WDPN32 PGTW 191500
MSGID/GENADMIN/NAVPACMETOCCEN PEARL//JTWC//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 13W WARNING 
NR 05//
RMKS/
1. FOR METEOROLOGISTS.
2. PROGNOSTIC REASONING FOR 191200Z3 TO 221200Z7 JUL 02.
   A. TROPICAL DEPRESSION (TD) 13W, JUST WEST OF SAMAR ISLAND IN THE 
PHILIPPINES, HAS TRACKED WESTWARD AT 10 KNOTS DURING THE PAST SIX 
HOURS. THE WARNING POSITION IS BASED ON 191130Z5 ENHANCED INFRARED 
SATELLITE IMAGERY AND SYNOPTIC REPORTS IN THE PHILIPPINE ISLANDS. 
THE WARNING INTENSITY IS BASED ON SATELLITE CURRENT INTENSITY 
ESTIMATES OF 30 KNOTS. A 191014Z6 SPECIAL SENSOR MICROWAVE IMAGER 
(SSM/I) PASS REVEALS THE LOW LEVEL CIRCULATION CENTER (LLCC) STILL 
EVIDENT OVER THE CENTRAL PHILIPPINE ISLANDS. HOWEVER, THE DEEP 
CONVECTION IS DECREASING OVER THE LLCC.
   B. TD 13W IS FORECAST TO TRACK WEST-NORTHWESTWARD TO NORTH-
NORTHWESTWARD ALONG THE EXTENSION OF THE SUBTROPICAL RIDGE SITUATED 
SOUTHEAST OF JAPAN. THE STEERING ENVIRONMENT IS NOT FORECAST TO 
CHANGE SIGNIFICANTLY OVER THE FORECAST PERIOD. THE AVAILABLE DYNAMIC 
AIDS CONSISTING OF NOGAPS, GFDN, UKMET GLOBAL (EGRR), JAPAN GLOBAL 
(JGSM) AND NCEP AVIATION (AVN) ARE DIVIDED INTO TWO CLUSTERS. AVN 
TRACKS THE SYSTEM NORTHWESTWARD AND OUT INTO THE SOUTH CHINA SEA BY 
THE END OF THE FORECAST PERIOD. THE OTHER CLUSTER CONSISTS OF GFDN 
AND NOGAPS AND TRACKS THE SYSTEM NORTHEASTWARD, INTERACTING WITH 
CYCLONIC CIRCULATIONS NEAR THE MARIANAS TO AN EXCESSIVE EXTENT. EGRR 
AND JGSM DISSIPATE THE SYSTEM AFTER TRACKING THE SYSTEM 
NORTHEASTWARD IN THE EARLY PERIOD. OUR FORECAST IS BASED ON 
PERSISTENCE AND THE AVN MODEL.
   C. TD 13W IS NOT EXPECTED TO INTENSIFY SIGNIFICANTLY IN THE EARLY 
PERIOD WHILE OVER THE CENTRAL PHILIPPINE ISLANDS AND TO WEAKEN WHILE 
TRACKING OVER LUZON. IN THE LATE PERIOD, TD 13W IS FORECAST TO ENTER 
THE SOUTH CHINA SEA WEST OF LUZON AND THEN BEGIN TO RECONSOLIDATE.
   D. FORECAST WIND RADII IS BASED ON CLIMATOLOGY FOR AN AVERAGE-
SIZED SYSTEM. 
3. FORECAST TEAM: BRYANT/JACOBS/SHERRY/NUTONGLA//



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