MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 31W (YUTU) WARNING NR 26// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUPER TYPHOON (STY) 31W (YUTU), LOCATED APPROXIMATELY 616 NM EAST-NORTHEAST OF MANILA, PHILIPPINES, HAS TRACKED WESTWARD AT 11 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS THE SYSTEM HAS MAINTAINED AN ENLARGING 36-NM RAGGED EYE AS COMPACT RAIN BANDS CONTINUE TO WRAP TIGHTLY TOWARD THE CENTRAL CONVECTION WITH VERY COLD CONVECTIVE TOPS (LESS THAN -80C) ESPECIALLY ALONG THE SOUTHWEST QUADRANT. THE INITIAL POSITION IS BASED ON THE EYE FEATURE IN THE EIR LOOP WITH HIGH CONFIDENCE. THE INITIAL INTENSITY OF 135 KNOTS IS AVERAGED FROM NEAR CONCENTRIC DVORAK FIXES FROM PGTW (T6.5), RJTD (T7.0), AND CIMS (T7.1). UPPER LEVEL ANALYSIS INDICATES THE SYSTEM IS IN AN AREA OF LOW (10-15 KNOT) RELATIVE EASTERLY VERTICAL WIND SHEAR (VWS) AND ROBUST RADIAL OUTFLOW WITH A STRONG POLEWARD CHANNEL. ADDITIONALLY, ALONG-TRACK SST AND OHC VALUES IN THE PHILIPPINE SEA ARE PERENNIALLY CONDUCIVE. THE CYCLONE IS TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF AN EAST-WEST ORIENTED SUBTROPICAL RIDGE (STR). 3. FORECAST REASONING. A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. STY 31W WILL TRACK WESTWARD THEN WEST-SOUTHWESTWARD TOWARD LUZON AS THE STR BUILDS, MAKING LANDFALL NEAR PALANAN, ISABELA AROUND TAU 54, DRAG QUICKLY ACROSS LUZON AND EXIT INTO THE SOUTH CHINA SEA (SCS) BY TAU 72. THE SYSTEM WILL INITIALLY MAINTAIN ITS CURRENT INTENSITY THEN SLOWLY WEAKEN TO 125 KNOTS BY TAU 36 AS OUTFLOW DIMINISHES. HOWEVER, BY TAU 48, PRIOR TO LANDFALL, THE CYCLONE IS EXPECTED TO RE-INTENSIFY TO 130 KNOTS AS POLEWARD OUTFLOW INCREASES AHEAD OF A MID-LATITUDE SHORTWAVE TROUGH APPROACHING FROM THE NORTHWEST. AFTERWARD, LAND INTERACTION WITH LUZON AND INCREASING VWS WILL REDUCE THE SYSTEM DOWN TO 80 KNOTS AS IT EXITS INTO THE SCS. NUMERICAL GUIDANCE IS IN GOOD AGREEMENT WITH MINIMAL SPREADING TO 180 NM AT TAU 72, LENDING HIGH CONFIDENCE IN THIS PORTION OF THE JTWC FORECAST THAT IS LAID VERY CLOSE TO CONSENSUS. CTCX CONTINUES TO BE THE RIGHT OF TRACK OUTLIER AND JGSM ON THE LEFT. C. BEYOND TAU 72, THE AFOREMENTIONED MID-LATITUDE TROUGH WILL WEAKEN THE STR AND ALLOW STY 31W TO TURN NORTHWARD. ENVIRONMENTAL CONDITIONS WILL BE MARGINALLY FAVORABLE AS THE CYCLONE STARTS TO RECURVE AROUND THE STR AXIS AND SOME INTENSIFICATION IS ANTICIPATED ONCE THE CYCLONE MOVES BACK OVER WATER, TEMPERED ONLY BY A COLD SURGE EVENT IN THE SCS. ALL MEMBERS OF THE CONSENSUS ARE NOW DEPICTING RECURVATURE IN VARYING DEGREES. THE SPREAD BETWEEN THE LEFTMOST (JGSM) AND RIGHTMOST (CTCX) MEMBERS HAS DECREASED TO 480 NM AT TAU 120, LENDING FAIR CONFIDENCE IN THE EXTENDED PORTION OF THE JTWC FORECAST TRACK THAT IS ALSO LAID CLOSE TO CONSENSUS.// NNNN NNNN