Photo: Patricia Chang/Special To The SFGATE
Image 1 1
Heat that the National Weather Service is calling “dangerous” and “life-threatening” is on track to impact nearly all of California over the three-day Labor Day weekend.
In the San Francisco Bay Area, peak temperatures are expected Sunday and Monday when the hottest interior locations could exceed 110 degrees.
The National Weather Service issued an Excessive Heat Warning for interior locations, 11 a.m. Saturday to 9 p.m. Monday, and a Heat Advisory for coastal areas during the same time frame.
“The severity of the heat is on the dangerous side because the heat wave will last Saturday-Monday with little to no relief at night,” according to the National Weather Service report. “When it’s all said and done by Tuesday many temperature (day/night) records will be broken.”
The uptick in heat begins Saturday, with widespread high-90s to mid-100s forecast across the interior, 80s to low-90s near the San Francisco Bay shoreline and 70s to 80s just inland from the immediate coastline.
“It’s setting up for a very hot day,” NWS forecaster Will Pi said Saturday morning.
Temperatures will peak Sunday and Monday as the hottest interior locations reach 100 to 105 degrees and several spots exceed 110. Coastal locations on Sunday and Monday will warm up into the 80s to 90s, but a light ocean breeze will prevent excessive heat. Places immediately on the coast, such as Ocean Beach in San Francisco, will likely stay in the mid-70s to low-80s.
A slight cooling trend is expected Tuesday, with temperatures remaining warm, rather than hot, after Labor Day.
Except for a light ocean breeze, winds will be calm through most of the weekend, picking up Monday night and continuing into Tuesday. The offshore wind event next week is predicted to be moderate but will increase the wildfire risk, said Pi. Public Safety Power Shutoff (PSPS) Watch in effect for Tuesday and Wednesday (read more on SFGATE).
Here’s a look at the high temperatures forecast for the three-day weekend in several locations around the Bay Area, according to the NWS.
San Francisco: 79
San Jose: 96
Santa Rosa: 97
San Francisco: 90
San Jose: 102
Santa Rosa: 106
San Francisco: 85
San Jose: 100
Santa Rosa: 103
Cities across the Bay Area plan to open cooling centers for residents to find daytime respite from the weekend’s most intense heat. All plan to enforce COVID-19 prevention measures, including requirements to wear face coverings. Some will allow food, others no. Most will not allow pets.
The most accurate information will be available on each city’s own website. Here is a sampling.
In Santa Clara County, cooling centers will be open in Cupertino, San Jose, Morgan Hill and Mountain View on Saturday through Monday, or on just Sunday and Monday, depending on the center. More information is posted here.
In Concord, where temperatures are expected to top 100 from Saturday through Tuesday and could hit 109 on Sunday, a cooling center will be open from 1 p.m. to 6 p.m. on Saturday through Monday at the Concord Senior Center, 2727 Parkside Circle. Residents should bring a snack and drinking water.
And in Santa Rosa residents can cool off from 11 a.m. to 7 p.m. on Sunday and Monday at the Steele Lane Community Center, 415 Steele Lane. Food and pets will not be permitted.
The California Independent System Operator (ISO), which oversees the state’s power grid, is issuing a statewide Flex Alert calling for voluntary electricity, Saturday through Monday, 3 p.m. to 9 p.m., due to the forecast heat event. ISO is expecting increased demand in electricity, mainly from air-conditioners.
Poor air quality due to wildfire smoke is likely to be an issue through the weekend. While the fires in the region are coming under containment, they continue to emit smoke and the high-pressure ridge over the region can act as a lid, trapping smoke produced by the wildfires in the atmosphere.
The Bay Area Air Quality Management District issued a Spare the Air Alert for Friday and Saturday, which makes it illegal to burn wood or wood products.
“Another week, another major California heat wave,” Daniel Swain, a climate scientist with the Institute of the Environment and Sustainability at the University of California, Los Angeles, shared on Twitter. “This will undoubtedly complicate ongoing wildfire situation, & may have elevated health impacts given ongoing ‘smoke storm’ conditions that make it difficult to spend time outdoors/open windows.”
Bay City News contributed to this story.
Amy Graff is the news editor for SFGATE. Email her: [email protected]