A short-lived heat wave will send temperatures soaring across California and the U.S. West through the weekend, elevating power demand and raising the risk of health impacts.

At least 26 daily records may be broken or tied across the West on Friday and Saturday, with temperatures forecast to reach 102F (39C) in California’s capital of Sacramento and 105F in Fresno to the south, the National Weather Service said.

“It looks like it will be a pretty short heat wave,” said Bob Oravec, a senior branch forecaster with the US Weather Prediction Center.

Blistering conditions will extend across the Great Basin, with an extreme heat warning in place for Las Vegas and Lake Mead, as well as parts of Arizona and California’s desert southeast. The rapid snowmelt should help hydroelectric generation in the immediate term, but depending on power demand, operators may push to fill reservoirs, said Omolade Fasusi, an analyst at BloombergNEF.

Early heat waves like this one can raise the risk of drowning. As streams and rivers fill with frigid melt water from mountain snow, people who swim in them can be shocked by the cold or swept away in the current, according to the weather service.

Temperatures will start to break on Sunday as a low-pressure trough builds across the West and there is a general pattern shift in the US, Oravec said. This will end days of drizzle and showers in the East, and New York City will see the sun on Sunday and Monday.

Top photo: A construction worker at the Regency at Folsom Ranch housing development by Toll Brothers in Folsom, California, on Wednesday, July 3, 2024. California’s biggest power utility had warned of potential outages as the state faces a period of high wildfire risk and power demand surges to keep air conditioners running, with temperatures in Sacramento remaining above 110F (38C) for daytime highs this week, National Weather Service computer models show.

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