Polar vortex makes an icy return in April weather forecast

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Don't put away those winter coats just yet.

An April cold snap is forecast for much of the eastern half of the U.S. early next week, forecasters said, with freezes likely across portions of the central and southern U.S. The freezes could impact new spring vegetation, forecasters warned. It's also likely to annoy cold-weather haters who were ready to ditch winter until next year.

Indeed, according to AccuWeather, several days with temperatures of 10-20 degrees below the historical average could put a bit of a strain on ball games, bike rides, golf rounds and outdoor activities in general.

"The large polar vortex disruption from the second week of March is playing a key role in next week’s eastern US cold snap," meteorologist Judah Cohen of Atmospheric and Environmental Research told Paste BN.

'A big cool down'

Following a deadly and devastating week of weather across a large portion of the nation, "we are going to get a much deserved break" from severe weather as a powerful cold front moves off the East Coast late Sunday and Monday, meteorologist Tiffany Savona reported for Weather.com.

Overall, the summerlike warmth and torrential rain will be replaced with cold, mostly quiet weather.

"A big cool down is on the way especially across the Great Lakes and Northeast, where it will feel more like late February in Chicago and New York early next week as highs drop into the 30s and 40s," Savona said.

She said it will be cold enough to support light snow across the Great Lakes Monday and New England Monday night into Tuesday. However, any accumulations would be minor.

Specifically, the National Weather Service in Cleveland said a couple of inches of snow are possible in northwest Pennsylvania, with an inch or less in northeast Ohio.

Cover your plants!

Weather service forecast offices across the central U.S. are already warning about the upcoming cold. For example, the weather service in Springfield, Missouri, said "colder temperatures are expected late in the weekend into early next week and for those with agricultural interests, we may see some frost and sub-freezing temperatures Sunday night into Monday morning, with near freezing temperatures again on Monday night into Tuesday morning."

"We do have some upper 20s going in the forecast for Sunday night, so if you have some plants already outside you might want to be prepared to cover them or bring them inside for a couple days."

As far south as Huntsville, Alabama, the weather service said that "for those who have agricultural interests, mid next week will be concerning as frost becomes a potential concern."

Farther east, in Greenville-Spartanburg, South Carolina, the weather service said they will be watching for possible frost advisories early next week, "now that the growing season has started."

More: Powerful polar vortex in the stratosphere brings frigid temperatures to US

Polar vortex to blame?

Experts say the polar vortex will play a role in next week's cold snap.

The polar vortex is a gigantic, circular area of cold air high up in the atmosphere that typically spins over the North Pole (as its name suggests). It's a normal pattern that's stronger in the winter and usually tends to keep the coldest weather bottled up in the Arctic.

Previously this winter: Icy air has descended on the US. Is the polar vortex to blame?

However, a disruption in the vortex – known as "sudden stratospheric warming" – back in mid-March will finally be making its way down to the surface in the eastern U.S. next week, Cohen said.

Complex interactions between the stratosphere and troposphere (where our weather occurs) can eventually affect the jet stream and can "increase the odds of colder than average temperatures for the time of year, particularly for the eastern U.S.," noted NOAA scientists Amy Butler and Laura Ciasto in NOAA's polar vortex blog.

While the temperatures won't be at midwinter levels, they will be well below average for April, forecasters said.