MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 28W (TRAMI) WARNING NR 25// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON 28W (TRAMI), LOCATED APPROXIMATELY 315 NM SOUTH- SOUTHEAST OF KADENA AB, HAS TRACKED NORTHWARD AT 01 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY SHOWS TY 28W MAINTAINS A WIDE EYE, WITH RESURGENT CONVECTION IN THE EYEWALL. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE WIDE EYE IN THE EIR LOOP. THE INITIAL INTENSITY IS MAINTAINED AT 90 KNOTS, BETWEEN MULTIAGENCY DVORAK CURRENT INTENSITY (CI) ESTIMATES RANGING FROM T4.5 (77 KTS) TO T5.5 (102 KTS), AND IN AGREEMENT WITH A 261705Z SATCON ESTIMATE OF 91 KNOTS. ENVIRONMENTAL ANALYSIS SHOWS TY 28W IS EXPERIENCING FAVORABLE VERTICAL WIND SHEAR (5 TO 10 KNOTS) ALONG WITH GOOD RADIAL OUTFLOW, WHICH IS BEING ENHANCED BY A PASSING MIDLATITUDE TROUGH TO THE NORTH. SEA SURFACE TEMPERATURES REMAIN FAVORABLE NEAR 28 DEGREES CELSIUS, ALTHOUGH THE SLOW MOTION OF TY 28W IS CAUSING UPWELLING AND REDUCING THE AVAILABLE OCEAN HEAT CONTENT (OHC) FOR THE SYSTEM, CONTRIBUTING TO ITS STRUGGLE TO MAINTAIN DEEP CONVECTION. TY 28W IS ALMOST QUASI-STATIONARY IN A WEAK STEERING ENVIRONMENT WHILE 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 NORTH TO NORTHWESTWARD IN THE AMBIGUOUS STEERING ENVIRONMENT WHILE MAINTAINING ITS INTENSITY, CAUGHT IN A BALANCE BETWEEN FAVORABLE OUTFLOW AND LOW VWS, AND THE UNFAVORABLE LOWER OHC. AFTER TAU 12, THE STR TO THE EAST WILL BUILD, BECOME THE DOMINANT STEERING FEATURE, AND ALLOW TY 28W TO INCREASE FORWARD MOTION AND TRACK NORTHWESTWARD THROUGH TAU 48. BY TAU 36, TY 28W WILL ENCOUNTER AN AREA OF WARM (28-30 C) SSTS THAT IT HAS NOT ALREADY CHURNED UP, WHICH WILL ALLOW FOR A PERIOD OF RE- INTENSIFICATION, REACHING 110 KTS BY TAU 72. MODELS ARE IN AGREEMENT THAT TY 28W WILL TRACK NORTHWESTWARD, WITH NAVGEM A NOTABLE OUTLIER TO THE WEST DUE TO IT BUILDING IN A MORE ROBUST STR TO THE EAST. THE JTWC FORECAST TRACK IS PLACED JUST TO THE WEST OF THE MULTI-MODEL CONSENSUS, CLOSER TO THE ECMWF SOLUTION, PASSING CLOSE TO OKINAWA AROUND TAU 60. THE LAST SEVERAL MODEL RUNS SHOW THE MULTI-MODEL CONSENSUS TRENDING CLOSER TO OKINAWA, FAVORING A TIGHTER RECURVE SCENARIO. DUE TO THE 360 NM MODEL SPREAD AT TAU 72, THERE IS LOW CONFIDENCE IN THIS PORTION OF THE JTWC FORECAST TRACK. C. AFTER TAU 72, TY 28W IS FORECAST TO ACCELERATE NORTHEASTWARD TOWARD MAINLAND JAPAN AS IT ROUNDS THE STR AXIS AND IS PULLED BY A PASSING MIDLATITUDE TROUGH. INCREASED VERTICAL WIND SHEAR, COOLER SEA SURFACE TEMPERATURES, AND EVENTUAL LAND INTERACTION WILL WEAKEN THE SYSTEM AS IT TRACKS NORTHEASTWARD. TY 28W WILL BE EMBEDDED IN THE BAROCLINIC ZONE AND BEGIN EXTRA-TROPICAL TRANSITION (ETT) BY TAU 96, AND WILL COMPLETE ETT BY TAU 120. THE JTWC FORECAST TRACK IS PLACED NEAR THE MULTI-MODEL CONSENSUS. MODEL GUIDANCE IS IN GOOD AGREEMENT THAT TY 28W WILL TRACK NORTHEASTWARD, BUT MODELS DIFFER ON THE TRACK SPEED. THEREFORE, THERE IS LOW CONFIDENCE IN THIS PORTION OF THE JTWC FORECAST TRACK.// NNNN NNNN