The air feels so cold, frostbite on exposed skin can occur in under 10 minutes in most of the impacted areas, and some isolated locations in under five minutes, forecasters warn. On Tuesday, the sprawling weather system is delivering dangerously cold temperatures and snow to Montana, North Dakota, South Dakota and most of Minnesota, where high temperatures will remain below zero, according to forecasters at the NWS. Parts of Alabama and Tennessee are also under a wind chill watch as the “feel like” temperatures are expected to plummet below zero.Īrctic blast this week brings the coldest Christmas in nearly 40 years for millions More than 40 million people are under wind chill alerts across much of the central and northwestern US, including in places slammed with blizzard conditions by a separate storm system last week. This weather phenomenon is expected to be the pressure equivalent of a category 2 hurricane as it reaches the Great Lakes, with the weather service now calling the strength of the low a “once-in-a-generation” event. That’s because of the extreme temperature difference between the warm and moist air in advance of the storm and the extreme Arctic air mass moving in from Canada. These storms frequently occur with winter nor’easters, but in this case, the bomb cyclone is expected to occur in the Plains.

Specifically, it means a drop of 24 millibars (a term used to measure atmospheric pressure), in 24 hours. For millions of Americans across a large swath of the country, the holiday week is beginning with unrelenting below-freezing temperatures made even more miserable by heavy snow expected Tuesday and Wednesday in several central and northwestern states.Ī developing ‘bomb cyclone’ has prompted alerts from Washington state to Maryland that cover over 50 million people, according to the National Weather Service, and that number is expected to grow over the coming days.Ī ‘bomb cyclone’ is a term used by meteorologists to describe a rapidly strengthening storm.

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