The weather experts agree: Scorching, extreme heat will bake the San Joaquin Valley starting Saturday.

The question is, how high will the thermometer go?

Excessive Heat Warning for most of Central California from 11 AM PDT Saturday morning until 8 PM PDT Monday evening. Dangerous heat will result in a major to extreme risk for heat-related illnesses for much of the population, especially those without effective cooling. #CAwx pic.twitter.com/CyWpKdC9X5

— NWS Hanford (@NWSHanford) July 12, 2023

The National Weather Service in Hanford expects Saturday’s high to be 109 degrees, followed by 111 Sunday, and 109 Monday.

But Daniel Swain, a climate scientist at UCLA, writes on his Weather West blog that “numerous calendar date record high temperatures will likely be tied or broken” across the San Joaquin (locally 115F+) Valley.

“Additionally, the (European Centre for Medium-Range Weather Forecasts) ensemble is suggesting a relatively high probability that some places in the San Joaquin Valley could reach or exceed *all time* temperature records on Sunday, which are generally in the 114-118F range in that part of the state.”

Record and Near Record Heat Throughout the Valley: NWS

The NWS agrees that record-breaking temperatures are heading our way.

“Near record heat is projected in Fresno, Merced, Hanford, and Madera Saturday. Record heat is forecast in Fresno, Merced, and Hanford Sunday,” the Hanford office said in its Wednesday morning discussion. Near record heat is projected in Madera Sunday. Near record heat is forecast in Hanford and Madera Monday.”

A slight cool-off is expected Tuesday, with Fresno dipping to about 106, the NWS says. Triple digits are in the weather.com forecast through at least July 26.

Where in California Will It Be Cool?

Swain says that coastal California communities will be spared from the heatwave, but temperatures will rise dramatically 10 to 15 miles inland.

“This will not be an extreme heatwave along the coast —the coastal parts of the SF Bay Area and Los Angeles/San Diego metros will certainly be warmer than usual, though not very hot. The marine layer will still be greatly suppressed, so expect a minimum of coastal fog and genuine t-shirt weather even in the usual coastal cool spots.”

Will There Be Power Outages?

Siva Gunda, commissioner at the California Energy Commission, told the Los Angeles Times in May that the state is “better situated than last year. We are cautiously optimistic. But given the extreme wildness of the climate change, you know we have to be cautious as we move forward, and prepared to support the grid.”

“Support the grid” means ratepayers doing what they can to save electricity during the 4 p.m. to 9 p.m. peak demand. It was only through the cooperation of ratepayers that the utility companies avoided power blackouts last summer.

Heavy winter and spring rains are helping the power situation as hydropower generators at the state’s dams are producing much more electricity than during the drought.

In addition,  California ISO said Tuesday that more than 5,000 megawatts of battery storage capacity has been integrated into the electrical grid. That’s a ten-fold increase since 2020.

One megawatt equals 1 million watts or 1,000 kilowatts. California ISO says a megawatt can power 750 homes simultaneously.

Officials recommend that consumers sign up for Flex Alert. It sends texts or emails with warnings of possible power shortages.

An important milestone was reached recently when the California ISO reported more than 5,000 megawatts (MW) of battery storage capacity online and fully integrated into the electrical grid. Read the news release: https://t.co/FAfxVupbkn pic.twitter.com/ZpVAwDmaPy

— California ISO (@California_ISO) July 11, 2023

Fresno Cooling Centers

City of Fresno cooling centers will be open from noon to 8 p.m. beginning today and will be open daily whenever temperatures are expected to exceed 100 degrees.

#ATTENTION: City of Fresno cooling centers will open Wednesday, July 12, 2023.

The four cooling centers will open at 12:00 PM on July 12 and close at 8:00 PM that night. @FresnoFAX will provide free transportation to and from the centers. pic.twitter.com/96B67l4Ej1

— City of Fresno (@CityofFresno) July 9, 2023

Dealing With Extreme Heat

Older people, children, and those with health conditions can face greater risks when temperatures are high.

During extreme heat events, one of the most common ways people can die is from cardiovascular collapse, experts say, because of the extra energy the heart has to expend to help the body compensate for the hot temperatures.

In the case of heat stroke, experts suggest calling 911 and trying to lower the person’s body temperature with cool, wet cloths, or a cool bath.

With heat exhaustion, the body can become cold and clammy. Other signs include heavy sweating, nausea, muscle cramps, weakness, and dizziness. Experts say the best thing to do is to move to a cool place, loosen your clothes, and sip some water.

In general, health officials say staying indoors, seeking air-conditioned buildings, and drinking more water than usual can stave off heat-related illnesses. Caffeine and alcohol are no-nos. Eating smaller meals more often throughout the day can help.

(Associated Press contributed to this report.)