MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 13W (SOUDELOR) WARNING NR 24// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON 13W (SOUDELOR), LOCATED APPROXIMATELY 574 NM SOUTHEAST OF KADENA AB, HAS TRACKED WESTWARD AT 11 KNOTS OVER THE PAST SIX HOURS. RECENT ANIMATED MSI SHOWS THE SYSTEM CONTINUES TO HAVE GOOD CONVECTIVE BANDS WRAPPING INTO A SHARPLY-OUTLINED 16-NM DIAMETER EYE WITH SOME DRY AIR ENTRAINMENT. ADDITIONALLY, SUBSIDENCE CAN BE SEEN ALONG THE NORTHWEST PERIPHERY, LIMITING CONVECTION ON THE NORTHERN SIDE OF THE SYSTEM. THIS IS REINFORCED BY A 042309Z SSMIS PARTIAL PASS SHOWING THE DEEP CONVECTION ON THE SOUTHERN PORTION OF THE LLCC. THE INITIAL POSITION IS BASED ON THE EYE FEATURE IN THE MSI LOOP WITH HIGH CONFIDENCE. THE INITIAL INTENSITY OF 115 KNOTS SUPPORTS DVORAK ESTIMATES FROM ALL REPORTING AGENCIES AND REFLECTS THE WEAKENED STATE OF THE SYSTEM. UPPER LEVEL ANALYSIS INDICATES TY 13W IS LOCATED IN AN AREA OF LOW VWS AND GOOD DIFFLUENCE ALOFT. HOWEVER, A TUTT IS CAUSING SUBSIDENCE ALONG THE NORTHWEST PERIPHERY. TY SOUDELOR IS CURRENTLY TRACKING ALONG THE SOUTHERN PERIPHERY OF A DEEP-LAYERED STR TO THE NORTH. 3. FORECAST REASONING. A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TY 13W WILL CONTINUE ON A WEST-NORTHWESTWARD TRAJECTORY THROUGH TAU 72 UNDER THE STEERING INFLUENCE OF THE STR. TY SOUDELOR WILL SLOWLY WEAKEN OVER THE NEXT 24 HOURS AS THE SUBSIDENCE REMAINS ON THE NORTHERN SIDE. BEYOND THAT, EXPECT THE SYSTEM TO GRADUALLY INCREASE IN INTENSITY DUE TO GOOD OHC, LOW VWS AND GOOD OUTFLOW WITH A SECONDARY PEAK OF 125 KNOTS AT TAU 48. BY TAU 72, TY SOUDELOR WILL IMPACT CENTRAL TAIWAN, WITH THE TOPOGRAPHICAL AFFECTS OF THE YUSHAN RANGE DECAYING THE SYSTEM. C. IN THE EXTENDED FORECAST PERIOD, TY SOUDELOR WILL TRACK ACROSS THE TAIWAN STRAIT, MAKING LANDFALL IN THE FUJIAN PROVINCE. LAND INTERACTION AND WEAK UPPER-LEVEL OUTFLOW WILL CONTINUE TO DEGRADE THE SYSTEM AS IT TRACKS TOWARDS PUQI BY THE END OF THE FORECAST PERIOD. NUMERIC MODEL GUIDANCE REMAINS IN TIGHT AGREEMENT THROUGHOUT THE FORECAST PERIOD, LENDING HIGH CONFIDENCE IN THE JTWC TRACK FORECAST.// NNNN NNNN