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Forecast Discussion:
The first frontal system is stalled down the mountains and into southeastern parts of the state (Figure 1). Light showers behind the front and mountain snows were the story Sunday with cooler weather than Saturday. Another front is on its way for Monday afternoon to really kick up winter weather... but, before that, we should see a good amount of fog behind the front Monday morning with some clearing skies overnight. There may be a dense fog advisory issued for regions along I-25 by Monday morning.
The next front will enter the state early afternoon and pass through Longmont around 3-4pm. Snow will begin falling behind the front around sunset (which now happens just before 5pm). And the temperatures will drop to hover around and below freezing through Tuesday.
In the longer range:
Figure 2 shows the complex upper air pattern with a trough passing over the state late Tuesday night. The area of lift will be pushing east of us by then ending the snow.
Amounts: According to weather5280.com, the forecasters there are calling for:
Fort Collins: 2 - 5"
Boulder: 1 - 4"
Denver: 0 - 3"
Castle Rock: 0 - 3" / Some icing potential
Colorado Springs: 0 - 2" / Some icing potential
I'll add that Longmont will be in the 1/2 - 3" area for snowfall. Estes park is in the 3-6" area.
We can also take a quick look at a number of models for Longmont.
Figure 3 and 4 are the GFS (the first is the zoomed in version). It has Longmont at about 2-3"
Figure 5 is the NMM that puts us in the 1-2" area.
Figure 6 is the NAM that puts us in the 1 to 1 1/2" area.
It just isn't a big storm. We have yet to really get hit yet this season.
Timing: The snow will fall primarily between 8pm Monday and 12pm Tuesday with lingering snow flurries possible into Tuesday night. A light dusting now and then might still occur through early Wednesday AM.
