By Aidin Vaziri, Anthony Edwards, Greg Porter, San Francisco Chronicle The Tribune Content Agency
Today is forecast to be the hottest of the heat wave sweeping across the Bay Area, with temperatures as much as 25 degrees above normal and likely setting records in many areas. Inland cities may go up to 108 degrees, while San Francisco could hit 100 depending on the strength and timing of the sea breeze. Numerous other California cities are forecast to break record temperatures this week. Along with the hot days, exceptionally warm nights will not provide much relief.
PG&E has warned customers that weather conditions could necessitate power shut-offs in sections of nearly a dozen Northern California counties and that shut-offs might continue through Tuesday. The company regularly disrupts electricity service in regions where weather conditions heighten wildfire risks. High winds and dry conditions can cause PG&E's equipment to topple, potentially igniting wildfires.
-PG&E outage map: Bay Area shut-off details by address
-S.F. is uniquely vulnerable to extreme heat. Maps show areas most at risk
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Heat in California: The science behind California's worsening heat waves, explained
San Francisco could rival hottest October days on record
San Francisco has the latest "summer" weather of any major American city, but even Tuesday's temperatures are predicted to be unusually high for October standards.
If the city's official weather station at Duboce Triangle surpasses 95 degrees, it would be the hottest October day since 1996 and would rank among the 10 hottest October days in 150 years of weather records.
With the Bay Area scorching, here is where to find a local cooling center
As an intense heat wave grips the Bay Area this week, residents without spaces to escape the high temperatures can find refuge at local cooling centers. The National Weather Service has issued excessive heat warnings and advisories in the area until 11 p.m. Wednesday.
For those outside the Bay Area, here is a link to cooling centers across California.In addition to seeking air-conditioned buildings, the National Weather Service recommends the following safety tips during periods of excessive heat:
- Drink more water than usual.
- Limit strenuous outdoor activities during the hottest time of day.
9:23 a.m. - Excessive heat warning expanded for other parts of California
National Weather Service extended its excessive heat warning to encompass San Francisco, Salinas Valley (Monterey County) and San Benito County, effective until 11 p.m. Wednesday. Concurrently, the warning remains in force for the interior regions, while a heat advisory remains along coastal areas.
9:08 a.m. - Mount Diablo running 22 degrees warmer than Monday morning
Temperatures are trending much higher than 24 hours ago across the Bay Area. San Francisco is 5 to 10 degrees warmer than Monday morning, while the summit of Mount Diablo is 84 degrees versus just 62 degrees this time yesterday.
This morning-to-morning temperature difference is precursor to an even hotter afternoon.
Oakland bakery closes due to excessive Bay Area heat
Edith's Pie, a bakery in Oakland, announced on Instagram that it would close Tuesday as a result of the excessive heat lingering over the East Bay and much of the region.
"We'll be back tomorrow when the skies cool a little bit and we can turn the ovens on," the bakery said in its social media post.
Excessive heat warning issued for San Francisco
The National Weather Service issued an excessive heat warning for San Francisco on Tuesday, warning residents of "dangerously hot" conditions and temperatures reaching up to 96 degrees.
The warning will be in effect between 10 a.m. and 8 p.m. After that, a heat advisory will go into effect through 11 p.m. Wednesday, the weather service said.
8:19 a.m. - Latest on PG&E planned outages
Pacific Gas & Electric Co. said late Monday that just over 200 customers were without power in Shasta County, but electricity was expected to be restored there by noon on Tuesday. "Service has been restored for all other customers who experienced an outage during the" planned outages, the utility company said.
Several thousand customers, mostly in counties north of the Bay Area, had their power preemptively cut in an effort to reduce the chance that PG&E's equipment could spark a wildfire in hot, dry and windy conditions.
How electricity prices might be different from a summer heat wave
Californians will start cranking their air conditioners just as lower electricity prices kick in for the fall. Starting Oct. 1, electricity rates dropped for many Pacific Gas and Electric Co. customers and will remain lower than summertime prices through May 31. PG&E's time-of-use plans, which have varied rates based on when people use electricity charge the most for power in the 4-9 p.m. range partly because people are home using more energy at that time. That's also when daytime temperatures are hottest in inland areas of Northern California.
Where excessive heat warnings and heat advisories are in effect - 7:20 a.m.
An autumn heat wave is prompting excessive heat warnings and heat advisories throughout the western U.S. due to potential health impacts amid scorching conditions. Over 30 million people across the Southwest are under excessive heat warnings and heat advisories.
An excessive heat warning is in effect until 11 p.m. Wednesday for a large part of the Bay Area, spanning Alameda, Contra Costa and Santa Clara counties. The warning is also in place for coastal ranges and interior mountains in the North Bay, the San Francisco Bay shoreline and the Santa Cruz Mountains.
In San Francisco, the excessive heat warning begins at 10 a.m. this morning through 8 p.m. and will then become a heat advisory until 11 p.m. on Wednesday.
Dangerously hot conditions could bring temperatures in inland locations like Concord and Pleasanton up to 108, with overnight lows ranging from the lower 70s to lower 80s, according to the National Weather Service Bay Area.
Go here to read more on active excessive heat warnings.
San Francisco could hit 100 degrees
The city is expected to experience its hottest October day in decades. Sunshine will be plentiful from daybreak and temperatures will rise quickly through the morning. Highs should reach the mid- to upper 90s downtown and east of Twin Peaks, with some areas flirting with 100 degrees. Temperatures will be in the low to mid-90s in the Sunset and Mission districts, with readings in the 80s along the immediate coast. A light sea breeze is expected to develop in the afternoon, bringing temperatures down a few degrees before sunset. Overnight, it will remain mostly clear and mild, with lows in the 60s.
The heat wave is being driven by an unusually strong high-pressure system over California and weak offshore winds that are pushing the chilly marine layer away from the coast.
The eastern edge of Marin County may see some of the highest temperatures Tuesday. Highs in San Rafael, Novato and Santa Rosa will range from 100 to 105 degrees, with similar readings in Fairfield and Vacaville. Vallejo, Napa and Sonoma will see highs in the mid- to upper 90s, while highs along the Marin and Sonoma coasts will be in the 80s. Overnight, expect mostly clear skies and warm conditions, with lows in the low to mid-60s.
East Bay forecast
Tuesday will be very hot across the interior east bay, with highs topping out around 105 degrees in Concord, Walnut Creek and Livermore. West of the Berkeley hills, temperatures will be quite warm as well, with highs in the low to mid-90s in Richmond and Berkeley and the mid-90s to 100 in Oakland, Hayward and Fremont. Mostly clear overnight with lows in the mid-60s to low 70s.
Pacific Coast and Peninsula forecast
It will be a rare day along the Pacific Coast where there will be no cloud cover and lots of sunshine. Temperatures will respond as well, with highs in the mid-to upper 80s in Half Moon Bay, Pacifica and Daly City. It will be toasty along the Peninsula as well, with highs in the low to mid-90s in South San Francisco and San Bruno and highs in the upper 90s to around 105 degrees in San Mateo and Redwood City. Clear and warm overnight with lows in the upper 50s to low 60s.
How to stay cool and cut your AC bill in a heat wave
While health officials advise that it's best to seek out air conditioning during extreme heat if you can, there are other measures you can take to stay as cool as possible - or avoid a big hit on your PG&E bill.
Here are several tips, gathered from national, state and local health agencies and emergency departments as well as the National Weather Service:
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Keep your home to 78 degrees, and turn the thermostat up to 85 when you are out.
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Take a cold shower or bath: The cold water from a shower or bath can help bring your body temperature down quickly. You can also place cold towels on your neck and wrists throughout the day or when you can't shower.
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Shut blinds or curtains and close windows during the sunniest parts of the day: Keeping sunlight out can help keep a room cool, and closing the windows when outside air is warmer than inside air keeps the cool air from escaping. At night, you can open windows back up to get the cooler evening air in.
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Make sure your ceiling fan is turning the right way: When it's hot outside, your ceiling fan should be set to turn counterclockwise when you are looking up at it. That pushes air down to create a cool breeze. A fan turning clockwise does the opposite - it redistributes the warm air that rises and accumulates near the ceiling, according to California's electric grid operator.
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Use portable fans strategically: Place portable fans in hallways or near windows to help create a cross breeze that moves cool air throughout the house or apartment. You can also place a bowl of ice in front of a fan to create a cool, misty breeze. But several agencies noted that while fans may feel nice, they do not protect you from heat-related illness when the temperature passes 90° - in that case, it's best to get to air conditioning at a cooling center or take a cold shower.
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Turn off unnecessary lights and avoid using the oven, stove or clothes dryer: Home appliances can quickly generate heat in a room. If possible, wait until night to use unneeded lights and heat-producing appliances, and avoid using the oven or stove altogether - instead, use the microwave to cook, or eat food that doesn't require heat.
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Find places near where you live with air conditioning to cool down during the day: In many cities and counties, public libraries serve as cooling centers during heat waves. Public areas like large indoor shopping malls or even movie theaters can also be a good place to cool down, according to local health agencies.