The heat, along with continued long-term drought
conditions in California, Arizona and Nevada, also brings extreme fire danger.
The NWS also issued a Red Flag Warning
from Sunday afternoon through Tuesday morning, for sundowner winds, low relative humidity and very high temperatures for the Santa Barbara County mountains.
The warning includes the area in the Los Padres National Forest, northwest of Santa Barbara, where firefighters from the U.S. Forest Service, Cal Fire and the Santa Barbara County Fire Department are working to contain the Sherpa Fire.
The Sherpa Fire is one of several large, active wildfires
burning in California, Arizona and New Mexico. More than 2,016 personnel are working to get the upper hand on the Sherpa Fire
, which is burning in chaparral, tall grass and brush.
The fire has caused the on and off closure of a stretch of Highway 101. Fire managers say if fire activity increases with anticipated high heat, low humidity and sundowner winds, then the highway may closed again if the fire is determined to be a hazard to drivers. The wildfire started June 15 and the cause is under investigation.
A plane makes a Phos-Chek drop Saturday, June 18, off West Camino Cielo, as part of the effort to contain the Sherpa Fire in Santa Barbara County. Santa Barbara County Fire Department / Courtesy
Meanwhile, high temperature records were set for June 19 from Phoenix to Burbank. The National Weather Service in Phoenix tweeted that the city reached 118 degrees, "the 5th hottest temperature ever recorded in Phoenix." Burbank also set a record with 106 degrees.
The heatwave and wildfires come as long-term drought persists in California, western Nevada, Arizona and New Mexico. Forecasters say the drought will continue through at least the summer and dryness recenly expanded in Oregon and Washington.
Chief Ken Pimlott says California, in the fifth year of drought, is "ripe for wildfires" and an above-average season was already expected.
Cal Fire started staffing up a month earlier than normal to prepare for this summer. The agency says it has already responded to more wildfires so far in 2016, covering more than 30,000 acres. Cal Fire says that is more than twice the amount of acres during the same period in 2015.
In the past, Cal Fire has said "wildfire season" is year-round, at least in Southern California. This year, fires started in February.
The Butte Fire in Amador and Calaveras counties burned more than 70,000 acres. This view of the fire in September 2015 was taken from an evacuation center off Clinton Road in Amador County. Capital Public Radio / File
Statistical data show that over the last 30 years, fire seasons have gotten longer and the area burned by wildfires has doubled. Climate change researchers, and other scientists, have published numerous studies over the past 10 years that show wildfires will be more intense and larger over time in the southwest U.S.
The costs of fighting those fires continue to climb too. The U.S. Forest Service spent nearly $2 billion in 2015 just fighting wildfires, and that is roughly half of the agency's yearly budget.
In California, the USFS Southwest Region spent nearly 40 percent of its budget on fire suppression in 2015.
The 2015 wildfire season was one of the worst on record, also one of the most expensive. And 2016 may be headed in the same direction. As of June 17, nearly 23,000 wildfires in the U.S. have burned 1,869,563 acres.
Prolonged drought and bark beetles are taking a toll on trees in California. This view of dead and dying trees in the Stanislaus National Forest was taken in May 2016. Woranuch Joyce / Capital Public Radio
More than 40 million trees are dead in state and federal forests in California, due to drought, bark beetles and wildfire.
Officials in California say they're preparing to use large air-blasting incinerators to burn some of the trees killed by drought and a beetle epidemic ravaging Sierra Nevada forests.
The latest U.S. Drought Center report shows severe and moderate to abnormally dry conditions in the southwestern U.S., with long-term drought persisting in California, Nevada, Arizona and New Mexico.
The California Independent System Operator is declaring a Flex Alert for Southern California, from 10 a.m. to 9 p.m. Monday, June 20, due to high temperatures in the region.
People are urged to conserve electricity especially during the late afternoon when air conditioners typically are at peak use. Cal ISO suggests people turn off all unnecessary lights, use major appliances after 9 p.m. and set air conditioners to 78 degrees or higher.
Earlier this year, the agency that operates California's power grid said power supplies would be "adequate" for the summer.