Temps forecast to drop about on cue with start of climatological winter

Based on European Model ensemble forecasts, the remaining days of November are expected to bring a continuation of above normal temps across most of the continental U.S. as upper-level winds maintain a general W-E flow pattern. The exception will be over the Pacific NW and the northern Rockies where a dip in the jet stream will allow an influx of colder air.

With the arrival of December, much colder air is forecast to take hold as an expansive upper-level low develops over Canada and dominates the flow pattern over much of the continent. The month’s opening days are to bring a build-up of cold air over the Northwest which is to spread across the northern and central Plains. By the December 4-9 period, polar air is forecast to cover much of the northern half of the nation.

The transition to a colder pattern may eventually turn snowy based on the precipitation outlook from the Climate Prediction Center covering the period from December 4th through the 9th.