Folks, it’s time to brace for a major heatwave hitting California this week! Authorities are sounding the alarm about extreme health and wildfire risks as the longest heatwave of the year kicks off Tuesday, bringing triple-digit temperatures and minimal overnight cooling to most of the state.
Antoinette Serrato, a National Weather Service meteorologist in Hanford, California, warns, “This is really just a long-duration heat event that will provide little to no overnight temperature relief.” The heatwave is expected to bring dangerous temperatures through the Fourth of July holiday and into early next week, especially in Northern California, the Central Valley, and southwestern deserts.
Much of Los Angeles County’s inland valleys and mountains, including the San Fernando Valley and San Gabriel Mountains, are under an excessive heat watch from Wednesday through Sunday, with high temperatures expected to range from 95 to 110 degrees. However, Southern California’s coastline should be largely spared from the worst of the heat.
UCLA climate scientist Daniel Swain described this as a statewide heat event that might last quite a while, potentially from July 1 until July 8 or 9, or even later in some spots. He noted that inland areas and higher elevations could experience above-average temperatures for over two weeks straight, leading to increased human heat stress and wildfire risk due to a persistent heat dome and lack of overnight cooling.
On Tuesday, parts of the northern San Francisco Bay Area and Sacramento Valley are expected to face a combination of excessive heat and a red flag warning for extreme fire weather. Low humidity, winds up to 30 mph, and high temperatures could create perfect conditions for wildfires. Pacific Gas & Electric Co., California’s largest utility, announced potential power cuts in some Northern California counties on Tuesday and Wednesday to prevent accidental fire ignitions.
In response to the fire risk, the California Governor’s Office of Emergency Services has pre-positioned fire engines and personnel across the state. The National Weather Service issued a red flag warning for the Sacramento Valley and North Bay interior mountains from Monday night through Wednesday due to strong winds, low humidity, and hot temperatures, which can contribute to extreme fire behavior.
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California Electric Company Announces It’s Turning Off Power for Thousands of Residents Amid Heat Wave and Raging Fires— Lisa Leece (@lleece2) July 2, 2024
Adding to the fire risk is the Fourth of July holiday, which often sees increased use of fireworks. Already, firefighters are battling two major fires in Fresno County, including the Basin fire and the Fresno June Lightning Complex blaze, which have grown significantly in recent days.
The primary concern this week, however, is the extreme, extended heat, which poses significant health risks. Serrato emphasized that many areas will see extreme heat risk starting this weekend, with overnight lows around 70 degrees or higher. The National Weather Service has issued an excessive heat warning for most of California from Tuesday through at least Friday and in some areas until Monday.
High temperatures are expected to reach or exceed 107 degrees in the Central Valley, with the Coachella Valley and San Diego County deserts facing highs up to 121 degrees. Death Valley could see highs peak at 125 degrees later this week, with lows not dropping below 90 degrees for several days.
Northern Humboldt County may see record-breaking temperatures above 110 degrees from Wednesday into the weekend, with parts of Trinity and Lake counties possibly reaching 115 degrees. Much of the inland Bay Area could see highs up to 110 degrees, while San Francisco is under a less intense heat advisory with highs reaching the mid-90s.
The Bay Area Air Quality Management District issued a “Spare the Air” alert for Tuesday due to unhealthy air quality from high ozone concentrations. The National Weather Service’s detailed forecast extends only a week, but long-range predictions suggest above-average temperatures continuing through at least July 10.
This extended, extreme heatwave is expected to have widespread impacts, particularly on vulnerable populations like babies, the elderly, and pregnant people. Serrato advises residents to take precautions, stay hydrated, avoid going outside during the hottest parts of the day, and seek out cooling centers if necessary.
