Polar Express: Arctic outbreak to invade parts of US

Parts of U.S. 50 degrees below normal post-Valentine’s Day

Feels like temperatures Monday
Feels like temperatures Monday

ORLANDO, Fla. – The northern tier of the country has been in the grasp of Arctic air for the last week. The high temperature in Minneapolis hasn’t seen double digits since Feb. 5.

The cold air that has been in place will not only intensify, but expand far south into regions not use to the bitter cold. By the end of the week, a strong Arctic cold front will plow south of the Upper Midwest and move right into the Southern Plains.

The core of the potentially record-breaking cold air will settle right into the Nation’s heartland over the weekend.

The core of the cold will impact the Upper Midwest and Southern Plains

Parts of the Plains States could be 50 degrees below normal early next week. Low temperatures in Oklahoma City could fall well below zero. High temperatures in Dallas could struggle to climb out of the single digits Monday.

High temperatures Monday

Florida looks to fend off this outbreak of Arctic air this time around. Temperatures will be about 100 degrees warmer in parts of Florida when compared to the Plains.

Meanwhile, wind chill values in the Upper Midwest and Northern Plains will routinely be running 40 degrees below zero or colder for several days.

Feels like temperatures Monday

Why so cold?

You may have heard of the polar vortex? It’s not just some buzzword to get clicks on the internet. It’s actually a thing and there are two of them. First is the tropospheric polar vortex. This hangs out in the lower levels of our atmosphere where humans live. This circles the globe as a fast-moving ribbon of air where jet aircraft fly and is the dividing line between warm and cold air. The second is the stratospheric polar vortex which forms in the winter and resides over the polar regions way up in the stratosphere.

The two are related to one another and both can impact the behavior of the other. When the stratospheric polar vortex is strong, the coldest air remains bottled up north, close to the North Pole. When the stratospheric polar vortex is weak, the tropospheric polar vortex or polar jet stream also tends to weaken, allowing for Arctic air to spill into the Lower-48.

The science behind the polar vortex.(NOAA)

The Arctic oscillation tracks the stability of the polar vortex. When the oscillation is negative, the vortex is weak and outbreaks of cold air are more likely. The Arctic oscillation is significantly negative at this time.

Arctic Oscillation observed and forecast. NOAA/CPC

When the oscillation is negative, the vortex is weak and outbreaks of cold air are more likely. The Arctic oscillation is significantly negative at this time.


About the Author:

Jonathan Kegges joined the News 6 team in June 2019 as the Weekend Morning Meteorologist. Jonathan comes from Roanoke, Virginia where he covered three EF-3 tornadoes and deadly flooding brought on by Hurricanes Florence and Michael.