A change in the upper air pattern across the North American continent is expected to develop late in the weekend, which will send much colder air into the Red River Valley Region next week. Since the middle part of December 2007, the overall upper air pattern has featured a strong Pacific jet stream pushing across the southern and central U.S. A weaker branch of the jet stream has been in place across southern Canada. As a result, the weather across much of the Northern Plains has been 10 to 15 degrees warmer than normal.
At the same time, seasonally cold air has been building across far northern Canada, Alaska and Siberia. The weak jet stream north of our area has been holding that cold air at bay. However, a strong weather system currently in the central Pacific is forecast to push into the Pacific Northwest early next week, then cross the Rocky Mountains by mid week. At the same time, a broad area of high pressure will build into the Alaskan region, turning the upper level flow to the north. This will allow the cold air to begin moving south into our area.
As is often the case with weather systems that are a week or so away, timing and intensity is always a big question. However, at this time, confidence is reasonably high that there will be a significant change in our weather next week. As sometimes happens with these types of systems, light to moderate snows may fall with the passage of the front.
At this time we expect temperatures to fall to or a bit below seasonal values mid to late next week. While not at all unusual, coming on the heels of a very mild stretch of weather, the change will be quite dramatic. Stay tuned to updated forecasts as the weather pattern develops. Your NOAA’s National Weather Service will continue to issue regular updates as the weather pattern develops.