(Thumbnail image: via Meteociel.fr) Much of the US / Canada has remained relatively freeze free so far this winter, but for a few places (the Priaries and North Montana), that is expected to change.
An extremely cold wave of Arctic air is expected to head into these areas in the coming days. Temperatures are expected to be between 30 and 50°F below normal during the early part of next week. The level of cold expected can be best described as “frigid” or “brutal”, with a real risk to life from this cold. Similar temperatures were experienced in Wisconsin during January 2019’s outbreak, you may remember.
This following temperature anomaly chart shows the depart from average of temperatures on Tuesday. Notice how much of central and eastern continental U.S. is rather milder than average. This contrasts, significantly, with the severe and intense cold over the north west. The cold will be intense over the Prairies, southern Columbia, Alberta and Saskatchewan. However, the far north of Washington, Idaho and Montana will also see intense cold. (Image credit: pivotalweather.com)
Fast forwards 24 hours, and by Wednesday the cold is still in the same area. if anything moving a little further south east so that parts of the Dakotas are turning cold. The severe cold is really starting to fester at this point, in fact overnight lows approaching -50F are possible in some parts of southern Alberta and SW Saskatchewan, whilst lows between -30 and -40C are possible in northern Montana.
Snow flurries will also affect the North West in the coming days. Some persistent snowfall is looking likely over higher parts of Oregon, Washington, Idaho and Montana during Sunday and Monday. Even Seattle could see a dusting of snow on Monday, and will struggle to reach 32 (freezing) on Wednesday. Continued snow showers are possible in the North West through the middle part of next week, leading to accumulations of up to 6″ over higher ground, e.g. the Northern Rockies.