- đź“Ś Prolonged extreme heat and dry conditions create elevated to critical fire weather across Southern California through Monday.
- đź“Ś Humidity levels could drop to 5-10% in interior areas, with triple-digit temperatures in valleys and mountains. In the Coachella Valley, temperatures could hit 120 degrees.
- đź“Ś Poor overnight humidity recovery increases wildfire risk, especially in foothill and mountain communities.
Introduction
Southern California is bracing for a dangerous stretch of fire weather as a prolonged heat wave combines with low humidity and dry vegetation. The National Weather Service warns of elevated to briefly critical conditions through at least Monday, raising the risk of rapidly spreading wildfires. The heat wave, expected to rank among the hottest of the year so far, will peak on Sunday, with sultry nights increasing the risk of heat illness as well as fire danger. The CBS LA Next Weather Alert has been extended through Monday due to the prolonged heat. Forecasters say it’s likely to stay that way through the end of July.
Main Content
Heat and Humidity Create Perfect Storm
Forecasters say the combination of above-normal temperatures, low humidity, dry vegetation, and breezy conditions will increase wildfire risk. The NWS notes that “with hotter and more unstable conditions, there will be an increased risk for large plume dominated fires across the interior,” especially from Thursday through Monday when the heat wave peaks and humidities drop. Temperatures will be 8 to 12 degrees above normal, with muggy conditions limiting overnight cooling, said Kristan Lund, a meteorologist with the National Weather Service in Oxnard. Valley areas should reach triple digits, with Woodland Hills hitting 105 to 106 degrees. In the San Fernando and San Gabriel valleys, highs are expected to range from the mid-90s to about 105 degrees. Downtown Los Angeles and much of Orange, Ventura and Santa Barbara counties will get up to the lower 90s. Beaches also will be warmer than usual, with temperatures in the lower 80s, due in part to unseasonably warm ocean water temperatures driven by El Niño. In downtown Los Angeles, where temperatures are forecast to reach the mid-90s, Langer’s Deli owner Norm Langer said staff would place air conditioning units in front of the store and hand out cold bottled water to customers waiting in line. “Extreme heat is part and parcel of our lives these days, and we must adapt to it,” Langer said in a statement. A Weather Service heat advisory is in effect for many areas, including the beaches of Los Angeles and Ventura counties and the southern coast of Santa Barbara County, through 8 a.m. Monday. Forecasters aren’t expecting the heat to break any temperature records but said that some places, including Woodland Hills, Van Nuys and Palmdale, might come within a few degrees of setting new daily highs. The Santa Maria airport set a new daily record Tuesday with a high of 92 degrees, breaking an old record of 89 degrees set in 1960, according to preliminary information from the weather service. Additionally, an extreme heat warning remains in effect until 8 p.m. Monday for the San Bernardino and Riverside County valleys and the Inland Empire, where temperatures could get up to 108 degrees, and for the Coachella Valley, where they could hit 120. Meanwhile, a heat advisory covers the entire Southern California region through the same time. Inland Empire temperatures will likely reach the high 90s to triple digits by early afternoon, while coastal areas in Los Angeles and Orange Counties will see highs in the 80s to 90s. CBS LA chief meteorologist Paul Deanno notes that humid air holds onto its heat more efficiently at night, which means there will be minimal relief during the overnight hours. Humidity will be concentrated in areas closer to the coast, where it will keep nighttime temperatures relatively warm and make it more difficult to cool down. Inland areas will feel drier. Overnight temperatures in the Inland Empire will remain in the 70s. The National Weather Service adds that the large area of high pressure will remain the dominant weather feature through next week, with the core shifting slightly east Monday through Wednesday, bringing a touch of relief to the heat but only by a few degrees.
To help residents understand the risks, here's a quick guide to the terms forecasters use: A heat advisory is issued when temperatures are expected to be hot enough to cause discomfort and potentially lead to heat-related illnesses, especially for vulnerable populations like young children and the elderly. An extreme heat watch is essentially a forecast for upcoming extreme heat, often covering wide areas and later revised into more focused warnings and advisories; it's a good time to prepare. An extreme heat warning means heat levels are or will likely become extremely dangerous, and officials recommend avoiding strenuous outdoor activity, staying hydrated, and helping loved ones and pets stay cool.
Critical Conditions in Foothills and Mountains
Warm overnight temperatures and poor humidity recovery will further elevate fire danger in foothill and mountain communities. Very dry air could spread into interior areas Sunday and Monday, with humidity levels falling to between 5% and 10%. Triple-digit temperatures are expected in many valleys, mountain communities, and desert locations. Forecasters also warned of the risk of fast-spreading fires, with the Weather Service calling for elevated to brief critical fire weather conditions across Southern California’s valley, mountain and desert areas through Monday due to hot temperatures and dry vegetation. Southern Santa Barbara County is also expected to see dry, gusty sundowner winds in the evenings through Thursday, Lund said. “Just because we have higher humidities,” she said, “the mugginess doesn’t mean that the vegetation won’t burn.” Overnight temperatures in the Inland Empire will remain in the 70s, offering minimal relief from the heat.
Fire Risk and Wind Patterns
Forecasters are warning that conditions are ripe for fires, driven by a combination of wind and dry vegetation. Southern California hasn’t seen much rain recently, despite the humidity, leaving plants with little moisture and turning them into the perfect fuel. Rong Fu, an atmospheric scientist at UCLA who specializes in weather patterns and wildfires, explained that “We have humidity, but it's not reaching the saturation point. Therefore, we won't have a cloud. We won't have precipitation.” “Even though the air feels kind of moist, we're in the time of season where it doesn't matter. The fuels are dry and they're ready to go,” said NWS meteorologist Ryan Kittell. Kittell said people should take extra care with anything that could create a spark, and residents in fire-prone areas should remain aware of their surroundings in case a fire starts. The fire risk is likely to be concentrated in a few specific areas that will experience higher winds than others, including parts of the 5 Freeway corridor in northern L.A. County, especially around the Grapevine, and in southern Santa Barbara County. For most of the region, though, winds should stay fairly mild. However, a system of high atmospheric pressure over the Western U.S. is pushing warm, dry air across the Sierra Nevada from inland deserts and into Southern California, generating what is known as downslope wind. Those winds plus the already dry conditions align to create some especially dangerous fire weather. The greatest fire risk is away from the coasts in areas with dry vegetation. The public can help minimize fire danger by properly discarding cigarettes, avoiding activities with open flames, such as improperly extinguished camp fires, and monitoring weather alerts. According to the U.S. Forest Service, humans are the most common cause of wildfires in Southern California; even a spark from a lit cigarette or a chain dragging behind a vehicle can ignite a blaze. Lightning can also start wildfires but is unlikely under current weather conditions. Southern California has seen minimal thunderstorms this summer, further reducing natural ignition sources.
Local California Context
Los Angeles County faces the highest risk, with the NWS forecasting moderate to high heat risk across the region from Wednesday through Monday. Residents in foothill communities like those in the San Gabriel Mountains and Santa Monica Mountains should prepare for rapidly changing conditions. The Los Angeles County Department of Public Health issued an extreme heat warning for residents of many areas, citing both daytime temperatures and unusually warm overnight conditions. Hotter nights can prolong the stress that heat places on the human body by depriving people of a chance to recover, increasing the risk of heat-related illness. The county extended the hours of cooling centers in the Antelope Valley, where temperatures are expected to reach 100 to 108 degrees. Those who are most at risk from the heat are people who work or spend time outside, people without access to air conditioning, and those who are either over 65 or young children.
Background
Southern California has experienced devastating wildfires in recent years, including the 2020 Bobcat Fire and 2025 Palisades Fire, both fueled by extreme heat and dry conditions. Current forecasts mirror those patterns, with the NWS emphasizing the need for vigilance. The conditions are brought on by a powerful ridge of high pressure moving in from the east as well as the unusual path of the remains of Tropical Storm Elida. The system lost its tropical storm status Monday morning as it moved into cooler waters but was still traveling northward in the Pacific Ocean and sending hazardous surf and strong rip currents to Southern California beaches. The surf is expected to peak Thursday and Friday with heights of 4 to 8 feet at south-facing beaches along the Central Coast and Ventura and Los Angeles counties, according to the weather service, which issued a beach hazards statement, warning of an increased risk of ocean drowning through Sunday. People should either stay out of the water or swim near lifeguards and avoid rock jetties, which can be deadly in such conditions. Although it’s unclear to what extent climate change is influencing this particular heat wave, scientists have found that global warming from the burning of fossil fuels is making Western heat waves more frequent, persistent, humid and lethal. “The evidence shows that heat waves are increasing in frequency, intensity and duration, and using sophisticated modeling, it’s possible to show that those absolutely are because of climate change,” said Kristie Ebi, a professor of global health at the University of Washington, on Tuesday at a media briefing held by journalism and science nonprofit SciLine. Things have reached the point, she said, “where many climatologists will tell you there is now no heat wave that hasn’t been exacerbated in some way by climate change.” Much of the heat currently blanketing the region is being driven by the high-pressure system, which traps warm air and compresses it against the ground, heating it even further. Heatwaves in the summer and fall are obviously not new for Southern California, but they are getting worse. Rong Fu, an atmospheric scientist at UCLA who specializes in weather patterns and wildfires, noted that high-pressure systems like this one usually don’t stick around this long. “For this pattern to linger almost two weeks — yeah, I would say, from a historical perspective, it’s unusual,” Fu said. She explained that the system is pushing warm, dry air across the Sierra Nevada, generating downslope winds that combine with dry vegetation to create dangerous fire conditions.
Conclusion
Residents should stay alert, avoid outdoor activities that could spark fires, and have evacuation plans ready. Monitor local alerts and follow guidance from fire officials. To reduce the risk of heat-related illnesses, limit outdoor activities to early morning hours, stay in air-conditioned spaces during the afternoon and evening, and never leave children or pets in unattended cars. Hot temperatures can place added stress on the power grid, especially during peak hours, due to the need to run air conditioners, said David Eisenhauer, a spokesman for Southern California Edison. Edison is monitoring the situation but, overall, expects the grid to be reliable this summer, he said. He said the utility prepares year-round for high-demand summers by performing maintenance and modernizing infrastructure, and that it has added 1,500 megawatts of battery storage over the past year, which “has made a significant difference.” Customers can help by cutting back their energy use between 4 p.m. and 9 p.m. and signing up for demand response programs, which provide incentives for doing so, Eisenhauer said. The California Independent System Operator, which manages the flow of energy through most of the state’s high-voltage power lines, said Tuesday that it is not anticipating strain on the power grid but will continue to monitor the weather and wildfire activity.
Sources and Materials
- mynewsla
- CBS Los Angeles