It is the first day of fall, but it feels like the middle of summer in Minneapolis.
Temperatures in southern Minnesota and western Wisconsin hit more than 20 degrees above average Friday.
A temperature of 93 degrees was recorded at Milwaukee's Mitchell Airport — a record for this time of year.
The reason: A long ridge of high pressure in the atmosphere over much of the central and Eastern United States, National Weather Service meteorologist Tom Hultquist told CNBC.
"It is allowing this heat that would normally stay south come up here," he said.
This ridge is caused by a fluctuation in the fast band of high altitude winds known as the polar jet stream. Jet streams do not follow a straight pattern as they blast their way around Earth. They actually wiggle and wobble, developing bends in places as they encircle planet.