Big storms may slow 4th of July travel into Wednesday night

By Alex Sosnowski, AccuWeather senior meteorologist

As millions begin their journey or start their Fourth of July activitiesinto Wednesday night, thunderstorms will be on the prowl from parts of the northern Plains to the mid-Atlantic states.

The weather pattern is fairly typical of early July, where daytime heating combined with high humidity levels will help to trigger some summer storms.

The area at greatest risk for multiple severe storms or a large complex of storms into Wednesday night will focus over the northern Plains, according to AccuWeather Senior Meteorologist Kristina Pydynowski.

"Storms from parts of the Dakotas to western Minnesota, northwestern Iowa, northern Nebraska and eastern Wyoming will bring the risk of 70-mph wind gusts, hail and some incidents of flash flooding," Pydynowski said.

"An isolated tornado cannot be ruled out," Pydynowski added.

The severe nature of the storms in this area will likely hold off until Wednesday evening and continue well into Wednesday night when there could be sporadic power outages and property damage.

The northern Plains will not be the only area at risk for a nasty summer storm.

Farther to the east, a long and broad swath of spotty thunderstorms is forecast to bubble up and pulse to heavy, gusty and even severe levels on a neighborhood basis.

"This zone is expected to extend from the middle Mississippi Valley through the lower Great Lakes and Ohio Valley to the central Appalachians and the mid-Atlantic and Carolina coasts," Pydynowski said.

A couple of isolated storms will also erupt over the southern Appalachians into Wednesday evening.

Farther south, part of the lower Mississippi Valley to the Texas coast can also experience some slow-moving and drenching storms.

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Stay safe as summer storms come calling

Motorists should never drive through flooded areas. The water may be much deeper than it appears or may be rising rapidly and the road surface beneath the water may have been washed away.

Driving through a torrential downpour at high speed when the highway is bumper to bumper with traffic is very dangerous. Stopping distance is greatly increased during wet conditions and reaction time may be substantially delayed in poor visibility.

If on the Interstate when a downpour hits, it is best to exit the high-speed highway as storms approach and wait until they pass. During a blinding downpour, oncoming motorists may not realize a vehicle has stopped on the shoulder of the road and doing so could lead to a collision. This is possible even if hazard flashers have been turned on.

Remember, if outside, move indoors at the first rumble of thunder. If you can hear thunder, you are at risk for being struck by lightning. Standing beneath trees, sheltering under picnic pavilions and sitting in golf carts are not safe places to be during thunderstorms.

A metal, hardtop vehicle is a relatively safe second option if a house or business building is not nearby as a storm approaches.

While water does not attract lightning, water is a good conductor of electricity. Get out of the pool and get off the lake as thunder begins to rumble.

When camping near small streams in the mountains, be sure to monitor for thunderstorm activity and the potential for flash flooding.

During a thunderstorm, camping in a widespread, thick forested area with trees of uniform height is a safer alternative to an open field or high in the mountains above the tree line. Be alert for high winds which can cause trees or large branches to fall.

Download the free AccuWeather app to receive any severe weather watches and warnings. Keep checking back for updates on AccuWeather.com and stay tuned to the AccuWeather Network on DirecTV, Frontier and Verizon Fios.