MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 20W (MEGI) WARNING NR 08// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON 20W (MEGI), LOCATED APPROXIMATELY 544 NM SOUTH-SOUTHEAST OF KADENA AB, HAS TRACKED WEST-NORTHWESTWARD AT 12 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY DEPICTS A BROAD CONSOLIDATING SYSTEM WITH DEEP FLARING CENTRAL CONVECTION OBSCURING THE LOW LEVEL CIRCULATION CENTER. THE INITIAL POSITION IS BASED ON SATELLITE FIXES FROM PGTW AND RJTD WITH LOW CONFIDENCE. THE INITIAL INTENSITY IS ASSESSED AT 75 KNOTS AND IS BASED ON MULTI- AGENCY DVORAK ESTIMATES OF T4.5 (77 KNOTS). UPPER-LEVEL ANALYSIS SHOWS EXCELLENT RADIAL OUTFLOW OVER THE SYSTEM WITH A TUTT CELL POSITIONED TO THE EAST. THE TUTT CELL HAS BEEN ENHANCING OUTFLOW, BUT IS NOW SHOWING SIGNS OF ENCROACHMENT ON THE SYSTEM. VERTICAL WIND SHEAR IS VERY LOW (5 TO 10 KNOTS) AND SSTS ARE VERY WARM, NEAR 30 CELSIUS. CURRENTLY TY MEGI IS TRACKING WEST-NORTHWEST ALONG THE PERIPHERY OF A DEEP-LAYERED SUBTROPICAL RIDGE. 3. FORECAST REASONING. A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING BULLETIN. B. TY MEGI WILL CONTINUE ON A WEST-NORTHWEST TRACK ALONG THE CURRENT STEERING RIDGE THROUGHOUT THE FORECAST PERIOD. INTENSIFICATION IS EXPECTED OVER THE NEXT 48 HOURS REACHING A PEAK INTENSITY OF 110 KNOTS AS ENVIRONMENTAL CONDITIONS CONTINUE TO REMAIN FAVORABLE. THE EASTWARD POSITIONED TUTT CELL WILL LIKELY HINDER OUTFLOW OVER THE NEXT 12 HOURS, BUT NOT SUFFICIENTLY TO MITIGATE FURTHER INTENSIFICATION. TY MEGI IS EXPECTED TO MAKE LANDFALL OVER THE MOUNTAINOUS REGION OF SOUTHERN TAIWAN NEAR TAU 60, WEAKENING RAPIDLY INTO A TROPICAL STORM AS IT RESURFACES OVER WATER NEAR TAU 72. C. IN THE EXTENDED FORECAST TY MEGI WILL CONTINUE WEST-NORTHWEST ALONG THE CURRENT STEERING RIDGE INTO CHINA. RAPID DISSIPATION IS EXPECTED OVER LAND JUST BEYOND TAU 120. DYNAMIC MODEL GUIDANCE IS IN VERY TIGHT AGREEMENT WITH BOTH THE SPEED AND TRACK OF TY MEGI. THE FORECAST TRACK IS PLACED WITH HIGH CONFIDENCE ALONG THE MULTI- MODEL CONSENSUS.// NNNN NNNN