WDPN31 PGTW 260300 
MSGID/GENADMIN/NAVPACMETOCCEN PEARL//JTWC//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 23W (LEKIMA) 
WARNING NR 17//
RMKS/
1. FOR METEOROLOGISTS.
2. PROGNOSTIC REASONING FOR 260000Z8 TO 290000Z1 SEP 01.
   A. TYPHOON (TY) 23W (LEKIMA), LOCATED APPROXIMATELY 25 NM 
SOUTHEAST OF TAIWAN, HAS TRACKED NORTHWESTWARD AT 04 KNOTS DURING 
THE PAST SIX HOURS. THE WARNING POSITION IS BASED ON 252330Z5 
VISIBLE AND INFRARED SATELLITE IMAGERY. THE WARNING INTENSITY IS 
BASED ON SATELLITE CURRENT INTENSITY ESTIMATES OF 90 TO 102 KNOTS. 
ENHANCED INFRARED SATELLITE IMAGERY REVEALS A SMALL BANDING EYE AND 
RAINBANDS SURROUNDING THE EASTERN AND SOUTHERN QUADRANTS. 
   B. LITTLE CHANGE IN ORIENTATION OF THE SUBTROPICAL RIDGE IS 
FORECAST THROUGH THE FIRST 36 HOURS. AFTERWARDS, THE RIDGE SITUATED 
TO THE NORTHWEST OF TY 23W IS EXPECTED TO SLIDE EASTWARD AND DRIVE A 
MORE WESTWARD MOTION. THE NUMERICAL MODELS ARE IN COMPARABLE 
AGREEMENT WITH THE EXCEPTION OF AVN, WHICH TRACKS THE SYSTEM 
POLEWARD IN A WEAKNESS GENERATED BY A SHORTWAVE TROUGH PASSING TO 
THE NORTH. THE NUMERICAL CONSENSUS CONSISTS OF FIVE MODELS (JMA 
TYPHOON (JTYM) AND GLOBAL SPECTRAL (JGSM), UKMET OFFICE (EGRR), 
GEOPHYSICAL FLUID DYNAMICS-NAVY (GFDN), AND NOGAPS). OUR FORECAST IS 
BASED ON THE NUMERICAL CONSENSUS BLENDED WITH PERSISTENCE. 
   C. TY 23W IS EXPECTED TO INTENSIFY FOR THE NEXT 12 HOURS UNDER 
FAVORABLE UPPER LEVEL CONDITIONS AS IT TRACKS UNDER THE SUBTROPICAL 
RIDGE AXIS BEFORE LAND INTERACTION COMMENCES AND THE SYSTEM IS 
EXPECTED TO REINTENSIFY IN THE TAIWAN STRAIT BEFORE MAKING LANDFALL 
IN CHINA.
   D. WIND RADII ARE BASED ON CLIMATOLOGY FOR AN AVERAGE SIZE 
TROPICAL CYCLONE, SYNOPTIC REPORTS, AND A 252227Z0 SPECIAL SENSOR 
MICROWAVE IMAGER (SSMI) PASS.
FORECAST TEAM: SMITH/MAYER/TON//
BT
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