Thousands of fans are expected to descend on the White House South Lawn on Sunday for an unprecedented Ultimate Fighting Championship event. But forecasters warned that an unpredictable opponent could disrupt the event, with severe storms possible during the evening.
Jared Guyer, a meteorologist at the Storm Prediction Center, said a “fairly potent” weather system was expected to sweep through the Ohio Valley and the Northeast on Sunday, likely leading to widespread severe thunderstorms across parts of the Mid-Atlantic and the Northeast.
“Especially going through Sunday afternoon and evening,” he said. “From Virginia up toward southern New York would appear to be the main threat area, and that could certainly include the greater D.C. area.”
Mr. Guyer said the primary threat was likely to be damaging winds, but large hail and lightning were also possible, and a tornado couldn’t be ruled out.
Thunderstorms are common in Washington in the warmer months, though injuries are exceedingly rare. Still, in August 2022, three people were killed when lightning struck in a park just north of the White House during evening storms.
The U.F.C. said it was preparing for the possibility of severe weather.
Speaking at a media day on Wednesday, Craig Borsari, the U.F.C.’s chief content officer, said the organization was receiving hourly reports from an on-site meteorologist and had developed contingency plans.
“But when you get into these scenarios where you got rain, wind, lightning, you don’t know how long it’s going to be,” he said. “We’ll get a much better idea when we’re 24 hours out for Sunday.”
While storms pose one challenge, heat is another.
Much of the East Coast has been sweltering through a surge of unusually hot weather on Thursday and Friday.
Allison Santorelli, a meteorologist at the Weather Prediction Center, said temperatures were forecast to climb into the mid- to high 90s on both days, with daily record temperatures likely to be broken in several locations, including in the Washington area.
“We should get a brief break from the heat on Saturday,” she said. “But then on Sunday, it looks like the heat may return briefly. On Sunday afternoon and evening, I’m seeing high temperatures in the low to mid-90s in the D.C. area.”
The heat has raised concerns about conditions for the fight itself. Mr. Borsari said the U.F.C. had taken steps to reduce the impact of high temperatures, including installing a custom cover over the canvas and a canopy overhead to provide shade.
Humidity is also expected to remain elevated. The heat index — a measure of how hot the body feels when humidity combines with air temperature — is forecast to reach up to 105 degrees through Friday. But Ms. Santorelli said the region’s weather should feel less oppressive by Sunday.
This is not the first outdoor U.F.C. event. In April 2010, U.F.C. 112 was held in Abu Dhabi, United Arab Emirates, which was also the organization’s first outdoor event. Temperatures that day reached around 95 degrees Fahrenheit, similar to what is forecast in Washington on Sunday.
