Cool air sweeping from the Midwest will bring a taste of fall to the northeastern United States next week.
High temperatures in the middle 80s to the middle 90s will be replaced by highs ranging from the upper 60s and lower 70s in the mountains to the middle 70s to lower 80s along the Atlantic coast.
The cooler air since June will not only slash temperatures but also substantially lower humidity levels. As a result, air quality will greatly improve.
The leading edge of the cooler and less humid air will progress through the Midwest this weekend and will reach the Appalachians into Sunday evening.
The wave of cool air will reach the Interstate 95 corridor and beaches by Monday morning.
"Temperatures at the peak of the cooldown will be more typical of the middle of September," AccuWeather Meteorologist Brett Rathbun said.
Nighttime temperatures will dip into the 40s in parts of the Appalachians and into the upper 50s and lower 60s in the I-95 cities from Boston to New York City, Philadelphia, Washington, D.C., and Richmond, Virginia.
Even portions of the Southern states will get a break from the steamy air.
"The cool shot will give area residents an excellent opportunity to open the windows and give air-conditioning units a break," AccuWeather Meteorologist Renee Duff said.
"Sleeping will be more bearable in non-air conditioned dwellings," she said.
In the mountains, temperatures will get low enough at night to cause some people who mind the cool air to put on long sleeves and jackets.
People who have held back on vigorous exercise or manual labor in recent weeks for safety concerns will be able to resume those activities. Those with respiratory or cardiac problems will be able to go outside and get some fresh air.
Despite the cooldown, midday and afternoon temperatures will still be high enough for swimming.
As pleasant as the upcoming weather pattern may seem to some people, it could result in travel problems.
Showers and locally heavy, gusty thunderstorms will mark the leading edge of the cooler air as it advances eastward through Sunday night.
Even after the humid air departs, locally dense late-night and early-morning fog could form, especially in the river valleys of New England and the mid-Atlantic during the early and middle part of the week.
The cooldown does not mark the end of summer weather, however.
"Very warm and more humid air will return to the Midwest at midweek and the Northeast late next week," AccuWeather Chief Meteorologist Elliot Abrams said.