WDPN31 PGTW 231500 
MSGID/GENADMIN/NAVPACMETOCCEN PEARL//JTWC//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 23W (LEKIMA) 
WARNING 
NR 7//
RMKS/
1. FOR METEOROLOGISTS.
2. PROGNOSTIC REASONING FOR 231200Z8 TO 261200Z1 SEP 01.
   A. TROPICAL STORM (TS) 23W (LEKIMA), LOCATED APPROXIMATELY 55 NM 
NORTH OF LUZON, HAS TRACKED WESTWARD AT 5 KNOTS DURING THE PAST SIX 
HOURS. THE WARNING POSITION IS BASED ON 231130Z0 INFRARED SATELLITE 
IMAGERY. THE WARNING INTENSITY IS BASED ON SATELLITE CURRENT 
INTENSITY ESTIMATES OF 55 KNOTS.
   B. TS 23W IS CURRENTLY UNDER THE WEAK STEERING INFLUENCE OF THE 
MID-LEVEL SUBTROPICAL RIDGE OVER CHINA. THE DYNAMIC AIDS, JMA GLOBAL 
SPECTRAL (JGSM) MODEL, THE UKMET OFFICE GLOBAL (EGRR), NOGAPS 
(NGPS), AND THE GEOPHYSICAL FLUID DYNAMICS NAVY (GFDN) MODELS ARE IN
FAIR AGREEMENT. NGPS, EGRR, AND GFDN TRACK THE SYSTEM NORTHWESTWARD 
THROUGH THE PERIOD AS THE RIDGE OVER CHINA STRENGTHENS. JGSM, 
HOWEVER, TRACKS THE SYSTEM NORTHWARD THROUGH THE FORECAST PERIOD DUE 
TO A COMBINATION OF POSSIBLE OVER-DEVELOPMENT OF THE SYSTEM AND THE 
CORRESPONDING OVER-DEVELOPMENT OF THE PERIPHERAL RIDGE TO THE 
SOUTHEAST OF THE SYSTEM. THE SYSTEM IS FORECAST TO TRACK 
NORTHWESTWARD THROUGH THE FORECAST PERIOD UNDER THE STEERING 
INFLUENCE OF THE RIDGE OVER CHINA. THE NUMERICAL CONSENSUS CONSISTS 
OF FOUR MODELS. THE OFFICIAL FORECAST, HOWEVER, IS BASED ON 
PERSISTENCE AND THE SELECTIVE CONSENSUS OF NGPS, GFDN, AND EGRR. 
   C. TS 23W IS EXPECTED TO INTENSIFY THROUGH THE 48-HOUR FORECAST 
PERIOD AS IT TRACKS OVER WARM SST'S AND FAVORABLE UPPER LEVEL 
CONDITIONS. 
   D. WIND RADII ARE BASED ON CLIMATOLOGY FOR AN AVERAGE SIZE 
TROPICAL CYCLONE AND A RECENT QUIKSCAT PASS.
FORECAST TEAM: CANTRELL/WAUGAMAN/SHERRY//