WDPN32 PGTW 201500
MSGID/GENADMIN/NAVPACMETOCCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION (TD) 21W/
WARNING NR 01//
RMKS/
1. FOR METEOROLOGISTS.
2. PROGNOSTIC REASONING FOR 201200Z5 TO 251200Z0 OCT 2003.
   A. TROPICAL DEPRESSION (TD) 21W, LOCATED APPROXIMATELY
275 NM SOUTH-SOUTHEAST OF IWO JIMA, HAS TRACKED WEST-
NORTHWESTWARD AT 06 KNOTS OVER THE PAST 06 HOURS. THE 
WARNING POSITION IS BASED ON 201130Z7 MULTISPECTRAL SATELLITE 
IMAGERY. THE WARNING INTENSITY IS BASED ON SATELLITE CURRENT 
INTENSITY ESTIMATES OF 25 AND 30 KNOTS. 200MB ANALYSIS 
DEPICTS FAIR OUTFLOW WITH MINIMAL VERTICAL WIND SHEAR.
   B. TD 21W IS DRIFTING SLOWLY WEST-NORTHWESTWARD ALONG THE 
WESTERN PERIPHERY OF A LOW TO MID LEVEL STEERING RIDGE LOCATED TO THE 
EAST OF THE SYSTEM. TS 20W IS EXPECTED TO GRADUALLY PICK UP SPEED
AS THE RIDGE BUILDS IN FROM THE EAST, CREATING A STRONGER STEERING
MECHANISM, AND THEN VEER TOWARD A NORTHEASTWARD TRACK AFTER 12 HOURS. 
THE AVAILABLE DYNAMIC AIDS CONSISTING OF THE UKMET (EGRR), JGSM, NOGAPS, 
AND AVN (GFS) MODELS ARE IN GOOD AGREEMENT WITH THE TRACKING OF TD 21W.  
THIS FORECAST IS BASED ON A CONSENSUS OF ALL AVAILABLE DYNAMIC MODELS.
   C. TD 21W IS EXPECTED TO INTENSIFY AT A LESS THAN CLIMATOLOGICAL RATE 
AS A HIGH VERTICAL SHEAR ENVIRONMENT IS JUST POLEWARD OF TD 21W WITH FAIR
OUTFLOW ALOFT. 
   D. FORECAST WIND RADII ARE BASED ON CLIMATOLOGY FOR AN LESS THAN AVERAGE 
SIZED SYSTEM.
3. FORECAST TEAM: DAMRON/KLINZMANN/BIRD/CHITWOOD//

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