A flow of tropical moisture and a slow-moving front are expected to bring heavy rain from South Carolina into the Northeast through the early part of the weekend.
The National Hurricane Center was tracking a swirling area of low pressure off the southeastern U.S. coast as a possible tropical storm, but it did not become a tropical storm and is still dumping a lot of rain.
Meanwhile, strong but stationary fronts act as a source of updrafts of atmospheric air, providing a constant focal point around which storms can develop. Tropical cyclones move north along the fronts, dumping a line of heavy rain along the way.
Flood watches were in effect for at least the first half of the weekend for 45 million locations along the Interstate 95 corridor, stretching from Boston to New York City and Philadelphia through the Carolinas.
“I don’t think there’s going to be any rain, and I think communities are going to be spending part of the weekend outside enjoying themselves,” said Fox Weather forecaster Britta Merwin, “but I think part of the weekend will be board games, movies and staying indoors.”
Most of Friday’s rainfall will be concentrated in eastern Virginia and North Carolina, with some stronger storms expected to move north along the Interstate 95 corridor between Philadelphia and New York, according to the FOX Forecast Center.
As conditions remain relatively stable, multiple storms are expected to develop in these areas along the front in a northeasterly direction from Friday into Friday night.
According to NOAA’s Weather Prediction Center, widespread rainfall of 2 to 3 inches is expected along the Virginia and North Carolina coasts, with some areas expected to get up to 5 inches. Some storms could dump as much as 2 inches per hour.
“The moisture is coming from the tropics,” Merwin said, “which means we’re getting a lot of rain from thunderstorms and showers, so we’re seeing some flooding.”
Parts of the Southeast have been fairly dry recently, but where increased rainfall is expected, localized or scattered flooding may occur in urban areas.
By Friday night, the heaviest rainfall will shift to northeastern Maryland, northern Delaware, southeastern Pennsylvania, and southwestern New Jersey, where the threat of flooding may be highest because drought conditions are less severe than in the south.
Overall, the WPC has placed communities such as Raleigh, New York, Baltimore and Washington, D.C., at a Level 2 out of 4 flood risk through Saturday morning, with a possible upgrade to Level 3 for parts of the region later on Friday.
Rain at times in the Northeast on Saturday
The most moisture will move toward the northeast on Saturday, and the storm will move with it, according to the FOX Forecast Center.
A unsettled day with multiple chances of heavy rain is expected from the Mid-Atlantic coast to southern New England.
Flooding will be a threat across parts of New England, where the storm is expected to move very slowly over mostly waterlogged ground.
Widespread sunny skies will return on Sunday.
