MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 15W (LINGLING) WARNING NR 018// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON (TY) 15W (LINGLING), LOCATED APPROXIMATELY 384 NM SOUTH OF KUNSAN AB, HAS TRACKED NORTHWARD AT 15 KNOTS (KTS) OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY SHOWS TY 15W WITH A WELL-DEFINED 8-NM EYE FEATURE LENDING HIGH CONFIDENCE TO THE PLACEMENT OF THE INITIAL POSITION. A 060507Z AMSR2 89 GHZ MICROWAVE IMAGE DEPICTS A TIGHT CIRCULATION WITH SHARPLY OUTLINED RAIN BANDS WRAPPING INTO THE EYE AND A VERY DEEP EYEWALL OVER 50 PERCENT OF THE STORM. THE INITIAL INTENSITY OF 110 KTS IS BASED ON AN ASSESSMENT OF DVORAK FINAL T AND CURRENT INTENSITY ESTIMATES RANGING FROM T5.0-6.0 (90-115 KTS) THAT INDICATES SUBTLE WEAKENING OF THE SYSTEM FROM THE PRIOR FORECAST. UPPER LEVEL ANALYSIS INDICATES THAT THE SYSTEM IS PASSING THROUGH AN AREA OF MODERATE (15-20 KTS) VERTICAL WIND SHEAR (VWS); HOWEVER, THERE CONTINUES TO BE EXCELLENT POLEWARD AND EQUATORWARD OUTFLOW. ADDITIONALLY, ALONG-TRACK SEA SURFACE TEMPERATURE (SST) REMAINS FAVORABLE AT 28-30 CELSIUS. TY 15W IS TRACKING NORTHWARD, TRANSITING ALONG THE WESTERN PERIPHERY OF A 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. PRIOR TO TAU 24, TY 15W WILL MAINTAIN THE CURRENT NORTHWARD TRACK ALONG THE PERIPHERY OF THE STR. AFTER TAU 24, THE TRACK WILL SHIFT NORTH-NORTHEASTWARD WHILE MAKING LANDFALL ALONG THE SOUTH COAST OF NORTH KOREA. INCREASING VWS AND COOLING SST VALUES WILL GRADUALLY WEAKEN TY 15W AS IT APPROACHES THE COAST. AFTER MAKING LANDFALL, THE RUGGED TERRAIN WILL CAUSE MORE RAPID WEAKENING. AROUND TAU 24, TY 15W WILL BEGIN EXTRA-TROPICAL TRANSITION (ETT) AS IT BEGINS INTERACTING WITH THE MIDLATITUDE BAROCLINIC ZONE. THE TAU 36 POSITION SHOWS AN INCREASING TRACK SPEED AND WIND RADII AS THE SYSTEM COMPLETES ETT AND TRANSFORMS INTO A COLD CORE LOW. NUMERICAL MODELS ARE IN TIGHT AGREEMENT THROUGHOUT THE FORECAST, THUS THERE IS HIGH CONFIDENCE IN THE JTWC TRACK FORECAST.// NNNN NNNN