MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 28W (TRAMI) WARNING NR 31// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON (TY) 28W (TRAMI), LOCATED APPROXIMATELY 205 NM SOUTH OF KADENA AB, OKINAWA, JAPAN, HAS TRACKED NORTHWESTWARD AT 07 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY SHOWS TY 28W CONTINUES TO HAVE A WIDE AND RAGGED EYE AND HAS MAINTAINED DEEP CONVECTION AROUND THE EYE, ESPECIALLY IN THE NORTHEAST QUADRANT. THE INITIAL POSITION IS BASED ON A 280600Z HIMAWARI VISIBLE SATELLITE IMAGE WHICH SHOWS THE LARGE CLOUD FILLED EYE. THE INITIAL INTENSITY OF 90 KNOTS IS BASED ON A DVORAK CURRENT INTENSITY (CI) ESTIMATE OF T5.0 (90 KNOTS) AND AN ADT CI OF T4.9 (87 KNOTS). ENVIRONMENTAL ANALYSIS SHOWS THAT TY 28W IS EXPERIENCING FAVORABLE VERTICAL WIND SHEAR (5 TO 10 KNOTS) AND HAS EXCELLENT RADIAL OUTFLOW. SEA SURFACE TEMPERATURES REMAIN FAVORABLE, BETWEEN 28 AND 29 DEGREES CELSIUS. TY 28W IS TRACKING NORTHWESTWARD ALONG THE WESTERN EDGE OF THE SUBTROPICAL RIDGE (STR) LOCATED TO THE EAST. 3. FORECAST REASONING. A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TY 28W WILL CONTINUE TO TRACK TO THE NORTHWEST ALONG THE WESTERN PERIPHERY OF THE STR THROUGH TAU 12. AFTER TAU 12, TY 28W WILL BEGIN TO TRACK NORTHEASTWARD AS IT ROUNDS THE STR AXIS. CONTINUED FAVORABLE SEA SURFACE TEMPERATURES, UPPER LEVEL OUTFLOW, AND VERTICAL WIND SHEAR WILL ALLOW TY 28W TO RE-INTENSIFY TO 105 KNOTS BY TAU 36 AS IT TRACKS NORTHEASTWARD AROUND THE STR. AN APPROACHING SHORTWAVE TROUGH WILL HELP TO ACCELERATE TY 28W AS IT TRACKS NORTHEASTWARD. TY 28W WILL BEGIN EXTRATROPICAL TRANSITION (ETT) BY TAU 48 AS IT INTERACTS WITH THE TROUGH AND ACCELERATES NORTHEASTWARD. TY 28W WILL COMPLETE ETT BY TAU 72. DYNAMIC MODEL GUIDANCE IS IN AGREEMENT THAT TY 28W WILL TRACK NORTHWESTWARD AND THEN NORTHEASTWARD AROUND THE STR. THEREFORE, THERE IS HIGH CONFIDENCE IN THE JTWC FORECAST TRACK.// NNNN NNNN