Fox News Weather Center

Midwest, East: Cool Weather to Fade, Summer Heat to Arrive in August

While persistent waves of cool weather have some people in the Midwest and East saying that 2014 is the year without a summer, a forecast pattern change during August could have people thinking otherwise.

A shift in the jet stream is forecast during the middle of August that will lead to longer-lasting warm weather over much of the eastern two-thirds of the nation and less extreme heat over the Northwest.

The jet stream is a river of high-speed air, high above the ground that guides storm systems and air masses along.

According to AccuWeather Long Range Expert Paul Pastelok, "We expect the jet stream to flatten out over the West and retreat northward over the Central and Eastern states."

A break in the cool pattern is forecast next week for the Midwest and East, but the long-lasting warmth will hold off until mid-August.

"The jet stream will split apart prior to fully flattening out and will allow some warmth to build from the Tennessee and Ohio valleys to the East during the middle of next week."

Only brief, limited cooling is likely for parts of the Central and Eastern states later next week.

During the middle of the month, an area of warm air and generally fair weather is forecast to build westward from the Atlantic. This system is known as the Bermuda High.

"It is possible that during the period from around Aug. 14 to Aug. 24 areas in the Midwest, Texas and the Northeast will have their warmest weather of the summer," Pastelok said.

The upcoming pattern is good news for kids and adults hoping for warmer swimming weather. Area lake and ocean water temperatures typically peak during August.

However, the surge in warmth will also mean an uptick in cooling costs. In portions of the Midwest, the weather during July has allowed some people to use 30 to 40 percent less energy to cool their homes and businesses.

Students heading back to schools without air conditioning during the second half of August could struggle with the warmth.

The pattern shift may be most dramatic for those over the Central states, where the cool conditions thus far this summer have been the most extreme.

Pastelok still feels that prior and ongoing wet weather in the South will limit the uptick in daytime temperatures.

"In the South, while daytime highs may not be that extreme during the middle and latter part of August, nighttime lows are likely to be significantly higher than average."

In the Southwest, no significant change in temperature is forecast. However, some cooling is possible on a local basis from day to day as monsoon thunderstorms ignite.

The warmer-than-average conditions are forecast to last into the first week or so of September over much of the Central and Eastern states before another pattern change may take place.