WDPN31 PGTW 271500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 28W (TRAMI) WARNING NR 28// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON (TY) 28W (TRAMI), LOCATED APPROXIMATELY 275 NM SOUTH-SOUTHEAST OF KADENA AB, OKINAWA, JAPAN, HAS TRACKED NORTHWESTWARD AT 05 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY SHOWS TY 28W CONTINUES TO HAVE A WIDE AND RAGGED EYE AND THAT DEEP CONVECTION AROUND IT HAS INCREASED OVER THE PAST SEVERAL HOURS. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE AND IS BASED ON A 271200Z HIMAWARI INFRARED SATELLITE IMAGE SHOWING THE LARGE EYE. THE INITIAL INTENSITY OF 90 KNOTS IS BASED ON DVORAK CURRENT INTENSITY (CI) ESTIMATES OF T5.0 (90 KNOTS) FROM PGTW, RJTD, AND KNES AND ALSO HEDGED SLIGHTLY ABOVE A 271014Z SATCON ESTIMATE OF 85 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. HOWEVER, OCEAN HEAT CONTENT HAS DIMINISHED DUE TO THE FACT THAT TY 28W HAS REMAINED QUASI-STATIONARY AND HAS CAUSED UPWELLING IN THE AREA. TY 28W REMAINS IN A WEAK STEERING ENVIRONMENT WHILE IN BETWEEN A SUBTROPICAL RIDGE (STR) LOCATED TO THE WEST AND A SECOND 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 IS FORECAST TO TRACK SLOWLY NORTHWESTWARD WHILE IT REMAINS POSITIONED BETWEEN THE TWO AFOREMENTIONED STRS. THE STR TO THE EAST WILL EVENTUALLY BECOME THE DOMINANT STEERING FEATURE AND ALLOW FOR TY 28W TO INCREASE IN TRACK SPEED AS IT MOVES TO THE NORTHWEST. SHORTLY AFTER TAU 24, TY 28W WILL BEGIN TO ROUND THE STR AXIS AND THEN START TO TRACK NORTHEASTWARD. AS TY 28W ROUNDS THE STR IT WILL ENCOUNTER WARMER SEA SURFACE TEMPERATURES AND OUTFLOW WILL IMPROVE AS IT TAPS INTO THE WESTERLIES. THIS WILL ALLOW TY 28W TO RE-INTENSIFY TO 105 KNOTS BY TAU 48. THE JTWC FORECAST TRACK IS PLACED NEAR THE MULTI-MODEL CONSENSUS. MODELS AGREE THAT TY 28W WILL TRACK NORTHWESTWARD AND THEN NORTHEASTWARD. DYNAMIC MODEL GUIDANCE HAS COME INTO BETTER AGREEMENT AND HAS A SPREAD OF 85 NM BY TAU 48 WITH NAVGEM THE WESTERN MOST OUTLIER AND CTCX THE EASTERN MOST OUTLIER. DUE TO THE IMPROVED AGREEMENT AMONG THE MODELS, THERE IS NOW HIGH CONFIDENCE IN THIS PORTION OF THE JTWC FORECAST TRACK. C. AFTER TAU 72, TY 28W WILL CONTINUE TO ACCELERATE TO THE NORTHEAST AROUND THE STR AS IT INTERACTS WITH THE APPROACHING WEST TO EAST MOVING SHORTWAVE THOUGH. ADDITIONALLY, AFTER TAU 72, TY 28W WILL CONTINUE EXTRA-TROPICAL TRANSITION (ETT) AS IT INTERACTS WITH THE TROUGH. AS TY 28W ACCELERATES NORTHEASTWARD IT WILL DECREASE IN OVERALL INTENSITY WITH AN EXPANDING WIND FIELD. TY 28W WILL COMPLETE ETT BY TAU 96. DYNAMIC MODEL GUIDANCE IS IN GOOD AGREEMENT THAT TY 28W WILL TRACK NORTHEASTWARD BUT THERE IS A WIDE RANGE IN TRACK SPEED. THE JTWC FORECAST TRACK IS PLACED SLIGHTLY AHEAD OF THE MULTI-MODEL CONSENSUS. OVERALL, THERE IS STILL LOW CONFIDENCE IN THIS PORTION OF THE JTWC FORECAST TRACK.// NNNN