WDPN31 PGTW 021500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 20W (NURI) WARNING NR 11// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUPER TYPHOON (STY) 20W (NURI), LOCATED APPROXIMATELY 566 NM NORTHWEST OF YAP, HAS TRACKED NORTHWARD AT 10 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED IMAGERY CONTINUES TO DEPICT A CENTRAL DENSE OVERCAST FEATURE WITH A 10-NM EYE. A 020906Z WINDSAT MICROWAVE IMAGE SHOWS A CORE OF CENTRAL CONVECTION WITH SYMMETRICAL CONVECTIVE BANDS, THE MAJORITY OF WHICH ARE ON THE EASTERN HALF OF THE SYSTEM. STY 20W HAS BEEN RAISED TO 130 KNOTS BASED ON DVORAK CURRENT INTENSITY ESTIMATES FROM ALL AGENCIES. UPPER-LEVEL ANALYSIS SHOWS EXCELLENT DUAL CHANNEL POLEWARD AND EQUATORWARD OUTFLOW AND LOW VERTICAL WIND SHEAR. THERE IS GOOD CONFIDENCE IN THE INITIAL POSITION BASED ON THE EYE FIX. STY 20W IS CURRENTLY TRACKING ALONG THE WESTERN PERIPHERY OF A BROAD NORTH- SOUTH ORIENTED SUBTROPICAL RIDGE (STR). 3. FORECAST REASONING. A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. STY NURI IS FORECAST TO CONTINUE TO TRACK NORTHWARD ALONG THE WESTERN PERIPHERY OF THE STR OVER THE NEXT 12 HOURS THEN BEGINNING A SLOW AND WIDE NORTHEASTWARD RECURVE. DUE TO CONTINUED FAVORABLE CONDITIONS INCLUDING RADIAL OUTFLOW, WARM SST AND HIGH OCEAN HEAT CONTENT, AND SLOWER TRACK SPEEDS, STY 20W IS EXPECTED TO INTENSIFY OVER THE NEXT 24 HOURS WITH A PEAK INTENSITY OF 145 KNOTS AT TAU 24. BEYOND TAU 36, EXPECT LOWER OCEAN HEAT CONTENT AND INCREASED VERTICAL WIND SHEAR TO LEAD TO A DECREASE IN OVERALL INTENSITY. DYNAMIC GUIDANCE IS IN VERY TIGHT AGREEMENT THROUGH TAU 72 LENDING HIGH CONFIDENCE TO THE FORECAST TRACK. C. IN THE EXTENDED FORECAST, THERE CONTINUES TO BE HIGH CONFIDENCE IN OVERALL FORECAST TRACK, WITH DYNAMIC MODELS HANDLING THE BLOCKING NATURE OF THE REDEVELOPING STR WELL. THE SYSTEM WILL BEGIN EXTRA-TROPICAL TRANSITION (ETT) JUST PRIOR TO TAU 72 AND COMPLETE ETT BY TAU 120 AS STY NURI ACCELERATES EAST OF JAPAN, WEAKENING ALONG ITS TRACK.// NNNN