Multiple rounds of storms will bring torrential downpours to some locations and the risk of damaging winds to others in the northeastern United States into Saturday.
Storms will carry the risk of severe weather from Ohio and western Pennsylvania to parts of Indiana, Kentucky, West Virginia and Illinois Friday afternoon into Friday night.
The storms later Friday will follow a round of strong and drenching thunderstorms from Friday morning. As a result, portions of Ohio and western Pennsylvania will be hit by two rounds of potent thunderstorms into Friday evening.
"Rounds of storms forming around Ohio will produce heavy rain, high winds, hail and a couple of isolated tornadoes," according to AccuWeather Senior Meteorologist Dan Pydynowski.
People should be prepared for sporadic fallen tree limbs and power outages. Blinding downpours can lead to localized urban and flash flooding.
Motorists should expect sudden poor visibility and excess water on the roads along parts of the Interstate-70 corridor and I-71, I-75, I-77, I-79, I-80 and I-90.
Cities at risk for severe storms and related flight delays include Detroit; Cleveland, Cincinnati, Dayton, Columbus and Akron, Ohio; Pittsburgh, Erie and Johnstown, Pennsylvania; Morgantown and Huntington, West Virginia; Indianapolis and Louisville and Lexington, Kentucky.
The storms will drift southeastward into the Appalachians and weaken late Friday night.
However, storms are likely to re-fire from parts of the Appalachians to the Atlantic coast on Saturday. The storms on Saturday along the coast will follow a batch of soaking rain that has a history of flash flooding from Thursday to Friday.
While most of the storms will not be severe on Saturday, a few can bring torrential downpours and strong gusts of wind.
Storms of this nature are most likely over the mid-Atlantic, while areas in upstate New York and New England may be too cloudy for locally severe storms.
Motorists, airline passengers and those outdoors on Saturday should be prepared for sporadic disruptions from storms and/or downpours in New York City; Philadelphia; Dover, Delaware; Washington, D.C.; Richmond, Virginia; Baltimore; and Atlantic City, New Jersey.
"While the storms will be locally heavy, they will be spotty in nature from the Carolinas to southern New England," Pydynowski said.
"People should keep an eye on the sky for changing conditions, but there is probably no need to cancel outdoor plans as an all-day rain is not expected from Raleigh, North Carolina, to New York City," he said.
In parts of northern upstate New York and New England, showers and storms may be frequent enough where an indoor backup plan for outdoor activities may come in handy.
Less humid and slightly cooler air will end the shower threat in most areas west of the Appalachians early in the day on Saturday and then Sunday along the Atlantic coast.