California weather shift: Heat, monsoon thunderstorms enter forecast
Heat is predicted to peak Thursday through Saturday, but there's a chance it lasts even longer. High temperatures are forecast to be 10 to 15 degrees above normal and flirt with record territory in the mountains, deserts and valleys. San Francisco should be spared from the worst of the heat, as is typical with August heat waves.
Subtropical moisture from the North American Monsoon will also bring a chance of thunderstorms and potential wildfire ignitions from dry lightning. The weather service warns of elevated fire weather danger in Southern California beginning Wednesday. Thunderstorms are predicted to spread northward toward the Lake Tahoe area Friday and Saturday.
Here's what to expect as temperatures climb this week:
Cool start, hot finish to week
It'll be a slow warmup across California. An area of low pressure will linger off the coast Monday, keeping temperatures below normal as winds blow from sea to land. Temperatures will inch closer to normal Tuesday, but the big shift is anticipated Wednesday.
A high-pressure system that brought hot weather to the East over the weekend will get shunted westward as Hurricane Erin approaches the Atlantic Coast. This area of high pressure will park itself over the Four Corners by Wednesday and warm up the West.
By Thursday, triple-digit temperatures are predicted in California's valleys and deserts. The National Weather Service already forecasts temperatures to flirt with record territory in the Mojave Desert and San Joaquin Valley on Thursday, Friday and Saturday.
In the Bay Area, Santa Rosa, Walnut Creek, Concord and Livermore are among the cities with a chance of hitting 100 degrees Thursday and Friday. Highs in Lake Tahoe are forecast to be in the mid-80s to low 90s, well above August normals.
Nights will be warm, too. Overnight lows may not drop below 70 degrees in the Central Valley from Thursday through Sunday, threatening records.
High-pressure systems that move east to west typically don't bring hot weather to San Francisco and Oakland because their position promotes a shallow marine breeze that keeps the coast cool. Still, downtown San Francisco should have a few days in the 70s and Oakland will probably reach 80 degrees at least once, warm relative to recent months.
Areas removed from the coast slightly will be significantly warmer. San Jose and downtown Los Angeles have a shot at the 90s Thursday and Friday.
Monsoon thunderstorms to hit mountains
Hot weather always coincides with increased wildfire danger, but the added possibility of thunderstorms has prompted the weather service to issue a fire weather watch for the mountains of Southern California beginning Wednesday.
Monsoon moisture spinning clockwise around the high-pressure system will inch toward the San Diego County mountains on Wednesday and the Ventura Mountains, San Gabriel Mountains, Antelope Valley and southern Sierra Nevada on Thursday. This moisture will increase the chance of mountain thunderstorms, but the exact timing and location of storms will become clearer by midweek. Storms may even extend toward the Tahoe basin Friday and Saturday.
A mix of wet and dry lightning could spark wildfires. Flammable vegetation could burn quickly if lightning sparks a fire.
Even areas that aren't hit by thunderstorms will be impacted by the monsoon moisture. The humid air mass will trap heat near the ground at night and keeps temperatures much higher than they would be typically. The National Weather Service forecasts record overnight temperatures in the Sierra Nevada and Central Valley from Thursday through Saturday.
It is unclear if the hot weather will stick around beyond Sunday, but for now, at least four days of heat and mountain thunderstorms are expected in interior California.
Monday Bay Area breakdown
San Francisco: Thick morning fog could produce drizzle in the hills, but sunshine should prevail by midmorning at the Embarcadero with partial clearing west of Twin Peaks in the afternoon. Winds will gust 15 to 25 mph in the afternoon. Highs will be in the low to mid-60s in West Portal, Lakeshore and the Richmond and Sunset districts. Downtown, SoMa, the Mission, Dogpatch and Bayview should reach the mid- to upper 60s. Lows will be in the upper 50s with increasing clouds.
North Bay: Patchy fog will slowly retreat to the coast for a mostly sunny afternoon across Wine Country. Highs will be in the mid-70s to low 80s in Santa Rosa, Sonoma, Petaluma, San Rafael, Napa and Vallejo. Mill Valley and Sausalito will be cooler, in the upper 60s to low 70s. Fairfield and Santa Rosa should reach the mid- to upper 80s. Westerly winds will gust up to 20 mph in the afternoon and evening. Patchy fog is expected to form overnight with lows in the 50s, coolest in the valleys and warmest in Solano County.
East Bay: Dense fog in the Berkeley and Oakland hills could be accompanied by drizzle in the morning. Clouds should be less widespread and are expected to burn off quicker than they did over the weekend. Highs will be in the upper 60s to mid-70s along the bay shoreline from Richmond to Fremont. Upper 70s to low 80s are forecast in Lamorinda, Walnut Creek, Pittsburg and the Tri-Valley. The sea breeze will bring gusts up to 20 mph in the late afternoon. Clouds will increase overnight, especially west of the Caldecott Tunnel. Lows will be in the mid-50s.
Pacific Coast and Peninsula: More morning fog is expected at the coast, although it won't be nearly as thick as over the weekend when heavy drizzle totaled up to more than a tenth of an inch in Half Moon Bay. Those clouds could even break up enough for a partly sunny afternoon sunshine at the beaches with highs in the low to mid-60s. More sunshine will be found along the Highway 101 corridor with highs in the mid- to upper 60s in South San Francisco and the mid-70s near the San Mateo-Santa Clara county border. Gusts of 15 to 25 mph are expected in the afternoon. Lows will be in the mid- to upper 50s with increasing clouds.
South Bay and Santa Cruz: Clouds will burn off more quickly over the South Bay compared to the weekend, which will yield warmer temperatures. Highs will reach the mid-70s in Santa Clara, Sunnyvale and Milpitas and the upper 70s to near 80 in San Jose, Saratoga and Los Gatos. The hottest weather will be found in Morgan Hill, Gilroy and the Santa Cruz Mountains, with highs in the low to mid-80s. Scotts Valley will be around 80 while Santa Cruz should reach the low to mid-70s. Northwest wind gusts will exceed 15 mph in the afternoon, but shouldn't be much stronger. Lows will be in the mid- to upper 50s with patchy clouds near the bay and coast.
Try Our AI Features
Explore what Daily8 AI can do for you:
Comments
No comments yet...
Related Articles
New York Times
a few seconds ago
- New York Times
How Climate Change Affects Hurricanes Like Erin
Hurricane Erin is whipping up the Atlantic Ocean at speeds over 100 miles per hour. The trajectory of the storm has it staying out to sea, though many effects will be felt close to shore and on land. And some of those effects are made worse by global warming. Overnight on Friday, Hurricane Erin ratcheted up to a Category 5 storm, from a Category 1, becoming one of the top five most quickly intensifying hurricanes on record. As the planet warms, scientists say that rapidly intensifying hurricanes are becoming ever more likely."It's a very easy set of dots to connect,' said Jim Kossin, who worked at the National Oceanic and Atmospheric Administration as a hurricane specialist and climate scientist before he retired. 'These rapid intensification events are linked pretty directly to that human fingerprint.' According to the National Hurricane Center, rapid intensification is an increase in a storm's sustained wind speeds of at least 35 miles per hour in a 24-hour period. Between Friday morning and Saturday morning, Hurricane Erin's wind speeds increased by nearly 85 miles per hour, peaking at 161 mph. Daniel Gilford, a climate scientist at Climate Central, a science communication nonprofit, likens hurricanes to the engine of a car. 'They need some fuel source in order to spin, and the fuel source is the ocean surface,' he said. 'So as the temperature of the ocean surface goes up, that adds more fuel that these storms can use to intensify.' For over a century, greenhouse gases emitted by human activity have trapped heat inside the planet's atmosphere. A recent streak of record-breaking temperatures crowned 2024 as the hottest year on record. Want all of The Times? Subscribe.
Boston Globe
an hour ago
- Boston Globe
New England dries out a bit Thursday, but winds and high surf ramp up as Erin approaches
Staying cool in the upper 50s and low 60s, and drying out after a few early-morning sprinkles. The skies across Greater Boston should turn from mostly cloudy to partly sunny in the afternoon. Highs will reach around 70 degrees. Hurricane Erin will lurk close to New England and increase winds throughout the day. Boston and the Southern New England coast may feel a healthy easterly breeze to about 15 miles per hour, with gusts ranging from 20 to 30 miles per hour into the evening. A few showers could push into Southern New England later Thursday, but mostly south of the Mass Pike and near the shore. Staying partly cloudy overnight with lows around 60 with gusts continuing. Advertisement Highs on Thursday will reach the low 70s for most of the region. Boston Globe The setup — breezy conditions build as Erin nears Wednesday's system will clear the region by early Thursday morning, with most showers wrapping up before we get up for the day. For early commuters, you may see some patches of fog with lingering sprinkles, but Boston should be clear of raindrops by the time you get going. It might be a good idea to pack the umbrella just in case there is a spot shower lingering. Advertisement High pressure will build near the region, leading to decreasing clouds throughout the day. Northern New England sees sunshine before Boston does, but eventually, mostly cloudy skies in the morning should lead to more periods of sunshine in the afternoon. Not everyone will see afternoon sunshine, however, as Erin's outermost clouds infringe on Massachusetts' South Coast and the Cape and Islands. There may be a shower or two that clip the Cape later in the day. This high pressure is perfectly timed as Erin makes a near approach to New England Thursday, directing the storm out to sea. The storm's eye will pass more than 400 miles offshore, but the pressure difference between Erin and the building high pressure to the northwest of New England will be felt. Aside from the few sprinkles on the Cape from Erin, Boston and coastal Southern New England will feel the gusty conditions build during the day. Wind speeds will be from the east, thanks to the strong counterclockwise rotation of Erin, at about 10 to 15 miles per hour. Wind gusts will build to 20 to 30 miles per hour Thursday afternoon in Boston, the North and South Shores, the Cape and Islands, and along the South Coast and Southern Rhode Island. The strongest wind gusts will be concentrated over the Cape and Islands Thursday night into Friday morning. Breezy conditions will develop throughout Thursday and into Friday. Some gusts across the Southeast may build to 30 mph. Boston Globe High surf advisory, dangerous rip currents With Erin approaching, high surf and rip currents will stretch along the New England shoreline. Some breaking waves could reach as high as 15 to 20 feet. Boston will be protected by the harbor, but if you have beach plans, I wouldn't risk taking a dip in the ocean or a boat out to sea; it'll be too choppy out there and, quite frankly, dangerous. Advertisement High surf advisories and rip current statements have been posted through Saturday for parts of the New England coastline. Boston Globe The high pressure will also bring more dry air into the region to close out the work week, keeping dew points around 60 degrees on Thursday, with Friday and Saturday closer to the mid-50s. Dew points will stay low enough to keep the air feeling comfortable through the rest of the work week. Boston Globe Highs on Friday will reach the mid to upper 70s, with some folks breaking into the low 80s. Boston Globe Wednesday's breakdown Greater Boston: A chance for an early-morning sprinkle, then drying out. Turning from mostly cloudy to overcast to partly sunny skies in the afternoon. There is a very low chance of a late shower near the city later in the day. Highs near 70. Breeze picks up in the afternoon with gusts of 20 mph or higher later Thursday. Southeastern Mass.: A chance for a morning sprinkle, otherwise mostly dry with some thinning clouds. Chance for more clouds in the afternoon with highs in the upper 60s and low 70s. Breeze picks up throughout the day with gusts to 20 mph or higher. Central/Western Mass.: A mostly cloudy start with some clouds breaking as the day goes on. Highs to the low 70s from Worcester to Springfield, mid- to upper 60s across the Berkshires. A slight breeze in the afternoon and evening. Cape and Islands: Seeing mostly cloudy skies with the chance for a sprinkle or brief shower. Highs in the upper 60s and low 70s. Breeze picks up as the day goes on with some gusts to 30 mph Thursday night into Friday. Rhode Island: Seeing mostly cloudy skies with a low chance for an afternoon sprinkle south of Providence. Otherwise, some sun is breaking through north of Providence. Highs to the upper 60s and low 70s. Advertisement New Hampshire: Different weather up north! Clearing skies early with partly to mostly sunny skies on Thursday. Highs in the low and mid-70s. A slight breeze of about 10 to 15 mph. Vermont/Maine: Partly to mostly sunny skies across both states with highs ranging in the 70s. A breeze of about 10 mph. A look at the forecast across Boston for the next seven days. Boston Globe for our , which will arrive straight into your inbox bright and early each weekday morning. Ken Mahan can be reached at
San Francisco Chronicle
an hour ago
- San Francisco Chronicle
Parents of kids swept away in Texas floods beg lawmakers to protect future campers
When floodwaters rushed through a girl's summer camp nestled in the Texas Hill County, Michael McCown's 8-year-old daughter was among 27 campers and counselors swept to their deaths. On Wednesday, McCown joined other Camp Mystic parents, some wearing buttons memorializing 'Heaven's 27,' in demanding that Texas lawmakers pass a bill that would boost camp safety, including generally keeping cabins out of floodplains, instituting new requirements for emergency plans and mandating weather radios. 'It will hurt my family forever that, for reasons I still do not know, these protections were not in place nor thought out thoroughly for my daughter and the rest of the girls here,' he said. "Please pass this bill, protect our kids and do not let their deaths be in vain.' His middle child, Linnie, was sandwiched between two brothers. She was sometimes a pest to her 11-year-old brother. But to the youngest, just 3, she was mother figure, making him cereal on weekends so her parents could catch a few minutes of sleep. 'To everyone else she was a joy," her father told lawmakers. "She hugged her teachers, was a friend to everybody, and spread an infectious giggle everywhere she went.' Then came the floods. Just before daybreak on the Fourth of July, destructive, fast-moving waters rose 26 feet (8 meters) on the Guadalupe River, washing away homes and vehicles. All told, at least 136 people died, raising questions about how things went so terribly wrong. County leaders were asleep and out of town. The head of Camp Mystic had been tracking the weather beforehand, but it's now unclear whether he saw an urgent warning from the National Weather Service that had triggered an emergency alert to phones in the area, a spokesman for camp's operators said in the immediate aftermath. Some of the camp's buildings — which flooded — were in what the Federal Emergency Management Agency considered a 100-year flood plain. But in response to an appeal, FEMA in 2013 amended the county's flood map to remove 15 of the camp's buildings from the hazard area. Upon learning of the flooding, McCown rushed to the town of Kerrville to pick up Linnie, receiving an email en route that if parents hadn't been personally contacted, then their daughters are accounted for. 'I felt a wave of relief, which was quickly shattered about 30 minutes later when my wife called incredibly distraught to say that Linnie is missing,' he recalled. He joined the search downstream from the camp and found the body of a deceased girl. He also made two trips to a funeral home to identify bodies. One was not Linnie; the other, he believed, was. He later provided authorities with a DNA swab. 'How," he asked, "could these girls vanish into the night without anyone having eyes on them while cabins literally just 20 yards away had no casualties? So what went wrong?' Texas State Sen. Charles Perry described the proposed legislation as a 'legacy to the loss' and an answer to what has been learned during hours of public testimony. He said it's dubbed the 'Heaven's 27 Camp Safety Act.' 'It's only appropriate," Perry said, "to memorialize the 27 little girls that lost their lives at Camp Mystic in this way.'
