WDPN31 PGTW 081500 
MSGID/GENADMIN/NAVPACMETOCCEN PEARL//JTWC//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 27W (LINGLING) WARNING 
NR 09//
RMKS/
1. FOR METEOROLOGISTS.
2. PROGNOSTIC REASONING FOR 080000Z8 TO 110000Z2 NOV 01.
   A. TROPICAL STORM (TS) 27W (LINGLING), LOCATED NEAR THE WEST 
COAST OF PANAY, HAS TRACKED WEST-NORTHWESTWARD AT 06 KNOTS DURING 
THE PAST SIX HOURS. THE WARNING POSITION IS BASED ON 072330Z5 
INFRARED AND VISIBLE SATELLITE IMAGERY, AND AVAILABLE SYNOPTIC DATA. 
THE WARNING INTENSITY IS BASED ON SATELLITE CURRENT INTENSITY 
ESTIMATES OF 45 KNOTS. ANIMATED INFRARED AND VISIBLE SATELLITE 
IMAGERY INDICATE THE SYSTEM HAS MAINTAINED ITS DEEP CONVECTION, BUT 
REMAINS LOOSELY ORGANIZED AS IT PASSES OVER THE PHILIPPINE ISLANDS. 
WATER VAPOR IMAGERY DEPICTS EQUATORWARD AND POLEWARD OUTFLOW 
CHANNELS.
    B. THE MID LEVEL HIGH CENTER OVER THE NORTHEAST COAST OF VIETNAM 
EXTENDS ALONG THE SOUTHERN COAST OF CHINA AND CONTINUES TO BE THE 
PRIMARY STEERING INFLUENCE FOR TS 27W. A MID-LATITUDE TROUGH IS 
FORECAST TO WEAKEN THE SUBTROPICAL RIDGE, BUT NOT ENOUGH TO TURN THE 
SYSTEM NORTHWARD. THEREFORE, THE SYSTEM IS FORECAST TO TRACK WEST-
NORTHWESTWARD THROUGH THE FORECAST PERIOD. THE AVAILABLE DYNAMIC 
AIDS INCLUDING NOGAPS, GFDN, UK-MET OFFICE GLOBAL, NCEP AVIATION AND 
THE JMA GLOBAL MODELS ARE IN GOOD AGREEMENT. THEY KEEP THE SYSTEM 
EMBEDDED IN THE TROPICAL EASTERLIES SOUTH OF THE SUBTROPICAL RIDGE. 
THE JMA TYPHOON MODEL (JTYM) OFFERS AN ALTERNATE SCENARIO DEVELOPING 
THE PERIPHERAL RIDGE EAST OF TS 27W AND TRACKING THE SYSTEM NORTH-
NORTHWESTWARD THROUGH THE WEAKNESS IN THE SUBTROPICAL RIDGE. OUR 
FORECAST IS BASED ON PERSISTENCE AND A BLEND OF THE AFOREMENTIONED 
MODELS.
   C. TS 27W IS EXPECTED TO INTENSIFY OVER THE FORECAST PERIOD 
IN A REGION OF DIFFLUENT EASTERLIES SOUTH OF THE UPPER RIDGE AXIS.
   D. WIND RADII CRITERIA BASED ON CLIMATOLOGY. 
FORECAST TEAM: VILPORS/WAUGAMAN/SCOTT/CUTMAN/NUTONGLA//



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