A powerful cold front is bringing the first frost or freeze of the season to parts of the Plains, Midwest and East this weekend, The Weather Channel's weather.com reported. Morning lows will drop from the 60s and 70s to the 30s and 40s, and frost advisories, freeze watches and freeze warnings are in effect across parts of the central and northeastern U.S., weather.com reported.

In the Chicago area, the National Weather Service issued a frost advisory starting at 5 a.m. Saturday for Lake, LaSalle and Kendall counties in Illinois and Kenosha County in Wisconsin, and a freeze warning for McHenry, DeKalb and Kane counties, NBC Chicago reported. The weather service called it the "coldest night of the season." The normal first freeze at O'Hare is Oct. 19, and last year's came on Nov. 9, NBC Chicago reported.

In Pennsylvania, the weather service in State College issued a freeze watch from 1 a.m. to 9 a.m. Sunday, with lows that could reach 25 degrees, LancasterOnline reported. "Frost and freeze conditions could kill crops, other sensitive vegetation and possibly damage unprotected outdoor plumbing," the weather service said, according to LancasterOnline.

Millersville University meteorologist Kyle Elliott said a large high-pressure system from Canada will move over Pennsylvania on Sunday and the wind will die down, LancasterOnline reported. "The first widespread frost of the season is a virtual 'lock,' and temperatures may even drop 1-2°F below freezing in the most rural/outlying areas," Elliott said.

The chill will not last. Weather.com meteorologist Rob Shackelford called it a "false fall" and said temperatures in the Upper Midwest should be back above average by Sunday, with warmth spreading east next week. LancasterOnline reported that highs in the 60s will return to Lancaster County next week.

What we know: Frost and freeze alerts cover parts of the Midwest and Northeast this weekend, and warmer weather is due next week.
What we don't: How much damage the cold will do to crops and late-season plants.