March is beginning with a major cold outbreak in the Rockies, Plains and Midwest, breaking daily records and a few monthly records in areas that shivered through much of February.
An all-time record low for the entire state of Montana may have been set at Elk Park Monday morning when the temperature fell to minus 46 degrees. This comes after two cities in Montana set all-time record lows for the month of March on Sunday morning, including Miles City (minus 31 degrees) and Livingston (minus 27 degrees).
Chicago fell below zero on Monday morning, something that has happened only eight other March days on record at O'Hare Airport, last occurring March 3, 2014. It was also the coldest March morning there since March 4, 2002.
North Platte, Nebraska, set an all-time March record low of minus 25 degrees early Monday. In addition, daily record lows for March 4 were set in Duluth, Minnesota (minus 19 degrees), and Indianapolis (2 degrees - tie).
Daily record lows for March 3 were also set Sunday morning in Sioux Falls, South Dakota (minus 17 degrees), Billings, Montana (minus 19 degrees), Rochester, Minnesota (minus 17 degrees - tie), and Minneapolis/St. Paul (minus 13 degrees - tie).
Denver dropped to minus 6 degrees Sunday morning, which is the coldest March low temperature there since March 2, 1960, according to the National Weather Service.
This latest cold outbreak is due to a blocked jet-stream pattern in the Arctic.
Namely, a nose of high pressure aloft from the Gulf of Alaska to the Canadian Arctic is forcing bitterly cold air southward into the U.S.
This arctic block has been responsible for abnormally mild weather in parts of Alaska, including record warmth at America's northernmost city, Utqiagvik, formerly known as Barrow.