WDPN31 PGTW 151500
MSGID/GENADMIN/NAVPACMETOCCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION (TD) 12W 
WARNING NR 02//
RMKS/
1. FOR METEOROLOGISTS.
2. PROGNOSTIC REASONING FOR 151200Z9 TO 181200Z2 AUG 2003.
   A. TROPICAL DEPRESSION (TD) 12W, LOCATED APPROXIMATELY 360 NM
SOUTHEAST OF GUAM, HAS TRACKED WEST-NORTHWESTWARD AT 08 KNOTS
OVER THE PAST 06 HOURS. THE WARNING POSITION IS BASED ON 151130Z1
ENHANCED INFRARED SATELLITE IMAGERY. THE WARNING INTENSITY IS 
BASED ON SATELLITE CURRENT INTENSITY ESTIMATES OF 25 KNOTS. TD 
12W HAS LOST MOST OF THE DEEP CONVECTION ASSOCIATED WITH IT IN 
THE PAST 06 HOURS, HOWEVER THE LOW LEVEL CIRCULATION CENTER 
(LLCC) REMAINS EVIDENT IN ANIMATED ENHANCED INFRARED SATELLITE 
IMAGERY. 
   B. TD 12W IS FORECAST TO TRACK WEST-NORTHWESTWARD UNDER THE
INFLUENCE OF THE LOW TO MID-LEVEL STEERING RIDGE TO THE NORTH. 
AVAILABLE DYNAMIC AIDS CONSISTING OF NOGAPS, NCEP (GFS), EGRR 
AND JGSM ARE IN GOOD AGREEMENT WITH THE TRACK, HOWEVER THEY 
VARY IN HOW MUCH EACH MODEL DEVELOPS THE SYSTEM. GFS AND JGSM
MAINTAIN OR DEVELOP THE SYSTEM WHILE EGRR AND NOGAPS WEAKEN
THE SYSTEM AND TRACK ONLY A PERTURBATION AT THE SURFACE AFTER 
24 HOURS. HENCE, THE ALTERNATE SCENARIO FOR THIS SYSTEM IS 
CONTINUED WEAKENING AND DISSIPATION WITHIN THE NEXT 24 HOURS.
THIS FORECAST IS BASED ON PERSISTENCE AND A BLEND OF THE 
AVAILABLE DYNAMIC AIDS.
   C. TD 12W WILL INITIALLY UNDERGO ONLY VERY SLOW DEVELOPMENT
WITH RESTRICTED OUTFLOW AND UNDER THE ALTERNATE SCENARIO FOR 
THIS SYSTEM, MAY DISSIPATE BEFORE ENTERING A REGION OF MORE
FAVORABLE OUTFLOW CONDITIONS. AN UPPER LEVEL LOW TO THE 
NORTHWEST OF THE SYSTEM IS SLOWLY FILLING AND ANOTHER UPPER 
LEVEL LOW TO THE EAST-NORTHEAST CONTINUES TO GAIN PROXIMITY 
TO 12W. GREATER DEVELOPMENT IS FORECAST AFTER TAU 12 AS THE 
FORMER LOW FILLS AND THE LATTER BEGINS TO PROVIDE ENHANCED 
OUTFLOW TO TD 12W. AFTERWARDS, DEVELOPMENT AT JUST BELOW A 
CLIMATOLOGICAL RATE IS FORECAST FOR THE REMAINDER OF THE PERIOD.
   D. FORECAST WIND RADII ARE BASED ON CLIMATOLOGY FOR A SMALL
TO AVERAGE SIZED SYSTEM.
3. FORECAST TEAM: BRYANT/JACOBS/NUTONGLA//

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