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Area forecast discussion 
National Weather Service Pueblo Colorado 
432 am MST Monday Nov 23 2009 


Short term... 
(today and tonight) 


Main forecast concern today centers on the effect of a low 
pressure system moving through Wyoming and northeast Colorado. 
Most recent model runs are digging this low a bit farther south 
than previous runs...but still keep the majority of the County Warning Area dry. 
Main forcing for precipitation remains to the north and east of the area...with 
northwest winds not too conducive to precipitation for the eastern and southern zones 
today. The NAM continues to forecast some light quantitative precipitation forecast over the plains 
today...in the late morning or afternoon. As mentioned...orographics 
not favorable and not much upper forcing...but the system is fairly 
robust and the NAM occasionally picks up mesoscale instabilities 
especially in the first 24 h or so. Current radar/observation showing most 
of the precipitation right now is to the north...with light snow now moving into 
the northern mts and Lake County. Best chances for accumulating snow will 
continue to be over the Sawatch...where 2-4 inches could fall today. 
Could possibly see a dusting or light accums over portions of Teller 
County or Palmer dvd this morning. Have expanded low grade (under 10 
percent) probability of precipitation to cover the plains...to account for the possibility 
of some isolated shsn...but accums seem pretty unlikely today and later 
shift may have to refine the probability of precipitation. 


Biggest effect from today's system will be the lower temperatures...40s over 
the plains and 20s or lower for the mts. Tonight will be a subzero night 
for some of the usual cold spots in the San Luis valley and upper 
Arkansas. Skies should clear fairly quickly tonight as the system 
pulls away to the east. Rose 


Long term... 
(tuesday through sunday) 


Dry conditions expected until possibly Saturday evening. 


Tuesday and Wednesday...the departing upper level low pressure system 
moves quickly eastward into the middle-miss River Valley Tuesday 
morning...with some brisk northerly winds persisting across the far 
east plains through the am. Northwest flow aloft remains in place for the 
remainder of Tuesday with temperatures warming into the 30s for the mts...40s 
to near 50 for the lower elevations. On Wednesday models indicate another 
system dropping out of Canada across the Dakotas and Minnesota. 
Alternating model runs are at odds on the western extent of this 
system...so for now will keep conditions dry but breezy...and temperatures 
similar to Tuesday. 


Thanksgiving through Saturday...upper ridge gradually slides across 
the 4 corners region bringing warmer temperatures to the County Warning Area...while 
another low pressure trough moves onshore over the West Coast. GFS 
and European model (ecmwf) models are disagreeing on the movement and look of this 
next system...with the GFS digging a closed low down across the 
Great Basin while the European model (ecmwf) keeps it further north with a longwave 
trough nearing the state on Sat. Both solutions...though very 
different...seem to keep the County Warning Area in a warm and dry flow at least 
through the first half of Sat...with perhaps precipitation returning to the 
Continental Divide by the evening. Ongoing forecast grids essentially painted 
this picture...so little adjustment needed. 


Sunday...the difference of opinion in solutions continue for 
Sunday...though extended models do agree on placing a significant 
positively tilted trough over the region for the end of the weekend. 
Given this is day 7 and confidence is low...no change made at this 
time. Moore 


&& 


Aviation... 
VFR conditions expected at taf sites through next 24 hours. Could see 
some light shsn over the Palmer dvd and possibly vicinity kcos this 
morning and early afternoon...but no significant reductions in visible 
or ceiling are expected there. Main area of precipitation will continue to be 
over the Continental Divide today...before clearing conditions tonight. 
Main effect of this system will be gusty north-northwest winds through much 
of today over the plains. Rose 


&& 


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


$$ 


44/27