MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 10W (SAOLA) WARNING NR 20// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON 10W (SAOLA), LOCATED APPROXIMATELY 40 NM SOUTHEAST OF TAIPEI, TAIWAN, HAS TRACKED NORTHWESTWARD AT 10 KNOTS OVER THE PAST SIX HOURS. ANIMATED INFRARED (IR) SATELLITE IMAGERY INDICATES A GENERAL WEAKENING TREND AS TY 10W MAKES LANDFALL OVER NORTHERN TAIWAN. IR IMAGERY SHOWS THAT THE 20NM IRREGULAR EYE THAT WAS PREVIOUSLY EVIDENT HAS BECOME CLOUD-FILLED OVER THE PAST 2 HOURS. A 011812Z AMSU IMAGE ALSO INDICATES SIGNIFICANT WEAKENING WITH TIGHTLY- CURVED BANDING WRAPPING INTO A DEFINED LOW-LEVEL CIRCULATION CENTER. RADAR IMAGERY FROM TAIWAN SHOWS THAT THE SYSTEM MADE LANDFALL AT 01/19Z AND IS CURRENTLY LOOPING OVER THE NORTHEAST COAST. SURFACE OBSERVATIONS FROM NORTHERN TAIWAN HAVE NOT BEEN TOO IMPRESSIVE AND CURRENTLY SHOW ONLY 15-20 KNOT SUSTAINED WINDS WITH 35-40 KNOT GUSTS. ANIMATED WATER VAPOR IMAGERY INDICATES RADIAL OUTFLOW. OVER THE PAST SIX HOURS, TY 10W IS TURNING NORTHWESTWARD ALONG THE SUBTROPICAL RIDGE POSITIONED TO THE NORTH; HOWEVER, AS MENTIONED PREVIOUSLY, THE SYSTEM IS GOING THROUGH A SHORT-TERM LOOP. TY 10W'S CENTER IS CURRENTLY SEPARATED BY ABOUT 487 NM AND IS EXPECTED TO CLOSE TO 426 NM BY TAU 12 AND 370 NM BY TAU 24. THIS WILL LIKELY RESULT IN SOME WEAK BINARY INTERACTION WITH 11W, RESULTING IN A CYCLONIC, RAPIDLY DISSIPATING TRACK FOR 11W. 3. FORECAST REASONING. A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM THE PREVIOUS PROGNOSTIC REASONING. B. TY 10W IS EXPECTED TO RETURN TO A NORTHWESTWARD TRACK AFTER FINISHING THE LOOP. THE 01/12Z 500 MB ANALYSIS CONTINUES TO DEPICT A SOLID STR EXTENDING FROM THE KOREAN PENINSULA WEST-SOUTHWESTWARD INTO CHINA WITH A SHORT-WAVE MIDLATITUDE TROUGH MOVING NORTHEASTWARD INTO MANCHURIA. DYNAMIC MODEL GUIDANCE IS IN TIGHT AGREEMENT AND SUPPORTS THE HIGH CONFIDENCE FORECAST TRACK. TY 10W IS FORECAST TO WEAKEN AS IT TRANSITS ACROSS TAIWAN AND WILL MAKE LANDFALL ALONG THE CHINA COAST BY TAU 24. THE SYSTEM IS EXPECTED TO DISSIPATE OVERLAND AFTER TAU 36.// NNNN NNNN