This content was originally published by the Longmont Observer and is licensed under a Creative Commons license.
Forecast discussion:
I've re-set up the Christmas decorations that blew around Sunday night in the breezy sunlight of Monday. Today we have a ridge off the west coast, another ridge a bit off the east coast and a tilted trough draped across the center of the nation. With a wavelength like this, the waves and troughs (red and blue lines) won't move (progress) to the east very quickly (Figure 1). And they don't.
Figure 2 shows a rapid series of brief fonts passing over the state each day, today, tomorrow and Thursday. The first two cool us down - the second might give us a sprinkle/dash of snow. I'm not counting on it. Those are caused by smaller ripples in the overall flow.
The longer range forecast:
Figure 2 shows the next two cool downs and associated few-hours-of-gusty-winds (bottom graph). On Friday, the front begins a warm advection (air moving from one place to another across the land) process that warms us nicely for the weekend. Figure 3 also shows how far east the western ridge finally moves that also contributes to the nice weekend. Then it stays quiet beyond that.
Fantasy Christmas Day Forecast (from Accuweather.com):
12/24 50F/14F partly cloudy 12/25 43F/13F mostly sunny.
