Severe Thunderstorm Watch Issued for New York City Metro, Mid-Atlantic Through Midnight

The National Weather Service’s Storm Prediction Center issued Severe Thunderstorm Watch 638 at 4:35 p.m. EDT Tuesday for a broad stretch of the Mid-Atlantic, including the New York City metro, warning of potentially dangerous storms through midnight. The watch says the main threats are damaging wind gusts up to 70 mph, large hail and the possibility of a tornado or two.

The watch covers portions of Delaware, northeast Maryland, New Jersey, southern New York, central and eastern Pennsylvania, and adjacent coastal waters. It includes New York City’s borough counties and nearby suburbs, putting one of the nation’s most densely populated corridors under a severe weather watch at a time when strong storms can snarl flights and surface travel and damage trees, power lines, roofs and vehicles.

The Storm Prediction Center said “scattered damaging wind gusts to 70 mph likely,” making wind the primary concern. It also said scattered large hail up to about 1.5 inches is possible and that “a tornado or two possible.” Earlier Tuesday, the center said the environment could support peak wind gusts of 55 to 70 mph and hail of 1 to 1.75 inches, with the brief tornado risk noted especially across northern New Jersey and far southern New York. By National Weather Service standards, a severe thunderstorm is one capable of producing hail at least 1 inch in diameter and/or wind gusts of at least 58 mph.

A watch means conditions are favorable for severe storms over a broad area; it is not the same as a warning. Local National Weather Service offices issue warnings when severe weather is occurring or imminent. After the watch was posted, warnings began to follow as storms developed. In one example, the National Weather Service office in Mount Holly issued a severe thunderstorm warning at 7:43 p.m. EDT citing radar-indicated 60 mph wind gusts and quarter-size hail near Honey Brook.

Forecasters had signaled the risk earlier in the day. In Mesoscale Discussion 2185, the Storm Prediction Center said, “Thunderstorm development is anticipated within the next 1-2 hours across portions of the Mid-Atlantic region.” The agency said supercell thunderstorms — a type of rotating storm that can produce large hail and severe wind — could develop during the afternoon, with the threat shifting more toward damaging winds in the evening as storms cluster together.

With the watch in effect until midnight, residents across the region should closely monitor local National Weather Service warnings and be prepared for quickly changing conditions as storms move through.