CHICAGO (AP) -- Unseasonably cool weather will arrive next week in the Midwest and as far south as Arkansas and Oklahoma.
It is not, however, the second coming of a polar vortex, a phrase the National Weather Service's Chicago office tweeted earlier this week to describe the upcoming sweater weather. The office quickly learned that wasn't such a good idea, said Amy Seeley, a weather service meteorologist who spent a good chunk of Friday morning fielding a flood of telephone calls from the media.
"I think people are pretty sensitive to those words," she said.
WHAT'S TO BLAME?: Though Typhoon Neoguri has weakened since hitting Japan, it altered the path of the North Pacific jet stream, allowing polar air behind a trough of low pressure to spill out of Canada and into the Midwest, said Weather Underground meteorology director Jeff Masters.
It's similar to the polar vortex pattern from the winter that turned much of the U.S. into a freezer for weeks at a time, breaking low temperature records in numerous states. But there are key differences, Masters said. This air mass is coming from western Canada and not directly from the arctic, plus the polar vortex is not nearly as strong in the summer and sometimes breaks down completely.
HOW COLD WILL IT GET?: Between Monday and Wednesday, temperatures in the Midwest will be as much as 15 degrees lower than normal, with the biggest drops seen close to the Great Lakes, though people in Oklahoma and Arkansas will need to break out pants, too.
Chicago would normally see highs in the 80s and lows in the mid-60s, but the weather service says highs early next week will climb no higher than the mid-60s -- maybe 70 degrees-- and lows could dip into the upper 40s.
WHAT DOES IT MEAN?: That sound you hear coming from Oklahoma might be thousands or people turning off their money-gobbling air conditioners. It could also be the cheers of those who make their living working outside, such as the employees at a Tulsa nursery, whose job entails hauling trees and shrubs around town.
"We love it," Paul James, marketing manager for Southwood Landscape & Garden Center, said of the forecast for temperatures running about 15 degrees lower than the typical 93- or 94-degree July days. "Any day you don't get above 100 degrees."