Heat wave to cool down by tomorrow, with rain on the way
Bay Area residents got an unseasonably warm start to the spring, but temperatures are expected to cool down by today before another shot at rain could move into the region over the weekend.
Heat records fell in six Bay Area locations Tuesday. Santa Rosa reached 89 degrees, topping the record of 86 set in 1926. Redwood City, downtown Oakland and Gilroy all hit 85 degrees, shattering records of 78 set in 1944, 77 in 1984 and 83 in 2015, respectively. The San Francisco International Airport hit 82, surpassing the mark of 73 in 2008. And San Jose reached 84 degrees, edging out the record of 83 set in 1915.
Temperatures are expected to drop today, returning daytime highs closer to normal Sunday and Monday, with highs in the 60s and 70s. Rain could reenter the forecast Sunday, but there's still some uncertainty with the weather models a few days out. The storm is expected to drop 0.2 to 0.5 of an inch of rain on the inland valleys, and the coastline, including the coastal mountains, could get half an inch to over an inch.
“One of the models has the storm pushing very far to the south and another one has it centering over us, where the moisture will be,” forecaster Brayden Murdock said. “It's a bit of a back and forth on that, but the one that's wetter is the looking to be the more consistent one, which is good news.”
A storm last weekend — the final one of the winter — dropped about one-tenth of an inch of rain to the North Bay and San Francisco, with about 0.15 to 0.2 inch in the
Santa Cruz Mountains and just under 0.1 inch in the Santa Clara Valley. The Sierra Nevada was blanketed with 2-4 inches of snow, with the highest elevations getting up to 6 inches.
The upcoming storm isn't expected to put a huge dent in California's ongoing drought, which is entering its third year in a row.
“This is kind of a regular spring setup,” Murdock said. “We do see these ridges get broken up by troughs and luckily, we didn't get too, too warm with yesterday's warm-up. We're not seeing prolonged days of heat, so we're not as worried about fire concerns as we would have last year.”
The heat and dry air have raised concerns for fire across the Bay Area, but Murdock said the conditions aren't as dire as last year's, when Northern California was starting to approach record dry conditions in terms of fire fuels.
Wildfires have ignited during what normally would be the wettest time of the year, extending the fire season. Fuels and vegetation also have dried out during the recent dry spell and require storms with higher precipitation totals to fill them up again.
Massive atmospheric river storms in October and December raised hopes of easing California's lingering drought, but January and February were the driest on record dating back to 1921. The statewide Sierra Nevada snowpack, which fulfills about 30% of the state's water needs, was at 168% of normal on New Year's Day but had dwindled to 50% as of Wednesday, according to the California Department of Water Resources.
The U.S. Drought Monitor also reported Thursday that 93% of California is in “severe drought,” an increase from 87% from a week ago, and 35% of the state is in “extreme drought,” the most dire stage, up from 13%.
Extreme drought has spread to the north coast, and all nine Bay Area counties are currently in a severe drought.
“These rains are a step forward, but it's after taking a few steps back,” Murdock said. “We could always use some more.”