Between late Saturday and Sunday, flood warnings were put in place for 39 million residents by federal meteorologists as a system of thunderstorms developed from Washington, D.C., to New Haven, Connecticut.
A series of flood advisories and watches was released by the National Weather Service spanning from late Saturday through early Sunday across regions of Pennsylvania, Maryland, New Jersey, and Delaware. A flood watch for Washington, D.C., expired at 1 a.m. Meanwhile, a flood watch for New York City was scheduled to start at 4 a.m.
Meteorological Drivers Behind the Storms
The severe weather is emerging as a trough of cold air high in the atmosphere moves east and clashes with warmer air, according to federal forecasters. In a forecast discussion published late Saturday, the National Weather Service noted that the mixture of profound moisture, atmospheric instability, and forcing could elevate the danger for severe thunderstorms and excessive downpours.
A flood watch for parts of southern Connecticut, including northern New Haven, remained in effect through Sunday afternoon, according to the weather service.
Did You Know? Federal forecasters noted that the active weather system is driven by a high-altitude trough of cold air moving east and colliding with warmer air, creating an elevated threat for excessive rainfall.
Regional Impacts and Local Preparations
According to an advisory from New York City Emergency Management, southern Connecticut along with Nassau and Suffolk counties could experience rainfall accumulations reaching 5 to 7 inches, alongside warnings that heavy downpours might also impact the eastern boroughs of the city. The office pointed out that even a minor variation in the storm’s placement could lead to 5 to 7 inches of rain and a drastically elevated flash flood hazard in Queens and eastern Brooklyn.
New Yorkers living in basements and below grade in those neighborhoods were urged to move to higher ground overnight as local officials opened 51 weather shelters.
Frequently Asked Questions
How many people were placed under flood alerts by federal forecasters?
Flood warnings were activated by federal forecasters covering 39 million individuals from late Saturday into Sunday.
What atmospheric conditions are causing the thunderstorms?
As a high-altitude trough of cold air travels eastward and interacts with warmer air masses, these thunderstorms are taking shape.
What specific rainfall totals were projected for Nassau and Suffolk counties?
Between 5 and 7 inches of rain were projected to hit southern Connecticut and Nassau and Suffolk counties, as indicated by a statement from New York City Emergency Management.
How will local communities manage rising floodwaters as the heavy rainfall continues through Sunday afternoon?
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