Dangerous and potentially violent storms will ramp up over the Midwest on Friday and may threaten part of the eastern United States on Saturday.
The storms will pack enough punch to hinder travel for a time and disrupt some outdoor activities.
Flash flooding and sudden low visibility from the storms will be the greatest threats to motorists.
Airline delays may ramp up in some of the major Midwest hubs during Friday afternoon and evening. These include the cities of Chicago, Indianapolis, Cincinnati and Detroit. The storms would not reach Cleveland, Pittsburgh and Nashville, Tennessee, until late Friday night.
There is the risk of the storms becoming intense enough to cause property damage, trigger power outages and threaten lives in a few communities.
"The strongest storms will produce powerful wind gusts and hail," according to AccuWeather Storm Warning Meteorologist Brian Knopick. "It is possible that a couple of the strongest storms produce an isolated tornado."
People, including school officials, will need to monitor severe weather bulletins as they are issued especially for activities during the afternoon and evening hours.
Motorists and pedestrians should be alert for rapidly changing weather conditions. Never attempt to drive through flooded roadways. Seek shelter indoors as storms approach.
"The thunderstorms on Saturday will continue to pack a punch in terms of gusty winds, brief torrential rainfall and travel disruptions in the eastern part of the U.S. including the Interstate 81, 95 and 99 corridors," according to AccuWeather Senior Meteorologist Henry Margusity.
Because of the gusty winds and heavy nature of some of the downpours, an umbrella may not be enough to keep people dry who will be heading out.
During Saturday afternoon and evening, the storms will affect cities such as Winston-Salem and Raleigh, North Carolina; Harrisonburg and Richmond, Virginia; Washington, D.C.; Baltimore and Hagerstown, Maryland; State College and Scranton, Pennsylvania; and Syracuse and Binghamton, New York.
Some of the storms into Saturday evening can be strong enough to knock down trees, tear shingles off some roofs and cause sporadic power outages.
The storms may lose some of their intensity upon reaching the immediate Atlantic coast during Saturday night. However, sporadic incidents of flash flooding can still occur, especially over eastern upstate New York, New England and adjacent Canada, where there is still a significant amount of snow on the ground.
"The weather for the outdoor NHL Stadium Series game between the Penguins and Flyers at Heinz Field in Pittsburgh will be windy and turning colder Saturday evening," according to AccuWeather Meteorologist Brian Lada.
While the heavy rain from Saturday will move away, there can be sprinkles and flurries with temperatures falling through the 30s for the game.
The sweep of cold air will end the severe weather threat for the Midwest and East for the short term.
However, another potent storm system could spark a new round of snow, heavy rain and perhaps a significant severe weather outbreak during the middle of next week as the April-like weather pattern returns.