MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 30W (NOCK-TEN) WARNING NR 19// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON (TY) 30W (NOCK-TEN), LOCATED APPROXIMATELY 134 NM EAST- SOUTHEAST OF MANILA, PHILIPPINES, HAS TRACKED WESTWARD AT 10 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE (EIR) IMAGERY SHOWS THE SYSTEM HAS MADE LANDFALL AND IS NOW DRAGGING ACROSS SOUTHERN LUZON. CONVECTIVE BANDS HAVE BECOME MORE SHALLOW AND SLIGHTLY UNRAVELED DUE TO THE LAND INTERACTION. ADDITIONALLY, THE EYE FEATURE HAS BECOME CLOUD-FILLED. THE INITIAL POSITION IS BASED ON A WARM PIXEL CLUSTER ON THE CENTRAL CONVECTION AND ON A CIRCULATION FEATURE ON A COMPOSITE RADAR REFLECTIVITY LOOP FROM TAGAYTAY CITY. THE INITIAL INTENSITY OF 100 KNOTS IS EXTRAPOLATED FROM DVORAK ESTIMATES PRIOR TO LANDFALL AND FROM NEARBY OBSERVING STATIONS. UPPER-LEVEL ANALYSIS INDICATES THAT SANS THE LAND INTERACTION, TY 30W CONTINUES TO TRACK IN AN AREA OF LOW (05-10 KNOT) VERTICAL WIND SHEAR (VWS) AND EXCELLENT RADIAL OUTFLOW. THE CYCLONE IS TRACKING ALONG THE SOUTHERN PERIPHERY OF A DEEP-LAYERED SUBTROPICAL RIDGE (STR) TO THE NORTH. 3. FORECAST REASONING. A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TY NOCK-TEN WILL TURN WEST-NORTHWESTWARD TOWARD A DEVELOPING WEAKNESS IN THE STEERING RIDGE, PASSING JUST SOUTH OF MANILA, BEFORE EXITING INTO THE SOUTH CHINA SEA (SCS) BY TAU 18. AFTER TAU 24, TY 30W WILL GRADUALLY TURN SOUTHWESTWARD AS A SECONDARY STR CENTERED OVER EASTERN CHINA ASSUMES STEERING. THE SYSTEM WILL STEADILY WEAKEN DUE TO LAND INTERACTION. AFTER TAU 24, CONCURRENT WITH THE CHANGE TO A SOUTHWESTWARD TRACK, TY 30W WILL RAPIDLY WEAKEN DUE TO INCREASED VWS (20-25 KNOTS) AND EXPOSURE TO THE STRONG COLD NORTHEASTERLY SURGE IN THE SCS. BY TAU 48, THE LOW LEVEL CIRCULATION IS EXPECTED TO BECOME DECOUPLED FROM THE CONVECTION, FULLY DISSIPATING BY TAU 72. DYNAMIC MODEL GUIDANCE REMAINS IN GOOD AGREEMENT WITH SOME SPREADING IN THE SCS. THE JTWC FORECAST TRACK IS POSITIONED CLOSE TO THE MULTI-MODEL CONSENSUS AND REMAINS CONSISTENT WITH PREVIOUS FORECASTS, LEADING TO HIGH CONFIDENCE IN THE JTWC FORECAST TRACK.// NNNN NNNN