WDPN31 PGTW 210300 
MSGID/GENADMIN/NAVPACMETOCCEN PEARL//JTWC//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 26W WARNING NR 09//
RMKS/
1. FOR METEOROLOGISTS.
2. PROGNOSTIC REASONING FOR 210000Z3 TO 240000Z6 OCT 01.
   A. TYPHOON (TY) 26W (PODUL), LOCATED APPROXIMATELY 700 NM EAST OF 
GUAM, HAS BEEN TRACKING NORTHWARD AT 11 KNOTS DURING THE PAST SIX 
HOURS. THE WARNING POSITION IS BASED ON 202330Z0 INFRARED AND 
VISIBLE SATELLITE IMAGERY. THE WARNING INTENSITY IS BASED ON 
SATELLITE CURRENT INTENSITY ESTIMATES OF 57 TO 65 KNOTS. THE 200 MB 
ANALYSIS AND ANIMATED WATER VAPOR IMAGERY REVEALS THAT TY 26W 
REMAINS IN A WEAK VERTICAL WIND SHEAR ENVIRONMENT WITH GOOD OUTFLOW 
ALOFT.
   B. A LOW/MID LEVEL SUBTROPICAL RIDGE NORTH OF TY 26W IS EXPECTED 
TO CONTINUE WEAKENING THROUGH THE FORECAST PERIOD AS THE BASE OF A 
SHORTWAVE TROUGH EAST OF JAPAN TRACKS EASTWARD. MEANWHILE, THE NEAR-
EQUATORIAL RIDGE WILL BUILD SOUTH AND EXTEND EAST OF THE SYSTEM, 
RESULTING IN A NORTH-NORTHWESTWARD TRACK THROUGH 72 HOURS. THE 
AVAILABLE DYNAMIC AIDS OF NOGAPS, GEOPHYSICAL FLUID DYNAMICS-NAVY 
(GFDN), THE UKMET OFFICE GLOBAL (EGRR), AND THE JMA GLOBAL (JGSM) 
AND TYPHOON (JTYM) MODELS ARE IN FAIR AGREEMENT WITH TWO DISTINCT 
CLUSTERS. JGSM, NCEP AVIATION, AND JTYM INDICATE A WEAK MID-LEVEL 
RIDGE NORTH OF THE SYSTEM AND TRACK THE SYSTEM NORTHEASTWARD INTO 
THE WEAKNESS THROUGH 72 HOURS. THE SECOND CLUSTER CONSISTING OF 
EGRR, GFDN, AND NOGAPS BUILD THE RIDGE TO THE NORTH, RESULTING IN A 
MORE NORTH-NORTHWESTWARD TRACK. DUE TO POSSIBLE COMPENSATING ERRORS, 
OUR FORECAST BLENDS PERSISTENCE WITH THE CONSENSUS OF THE AVAILABLE 
DYNAMIC MODELS.  
   C. TY 26W IS EXPECTED TO INTENSIFY AT A CLIMATOLOGICAL RATE 
AS IT TRACKS INTO A FAVORABLE UPPER LEVEL ENVIRONMENT.  
   D. WIND RADII ARE BASED ON CLIMATOLOGY FOR AN AVERAGE SIZE 
TROPICAL CYCLONE. 
FORECAST TEAM: MAZANY/WARREN/JACOBS/CUTMAN/NUTONGLA//



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