Memorial Day storms to rattle more than half of US

By Accuweather

Showers and thunderstorms threaten to interfere with Memorial Day festivities across more than half of the United States.

That does not mean that half of the picnics, parades and other outdoor events throughout the nation will not be able to go on as scheduled.

Monday will not be a complete washout in most communities being threatened by showers and thunderstorms. There will still be stretches of dry weather.

Residents should monitor their local forecast pages to determine the best time to schedule outdoor plans. On the actual holiday, a close eye will have to be kept on the sky andAccuWeather MinuteCast® to know when to move indoors.

Widespread severe weather is not a concern on Monday, but lightning is.

"While only a small number of storms become strong enough to produce damaging winds, large hail and tornadoes, every thunderstorm produces lightning," stated AccuWeather.com Brian Lada.

"Lightning is one of nature's deadliest phenomena, claiming roughly 55 to 60 lives every year across the United States and injuring hundreds more," added Lada.

The most active parts of the nation in terms of thunderstorms will lie from the Gulf Coast to the Midwest and into a part of the Northeast and across the Intermountain West.

A large corridor of showers and thunderstorms will be found on Monday from the Gulf Coast to the Midwest with steamy air in place and a storm system located over the Upper Midwest.

On the cool side of the storm, periods of rain will dampen the northern Plains--Fargo, North Dakota, included.

The greatest concern for the thunderstorms to be heavy and trigger flash flooding lies from the Texas coast to the lower Mississippi Valley, home to Houston and Shreveport, Louisiana.

On the other hand, the thunderstorms set to develop from the eastern Gulf Coast to the eastern Tennessee Valley will be limited to the afternoon and spotty in nature.

Along the leading edge of the surging warm and humid air, a steadier band of rain and thunderstorms threatens to cause more significant disruptions to holiday plans across the upper Great Lakes.

The eastern extent of this wet weather will nose into a part of the Northeast, separating steamy air set to pour into the mid-Atlantic and more comfortable air in place across New England.

"We know that warmer air is approaching [the Northeast], but we are less sure of the amount of moisture," stated AccuWeather Chief Meteorologist Elliot Abrams. "With sunshine, temperatures will climb to or into the 80s, while clouds and showers will keep temperatures 10 to 15 degrees lower."

"Either way, Monday will be warmer than Saturday, and even where showers occur, it is unlikely to be an all-day rain event," added Abrams.

Two other storm systems will work to keep a large part of the Rockies and interior Northwest unsettled with showers and thunderstorms. The afternoon hours will be the most active time of the holiday.

Anyone planning to spend Monday at a national park or forest, including Yellowstone or Rocky Mountain, should have a plan in place of where to seek shelter during a thunderstorm.

As soon as thunder is heard, the risk of being struck by lightning is present.

Severe weather may become a concern toward the end of the holiday and Monday night across western Texas, from Del Rio to Wichita Falls, depending on the exact timing of when one of the storm systems from the West emerges onto the southern High Plains.

The Carolinas, southern mid-Atlantic, the Desert Southwest and the immediate West Coast should escape wet weather on Memorial Day. In the Southwest, that means residents will have to remaindiligent when participating in some holiday festivities to avoid starting a brush or wildfire.

Away from the contiguous United States, showers will dot Alaska and a few windward communities on Hawaii this Memorial Day. The shower chance will come after Fairbanks, Alaska, experiences a rare feat of recording a high greater than Phoenix on Saturday.