Bay Area heat wave finally set to dissipate; temperatures to creep down

More than a week into October, the Bay Area finally was braced Tuesday for temperatures that weren’t quite so frightening.

Still, full relief from the extreme heat that’s marked one of the hottest starts to the month in recorded history still appeared to be about 24 hours away, according to the National Weather Service.

“Temperatures very slowly are going to start inching back toward normal,” NWS meteorologist Rick Canepa said Tuesday morning. “At the moment, there are factors in play that are continuing to help the (high-pressure) ridge, but the (low-pressure) trough is starting to deepen.”

The trough developing in the Gulf of Alaska wielded enough influence Tuesday that temperatures that soared above 100 degrees in the hottest area for most the past week are not expected to get there again for the foreseeable future. The hottest spots in the region Tuesday are expected to run from 95 to 98 degrees, Canepa said.

A heat advisory for the interior regions and hills in the East Bay and the Eastern Santa Clara Hills remained in place through 7 p.m. Tuesday, according to the weather service.

Elsewhere, temperatures are expected to reflect the beginning of a cooler time. In the South Bay, the hottest spot is expected to be in Morgan Hill at 93 degrees. San Jose is expected to peak at about 90, the weather service said.

More significant cool air is forecast for Wednesday, when the hottest spots are expected to peak in the mid-80s.

Along the coast and the Bay, the relief was expected to begin Tuesday, with temperatures in places such as Oakland and San Mateo not exceeding 80 degrees. San Francisco, which boiled at a record 97 degrees on Sunday, is expected to have a high of 73 Tuesday and 66 on Wednesday.

“Temperatures aloft are still above normal for this time of year,” Canepa said. “But they are not quite as warm as they’ve been the past several days. Overall, the structure of this system that created this is weaker, and we’ll see the effects of that over the next several days.”

The final day of excessively hot conditions broke more records. San Rafael reached 108 degrees, 9 degrees warmer than the mark set in 1996. Santa Rosa (102), Napa (101) and Redwood City (99) also broke 28-year-old heat records for the day. Oakland reached 95, surpassing the record mark of 92 it set last year. And San Jose reached 102, 8 degrees warmer than its record mark set a year ago.

That should be the last busy day for the record keepers, at least for the time being, Canepa said.

“That trough is going to keep its working its way toward us,” Canepa said. “We’re gonna have cooler air, more sea breezes, and a lot more comfort.”