The models have been hinting the past couple of days of a dynamic pattern change from Dec 20-24th. But the details remained fuzzy. Today, the models are actually showing some decent agreement this far out...and the ensembles are already supporting the operational models. That is raising confidence in the pattern that lies ahead.
The scoop: It appears we will see a warm front pass through near the 20th. Warmer weather is likely..and perhaps MUCH warmer weather. A strong low pressure will then pass very close to our area. Behind it, VERY cold air will surge southward into the lower 48...which will make for a cold Christmas around here. Any moisture at that time would fall as snow. :)
This is for when the storm is moving in ....around the 20th.
GFS--- low on top of us...not as warm/heavy rain
EURO-- low a bit more west...much warmer flow...thunderstorms.
As I mentioned, ensembles supporting the digging of the cold air that would develop a warm SW flow in advance of it.
GFS ENS EURO ENS
It is hard to tell how warm we could get. That would depend on the track of the low. If the EURO is right...60s....GFS...40s.
This likely would be a rain to snow setup. And whatever snow falls...will likely be on the ground through Christmas morning.
Not trying to hype this storm---this is a highly important week for snow lovers and travelers. So we plan to give any heads up that we can. To have good agreement this far out---is unusual.
We shall see how this turns out. It will be fun to track.