MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 15W (LINGLING) WARNING NR 017// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON (TY) 15W (LINGLING), LOCATED APPROXIMATELY 173 NM NORTHWEST OF KADENA AB, OKINAWA, JAPAN HAS TRACKED NORTHWARD AT 12 KNOTS (KTS) OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY SHOWS TY 15W REMAINS CHARACTERIZED BY A SYMMETRIC CIRCULATION WITH A WELL-DEFINED 30-NM EYE. RAIN BANDS CONTINUE TO WRAP TIGHT INTO THE EYE, WHICH LENDS TO HIGH CONFIDENCE IN THE INITIAL POSITION PLACEMENT BASED ON A DISCERNIBLE EYE FEATURE IN HIMAWARI-8 VISIBLE 1 KM IMAGERY. THE INITIAL INTENSITY OF 120 KTS IS BASED ON AN OVERALL ASSESSMENT OF AGENCY AND OBJECTIVE DVORAK ESTIMATES RANGING FROM T6.0 TO T6.2. UPPER LEVEL ANALYSIS INDICATES THAT THE SYSTEM REMAINS IN AN AREA OF LOW TO MODERATE VERTICAL WIND SHEAR (VWS) WITH VALUES OF 5-20 KTS. ADDITIONALLY, THERE CONTINUES TO BE EXCELLENT POLEWARD AND EQUATORWARD OUTFLOW. ALONG-TRACK SEA SURFACE TEMPERATURE (SST) REMAIN CONDUCIVE AT 29-30 CELSIUS. THE CYCLONE IS TRACKING ALONG THE WESTERN PERIPHERY OF THE SUBTROPICAL RIDGE (STR) TO THE EAST. 3. FORECAST REASONING. A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TY 15W WILL MAINTAIN THE CURRENT NORTHWARD TRACK AS IT IS STEERED BY THE STR. AFTER TAU 24, IT WILL SHIFT TO A MORE NORTH-NORTHEASTWARD TRACK AS IT ROUNDS THE STR AXIS, MAKING LANDFALL ALONG THE SOUTH COAST OF NORTH KOREA AROUND TAU 30. THE SYSTEM WILL TRACK OVER RUGGED TERRAIN AND MOVE INTO NORTHEASTERN CHINA BY TAU 72. THE AFOREMENTIONED FAVORABLE ENVIRONMENT WILL ALLOW TY 15W TO MAINTAIN CURRENT INTENSITY UNTIL TAU 12. AS IT MOVES THROUGH THE YELLOW SEA, TY 15W WILL GRADUALLY WEAKEN DUE TO INCREASING VWS AND COOLING SST VALUES. TY 15W WILL BEGIN EXTRA-TROPICAL TRANSITION (ETT) AS IT ENTERS THE MIDLATITUDE BAROCLINIC ZONE AROUND TAU 30 AND SUBSEQUENTLY RAPIDLY DECAY WITH LAND INTERACTION. THE TAU 72 POSITION SHOWS INCREASING TRACK SPEEDS AND WIND RADII AS THE SYSTEM COMPLETES ETT AND TRANSFORMS INTO A STRONG GALE FORCE COLD CORE LOW. NUMERICAL MODELS ARE IN TIGHT AGREEMENT THROUGHOUT THE FORECAST, WITH ONLY A SLIGHT INCREASE IN UNCERTAINTY DUE TO DIFFERENCES IN ALONG-TRACK SPEED AFTER TAU 36. BASED ON THE RELATIVELY LOW UNCERTAINTY, THERE IS HIGH CONFIDENCE IN THE JTWC TRACK FORECAST WHICH CLOSELY FOLLOWS CONSENSUS.// NNNN NNNN