MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 28W (TRAMI) WARNING NR 10// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON (TY) 28W (TRAMI), LOCATED APPROXIMATELY 705 NM SOUTHEAST OF KADENA AB, OKINAWA, JAPAN, HAS TRACKED WESTWARD AT 10 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS A DEEP AND PERSISTENT CORE OF CONVECTION WITH SPIRAL BANDS EXTENDING FROM THE SOUTHWEST TO THE NORTHEAST. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE AND IS BASED ON A 230017Z METOP-B ASCAT AMBIGUITY IMAGE SHOWING A WELL DEFINED LOW LEVEL CIRCULATION CENTER (LLCC). THE INITIAL INTENSITY OF 75 KNOTS IS HEDGED BETWEEN DVORAK INTENSITY ESTIMATES OF T4.0 (65 KNOTS) FROM PGTW AND RJTD, AND AN ESTIMATE OF T4.5 (77 KNOTS) FROM KNES AND ADT ALONG WITH A 222213Z SATCON ESTIMATE OF 82 KNOTS. ENVIRONMENTAL ANALYSIS SHOWS THAT TY 28W IS EXPERIENCING FAVORABLE VERTICAL WIND SHEAR (10 TO 15 KNOTS) ALONG WITH GOOD EQUATORWARD OUTFLOW AND EXCELLENT POLEWARD OUTFLOW. SEA SURFACE TEMPERATURES ARE ALSO CONDUCIVE FOR DEVELOPMENT, BETWEEN 29 TO 30 DEGREES CELSIUS. TY 28W IS TRACKING WESTWARD ALONG THE SOUTHERN PERIPHERY OF A DEEP-LAYERED SUBTROPICAL RIDGE (STR) LOCATED TO THE NORTH. 3. FORECAST REASONING. A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. THROUGH TAU 72, TY 28W WILL TRACK NORTHWESTWARD WHILE UNDER THE INFLUENCE OF THE AFOREMENTIONED STR. FAVORABLE ENVIRONMENTAL CONDITIONS (LOW VERTICAL WIND SHEAR, FAVORABLE OUTFLOW, AND WARM SEA SURFACE TEMPERATURES) WILL CONTINUE TO RAPIDLY INTENSIFY TY 28W. RAPID INTENSIFICATION IS STILL BEING INDICATED BY MODEL GUIDANCE. TRACK GUIDANCE IS IN FAIRLY GOOD AGREEMENT THROUGH TAU 48 WITH A SPREAD OF 90NM. HOWEVER, BY TAU 72 THE SPREAD IN MODEL GUIDANCE INCREASES TO 220NM. THEREFORE, THERE IS LOW CONFIDENCE IN THIS PORTION OF THE JTWC FORECAST TRACK. THE JTWC FORECAST TRACK IS PLACED NEAR BUT JUST SOUTH OF THE MULTI-MODEL CONSENSUS. C. AFTER TAU 72, A MIDLATITUDE SHORTWAVE TROUGH WILL DEEPEN OVER THE EAST CHINA SEA AND WESTERN JAPAN CREATING A BROAD, PERSISTENT BREAK IN THE STR. STRS TO THE WEST AND NORTHEAST WILL COMPETE TO BECOME THE DOMINANT STEERING FEATURE. AS A RESULT, TY 28W WILL SLOW IN FORWARD SPEED AND MAY BECOME QUASI-STATIONARY FOR A SHORT TIME. MODEL GUIDANCE IS IN POOR AGREEMENT WITH A SIGNIFICANT SPREAD OF 570NM BY TAU 120. GFS SHOWS A MORE NORTH-NORTHWESTWARD TRACK AFTER TAU 72 WHILE NAVGEM, JGSM, AN AFUM INDICATE A MORE WESTWARD TRACK. THE JTWC FORECAST TRACK IS PLACED SLIGHTLY SOUTH OF THE MULTI-MODEL CONSENSUS, FAVORING A MORE WESTWARD TRACK AND NEAR THE ECMWF TRACK. DUE TO THE CONTINUED WIDE SPREAD IN MODEL GUIDANCE, THERE IS LOW CONFIDENCE IN THIS PORTION OF THE JTWC FORECAST TRACK.// NNNN NNNN