Downpours, severe storms may interfere with weekend plans in US East

Have outdoor activities or travel plans in store for this weekend in the eastern United States? If so, get ready to dodge downpours and locally severe thunderstorms.

While a total washout is not likely in the East this weekend, there will be enough rain and thunderstorms around to interfere with some outdoor plans, as well as slow travel and perhaps create dangerous conditions in some locations, AccuWeather meteorologists warn.

A slow-moving storm will tap into a growing zone of warm and moist air from the Appalachians to the Atlantic coast this weekend. This will lead to drenching showers and thunderstorms, along with the possibility of localized severe weather and flash flooding.

Much of the Northeast had close to a week of dry weather since Debby unleashed torrential downpours that triggered flash flooding and rises on some of the region's rivers. That drying trend should prevent widespread problems on area river systems, though 1-2 inches and locally 3 inches of rain may fall this weekend.

"There can still be flash flooding of small streams and urban areas where it manages to pour for a couple of hours," AccuWeather Senior Meteorologist Dan Pydynowski said, "but that sort of condition would tend to be highly localized."

Areas that sustained infrastructure damage to drainage systems and roadways during Debby's deluge may be most vulnerable to the quick runoff from this weekend's downpours.

The main reason that the Northeast did not experience widespread major river flooding from Debby was that intense rain fell in a narrow zone that affected mainly rural communities in the Appalachians rather than widespread heavy rainfall over the entire watershed of the large rivers, AccuWeather Senior Director of Forecasting Operations Dan DePodwin explained.

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Farther south, Debby was not so kind to the Carolinas and part of Georgia. This zone was swamped by torrential rainfall over a broad area encompassing many major river systems. Rivers in the lowlands continued to run at moderate to high flood levels, with some not forecast to crest until later this weekend or next week.

This image shows accumulated rainfall from Monday, Aug. 5, to Monday, Aug. 12, 2024. Much of the rain occurred due to Debby, which was a tropical storm that transitioned to a tropical rainstorm.

Even though the bulk of the rain will focus on the Northeast this weekend, enough downpours may occur in the Southeast to trigger flash urban and small stream flooding in some areas. As the rain runs off into the larger rivers, water levels may rise again in some locations but not to the extent that Debby triggered.

Along much of the Interstate 95 zone, from Boston to New York City, Philadelphia, Washington, D.C., Richmond, Virginia; Raleigh, North Carolina; and Charleston, South Carolina, the wettest part of the weekend will be the second half with the likelihood of some rain lingering into early next week.

Across the Appalachians, it may be a multiple-day event where downpours can occur at any time into Monday.

Meanwhile, those still planning on heading to the beaches may encounter less rain this weekend, but another problem may be present. AccuWeather meteorologists continue to warn of the risk of frequent and strong rip currents due to Hurricane Ernesto that is affecting Bermuda this weekend and then Atlantic Canada early next week.

Severe thunderstorm threat exists into Monday

Some of the thunderstorms will get a bit feisty this weekend, especially during the afternoon and evening. A handful of the strongest storms will have the potential to produce a brief tornado.

Into Saturday evening, a broad zone where heavy, gusty and locally severe thunderstorms can occur will extend from southeastern Ohio and southwestern Pennsylvania to the northern parts of Georgia, Alabama and Mississippi.

On Sunday, the risk of locally severe thunderstorms will tend to shift toward the I-95 zone and extend from portions of eastern Pennsylvania and New Jersey to much of Georgia. Severe storms can also occur as far to the west as Mississippi.

Some of the most potent thunderstorms will pack wind gusts of 60-70 miles per hour with an AccuWeather Local StormMax™ gust of 75 mph.

On Monday, the risk of severe weather will be largely confined to the mid-Atlantic region.

But, there can be some pockets of severe thunderstorms even as far north as New England and eastern upstate New York.

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