WDPN31 PGTW 060300 MSGID/GENADMIN/NAVPACMETOCCEN PEARL HARBOR HI/JTWC// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 04W (NESAT) WARNING NR 28// RMKS/ 1. FOR METEOROLOGISTS. 2. PROGNOSTIC REASONING FOR 060000Z TO 110000Z JUN 2005. A. TYPHOON (TY) 04W (NESAT), LOCATED APPROXIMATELY 430 NM SOUTHEAST OF OKINAWA, HAS TRACKED NORTHEASTWARD AT 10 KNOTS OVER THE PAST SIX HOURS. B. TY 04W IS FORECAST TO TRACK ALONG THE NORTHWESTERN PERI- PHERY OF THE MID-LEVEL STEERING RIDGE LOCATED EAST OF THE SYSTEM THROUGH TAU 24. A SHORT-TERM NORTHWARD TRACK IS FORECAST BETWEEN TAUS 12 AND 36 CAUSED BY BRIEF ENHANCEMENT OF THE STEERING RIDGE DUE TO A PASSING MID-LATITUDE SHORTWAVE RIDGE. THE LONGWAVE TROUGH CURRENTLY OVER CENTRAL CHINA IS FORECAST TO WEAKEN THE STEERING RIDGE AFTER TAU 48 AND SHIFT TY 04W BACK TO A NORTHEASTWARD TRACK. THE AVAILABLE MODELS ARE IN GOOD AGREEMENT WITH THIS SCENARIO. C. WATER VAPOR AND MICROWAVE IMAGERY SHOW SUPPRESSED CONVECTION IN THE NORTHWESTERN QUADRANT DUE TO CONFLUENT FLOW ALOFT. BUT POLE- WARD OUTFLOW IS IMPROVING AND IS EXPECTED TO INCREASE INTENSITY SLIGHTLY IN THE EARLY PERIOD. AFTER TAU 48, TY 04W IS FORECAST TO WEAKEN DUE TO HIGHER SHEAR ASSOCIATED WITH THE BAROCLINIC ZONE AND BEGIN A RAPID EXTRATROPICAL TRANSITION. D. CURRENT WIND RADII ARE BASED ON RECENT QUIKSCAT IMAGERY. FORECAST WIND RADII ARE BASED ON CLIMATOLOGY FOR AN AVERAGE-SIZED SYSTEM. E. IN THE EXTENDED FORECAST, TY 04W IS FORECAST TO INTERACT WITH THE APPROACHING BAROCLINIC SYSTEM, WEAKEN, ACCELERATE AND COMPLETE EXTRATROPICAL TRANSITION BY TAU 120. 3. FORECAST TEAM: ALPHA// NNNN