The tail end of an atmospheric river storm from the Pacific Northwest dropped at least a tenth of an inch of rain on most locations in the Bay Area, with lingering scattered showers to continue into the weekend.
The storm moved into the North Bay from the Gulf of Alaska on Thursday morning, resulting in thunderstorms and showers along the Peninsula and East Bay, according to the National Weather Service. The bulk of the precipitation was focused on portions of the North Bay and along the East Bay and Peninsula coastline.
As of 7:30 a.m., 24-hour rainfall totals included: 0.30 inches at Bodega Bay, 0.23 inches in Danville, 0.20 inches in Palo Alto, 0.19 inches at Middle Peak at Mount Tamalpais and Redwood City, 0.09 inches at the Oakland International Airport, 0.09 inches in downtown San Francisco and 0.01 inches in San Jose.
The system is expected to pull offshore and descend into Southern California Friday morning before a “reinforcing shot” of moisture is expected to deliver more rain into mid-day Saturday before tapering off in the afternoon, ushering in dry conditions for the foreseeable future. Although much snow hasn’t been reported so far, lingering showers Friday night could put a dusting along the higher elevations in the region, mostly above 3,000 feet or so. There could also be some hail due to the cold air mass passing through, but it’s not expected to be a widespread concern.
“We’re not looking at any kind of atmospheric river, it’s more of a cold, upper level system moving through,” said forecaster Roger Gass. “Rainfall amounts are going to vary greatly, with most locations to get a tenth of an inch or less, give or take. If there’s a heavier shower, we could expect a quarter of an inch in some places.”
Rain showers remain possible for parts of the area into Saturday. We may even see a little mountain snow in the Santa Lucias. After that we turn our attention to gusty winds and colder conditions starting on Friday. More on that in the next post. (1/2) #cawx pic.twitter.com/UThpA9vgrV
— NWS Bay Area 🌉 (@NWSBayArea) March 4, 2022
A wind advisory was issued for 7 a.m. to 7 p.m. Friday for the coastal portions of the North Bay, San Francisco and the coast of the Peninsula. Northerly winds could reach 25 to 35 miles per hour, with gusts up to 50 miles per hour. The weather service advised residents to secure loose outdoor structures and objects and to be mindful of tree limbs that could be blown down, resulting in power outages. It could also be difficult for drivers of “high profile” vehicles or those pulling trailers.
Temperatures are expected to cool down to more typical wintertime weather, dipping down into the upper 50s and low 60s Friday before warming up a few degrees Sunday to the low-to-mid 60s. Overnight temperatures could drop to the low-to-mid 30s across the interior portions of the Bay Area, with the shoreline and coast seeing temperatures in the lower 40s.
The Sierra Nevada could also get several inches of snow, with the heaviest amounts to fall Friday night. Lassen Park was expected to receive 12 to 18 inches while Carson Pass could get eight to 12 inches. Donner Pass, Ebbetts Pass and Sonora Pass could get six to eight inches of snow. The weather service warned of hazardous mountain travel and advised drivers to bring emergency supply kits and chains.
Although a welcomed reprieve from the recent dry spell since the beginning of the new year, the storms this week aren’t expected to have a significant impact on the ongoing drought and wildfire risk.
“All and all, the systems are relatively weak,” Gass said. “We’re not seeing a significant moisture tap associated with them. It’s a run-of-the-mill type storm system. It’s definitely good news — we need the rain still — but we’re not seeing a significant amount of rainfall today through tomorrow.”
January and February were the driest in the state’s recorded history and that trend doesn’t seem to be letting up anytime soon. Over the past two months, San Francisco has gotten .65 of an inch of rain in what would usually be the wettest time period for the region. San Jose received .01 inches of rain in January and February.
There isn’t any more rain in the forecast for the next seven days and in the longer-term outlook up to 18 days out, the Bay Area is expected to see below-average rainfall through the middle of March.
Atmospheric river storms in October and December raised hopes of subduing California’s ongoing drought by filling the statewide Sierra Nevada snowpack to 168% of normal on New Year’s Day, marking the 21st wettest December on record for San Francisco. But by Thursday, the Sierra snowpack had dropped down to a mere 63% of historical averages for that date, according to the California Department of Water Resources.
Year-round fire risk is still posing a concern for a state going into its third year of drought in a row. Blazes have sparked in various portions of the state after vegetation and fuels dried out during the dry spell.
“You can see on the hillsides on the Bay Area and central coast that a lot of the greenery is beginning to dry up, especially in exposed and open areas,” Gass said. “That’s always a concern when we’re seeing fuels being dry in March. Typically, our hillsides would be lush and green through March and April. That can change if we get more rain throughout the month and in April that could provide relief, but as it stands right now, things are drying up.”
Source: www.mercurynews.com