WDPN31 PGTW 251500 MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC// SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 26W (NIDA) WARNING NR 15// RMKS/ 1. FOR METEOROLOGISTS. 2. 12 HOUR SUMMARY AND ANALYSIS. A. SUPER TYPHOON (STY) 26W (NIDA), LOCATED APPROXIMATELY 155 NM WEST-SOUTHWEST OF GUAM, HAS TRACKED NORTHWESTWARD AT 13 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY AND A 250943Z SSMIS PASS INDICATE STY 26W HAS MAINTAINED A WELL DEFINED, SYMMETRICAL STRUCTURE OVER THE PAST 12 HOURS, WITH A SIGNIF- ICANT INCREASE IN INTENSITY. A DVORAK FIX OF 7.5 FROM PGTW AND KNES, AND A 6.5 FROM RJTD, SUPPORT THE CURRENT INTENSITY OF 150 KNOTS. NIDA CONTINUES TO RAPIDLY INTENSIFY (50 KNOT IN 12 HOURS). THE SEA SURFACE TEMPERATURES REMAIN VERY FAVORABLE WITH INDICATIONS THAT A WARM POOL NEAR 14N 142E WILL CAUSE FURTHER INTENSIFICATION IN THE NEXT 12 TO 24 HOURS. UPPER LEVEL ANALYSIS SHOWS AN EXPANSION IN THE RADIAL OUTFLOW ALOFT SUPPORTING THE INCREASE IN LOW LEVEL INFLOW. THERE IS HIGH CONFIDENCE IN THE CURRENT POSITION AND MOTION BASED ON THE EYE FIXES AND RADAR IMAGERY FROM GUAM. 3. FORECAST REASONING. A. OVER THE PAST 12 HOURS THE INTENSITY FOR STY 26W HAS UNDERGONE A PERIOD OF RAPID INTENSIFICATION, WHICH HAS EFFECTED THE CURRENT INTENSITY FORECAST. B. STY 26W IS CURRENTLY TRACKING NORTH-NORTHWESTWARD ALONG THE SOUTHWEST QUADRANT OF THE MID-LEVEL SUBTROPICAL RIDGE (STR) CENTERED AT 25N 160E. NIDA IS FORECAST TO CONTINUE TRACKING ALONG THE PERI- PHERY OF THE STR, TURNING NORTHWARD BY TAU 72. OVER THE NEXT 24 HOURS AN INCREASE IN AVAILABLE OCEAN HEAT CONTENT WILL ALLOW FOR FURTHER INTENSIFICATION IN THE SHORT TERM. AS STY 26W TRACKS NORTHWARD GREATER INTERACTION WITH THE MID-LATITUDE WESTERLIES WILL INCREASE THE VERTICAL WIND SHEAR (VWS) CAUSING A SLOW WEAKENING TREND BEYOND TAU 48. MODEL GUIDANCE IS IN FAIR AGREEMENT WITH THE FORECAST. THE ONLY EXCEPTION IS UKMO, WHICH SHOWS A TURN TO THE WEST-SOUTHWEST AT TAU 48. THIS REMAINS THE OUTLIER HOWEVER, WITH THE FORECAST BASED PREDOMINANTLY ON THE CONSENSUS OF AVAILABLE MODEL GUIDANCE. C. IN THE EXTENDED TAUS, THE NUMERICAL GUIDANCE HAS PREDOMINANTLY SHIFTED TO A RECURVE SCENARIO AROUND TAU 96, HOWEVER THERE IS A LARGE DIFFERENCE IN THE RECURVE POINT. ECMWF, NGPS, AND WBAR SHOW A SHARPER RECURVATURE TOWARDS IWO TO AND CHICHI JIMA. GFS AND GFDN ARE MORE IN LINE WITH THE CURRENT FORECAST, INDICATING A SLOWER TURN TO THE NORTH. THE FORECAST FAVORS A RE-CURVATURE SCENARIO BEGINNING NEAR TAU 120 WITH SLOWER TRACK SPEEDS NEAR THE RIDGE AXIS. THE PRIMARY REASONING FOR THIS IS THAT IT IS UNLIKELY THAT STY 26W WILL WEAKEN RAPIDLY SOUTH OF 20N AND TRACK SOUTHWESTWARD UNDER THE NORTHEASTERLY COOL SURGE. ALL THE MODEL FIELDS INDICATE STRONG WESTERLY FLOW NORTH OF 22N WITH VWS IN EXCESS OF 50 KNOTS AS WELL AS A DEEPENING SHORTWAVE TROUGH NORTH OF THE SYSTEM BY TAU 120. THIS IS EXPECTED TO PRODUCE A RECURVE AROUND 20N WITH A RAPIDLY WEAKENING SYSTEM AFTER TAU 120.// NNNN