Severe Thunderstorm Watch 459: Damaging Winds, Hail Threaten Northeast on July 4

The National Weather Service’s Storm Prediction Center issued Severe Thunderstorm Watch 459 at 3:30 p.m. EDT Saturday for a broad stretch of the Northeast corridor, warning that damaging wind gusts up to 75 mph are possible through 11 p.m.

The watch covers Delaware, eastern Maryland, New Jersey, central and southeast New York, central and eastern Pennsylvania, and adjacent coastal waters. The Storm Prediction Center, the National Weather Service center that issues severe thunderstorm and tornado watches, said the main hazards are wind and hail. In the watch bulletin, it warned of “scattered damaging winds likely with isolated significant gusts to 75 mph possible” and said “isolated large hail events to 1 inch in diameter possible.”

A watch means conditions are favorable for severe thunderstorms in and near the area, not that every community will be hit. The agency said, “A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area.” The timing put much of the risk during the late afternoon and evening of the July 4 holiday, when many people would be outdoors or traveling.

In its summary, the Storm Prediction Center said storms were expected to become more numerous as the day went on. “Thunderstorms will increase in coverage through the afternoon across the watch area, in a warm and unstable air mass,” the bulletin said. It added that locally damaging wind gusts and some hail were possible with the stronger storms. The watch product also notes that severe thunderstorms can occasionally produce tornadoes, but this watch was centered on the threat of wind damage.

The severe weather threat arrived amid a broader early-July heat wave that had already raised concerns about electricity demand and possible outages in the Mid-Atlantic. On June 30, the U.S. Department of Energy said it had issued emergency orders to mitigate blackout risks ahead of forecast peak loads.

Preliminary local storm reports later compiled by the Storm Prediction Center from local National Weather Service offices showed strong gusts and scattered damage in New Jersey. Those reports included “Perth Amboy mesonet gusted to 61 kt,” or about 70 mph, along with a gust listed as 71 at Newark Liberty Airport and 67 in Bayonne. The preliminary reports also logged downed trees, wires and localized damage, including a destroyed medical tent in Bayonne and a tree into a house in Passaic.