Mid-Atlantic faces flash flooding before drier air slows works in early this week

By Renee Duff, AccuWeather meteorologist

Slow-moving downpours are renewing the risk for flooding across the mid-Atlantic through Sunday night, but a push of drier air will gradually sweep southward Monday through Tuesday.

New England has welcomed the return of dry weather following Saturday's severe weather that rattled a large swath of the Northeast.

One fatality and two injuries were reported on Saturday when a tree fell on three kayakers after they pulled ashore to take shelter from the storms on the Susquehanna River.

However, residents of the mid-Atlantic may have to wait until Monday or even Tuesday to put away umbrellas.

"A large area of high pressure will sink southeastward across the region into the middle of this week, which will gradually suppress thunderstorm activity farther south each day," AccuWeather Meteorologist Brett Rathbun said.

Before that happens, there can be more incidents of flash flooding across the mid-Atlantic, central Appalachians and the upper Ohio Valley.

"There is concern that the showers and thunderstorms rumbling to end the weekend can be slow-moving and produce downpours," according to AccuWeather Senior Meteorologist Kristina Pydynowski.

"Worse than ruining outdoor plans, the heaviest rain can trigger areas of flash flooding and poor travel conditions from southeastern Ohio and southern Pennsylvania to Virginia and the Delmarva Peninsula," she added.

Communities at risk for flooding issues in low-lying and poor drainage areas include Pittsburgh and State College, Pennsylvania; Morgantown, West Virginia; Baltimore; Washington, D.C.; and Richmond and Charlottesville, Virginia.

Officials may be forced to close roads that become inundated with flood waters. Small streams can overflow their banks and flood neighboring land and homes. There have been incidents of both around Pittsburgh earlier on Sunday.

On Monday, stormy weather can occur in portions of Pennsylvania and points southward.

Monday's storms could washout beach plans for those along the Delmarva Peninsula and the Carolinas.

The downpours on Monday from Virginia to the Carolinas can trigger more flash flooding, especially in areas hit hard with rainfall to end the weekend or during last week.

People are reminded to seek proper shelter at the first rumble of thunder to avoid being struck by a potentially fatal lightning strike.

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While storms are slow to exit the mid-Atlantic, beautiful, sunny weather will prevail in New England through the start of the week.

"Humidity levels will drop, which will make it more comfortable for outdoor activities," Rathbun said.

After Boston recorded its hottest day yet this year on Saturday with a high of 95 degrees Fahrenheit, temperatures were held to the 70s on Sunday and will be at a seasonable level, near 80, on Monday.

Highs will be in the upper 70s and lower 80s elsewhere across the Northeast on Monday.

By Tuesday, the entire Northeast will enjoy rain-free weather as downpours are suppressed to the Carolinas.

Highs will return to seasonable levels in the upper 80s to near 90 for the major Interstate-95 cities on Tuesday.

People heading to Progressive Field in Cleveland, the site of the 2019 Home Run Derby on Monday evening and MLB All-Star Game on Tuesday evening, can expect dry weather to prevail for both events. Temperatures will be in the 70s on both evenings.

"Air conditioners may still need a workout during the daytime hours early this week, but can be substituted with open windows and window fans during the overnight, especially in rural areas," Rathbun said.

Cooling demands are likely to increase as temperature and humidity levels climb at midweek, especially over the interior.

"The threat for a few thunderstorms will return late in the week," Rathbun said.

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