US Labor Day weekend outlook: Storms may threaten plans in Midwest, South

As millions are gearing up for the Labor Day holiday weekend, many are wondering if the weather may foil their plans.

Showers and thunderstorms threaten to put a damper on a part of the holiday weekend across the Midwest, South and interior Southwest. Any wet weather in the Northeast may only impact a fraction of the weekend.

Mostly dry but not bright sunshine in store for the Northeast

"Most of the holiday weekend will be dry from Philadelphia to New York City and Boston," according to Lead Long-Range Meteorologist Paul Pastelok, “Don’t anticipate a bright blue sky as it can be murky early in the weekend.”

The weekend may start on a cool note with highs in the lower 70s across New England on Saturday as humidity hangs on over the mid-Atlantic.

Humidity may surge back northward for a time as the weekend progresses.

“A line of showers and thunderstorms will attempt to press eastward across the Northeast later Sunday into Labor Day, but most should diminish as they cross the Appalachian Mountains,” Pastelok said.

"It can still be warm in Boston and New York City on Labor Day with lowering humidity," he said. "Humidity may hang on longer around Washington, D.C."

Some of the nicest weather on Labor Day may be found around the eastern Great Lakes and the St. Lawrence Valley.

Not a washout in the South for the holiday weekend

Highs near 90 F are anticipated in many communities across the South each day from Saturday to Monday. Humidity will create even higher AccuWeather RealFeel® Temperatures.

That steamy air can spark showers and thunderstorms daily.

The holiday weekend will not be a washout across the entire region with the showers and thunderstorms being more hit-and-miss in nature, mainly during the afternoon and evening hours.

Men vs. women: Which gender is more likely to be fatally struck by lightning?
2018 US fall forecast: Unseasonable warmth to grip Northeast; Extreme fire season predicted in West
Is it safe to talk on your cell phone during a thunderstorm?

"For those with afternoon picnics, keep an eye to the sky as spotty thunderstorms will be around," Pastelok said.

Widespread severe weather is not anticipated, but anyone outside should seek shelter as soon as thunder is heard. The risk of being struck by lightning is then present.

Gusty thunderstorms may threaten plans in Midwest

A line of showers and thunderstorms is set to cross the Midwest in a west to east fashion Saturday into Sunday.

"Some of these thunderstorms can be strong and gusty," Pastelok said.

Residents planning to attend picnics, parades, sporting events or other festivals will want to download the free AccuWeather app and enable audible weather alerts to know when to move indoors.

While holiday plans can be in jeopardy early in the weekend around Detroit and Cleveland, Pastelok anticipates nice weather for Monday.

Farther to the west, Saturday and Sunday may be the better half of the holiday weekend to attend the Minnesota State Fair around the Twin Cities.

A new round of thunderstorms may target areas from Omaha, Nebraska, to Minneapolis on Labor Day.

Monsoon thunderstorms to increase in interior Southwest

An increase in monsoon moisture is expected to cause thunderstorms to expand across the Desert Southwest through the Labor Day holiday weekend. The afternoon and evening hours will be the most active times of each day.

Campers and hikers will want to closely monitor the sky and be ready to seek shelter as the thunderstorms may bring dangers of flash flooding and lightning.

“The majority of the thunderstorms that develop in the Desert Southwest should remain away from Phoenix,” Pastelok said.

The rain is expected south of where numerous wildfires are burning in the vicinity of Northern California and northern Nevada. Smoke from these blazes may ruin the holiday weekend in surrounding communities.

Heat to be absent in the Northwest as dry weather dominates

Dry weather is also expected to dominate the Northwest through the holiday weekend with temperatures gradually being trimmed.

"While the northern Rockies will start the weekend off warm, these areas will be a couple degrees below normal for Labor Day," Pastolok said. "The cooldown will be nothing like the chilly conditions that allowed snow to fall early this week.

Near-normal temperatures in the 70s are anticipated for Seattle and Portland. Pastelok expects Portland to see more sunshine than Seattle.

"No heat will sizzle the Pacific Northwest this holiday weekend," he said. "These cities may get their heat the following weekend."