006 
fxus65 kpub 212132 
afdpub 


Area forecast discussion 
National Weather Service Pueblo Colorado 
232 PM MST Sat Nov 21 2009 


Short term... 
(tonight and sunday) 


Upper trough is currently moving through the Great Basin and into the 
northern U.S. Rockies. Starting to see some isolated light echoes across 
portions of Utah...eastern Idaho...and western Wyoming associated with this feature. 
As moisture begins to move into the cen mts towards 00z...expect to 
see some isolated to scattered snow showers develop across the central 
mts...aided by west to northwesterly orographic flow. An inch or 
two of accumulation will be possible at best across the higher peaks 
of the Sawatch and mosquito ranges overnight. 


Meanwhile...Lee trough has stayed pinned up along the eastern slopes 
of the southeast mts this afternoon...with winds still rather light across much of 
the plains. Winds have been on the increase across the high country 
ahead of this advancing system with gusts up to 40 kts reported at 
myp. As the system moves across the mts tonight...a cold front 
currently up in Wyoming will drop through the southeast plains by 06z. 12z 
NAM was printing out some light snow across Pikes Peak/northern El Paso 
County tonight around 06z. However...latest NAM has backed off on 
this. Will maintain the inherited low grade isolated probability of precipitation for this 
area. Any snow showers that move eastward off the higher terrain and 
across the Palmer Divide will be brief with little or no 
accumulation expected. The remainder of the southeast plains will 
stay dry with only some passing wave cloudiness. 


Upper trough will be quick to exit the area Sunday morning and should 
see more sun than clouds on Sunday. It will be slightly cooler 
tomorrow behind the front but otherwise dry. Have hung on to some 
isolated probability of precipitation across the higher peaks of the Sawatch and mosquito 
ranges during the afternoon with some lingering moisture in 
favorable northwest orographic flow. -Kt 




Long term... 
(sunday night through saturday) 


Longer term computer models coming into better agreement that 
closed upper low will be in the vicinity of Nebraska by 00z 
Tuesday before pushing off into Illinois by 00z Wednesday. 


This projected path will allow the majority of the County warning forecast area to remain 
dry with the possible exception of the mountains(especially 
central mountains) and far northern sections from Sunday night 
into Monday evening and have painted generally low grade probability of precipitation 
these areas. 


At this writing...expect that portions of the central mountains may 
experience up to 3 inches of snow from Sunday night into Monday 
evening. Other than the Central Mountain snow...primary sensible 
weather with this passing system will be cooler 
temperatures...especially from Monday into Tuesday morning as well 
as gusty winds at times...especially eastern portions. 


From Wednesday into at least Friday...dry and mild northwest to 
zonal flow aloft should be noted over the County warning forecast area as upper ridging 
sets up over the Desert Southwest. This pattern will allow maximum 
temperatures to run at to above late November climatological 
averages most areas from Wednesday into at least Friday in 
combination with dry conditions cwfa-wide. Latest European model (ecmwf) still 
suggests that a weak/dry northerly surge may push across eastern 
sections of the County warning forecast area Wednesday night...bringing with it some 
clouds and cooler conditions by Thanksgiving morning...weather forecast office Pueblo 
will continue to monitor. In addition...gusty winds will again be 
possible...especially Wednesday night. 


Finally...12z/21st gfs40 suggests that dry and mild pattern to 
continue through Saturday...while 12z/21st European model (ecmwf) suggests that 
upper system rotates across region by next Saturday...bringing 
unsettled conditions to the region by next Saturday. Have started 
trending grids/zones to show increasingly unsettled conditions 
this time-frame. 


&& 


Aviation... 


VFR conditions expected at taf sites tonight and 
Sunday. Cold front will drop south of the Palmer Divide around 00z 
and move through kpub by 03z. Some brief northerly wind gusts up to 
20 kts may accompany frontal passage and last for an hour or two. Think any 
brief light snow showers...if they occur...will stay to the north of 
kcos...therefore will not introduce any -shsn to the kcos taf. On 
Sunday...afternoon winds will shift around from the south to 
southeast for all taf sites with wind speeds increasing to around 
8-12 kts. -Kt 


&& 


Pub watches/warnings/advisories... 
none. 
&& 


$$