Bay Area Cooling Trend To Last Through Wednesday

The Bay Area’s weather drama will be cooling off — literally — for the next few days as the region’s heat wave backs off and an unusual thunderstorm pattern heads east.

The daytime highs that blasted much of the inland regions last week will simmer down to the 80s and 90s through Wednesday, but are forecast to start picking back up again on Thursday, said National Weather Service Meteorologist Brook Bringaman.

“We’re definitely getting a bit of a reprieve. All across our forecast area we’re going to see a downward trend in temperatures,” Bringaman said.

That welcome relief comes on the heels of spiking daytime highs from the 90s to above 100 degrees in many inland areas, which lead to excessive heat warnings and a few record-setting temperatures.

The heat was so excessive, in fact, that on Sunday the NWS had to shut down its weather radar on Mount Umunhum near San Jose to give it a bit of a rest.

The cooling trend was preceded Sunday evening by unsettled meteorological conditions, including a large amount of moisture coming up from Baja California that wrapped around a high-pressure system.

Those conditions collided with hot air rising from ground-level, which led to atmospheric instability and some isolated thunderstorm activity, Bringaman said.

Lightening strikes were observed off the North Bay coast and throughout parts of Sonoma and Napa counties from about 8 p.m. to 10 p.m.

Most of the rainfall evaporated before it hit the ground, but a few places around the Bay Area, including the Livermore and Santa Rosa airports, reported “a little spritzing” of rain, Bringaman said.

That system has since moved off to the northeast and will bring some unsettled weather to the Sierra Nevada throughout the day.

After Wednesday, temperatures will start to rise.

“Once again across the interior, in the North Bay, East Bay and South Bay, we’ll see 90s with the potential for triple digit heat as you get closer to the Central Valley,” she said.

Things will stay cooler along the coastal areas and in San Francisco, where the summer’s typical marine influence will keep temperatures largely in the upper 50s and mid 60s, with a few low 70s here and there through midweek.