MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 28W (TRAMI) WARNING NR 09// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON (TY) 28W (TRAMI), LOCATED APPROXIMATELY 727 NM SOUTHEAST OF KADENA AB, OKINAWA, JAPAN, HAS TRACKED WESTWARD AT 15 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY DEPICTS AN AREA OF DEEP AND PERSISTENT CONVECTION LOCATED ABOVE THE LOW LEVEL CIRCULATION CENTER (LLCC) ASSOCIATED WITH TY 28W. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE AND IS BASED ON A 221608Z 89GHZ AMSR2 MICROWAVE IMAGE SHOWING A FORMATIVE EYE FEATURE. THE INITIAL INTENSITY OF 65 KNOTS IS BASED ON A DVORAK INTENSITY ESTIMATE OF T4.0 (65 KNOTS) FROM RJTD. THE INTENSITY IS HEDGED BETWEEN AN ADT ESTIMATE OF T4.4 (75 KNOTS), A 221641Z SATCON ESTIMATE OF 78 KNOTS AND A DVORAK INTENSITY ESTIMATE OF T3.5 (55 KNOTS) FROM PGTW. ENVIRONMENTAL ANALYSIS SHOWS THAT TY 28W IS EXPERIENCING FAVORABLE VERTICAL WIND SHEAR (5 TO 10 KNOTS) ALONG WITH EXCELLENT RADIAL OUTFLOW WHICH CONTINUES TO TAP INTO THE TROPICAL UPPER TROPOSPHERIC TROUGH (TUTT) CELL LOCATED TO THE EAST. 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 WEST-NORTHWEST WHILE UNDER THE INFLUENCE OF THE AFOREMENTIONED STR. FAVORABLE ENVIRONMENTAL CONDITIONS (LOW VERTICAL WIND SHEAR, FAVORABLE OUTFLOW, AND WARM SEA SURFACE TEMPERATURES) WILL LEAD TO RAPID INTENSIFICATION WHICH HAS BEEN CAPTURED BY MODEL GUIDANCE. INTENSITY GUIDANCE IS IN GOOD AGREEMENT. TRACK GUIDANCE IS IN FAIRLY GOOD AGREEMENT THROUGH TAU 48 WITH A SPREAD OF 150NM. HOWEVER, BY TAU 72 THE SPREAD IN MODEL GUIDANCE INCREASES TO 230NM. THEREFORE, THERE IS LOW CONFIDENCE IN THIS PORTION OF THE JTWC FORECAST TRACK. 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 500NM BY TAU 120. MODELS ARE BEGINNING TO SHOW A BIFURCATION WITH GFS AND COAMPS SHOWING A NORTHWESTWARD TRACK AFTER TAU 72 WHILE NAVGEM, JGSM, AN AFUM INDICATING 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. THEREFORE, THERE IS LOW CONFIDENCE IN THIS PORTION OF THE JTWC FORECAST TRACK.// NNNN NNNN