MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 15W (KALMAEGI) WARNING NR 13// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON (TY) 15W (KALMAEGI), LOCATED APPROXIMATELY 287 NM EAST- NORTHEAST OF MANILA, PHILIPPINES, HAS TRACKED NORTHWESTWARD AT 11 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY INDICATES THAT THE SYSTEM HAS MAINTAINED CONVECTIVE STRUCTURE WITH AN OBLONG CENTRAL DENSE OVERCAST FEATURE WITH DEEP CONVECTIVE BANDING OVER THE SOUTHWEST QUADRANT. A 131714Z GCOMW1 89 GHZ IMAGE SHOWS AN ELONGATED MICROWAVE EYE FEATURE WITH INTENSE DEEP CONVECTIVE BANDING WRAPPING INTO THE EASTERN QUADRANT OF THE LOW- LEVEL CIRCULATION CENTER. BASED ON THE GCOMW1 IMAGE, THERE IS GOOD CONFIDENCE IN THE INITIAL POSITION AND RECENT NORTHWESTWARD TRACK MOTION. THE INITIAL INTENSITY REMAINS ASSESSED AT 65 KNOTS BASED ON THE PERSISTENT CONVECTIVE STRUCTURE AND DVORAK INTENSITY ESTIMATES OF T4.0 (65 KNOTS). DESPITE PERSISTENT MODERATE NORTHEASTERLY VERTICAL WIND SHEAR (VWS), WHICH IS HINDERING DEEP CONVECTIVE DEVELOPMENT OVER THE NORTHERN SEMI-CIRCLE, TY 15W APPEARS TO BE FIGHTING THE ENVIRONMENT AND HAS SLIGHTLY IMPROVED POLEWARD OUTFLOW OVER THE PAST 12 HOURS. ADDITIONALLY, THE MODERATE VWS IS BEING REDUCED BY THE WESTWARD TRACK MOTION. RECENT 500 MB ANALYSES SHOW A STRONG, BROAD, EAST-WEST ORIENTED SUBTROPICAL RIDGE (STR) ENTRENCHED TO THE NORTH AND NORTHWEST. 3. FORECAST REASONING. A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TY 15W IS FORECAST TO ACCELERATE WEST-NORTHWESTWARD UNDER THE STEERING INFLUENCE OF THE STRONG STR THROUGH TAU 72. TY 15W IS FORECAST TO INTENSIFY THROUGH TAU 12, PRIOR TO MAKING LANDFALL NEAR TAU 18 OVER THE EASTERN COAST OF LUZON, UNDER FAVORABLE ENVIRONMENTAL CONDITIONS TO INCLUDE WARM SST, HIGH OCEAN HEAT CONTENT AND FAVORABLE OUTFLOW. AS TY 15W CROSSES THE MOUNTAINOUS TERRAIN OF LUZON, IT IS FORECAST TO WEAKEN BUT IS EXPECTED TO RE- INTENSIFY AFTER RE-EMERGING OVER THE SOUTH CHINA SEA. C. IN THE EXTENDED TAUS, TY 15W IS EXPECTED TO MAINTAIN A PREDOMINANTLY WESTWARD TRACK THROUGH THE REMAINDER OF THE FORECAST PERIOD AS THE STR REMAINS ENTRENCHED TO THE NORTH. NEAR TAU 72, TY KALMAEGI IS FORECAST TO WEAKEN AS IT APPROACHES THE SOUTHERN COAST OF CHINA AND SHOULD DISSIPATE BETWEEN TAU 96 AND 120 AS IT TRACKS WELL INLAND. DYNAMIC MODEL GUIDANCE (INCLUDING THE MODEL ENSEMBLES) IS IN TIGHT AGREEMENT, THEREFORE, THERE IS HIGH CONFIDENCE IN THE JTWC FORECAST TRACK, WHICH IS POSITIONED CLOSE TO THE MULTI-MODEL CONSENSUS.// NNNN NNNN