Flash Flooding, Severe Storms Expected From Appalachians Into the Northeast Through Monday Night

Brian Donegan
Published: July 23, 2019

The workweek has begun with a threat of flash flooding and severe thunderstorms from the Appalachians to the mid-Atlantic and Northeast as a cold front slices through a humid air mass in place over those regions.

NOAA's Storm Prediction Center has issued a severe thunderstorm watch valid until 10 p.m. EDT for Connecticut, the District of Columbia, Delaware, eastern Maryland, New Jersey, southern New York, southeastern Pennsylvania, Rhode Island and eastern Virginia. This watch area includes New York City, Philadelphia, Baltimore and Washington, D.C.


Current Radar, Watches and Warnings

A wind gust of 78 mph was measured in Wilmington, Delaware, just after 5 p.m. Monday as a severe thunderstorm moved across northern Delaware and into the Philadelphia metro area, including southeastern Pennsylvania and southern New Jersey. Philadelphia International Airport measured a 60-mph wind gust.

The National Weather Service in Mount Holly, New Jersey, said damage was observed in the vicinity of its office, including trees, limbs and wires down nearby.

Some trees were also knocked down by severe storms in Baltimore on Monday afternoon. One tree fell onto a house in the Hampden area of Baltimore.

The thunderstorms arrived in the New York City tri-state area early Monday evening, leading to a ground stop at Newark, JFK and LaGuardia airports. Street flooding was reported in parts of the city, including Brooklyn.

Heavy rain caused flooding in the St. Louis metro area Monday morning, prompting water rescues in Eureka and Chesterfield, Missouri.

(MORE: Flash Flooding Strikes St. Louis

The National Weather Service has issued flash flood watches through Monday night or early Tuesday from portions of Kentucky and Tennessee into the Interstate 95 corridor of the mid-Atlantic and Northeast. This includes Washington, D.C., Baltimore, Philadelphia and New York City.


Flash Flood Watches

A strong cold front will approach the Northeast and mid-Atlantic from the north and west into Monday night, causing rounds of thunderstorms to develop, which should continue overnight as the front continues its south and eastward advancement. These storms will produce heavy rain, with localized rainfall rates up to an inch or two per hour possible in spots.

In general, most areas should pick up between 1 and 3 inches of rain into Tuesday.

Due to this threat of heavy rain, NOAA's Weather Prediction Center has highlighted an area from the southern and central Appalachians into the mid-Atlantic and Northeast in its excessive rainfall outlook as having a moderate risk of flash flooding through Monday night.


Rainfall Forecast

Monday night's thunderstorms could also turn severe, particularly from southern New England into the mid-Atlantic. The main threats from these storms will be damaging wind gusts and hail. An isolated tornado also cannot be ruled out.

The combination of the heavy rain and potential severe storms will likely slow down commutes along the busy Interstate 95 corridor from New York City to Washington, D.C.


Monday Night's Severe Thunderstorm Forecast

The cold front will push off the Northeast coast on Tuesday, ushering in a cooler, drier air mass for much of the week ahead.


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