Incoming heat wave could be California's hottest and longest this year, forecasters say

VENTURA, Calif. — An excessive, prolonged heat wave will further parch large swaths of California in the longest and hottest heat wave of the year, according to forecasters at the National Weather Service.

Beginning Wednesday, the weather service predicts triple-digit temperatures will create hot, dry conditions in Southern California that will spread north later in the week. Excessive heat will dominate the forecast through at least Sunday. 

The heat may be record-breaking and will likely produce a very high heat-illness risk, said David Sweet, meteorologist for the National Weather Service in Oxnard.

"A large dome of hot air will be sitting over Southern and Central California," Sweet said. "The immediate coast will be the coolest with temperatures in the upper 70s to mid-80s. There will be an elevated fire danger, but no winds." 

IS THE ATLANTIC HURRICANE SEASON CRANKING UP EARLIER?:Study says yes, thanks to climate change

Sustained high pressure will keep temperatures in coastal areas above normal, and likely set up a "prolonged and likely dangerous heat event,” the Los Angeles-area weather office wrote.

As the heat wave expands into Northern California throughout the weekend, temperatures could hit 112 degrees in the Sacramento Valley on Monday and Sunday.

Much of the Western U.S. has been plagued by harsh drought for several years. Lake Mead, the country’s largest man-made reservoir that serves as a vital source of water for the Colorado River, has plummeted to less than a quarter full. At least five sets of human remains have been found in the lake amid shrinking water levels.                         

Heat kills more Americans each year than any other weather hazard, including hurricanes, tornadoes, and floods, according to the National Weather Service. And dramatic increase in deadly heat waves in places like North America and Europe is now likely inevitable, a study published this month found.

CALIFORNIA'S WATER CRISIS:In the Golden State, neighbors turn in neighbors and even celebrities aren't spared

Contributing: The Associated Press