Another prolonged heat wave has begun across California and much of the West, and is expected to bring several days of triple-digit temperatures to most inland areas again.
The second major heat wave in July is not expected to be as extreme as the last one, which broke several all-time high temperature records. However, the National Weather Service predicted it will be a “long-duration heat wave,” creating exceptionally dangerous conditions, especially when temperatures barely drop at night.
“The heat builds up over a number of days,” said David Gomberg, a meteorologist with the National Weather Service in Oxnard. “The longer it lasts, the more it affects people, and this has that going for it.”
The next few days of extreme heat could bring to a close a potentially historic month in terms of high temperatures.
“Given what’s already happened and the forecast for next week, it’s very likely that much of California and the Southwest will end up experiencing their warmest July on record,” UCLA climatologist Daniel Swain wrote in a blog post this weekend.
Much of inland Southern California will remain under an excessive heat warning through Thursday night, with high temperatures forecast to be 100 to 110 degrees and lows between 70 and 80 degrees, according to the warning.
“There is a high risk of dangerous heat-related illnesses for anyone, especially the very young, the very old, those without air conditioning and those who engage in outdoor activities,” the weather service warned.
Weather officials continue to urge inland California residents to take the heat seriously, especially after the latest heat wave was linked to several deaths across the region.
In Death Valley, temperatures may not drop below 100 degrees for the next three days, with daytime highs reaching as high as 125 degrees, the National Weather Service said.
This week, the heat will be affected by monsoon humidity in the state's mountains and deserts, which could bring thunderstorms through Wednesday, according to forecasters.
“Afternoon highs will be more oppressive than those experienced a few weeks ago due to increased humidity,” the Las Vegas weather service warned.
This week’s excessive heat warning also covers much of the San Joaquin Valley through Wednesday night, as well as the Bay Area’s interior mountains; both regions are expected to see temperatures easily exceed 100 degrees.
A less severe but still dangerous heat advisory will also be in effect through Wednesday across the Sacramento Valley and surrounding foothills, with high temperatures expected to exceed 110 degrees in some areas.
Much of the state's coastline will experience only minor temperature increases due to a persistent marine layer, weather service officials said.
A slight cool-down is expected to begin Friday and continue through the weekend, Gomberg said.
But as much of the state expects intense heat, officials are also preparing for an increased threat of wildfires.
“We definitely have a high concern for fires because the humidity remains fairly dry across much of our area,” Gomberg said. He added that low humidity coupled with high temperatures and some expected onshore winds could quickly spread any fires that do break out.
On Sunday, two fast-growing fires broke out in Riverside County, burning several buildings and forcing evacuations. Arson investigators were looking into reports that one of the fires, the Hawarden wildfire, was caused by children setting off fireworks.
