Labor Day weather: Where storms will spoil unofficial end of summer

There's good news and bad news for those traveling or spending time outdoors for the extended holiday weekend and the unofficial end to the summer season. Drenching downpours and gusty storms will be on the prowl.

As the last unofficial weekend of the summer unfolds and millions take to roads, rails and skies, travelers can expect both sunny days and potential trouble spots as thunderstorms make an appearance throughout Labor Day weekend, AccuWeather meteorologists say. Depending on your location and timing, your holiday plans might range from smooth sailing to navigating a few weather-related hurdles.

Showers and thunderstorms will be mainly focused across a broad zone from New Mexico, Texas and Louisiana to Michigan, western New York, central Pennsylvania, Maryland and Delaware from Friday to Friday night. Much of the Florida Peninsula will be active with thunderstorms as well.

Rain won't fall constantly across this large area, which spans more than 20 states, but some thunderstorms that occur, especially between 2 and 8 p.m. local time, could bring heavy rain, gusty winds and potentially severe conditions.

Thundery, drenching episodes to occur in the East

Continuing through much of Labor Day weekend, downpours can foil outdoor plans and slow travel while potential lightning strikes will be a risk for anyone spending time outside.

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A wedge of cool, dry air will keep much of New England and the upper part of the mid-Atlantic comfortable on Friday before a front surges in from the Midwest with locally drenching showers and thunderstorms.

Humidity levels will build ahead of that front on Saturday.

Some of the storms generated by the front will bring localized flash flooding and poor visibility on the roads while some locations may be affected by wind gusts strong enough to break tree limbs and rip away canopies.

A strong push of cooler, less humid air will follow the front over the northern Plains on Friday. That refreshing air will expand eastward across the Midwest from Friday night into Sunday and spread to much of the Northeast on Monday.

For much of the Southeast, especially from the coastal Carolinas to central Mississippi, the bulk of Saturday and Sunday will be free of rain. Some storms will sag slowly southward over the Tennessee Valley and southern Appalachians while other storms pop up around the Gulf Coast.

By Labor Day, the corridor of drenching showers and thunderstorms will extend from Texas to the Carolinas, Georgia and Florida, where localized flash flooding can occur.

Western US hot spots

Meanwhile, much of the West will be free of rain for the Labor Day weekend. Some exceptions will be spotty thunderstorms that erupt, mainly over the Rockies.

On Saturday and Sunday, these storms will bring the threat of lightning strikes and flash flooding to an area that extends from the mountains of Arizona and New Mexico to Colorado. By Labor Day, the sporadic, mainly afternoon and evening storms may fire up from Colorado to Montana and Idaho.

Expect the deserts to experience their usual heat this weekend while highs along the Interstate 5 corridor of the Southwest range from the 70s F on the beaches and bays to the middle to upper 80s inland.

Much of the Northwest will swelter in a late-summer heat wave this weekend. The worst of the heat will ease in areas along the I-5 zone as the weekend progresses but will continue into Labor Day east of the Cascades to the northern Rockies with widespread highs in the 90s to low 100s.

While no tropical systems will affect the United States mainland over the Labor Day weekend, Hawaii will have some direct impacts from Gilma as a tropical rainstorm in the form of showers, thunderstorms and gusty winds.

Hector, located a few hundred miles to the east-southeast of Gilma, has dissipated.

There will be budding activity in the Caribbean that could spread showers and thunderstorms to the U.S. Virgin Islands and Puerto Rico on Labor Day or Tuesday.

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