There is a risk of locally damaging thunderstorms Tuesday evening and again on Independence Day, which could not only impact daytime picnics and festivals, but also evening fireworks in the Northeast.
Just about every major city and small community has some sort of fireworks display on or around the Fourth of July in the Northeast (many displays have been canceled elsewhere, due to dry conditions). However, storms erupting in over a dozen states could impact activities and have some folks running for cover.
Another surge of humid air and a warm front/cool front combination could have the atmospheric volatility index on the rise for July Fourth from the Ohio Valley states to the mid-Atlantic and New England.
While not quite the same setup and crushing outcome as the Derecho of this past Friday and Saturday, thunderstorms that form will have the potential to bring localized power outages from damaging wind gusts and frequent lightning strikes.
Downpours from the storms can also cause disruptions to outdoor plans.
The storms are likely to hit some areas that were missed (New England and the northern mid-Atlantic) by the Derecho and could overlap areas that were hit (Ohio Valley and the southern mid-Atlantic) by the system.
One large batch of storms will swing through much of the region this afternoon into Tuesday night. Crews may want to protect displays and electronic equipment from gusty, drenching storms.
It is possible this first batch of fast-moving, gusty storms Tuesday evening may "steal the thunder" from potential storms on Independence Day.
During the Fourth of July afternoon, "independent" storms are likely to re-fire through the northern Appalachians, part of the Ohio Valley and eastern Great Lakes. Most of the storms are likely to push south and east of Buffalo, Cleveland, Cincinnati, Pittsburgh and State College in time for evening fireworks, but there may be a few trouble spots.
During the evening, a broken line of strong storms may extend from Boston to New York City, Philadelphia, Washington, D.C., to the central and southern Appalachians. Whether or not these move through prior to sunset and fireworks time in every location is impossible to say at this point.
We will continue to update you on the situation. Be sure to check AccuWeather.com for the latest radar in your local area.
It is rather easy for the atmosphere to produce thunderstorms this time of the year due to the long days and maximum heating. Only if dry air sweeps through in force, would the threat of pop-up storms on the Fourth of July be reduced.
Southeastward progress of the cool front and its dry air will be critical for the bulk of the thunderstorm activity during Independence Day. If the front fails to push far enough along, additional spotty storms could fire in the wake of the main line. AccuWeather meteorologists suspect this will be the case.
Since the holiday is in the middle of the week, there may be no desirable options for rescheduling fireworks, if storms come calling at the wrong time. Fortunately, most storms in this pattern will be brief. Despite some delays, the storms should generally move on in less than an hour.
In areas where rain falls and ceases just prior to fireworks, calm, moist conditions in its wake potentially could cause fog to form and inhibit smoke from clearing, perhaps leading to poor viewing conditions.
In other parts of the nation, it is drought and fire danger that are foiling fireworks plans.
Just a Reminder
Keep an eye out for rapidly changing weather conditions on your holiday ventures.
During a thunderstorms, severe or not, lightning poses the greatest risk to your life.
If you can hear thunder, you are at risk for being struck by lightning.
Seek shelter in a building or hard-top vehicle as storms approach. (Picnic pavilions, trees and golf carts are not safe places to be during thunderstorms.)
Preliminary reports are calling it an EF-4 tornado that has caused numerous fatalities and injuries in Moore, Okla.
Several tornadoes touched down from Oklahoma to Iowa, including near Wichita, Kan., and Oklahoma City, on Sunday.
Rising temperatures and humidity across the mid-Atlantic will have it feeling like the end of June.
Heavy rain returning to the northern Plains will generate a renewed flood threat for the Red River.
Tornadoes broke out from Texas to Missouri on Monday with a deadly tornado moving through the town of Moore, Okla.
A tornado touched down at about 2:53 p.m. CDT Monday in Moore, between Norman and Oklahoma City.
Kansas City, KS (1957)
Forty-five people killed and millions of dollars in damage by tornadoes.
Ohio Valley (1860)
Tornado swarm in Ohio Valley hit Louisville, KY, Cincinnati, OH, Chilicothe, OH, and Marietta, OH. Damage totalled $1 million; 4 people killed in Cincinnati.
Texas County, OK (1937)
Severe dust storm called "Black Blizzard" visibility near zero for 10 minutes.