EDGES OF THE MODEL ENVELOPE AND HAVE A MASSIVE SPREAD OF 2010 NM BY TAU 120. THE JTWC FORECAST TRACK IS PLACED NEAR THE MULTI-MODEL CONSENSUS, FAVORING THE GFS, HWRF AND ECMWF SOLUTIONS. DUE TO THE WIDE SPREAD IN MODEL GUIDANCE THERE IS LOW CONFIDENCE IN THIS PORTION OF THE JTWC FORECAST TRACK.// NNNN NNNN