Scattered thunderstorms may produce flash floods in the New York region late Wednesday and early Thursday, even as many communities are still reeling from the damage caused by the remnants of Hurricane Ida, which killed at least 46 people across four states one week ago, the National Weather Service said.
The scattered storms may produce heavy downpours, with a “marginal to slight risk” of flash flooding in northeast New Jersey, New York City, the Lower Hudson Valley and southwest Connecticut, the Weather Service said.
The storms were expected to bring 0.5 to 1.5 inches of rain, although 2 to 2.25 inches were possible in a worst-case scenario, the Weather Service said. It noted that flooding was possible in urban areas and in communities where small rivers, streams and creeks were already swollen.
Severe thunderstorms with damaging wind gusts were also possible and an isolated tornado “cannot be ruled out” north and west of New York City.
New York City was expecting 0.75 inches to 1 inch of rain, with some areas possibly receiving 1.25 inches.
“These systems are not forecast to be severe at this time, but please be prepared as conditions may change,” the New York City Emergency Management Department said.
Mayor Bill de Blasio of New York said at a news conference on Wednesday morning that the heaviest downpours were possible after midnight, bringing about half an inch of rain.
“That, normally, would not be an issue at all,” he said. “Obviously, we’re concerned about folks who were hit that any new water could be a problem. And we’re also concerned that we could see more than is projected.”
Mr. de Blasio urged homeowners and business owners to take precautions and said that city workers would be “out in force,” cleaning catch basins, particularly in areas hard hit by Ida.
Gov. Philip D. Murphy of New Jersey also asked residents to be aware of possible flooding.
“Please take every precaution given that the ground in many places remains saturated,” Mr. Murphy said on Twitter. “The potential for flash flooding always exists with a quick-moving thunderstorm. Do not attempt to drive into standing water.”
The possibility of additional rain came as states were still tallying the damage from Ida’s floodwaters, which killed at least 25 people in New Jersey, 16 in New York, four in Pennsylvania and one in Connecticut.