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FXUS65 KBOU 212018

Area Forecast Discussion
National Weather Service Denver/Boulder CO
218 PM MDT Wed Mar 21 2018

.SHORT TERM...(This afternoon through Thursday)
Issued at 217 PM MDT Wed Mar 21 2018

Snow showers will diminish over the mountains through the
afternoon. Additional moisture will move in tonight allowing for 
scattered rain and light snow showers for the mountains and 
foothills on Thursday. The plains should remain dry through

Temperatures throughout northeast and north central Colorado will
be 5 to 10 degrees warmer tonight and Thursday.

.LONG TERM...(Thursday night through Tuesday)
Issued at 217 PM MDT Wed Mar 21 2018

Ridge of high pressure will shift east of Colorado Thursday night
and Friday in response to next disturbance approaching Colorado.
Moisture will increase over the mountains Thursday night and
Friday as the disturbance moves over the state during the daytime
on Friday. Associated weak front will also move over the plains 
Friday afternoon and evening with a slight cool down for afternoon
highs on Friday. Moisture more limited on the plains but could a
few showers/thunderstorms east of the Front Range with some low
CAPE's of 200-500j/kg. As for the mountains, there will be a
period of light to moderate snow Late Thursday and Friday with
potential for low end advisory amounts over zones 31 and 33 with
migratory trof as mountain top flow transitions from southwest to

Drier airmass with weak ridging aloft for Friday night and 
Saturday. Could see elevated fire weather concerns over southern 
Lincoln county Friday afternoon and again over the weekend with 
gusty southerly winds developing and lower humidity levels. May 
need a fire weather watch over southern Lincoln county on Friday. 
Further north, qpf from last storm should keep things in a less 
heightened state. 

More large scale changes expected from Late Sunday through early
next week with the development of a major storm system over the
central and southern portions Great Basin. Long Range models
showing similar trends with track with latest GFS/Canadian models
taking the closed low southward across Nevada and down into 
Southwest Arizona towards the middle of next week. GFS ensemble 
runs however, are quite varied with upper low position over the 
Great Basin. Despite the distance away from Colorado there will be
some light to moderate QG ascent from this storm system with
diffluent flow over Colorado. GFS already quite bullish on qpf
with 2-4 inches of liquid over the Front Range through Tuesday and
temperatures becoming cold enough to change to snow on the plains
Monday night as 700mb temps drop to -8C by Tuesday morning. 
Certainly some potential for a good soaker/snow event over the 
Front Range but QPF seems way too high based on current track into
the desert southwest. Canadian/European have lower qpf of 
.25-1.00" looks more reasonable at this time. New 12z European
solution has come in a little further East of GFS solution so
model qpf has increased since 00z. For now will go chance-high
chance pops over cwa for early next week. 


.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 217 PM MDT Wed Mar 21 2018

VFR conditions are expected through Thursday afternoon. Winds will
remain light through the period.



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