WDPN31 PGTW 261500 MSGID/GENADMIN/NAVPACMETOCCEN PEARL//JTWC// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 23W (LEKIMA) WARNING NR 19// RMKS/ 1. FOR METEOROLOGISTS. 2. PROGNOSTIC REASONING FOR 261200Z1 TO 291200Z4 SEP 01. A. TYPHOON 23W (LEKIMA) REACHED THE SOUTHEASTERN COAST OF TAIWAN NEAR THE CITY OF TAWU, TAIWAN AT ABOUT 260900Z7. TY 23W WAS PACKING MAXIMUM SUSTAINED WINDS OF 90 KTS GUSTING TO 110 KTS. TY 23W, LOCATED APPROXIMATELY 140 NM SOUTH-SOUTHWEST OF TAIPEI, HAS TRACKED NORTHWARD AT 06 KNOTS DURING THE PAST SIX HOURS. THE WARNING POSITION IS BASED ON 261130Z3 INFRARED SATELLITE IMAGERY AND AVAILABLE SYNOPTIC DATA. THE WARNING INTENSITY IS BASED ON SATELLITE CURRENT INTENSITY ESTIMATES OF 65 TO 77 KNOTS. A 260942Z3 SPECIAL SENSOR MICROWAVE IMAGER (SSM/I) PASS INDICATED THAT TY 23W HAS LOST ITS EYE FEATURE. B. TY 23W WILL TRACK SLOWLY NORTH-NORTHWESTWARD FOR THE NEXT 24 HOURS WITHIN A WEAKNESS BETWEEN MID-LEVEL HIGHS NORTHWEST AND EAST OF THE SYSTEM. AFTERWARD, AS TY 23W WEAKENS, A LOW/MID LEVEL RIDGE SHOULD BUILD OVER NORTHEASTERN CHINA AND BECOME THE DOMINANT STEERING MECHANISM DRIVING THE SYSTEM WEST-NORTHWESTWARD. THE DYNAMIC AIDS JMA TYPHOON (JTYM) AND GLOBAL SPECTRAL (JGSM), UKMET OFFICE (EGRR), GEOPHYSICAL FLUID DYNAMICS-NAVY (GFDN), AND NOGAPS (NGPS) ARE CLUSTERED INTO TWO GROUPS. JGSM, JTYM, AND AVN CONTINUE TO TRACK TY 23W NORTH WHICH JTWC ATTRIBUTES TO THE MODELS PREMATURELY EMBEDDING THE SYSTEM WITHIN THE THE MID-LEVEL SOUTHWESTERLIES ASSOCIATED WITH AN APPROACHING MID LEVEL BAROCLINIC TROUGH. NGPS, GFDN, AND EGRR FOLLOW A WEAKENING TREND WITH A RIDGE OVER THE COAST OF CHINA INFLUENCING A WEST- NORTHWESTWARD TRACK. OUR FORECAST IS BASED ON THE FIVE MODEL NUMERICAL CONSENSUS (JTYM, JGSM, EGRR, GFDN, AND NGPS) BLENDED WITH PERSISTENCE. C. TY 23W IS FORECAST TO CONTINUE WEAKENING OVER THE NEXT 36 HOURS AS IT INTERACTS WITH THE MOUNTAINOUS TERRAIN OF TAIWAN. THEN, A SLIGHT INTENSIFICATION TREND OVER THE TAIWAN STRAIT IS FORECAST BEFORE LANDFALL AGAIN, THIS TIME, OVER SOUTHEASTERN CHINA. D. WIND RADII ARE BASED ON CLIMATOLOGY FOR AN AVERAGE SIZE TROPICAL CYCLONE. FORECAST TEAM: ROBERTS/VILPORS/HARRISON/CUTMAN// NNNN