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Forecast Discussion:
Welcome to the first day of Winter! It begins at 3:23 p.m. MT today when the sun is at its lowest point in the sky. Days are at about their shortest now, nights at about their longest.
Today's discussion is really an update to yesterday's as we wait for the first trough to bring us some Saturday a.m. and another round of p.m. snow. We'll hit near record heat (low 60's F) today - the record of 66° F set in 2003 is probably not in danger.
It is clear and beautiful for one more day today (Figure 1) - but you can see the front approaching from the northwest. It is knocking on Colorado's door.
You'll see below that this front will drop inches of snow in the mountains again, and spreads a trace to a coating across the Plains (and Longmont) Saturday a.m. and again p.m.
The longer range forecast:
This first front will cool us down a lot. (How could we not cool down? What goes up must come down.) The GFS (Figure 2) spreads 1/10th inch to 1 inch of snow out across the northern I-25 corridor.
For Christmas, the next big trough is rolling towards us (Figure 3). It is looking pretty strong and is expected to dig deep into the desert southwest. This should bring in some snow later on Christmas Day though it is looking less significant than it did yesterday.
Figure 4 is the GEM's idea, and it is very similar to the GFS snowfall idea through Christmas night. More of a trace to maybe an inch, rather than inches of snow.
Still... there is a major change coming with colder temperatures every day for a while and more snow. The next 10 days sees Longmont receive 1-2 inches of snow while the mountains and plains may see up to a foot plus in places. If WeatherBell forecasters are correct, this is the start of a very cold and stormy couple of months (January/February) (overall). More later!
