After days of sitting under a blanket of wildfire smoke, the Northeast on Saturday was being hit by thunderstorms that were flushing out the acrid air but also threatening the area with strong winds, heavy flooding rains and even possible tornadoes.
Forecasters with the National Weather Service said that the biggest concern with these storms was winds over 70 miles per hour in an area that spread from Cleveland to New York City to Washington, but that there was also a small chance for tornadoes. Tornado watches were in effect through Saturday evening across a broad area including southeast Pennsylvania and much of Delaware, Maryland and New Jersey.
These storms were also bringing a chance for scattered heavy rain that could lead to flash flooding across the Ohio Valley into the Mid-Atlantic and southern New England, with New York City, Newark and Philadelphia among the cities with a particularly high risk.
A flurry of flood watches, severe thunderstorm watches and tornado watches were issued Saturday across parts of the Mid-Atlantic, and forecasters said people could keep an eye out for more urgent warnings. While a watch is a heads-up that conditions are favorable for hazardous weather, a warning is an order to take immediate action.
Clusters of thunderstorms formed Saturday morning into the early afternoon from the lower Great Lakes into the Mid-Atlantic. Rain pounded New York City in the early afternoon, and the National Weather Service issued a flash flood warning for Manhattan, Brooklyn, Queens and surrounding areas.
“The worst of it is in Brooklyn and Queens, where we got over two inches of rain,” said Bill Goodman, a meteorologist with the Weather Service office in Upton, N.Y.
The New York Fire Department confirmed that rescue operations were underway “for people trapped in their cars citywide.” According to the police department, at least three major roadways were closed in sections in Brooklyn and Queens.
New York City Emergency Management warned that rainfall rates had “exceeded what the sewer system can drain” in some places on Saturday, and with more rain expected, the agency said people living in basement apartments and homes prone to flooding should be ready to move to higher floors.
This was the first round of storm activity. A second, more intense line of thunderstorms was expected to move across the region later Saturday afternoon into the evening, and these could kick up strong winds.
The area just north of Baltimore to New York City was likely to see the most severe storms, said Brian Hurley, a meteorologist with the Weather Prediction Center. Some of these storms could bring damaging winds to some areas, but not all of these areas will be hit by the strongest winds.
Mr. Hurley said it was difficult to pinpoint exactly where the most hazardous weather would occur. Thunderstorms are tricky to forecast, and they can suddenly form, darkening clear skies and bringing heavy bursts of rain, strong winds and lightning.
Mr. Goodman said it was unclear what the evening storms would bring to New York City.
“With this second round we’re going to have to wait and see what happens,” he said.
Claire Fahy contributed reporting.