Marin weather: Triple-digit temperatures in weekend forecast

A weather pattern that has cooked the Bay Area with record hot conditions since the start of October appeared primed to deliver a warm weekend following a brief period of cooler conditions Friday.

The “slight disturbance” in the weather pattern that sent the highest temperatures a tick under 100 degrees Friday won’t play any significant role Saturday and Sunday, National Weather Service meteorologist Roger Gass said. As a result, the weather service said temperatures again will approach or surpass 100 in a lot of places.

The weather agency expects the temperature to reach at least 100 degrees Saturday and Sunday in Novato, San Rafael and Kentfield, and close to that in some other inland parts of Marin County.

According to Gass, the disturbance in the pattern came from a low-pressure trough developing at the upper part of the atmosphere in the Alaskan Gulf, as well as moisture from the sub-tropical level down south.

That upper-level trough eventually should kick the heat out of the region for good, Gass said. However, that’s not expected to happen until at least early next week, meaning the weekend temperatures figure to be extra crispy and may rise into record-setting territory, he said.

The weather service forecast the hottest inland areas in Contra Costa and Alameda counties to reach as high as 103 Saturday and Sunday, while San Jose and other hot spots in Santa Clara County might get to 100. Areas closer to the water can expect to see the mid-90s, according to the weather service. San Francisco and Half Moon Bay were expected to settle into the 80s.

The hot spell will stick around long enough that it may give commentators from a college football preview show a wide range. ESPN’s College Gameday television show will make its first appearance at UC Berkeley today, debuting at 6 a.m. when Gass said the temperature in Berkeley is expected to be about 68 and leading up to the 12:30 p.m. kickoff, when it may already be 90.

The high in Berkeley is expected to be 93 Saturday.

The San Francisco 49ers’ scheduled home game at 1:05 p.m. Sunday in Santa Clara also figures to be played in blazing hot conditions. Gass said the highs in Santa Clara on Sunday were expected to be in the lower to mid-90s.

The conditions caused the weather service to issue a red-flag warning for fire danger Friday in the East Bay Hills, Santa Cruz Mountains and higher terrain of the central coast. It was scheduled to stay in place through this morning.

The weather service extended an excessive heat warning for the East Bay, South Bay, eastern San Mateo County, the Santa Cruz Mountains, southern Salinas Valley, interior Monterey County and San Benito County through 11 p.m. Saturday, as they did a heat advisory for San Francisco and other coastal areas.

The warning went into effect Monday and originally was expected to last through Wednesday.

The Bay Area Air Management District issued a “spare the air” alert for Saturday, and its forecast indicated another alert was possible for Sunday. The district, which inadvertently indicated an alert also was in effect for Friday before rescinding it, has issued 13 such alerts this year, five since Monday.

The heat wave — the longest and most intense to start October in more than 40 years — is expected to die out next week, though NWS meteorologist Nicole Sarment said it remains questionable when the bulk of the relief will arrive.

“The trend has been kind of just kicking the can down the road when it comes to that,” Sarment said. “We still need watch and see how a few things in the pattern work out, but we do see relief approaching.”

The Independent Journal contributed to this report.