What a difference a few days can make in weather models. All long range products were forecasting a generally flat (west-to east) jetstream a few days ago for the coming week or two. Now the reliable models are indicating a very deep low developing S of Alaska late on the weekend. It will develop a correspondingly big ridge along the west coast late Sunday that, in turn will generate strong NW flow from Canada into the Northern Plains Sunday, spreading to the Southern plains and Midwest Monday, covering nearly all of the E by Tuesday for the coldest day of winter so far. It doesn't look like a long cold-snap as the ridge over the W will gradually move east thru the latter half of next week. Still, a good reminder of the unpredictability of weather and maybe a short-term opportunity for some NG calls.