WDPN31 PGTW 251500 
MSGID/GENADMIN/NAVPACMETOCCEN PEARL//JTWC//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 23W (LEKIMA) 
WARNING NR 15//
RMKS/
1. FOR METEOROLOGISTS.
2. PROGNOSTIC REASONING FOR 251200Z0 TO 281200Z3 SEP 01.
   A. TYPHOON (TY) 23W (LEKIMA), LOCATED APPROXIMATELY 70 NM 
SOUTHEAST  OF TAIWAN, HAS TRACKED NORTHWESTWARD AT 04 KNOTS DURING 
THE PAST SIX HOURS. THE WARNING POSITION IS BASED ON 251130Z2 
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 CENTRALLY 
LOCATED WITHIN ORGANIZED CONVECTIVE SPIRAL BANDS. 
   B. LITTLE CHANGE IN ORIENTATION OF THE SUBTROPICAL RIDGE IS 
FORECAST ALTHOUGH, SOME STRENGTHENING OF THE PERIPHERAL RIDGE (MORE 
POLEWARD TC MOTION) IS POSSIBLE. THE NUMERICAL MODELS BREAK DOWN 
INTO TWO CLUSTERS. THE JMA TYPHOON (JTYM) AND GLOBAL SPECTRAL 
(JGSM), AVN, GEOPHYSICAL FLUID DYNAMICS-NAVY (GFDN), AND COAMPS 
MODELS TRACK TY 23W NORTHWESTWARD THROUGH 36 WHILE THE UKMET-O 
GLOBAL GRID (EGRR) AND NOGAPS (NGPS), TRACK TY 23W WEST-
NORTHWESTWARD THROUGH THE PERIOD. THE TRACK DIFFERENCES ARE BASED 
SOLELY ON TC STRENGTH/SIZE/STEERING LEVEL. NOGAPS AND THE UKMET-O 
MODELS REFLECT A WEAKER SYSTEM, HENCE, LOW/MID LEVEL RIDGE INFLUENCE 
COMPARED TO THE FIRST CLUSTER (MID/DEEP). OUR FORECAST IS BASED ON 
THE NUMERICAL CONSENSUS OF FIVE MODELS (JTYM, JGSM, EGRR, NGPS, AND 
GFDN).
   C. TY 23W IS EXPECTED TO INTENSIFY FOR THE NEXT 24 HOURS UNDER 
FAVORABLE UPPER LEVEL CONDITIONS AS IT TRACKS UNDER THE SUBTROPICAL 
RIDGE AXIS BEFORE LAND INTERACTION COMMENCES.
   D. WIND RADII ARE BASED ON CLIMATOLOGY FOR AN AVERAGE SIZE 
TROPICAL CYCLONE, SYNOPTIC REPORTS, AND A 290955Z0 SPECIAL SENSOR 
MICROWAVE IMAGER (SSMI) PASS.
FORECAST TEAM: ROBERTS/VILPORS/HARRISON/CUTMAN//



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