MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 23W (SONGDA) WARNING NR 15// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUPER TYPHOON (STY) 23W (SONGDA), LOCATED APPROXIMATELY 556 NM EAST-SOUTHEAST OF YOKOSUKA, JAPAN, HAS TRACKED NORTHEASTWARD AT 16 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY DEPICTS A VERY SYMMETRIC CORE STRUCTURE WITH A RESURGENCE IN DEEP CONVECTION SURROUNDING A SHARP 12NM EYE. ALTHOUGH THE SYSTEM IS NORTH OF THE SUB-TROPICAL RIDGE (STR) AXIS, IT HAS GONE THROUGH A PERIOD OF RAPID INTENSIFICATION OVER THE PAST 12 HOURS. THIS IS DUE TO THE CYCLONE MOVING IN-PHASE WITH THE 25 TO 30 KNOT SOUTHWESTERLY VERTICAL WIND SHEAR, REDUCING ITS OVERALL IMPACTS TO THE STORM. WATER VAPOR IMAGERY SHOWS AN ENHANCED POLEWARD OUTFLOW CHANNEL INTO THE STRONG MID-LATITUDE WESTERLY FLOW. THE CURRENT POSITION IS BASED ON THE EYE FEATURE WITH HIGH CONFIDENCE. THE INCREASE IN INTENSITY IS BASED ON THE INTENSE CORE STRUCTURE OF THE CYCLONE WHICH IS READILY APPARENT IN AN 111538Z AMSR-2 89GHZ MICROWAVE IMAGE SHOWING AN INTENSE RED RING FULLY SURROUNDING THE EYE. ADDITIONALLY, ALL AGENCIES ARE REPORTING DVORAK INTENSITY ESTIMATES OF T6.5 (127 KNOTS). STY 23W IS BEGINNING TO ACCELERATE NORTHEASTWARD ALONG THE NORTHWESTERN PERIPHERY OF THE DEEP LAYERED STR. 3. FORECAST REASONING. A. NO SIGNIFICANT CHANGE TO THE FORECAST TRACK PHILOSOPHY FROM THE PREVIOUS PROGNOSTIC REASONING MESSAGE. HOWEVER, THE CURRENT AND FORECASTED INTENSITY HAS BEEN INCREASED BASED ON THE RECENT RAPID INTENSIFICATION. B. STY SONGDA WILL CONTINUE ACCELERATING NORTHEASTWARD AS IT EMBEDS DEEPER WITHIN THE MID-LATITUDE WESTERLY FLOW. THE CYCLONE WILL SOON ENCOUNTER VWS OVER 40 KNOTS AND, ALTHOUGH IT WILL BE IN- PHASE WITH THE MOVEMENT OF STY 23W, WILL OFFSET THE OUTFLOW AND BEGIN THE FINAL WEAKENING PHASE. STY SONGDA WILL BEGIN EXTRA- TROPICAL TRANSITION (ETT) OVER THE NEXT 12 HOURS AND COMPLETE ETT BY THE END OF THE FORECAST PERIOD. DYNAMIC MODEL GUIDANCE REMAINS IN TIGHT AGREEMENT LENDING HIGH CONFIDENCE TO THE FORECAST TRACK.// NNNN NNNN