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Forecast Discussion:
The giant up slope cloud that dumped rain on the higher foothills and snow on the western slopes and higher elevations all Saturday, dominated our western horizon all day. Where the cloud evaporated, due to the start of its sinking motion (down slope), the warming of the air from precipitation formation, was added to by the sinking/compression of the air. We had some gusty winds a times in Longmont. Temperatures rose to the mid 70's.
A cold front came in overnight Saturday into Sunday and will cut temperatures today (Sunday) by 10-15 degrees. Light rain will fall behind the front up near Wyoming. You can see the front down to Colorado Springs by midday Sunday in Figure 1.
Before the next front arrives Monday night, we may warm a bit on Monday with some more strong breezes. The Monday front means business though (Figure 2)...
The longer range forecast:
Once the Monday PM front pushes in, rain will form and change over to snow at lower elevations including Longmont. Temperatures Tuesday midday (Figure 3) will be 20 to 25 F below normal!
Figure 4 shows the GFS's total snowfall through Tuesday night around 2-3" for Longmont (this 'could' be a long period of light snow). Fort Collins gets more snow at around 4-6".
Figure 5 is the WPC model take on total snowfall for the same period and we are in the 3-4" area there. This is shaping up to be a fairly notable 36 hours of cold and snow and/or very cold rain Monday PM to Tuesday PM and maybe into Wednesday AM. We'll keep watching it as the time approaches.
