MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 12W (LIONROCK) WARNING NR 26// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON (TY) 12W (LIONROCK), LOCATED APPROXIMATELY 269 NM EAST- SOUTHEAST OF KADENA AB, JAPAN, HAS TRACKED SOUTH-SOUTHWESTWARD AT 06 KNOTS OVER THE PAST SIX HOURS. TY 12W HAS RAPIDLY INTENSIFIED OVER THE PAST 24 HOURS FROM 55 KNOTS TO THE CURRENT INTENSITY OF 100 KNOTS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS A COMPACT SYSTEM WITH A 12NM EYE AND NEAR-RADIAL OUTFLOW. A 240731Z GPM 89GHZ IMAGE DEPICTS A SMALL CORE, APPROXIMATELY 30NM DIAMETER, WITH A PINHOLE EYE AND BANDING FEATURE. RECENT ANIMATED WATER VAPOR IMAGERY INDICATES THAT TY 12W HAS BEEN ABLE TO INSULATE ITSELF AND MAINTAIN RADIAL OUTFLOW DESPITE WEAKENING POLEWARD OUTFLOW AND CONVERGENT FLOW ASSOCIATED WITH THE BUILDING RIDGE TO THE NORTH. THE CURRENT INTENSITY IS ASSESSED AT 100 KNOTS BASED ON DVORAK INTENSITY ESTIMATES RANGING FROM T5.0 (90 KNOTS) TO T5.5 (102 KNOTS). ADDITIONALLY, THE 24/0630Z SATCON ESTIMATE HAS JUMPED TO 104 KNOTS. TY 12W IS TRACKING SLOWLY SOUTHWESTWARD ALONG THE EASTERN PERIPHERY OF THE WESTERN SUBTROPICAL RIDGE (STR). 3. FORECAST REASONING. A. THERE IS NO CHANGE IN THE FORECAST PHILOSOPHY FROM THE PREVIOUS PROGNOSTIC REASONING MESSAGE. HOWEVER, THE INTENSITY FORECAST HAS BEEN INCREASED SIGNIFICANTLY BASED ON THE RECENT PERIOD OF RAPID INTENSIFICATION. B. TY 12W WILL REMAIN TRAPPED WITHIN THIS COMPETING STEERING ENVIRONMENT WHILE DRIFTING SOUTHWESTWARD TO WESTWARD THROUGH TAU 36. THE WESTERN STR IS EXPECTED TO REMAIN ENTRENCHED OVER THE EAST CHINA SEA AND OKINAWA PROVIDING A BARRIER TO ANY SIGNIFICANT WESTWARD MOVEMENT. IN FACT, ALL DYNAMIC MODELS SHOW A SLOW, QUASI- STATIONARY MOTION THROUGH TAU 48 AND SHOW NO POSITION WEST OF 131E LONGITUDE. TY 12W IS FORECAST TO GRADUALLY INTENSIFY UNDER FAVORABLE CONDITIONS TO A PEAK OF 120 KNOTS BY TAU 24. C. IN THE EXTENDED TAUS, THE NEAR-EQUATORIAL RIDGE (NER) IS FORECAST TO BUILD TO THE SOUTH OF TY 12W WHILE A DEEP MIDLATITUDE TROUGH DEEPENS OVER JAPAN, ALLOWING THE SYSTEM TO ACCELERATE NORTHEASTWARD. WHILE THE MODEL VORTEX TRACKERS DIFFER ON THE EXACT NATURE OF THE TURN EASTWARD, THE TRACKERS ALL SHOW AN EASTWARD TURN WITH DIFFERENT TRACK SPEEDS. DUE TO THE COMPLEXITY OF THE STEERING ENVIRONMENT AND UNCERTAINTY IN THE EASTWARD TURN, THERE IS LOW CONFIDENCE IN JTWC FORECAST TRACK.// NNNN NNNN