Bay Area braces for 76-year high temperatures, fire danger in scorching heat wave

Bay Area meteorologists are urging residents to stay out of direct sunlight Saturday, with punishing rays prompting warnings of excess temperatures amid one of the region’s stronger heat waves in recent memory.

Saturday was widely expected to be hottest day during the ongoing high-pressure system, and morning temperatures did not disappoint, hitting the low to mid 90s — the highest mark since 1948 — at areas between 2,500 and 5,000 feet above sea level, such as many of the campsites on Mount Tamalpais.

San Jose braced for a dry day forecasted to reach a high of 95, while expected overnight lows of 64 would be just a touch cooler than historic nighttime marks set in the city during the early 20th century.

And a day after the Oakland Museum saw record temperatures, conditions were expected to be nearly as hot in the East Bay: Oakland’s expected high of 85 degrees would tie an on-the-date record set in 1985. Areas in Contra Costa County, such as Concord, were projected to see a high of 105.

“The lows overnight have been most uncomfortable on the hilltops and on mountains,” said Rick Canepa, a meteorologist at the National Weather Service Bay Area.

“Close to the sea level, we have some cooler air moving inland overnight,” Canepa added, “but, as is typical, it’s overwhelmed during the daylight hours once the sun comes up.”

Weather officials hope the heat will begin to let up starting Sunday, though not by much.

“It might cool off by 5 degrees,” another meteorologist, Nicole Sarment, said Friday. “If it goes from 115-110, or from 110-105, can you really tell?”

Even before Saturday’s apparent peak, the intense weather had already led to the death of a person experiencing homelessness in San Jose, the city’s leaders announced Wednesday.

The scorching conditions have heightened fire danger across the region’s inland areas, due to a combination of low humidity and dry fuels in the vegetation that sprung during a rainier winter.

Red flag warnings, issued by the National Weather Service to discourage outdoor fires of any kind, including fireworks, were expected to be in effect until 9 p.m. through much of the Bay, though a forecast of low wind speeds brought relief to meteorologists wary of major wildfire risks.

Weather officials also warned residents that outdoor activities under the sun could quickly lead to heat exhaustion or dehydration without proper care.

Still, advisories calling on residents to rely on air-conditioning units aren’t likely to resonate in the Bay Area: the larger San Francisco Metropolitan area lags behind all other major metro areas in the U.S. in rates of air conditioning.

“Staying out of direct sunlight is absolutely key,” Canepa said. “The radiation from the sun heats the ground up — there’s serious risk of getting sunburn or skin damage. Stay in the shade as much as you can.”

Staff writers Rick Hurd and Harriet Blair Rowan contributed reporting.