It might seem like an April Fool’s joke. But it’s not.
After a month of dry and sometimes record hot weather, rain is finally back in the Bay Area forecast. A low-pressure system from the Pacific Northwest is expected to bring rain to much of Northern California next Tuesday and Wednesday.
The showers would be the first rain in the Bay Area in a month — since March 2 — and although it is still early, could generate half an inch to 1 inch of precipitation across the Bay Area, forecasters say.
“In the grand scheme of things, it’s a light, beneficial rain,” said Jan Null, a meteorologist with Golden Gate Weather Services in Half Moon Bay. “It’s certainly better than nothing. And I won’t have to get my car washed.”
Weather conditions across the Bay Area will remain sunny and mild until early Tuesday, when temperatures are expected to cool into the 60s and the rain arrives. The North Bay Hills, Santa Cruz Mountains and Big Sur area will see the most rain, with cities at lower elevations around the bay expected to see less, said Joe Merchant, a meteorologist with the National Weather Service.
“It’s been really dry,” Merchant said. “Any rain that we get right now is welcome. Considering the heat wave we went through last week, a good wetting rain would really help our fire weather concerns going into spring. The forecast could still change, but the trend is improving and we’re eagerly anticipating it.”
“We’re not expecting any flooding or anything like that,” he added. “But you’ll probably need an umbrella. And it could impact commutes.”
The same two-day system is also likely to bring 1 foot or more of snow and cooler temperatures to the Sierra Nevada, where ski resorts have been closing early for the season and the snowpack has been dwindling due to record-high temperatures in recent weeks.
“It’s going to be a big change,” said Bryan Allegretto, a forecaster with OpenSnow, a company that tracks weather conditions at ski areas across the nation. “It’s going to get cold again. It will be a big shock to the system after a March with no cold and no rain.”
Temperatures at the Truckee airport are running 9 degrees Fahrenheit above the historical average for March, Allegretto said, and about 4 degrees above average there for the entire winter season.
Record heat in the past few weeks has decimated the Sierra Nevada snowpack, causing ski resorts like Dodge Ridge, Homewood, Badger Pass, and Sierra-at-Tahoe to close early for the season.
On Tuesday, Palisades Tahoe announced it plans to close at least a month earlier than expected, moving up from May 25 to late April.
On Wednesday, the statewide Sierra snowpack, the source of nearly one-third of California’s water supply, was at 27% of its historical average — down from 76% on Feb. 20.
Because the last three winters in California have been wetter-than-normal or near-normal, the state enters the summer with lots of water in its reservoirs, and a low likelihood of water restrictions in cities this year.
On Wednesday, Shasta Lake near Redding, the largest reservoir in California, was 89% full or 115% of its historical average. Oroville, the second largest, in Butte County, was also 89% full, and 125% of its historical average. San Luis, east of Gilroy, was 89% full. And Diamond Valley, the largest reservoir in Southern California, in Riverside County, was 97% full.
NOAA, the National Oceanic and Atmospheric Administration, forecasts above-average chances of wet conditions in California next week until April 4, 2026. (Map: NOAA)
A persistent ridge of high pressure created a heat dome over the West last week, sending temperatures across the Bay Area into the 90s, and breaking not only daily records but also records for the entire month in some cities. In desert areas, temperatures exceeded 100 degrees.
The ridge is finally breaking down and moving east, replaced with a trough of low pressure off the West Coast that is expected to bring the rain with it. In the days after next Wednesday, long-range computer models show California returning to a dry pattern.
This winter has been noteworthy for its extremes. It began dry, and stayed dry in November and December. Then several huge storms between Christmas and early January dumped more than 100 inches of snow in the Sierra. Dry weather followed for another month until another huge storm brought 100 more inches in mid-February. Since then, it has been dry.
California is not in a drought. It has received precipitation levels that are close to normal throughout much of the state this winter. San Jose on Wednesday was at 95% of its historical average for precipitation, with Oakland at 87%, San Francisco at 82%, Fresno at 105%, Los Angeles at 145%, and San Diego at 115%.
But because of the warmer temperatures, much more precipitation in the Sierra has fallen as rain, not snow, than normal. With less snow, water supplies aren’t as predictable, and wildfire danger can increase.
That’s a common trend with climate change, said Daniel Swain, a climate scientist with the University of California Agriculture and Natural Resources division.
“The reality is over the next few decades we are going to have additional warming,” Swain said. “Winters like this will become even more likely, and eventually will become relatively close to the norm. That is what the data show at this point.”
The warming climate doesn’t mean California and the West will see a huge reduction in rainfall in the decades ahead, he noted. Some years, big storms happen because a warmer climate allows storms to absorb more moisture. But it does mean a Sierra snowpack more prone to melting early, and whiplash weather patterns where some months are very dry and some very wet.
“The water will come increasingly in larger, more inconvenient and sporadic bursts, and also increasingly in the form of rain rather than snow in the mountains while it gets warmer,” Swain said. “It is decidedly a different problem than the tap completely shutting off and getting no water at all. That is something people worry about. It’s not what we really expect to see. But it brings its own problems, of course, as we are seeing this year.”
