“This heat event is a marathon, not a sprint,” the weather service said in its weekend forecast. “The peak of the heat has yet to come and remains focused for Sunday and Labor Day.”
How will this all play out?
On Saturday, temperatures are expected to recover, with afternoon highs slightly warmer than they were on Friday, when a low pressure trough brought a mild cooling. Inland areas will see temperatures soar from the low to high 90s. Coastal locations will see much cooler lows in the 70s, and San Francisco is expected to reach a high of 77. Bayside locations are expected to push into the 80s, and Oakland is forecast to reach 83.
Sunday marks the heat wave front and inland areas will begin to experience hazardous conditions. Livermore, for example, could sizzle at 102. “Expect a significant rise in temperatures, especially away from the coast,” the weather service said. “Inland highs will be in the 90s to lower 100s.”
Overnight lows Sunday into Monday are also forecast to be significantly above normal, with inland areas in the low to upper 60s and some areas perhaps even in the 70s.
Sunday is the start of the weather service’s extreme heat warning for the Inland Valleys, which continues until Tuesday at 8 p.m. .
An ocean breeze will keep coastal locations from getting too hot, and San Francisco could see a high of 78, the weather service said.
FILE – Lifeguards walk along the edge of Contra Loma Beach Club inside Contra Loma Regional Park in Antioch, California, on July 10, 2021.
Jungho Kim/ Special to SFGATE
Monday will be even warmer and will likely bring the peak temperatures of the heat event. SF is forecast to reach 83, Oakland 89, San Jose 100, Santa Rosa 101 and Livermore 109. Eastern Contra Costa County is likely to see some of the most extreme temperatures and Discovery Bay could reach 112 grades on Monday.
“It’s not going to feel very pleasant,” said Anna Snyder, a meteorologist at the weather service’s Monterey office. “He’ll feel pretty toasty. It’s not going to be humid heat. It will just feel like dry heat.”
Extended overnight lows in the 70s are expected Monday night into Tuesday morning, and temperatures at higher elevations may not top out of the 80s. “Monday night into Tuesday looks to be the warmest night,” Schneider said.
Tuesday afternoon highs could be slightly cooler inland than they were Monday, but still dangerously warm. Coastal locations will see more intense cooling.
Through it all, the coastal breeze will act as a natural air conditioner, preventing the coast from seeing too much heat. This may lead inland residents to head west in search of cooler weather.
“If you’re heading to the coast for relief, expect increased traffic and crowded beaches,” the weather service warned. “Be sure to stay safe on the beach as there will be strong currents and cold water.”
By Wednesday, inland areas are expected to see more significant cooling, but Schneider said triple-digit temperatures are still possible.
