339 
fxus65 kbou 192136 
afdbou 


Area forecast discussion 
National Weather Service Denver Colorado 
330 PM MDT Friday Mar 19 2010 


Short term...interesting storm continues in some areas and is 
winding down in many others. Got off to a slower start as the band 
in the early morning hours associated with the upper level jet 
actually produced some rain and even rare freezing rain for awhile 
before finally going to snow but by then had passed more to our 
south. Today we have been transisitioning to a more Front Range 
focused storm with deepening upslope as the main upper level low is 
still over western Colorado dropping to the southeast. Interesting 
on the radar as we have been getting convective like areas of snow 
forming even north of Cheyenne and moving to the SW and then into 
the Front Range. These have produced and continue to produce some 
very impressive snowfall rates often well in excess of 2 inches per 
hour and by the time it is over favorable foothill areas will be 
over 20 inches. There are still some really strong echoes over 30 
dbz that are now heading into the Denver area and will really hit 
Jefferson and Douglas counties into the evening. So will continue 
the Winter Storm Warning and we have worded things to indicate where 
the heavier snows will be. Many of the roads in the Denver area 
have been just wet but with heavy snow rates in these bands and 
decreasing sun angle could get slippery later this afternoon into 
the evening. 


In the mountains amounts have been much less with the unfavorable 
orgraphic flow west of The Divide and the warning will expire there 
at 00z. On the plains will let that one stay until expiration at 
00z more NE plains and 06z southern portions. Not a lot of 
additional snowfall but winds are gusty now and getting a little 
colder so any additional snow could create some slippery roads...so 
no sense cancelling it early at this point. Otherwise things 
improve rapidly by Saturday. Some early morning fog on the eastern 
plains depending on the amount of clearing. If enough clearing then 
some pretty cold temperatures will occur with the new snow cover. 


Long term...upper level ridge axis will be building across the 
northern and central rockies Saturday night through Sunday. This 
will bring dry conditions and warming temperatures. Warmup will be delayed 
a bit due to snow cover...but by Sunday afternoon most locations 
should still be able to reach 50f or slightly better. 


On Monday...downslope flow will increase with considerable warming 
aloft. This will help readings warm to at least the lower 60s 
across the plains under mostly sunny skies. 


By Tuesday...the next trough will approach the area...and each 
successive run of the ecwmf and GFS ensembles are pointing toward a 
potential for another healthy precipitation event late Tuesday into 
Wednesday. Most of this precipitation should end up in the form of 
snow as everything points to enough cold air coming in behind the 
next front. Have increased probability of precipitation a bit more and lowered temperatures a few 
more degrees Tuesday night and Wednesday as a result. We do have to 
watch how far south this trough digs...but there is potential for 
another accumulating snowfall across the forecast area Tuesday night 
through Wednesday. 


Then back to dry and warmer conditions in typical Spring fashion for 
the end of next week. 


Aviation...areas of heavier snow that have been forming up in Weld 
County continue to move to the SW and will bring some periods of 
heavier snows until about 00z with apa mainly in the path of some of 
these bjc and dia more on the edge. Otherwise improving conditions 
after 00z and should be done by 06z. Areas of fog possible at dia 
after 09z with some clearing skies late. 


&& 


Bou watches/warnings/advisories...Winter Storm Warning 
until midnight tonight for the Front Range mountains... 
foothills...and adjacent plains including most of the Front 
Range urban corridor and Palmer Divide...zones 33>36..39>41. 
..Winter Weather Advisory for the northeastern plains of Colorado 
until 6 PM MDT tonight...zones 42>44..and 48>51. 
..Winter Weather Advisory for east central Colorado...South 
Park...and the park/Gore ranges until midnight MDT tonight... 
zones 45..46..31..and 37. 


$$ 


Szoke/barjenbruch