Eastern US Heat Wave Starts to Retreat While Raising Storm Risk
(Bloomberg) -- Extreme heat that’s seared the eastern US, strained the power grid from Maine to the Carolinas and curtailed holiday celebrations is starting to break up.
About 130 million people from Texas to New Hampshire are under either heat advisories or extreme heat warnings. Temperatures are set to linger near 95F (35C) in New York City on Saturday, with high humidity that makes it feel closer to 103F, the National Weather Service said.
But the massive wall of alerts blanketing the eastern US from the Mississippi to the Atlantic has already started to lapse in areas including Upstate New York, Chicago and the spine of the Appalachian Mountains. As the heat retreats, the threat of thunderstorms will rise.
“We are going to go from a period of intense heat to what should be quite a few stormy days,” said Bryan Jackson, a forecaster at the US Weather Prediction Center. “The heat will be down but the storm chances will be way up.”
High temperatures and oppressive humidity strained power grids across the eastern US, slowed Amtrak and New Jersey Transit trains, and put a crimp on US Independence Day celebrations and World Cup matches on Friday.
The Great American State Fair — a two-week festival being staged on the National Mall in Washington — closed for several hours Friday as temperatures soared.
There’s an enhanced risk of severe thunderstorms — level 3 on a 5-point scale — across parts of Virginia and Maryland, including Washington and Baltimore, on Saturday, the US Storm Prediction Center said. A wider area including New York and Philadelphia face a level 2 threat from the storms that can bring high winds, hail and potentially tornadoes.
There were 400 reports of high winds and hail across the US on Friday, with many of them in a band stretching from Chicago to New York, the agency said.
From Iowa to Long Island, nearly 880,000 homes and businesses were without power as 5 a.m. New York time, according to the PowerOutage.com. Michigan topped the list of states suffering blackouts with 381,557, followed by New Jersey with 183,812.
PJM Interconnection LLC, a power grid serving 67 million people across 13 states from the District of Columbia to Illinois, said demand on Thursday likely surpassed the previous record of 165.563 gigawatts set in August 2006.
Even before the latest bout of intense heat, US grids were struggling with data center buildouts that have upended two decades of stagnant power demand. And now they’re even more susceptible to outages in periods of extreme temperature fluctuations, with implications for everything from residential air conditioners to hospital lighting.
Con Ed asked tens of thousands of homes across the New York City region to conserve energy this week. Households were asked to not use washers, dryers and microwaves, and to use only one air conditioner if they have two.
The worst of the heat sparking warnings and advisories will subside Saturday night across the Northeast and Mid-Atlantic, Jackson said.
Manhattan’s Central Park is likely to see a 25F swing in high temperatures from Thursday — when a record 100F reading was posted for the date — to Monday, when the forecast calls for a balmy 75F.
High temperatures in the nation’s capital will drop from 102F on Saturday to 95F Sunday, enough to take it out of extreme heat warning territory.
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