Update: Napa County rain forecast eases; Bay Area storm still expected to produce dangerous winds

Spectators watched as crews worked to close the Oxbow Commons flood gates on

Spectators watched as crews worked to close the Oxbow Commons flood gates on Wednesday while a powerful storm began passing through the Bay Area.

Leif Bryant, a technician with the Napa County Flood Control District cleans dirt from the rivets of the Oxbow Commons flood gates near McKinstry Street in Napa on Wednesday. The flood gates closed in anticipation of the major storm approaching the Bay Area.

People gathered near the Napa River on Wednesday, before authorities closed the Oxbow Commons flood gates to turn the linear park into a flood relief channel during a major Bay Area storm.

A pedestrian using an umbrella walked past a sign warning of a flooding hazard at Oxbow Commons in Napa on Wednesday.

A pedestrian walked Wednesday along McKinstry Street in Napa, which was closed later in the day in preparation for shutting nearby flood gates that would turn the Oxbow Commons into a flood bypass for the Napa River downtown.

PHOTOS: For more images of Napa's preparation for the Bay Area storms, point your smartphone camera at the QR code, then tap the link.

WATCH: The Napa County Flood District in coordination with the City of Napa closed the Napa River Bypass Flood Gates just before 5 p.m. Some community members even pitched in to help secure the gates! The flood gates were closed due to the projected overflow onto the Oxbow Bypass. Video courtesy of Napa County

Updated at 4:51 p.m. Wednesday — California on Wednesday issued a state of emergency in response to an atmospheric river storm that was poised to carry heavy rainfall and powerful winds into Napa County and Northern California, posing a significant risk of flooding and other damage.

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National Weather Service forecasts for Napa County later Wednesday called for somewhat less rain than earlier predictions, but still advised residents to expect 1 to 1½ inches through Wednesday night, followed by another quarter- to half-inch Thursday and three-eighths to one inch on Friday.

A flood watch remained in effect for the Napa Valley and the entire Bay Area through 4 p.m. Thursday – as well as a high wind warning through 10 a.m. Thursday for gusts as strong as 60 mph in valleys and 80 mph at higher elevations.

"We anticipate that this may be one of the most challenging and impactful series of storms to touch down in California in the last five years," Nancy Ward, director of the state Office of Emergency Services, said during a news conference after the office of Gov. Gavin Newsom made the emergency declaration shortly after 11 a.m. "If the storm materializes as we anticipate, we could see widespread flooding, mudslides and power outages in many communities."

Karla Nemeth, director of the state Department of Water Resources, said extremely gusty winds are expected to be the primary force behind Wednesday and Thursday's storm damage.

"This is an extreme weather event, and we’re moving from extreme drought to extreme flooding," Nemeth said.

"What that means is a lot of our trees are stressed after three years of intensive drought, the ground is saturated and there is a significant chance of downed trees that will create significant problems — potentially flooding problems, potentially power problems."

Wade Crowfoot, California's natural resources secretary, said state and local officials were working simultaneously Wednesday to prepare for the coming storms while responding to damage and impacts from the major New Year's Eve storm.

The newest storm is the Bay Area's third since last Friday, and more are on the way. Scientists said conditions are lining up for a series of additional "pineapple express" storms in the next few days that could create conditions not seen since 2017.

That year, multiple atmospheric river storms drenched California in succession, culminating with a massive one in mid-February that ended the 2012-16 drought, wrecked the spillway at Oroville Dam and caused $100 million in flood damage in downtown San Jose.

At least two more such storms are shaping up for Saturday and Monday in Northern California, with more potentially coming the following week or two, said Marty Ralph, director of the Center for Western Weather and Water Extremes at UC San Diego, and one of the nation's leading experts on atmospheric rivers.

"If these storms continue to come onshore for the next two or three weeks, that will end the drought," he said.

Because soils have become saturated after steady December rains, billions of gallons of water are finally flowing into reservoirs, which remain at low levels from the drought, but are starting to rise, Ralph noted. Multiple atmospheric storms in succession also could cause major flooding, an issue that state officials highlighted Wednesday.

State transportation leaders during Wednesday's Cal OES news conference urged Californians not to traverse the roadways Wednesday or Thursday unless absolutely necessary.

"Stay home; avoid those nonessential trips, at least until the peak of this storm subsides," Caltrans director Tony Tavares said.

Caltrans and the California Highway Patrol "will be proactively closing roadways if we feel the conditions are unsafe," Tavares said.

Across Napa County and the rest of the Bay Area, heavy downpours accompanied by winds with gusts of up to 60 mph were expected later Wednesday and through Thursday and could cause flooding, downed trees and power outages, making driving conditions difficult, the National Weather Service said.

The storm comes days after a New Year's Eve downpour led to the evacuations of people in rural Northern California communities and the rescue of several motorists from flooded roads. A few levees south of Sacramento were damaged, increasing flooding in the mostly rural area.

"Excessive rainfall over already saturated soils will result in rapid rises on creeks, streams and rivers as well as flooding in urban areas," forecasters said in a report.

The storm, driven by moisture and winds forming over the Pacific Ocean, led the weather service to issue a flood watch and high wind warning for the entire Bay Area. In addition to the rains, winds are also expected between 20 and 40 mph in low-lying areas with gusts as high as 80 mph at higher elevations.

The Napa County Office of Emergency Services announced a winter weather watch starting Wednesday morning for the entire county, citing the potential for flooding and power outages as rainfall increases and wind speeds pick up.

As for potential flooding, the county Flood Control and Water Conservation District was preparing to close the Oxbow Commons flood bypass gates in downtown Napa at about 5 p.m. Wednesday. The city of Napa closed McKinstry Street, where the gates are located, at 1 p.m. ahead of the closing of the flood gates.

City and flood district officials predicted that water would enter the Oxbow bypass starting Thursday morning, and said McKinstry will likely remain closed through the weekend as the rains continue.

As of 3:30 p.m. Wednesday, the forecast for Napa River levels at Oak Knoll had been pulled back to below 20 feet, compared to the river's 25-foot flood-stage level. The bypass in the city of Napa usually flows when levels reach 22 feet.

Still, the closure of McKinstry Street running through the flood bypass was to proceed.

"These are just forecasts," said Richard Thomasser of the flood control district. "It's close enough to our 20-foot trigger (for closing) that we think it's just wise to follow through with our plan."

But based on forecasts at that point amid an unfolding situation, he didn't expect the bypass to flow.

Small streams could have some issues, Thomasser said. Predicted strong winds could down trees. Downed trees can completely block a small stream.

"Property owners who live along streams should be very cautious…be very watchful," he said.

Meanwhile, powerful winds will raise the risk of downed trees and power lines, and widespread power outages should be expected, the weather service said earlier. Travel will be difficult, especially for high-profile vehicles such as trucks and vans.

California Highway Patrol Officer Ross Lee advised drivers to take extra precautions as visibility can be low in intense storms. Drivers are always advised not to steer their vehicles through flooded intersections or other roadways, as waters may often be deeper than people realize.

"We’re advising people to remember to slow down, primarily," Lee said. "Make sure your vehicle is in proper functioning and working condition. That includes tires, lights and windshield wipers."

Pacific Gas & Electric Co., which reported having about 500,000 customers lose power during the New Year's Eve storms, said about 3,000 workers from the utility, contractors and other utilities are poised to respond to service interruptions during the storms expected this week. The effort includes 16 crews from Southern California Edison and mutual aid assistance from other West Coast utilities, PG&E said in a statement Tuesday night.

As of 12:15 p.m., 162 PG&E customers were without power in Napa, Sonoma and Marin counties, but more outages were expected as the storm's full force pushed through Northern California, according to Megan McFarland, spokesperson for the utility.

In Napa, Trancas Crossing Park became the city's first recreational space to close as a result of the storm, starting at 11 a.m., the city said in a Facebook post. The park will reopen when the flooding threat abates, officials said.

Officials in California ordered evacuations in a high-risk coastal area where mudslides killed 23 people in 2018 as a huge storm barreled into the state on Wednesday, bringing high winds and rain that threatened to knock out power and flood roadways.

The first evacuations were ordered for those living in areas burned by three recent wildfires in Santa Barbara County, where heavy rain forecast for overnight could cause widespread flooding and unleash debris flows. County officials did not have a firm number for how many people were under evacuation orders, but Susan Klein-Rothschild, a spokesperson in the county's emergency operations center, estimated it was in the hundreds.

Among the towns ordered to evacuate was Montecito, where five years ago huge boulders, mud and debris swept down mountains through the town to the shoreline, killing 23 people and destroying more than 100 homes. The town is home to many celebrities, including Oprah Winfrey and Prince Harry and his wife, Meghan.

"What we’re talking about here is a lot of water coming off the top of the hills, coming down into the creeks and streams and as it comes down, it gains momentum and that's what the initial danger is," Montecito Fire Department Chief Kevin Taylor said.

Elsewhere, a 45-mile (72-kilometer) stretch of the coastal Highway 1 that runs through Big Sur was closed Wednesday evening in anticipation of flooding and rock falls. Further north, a 25-mile (40-kilometer) stretch of Highway 101 was closed due to several downed trees.

For the latest forecast updates, visit weather.gov/bayarea.

This story includes reporting from Napa Valley Register city editor Howard Yune and reporter Barry Eberling, Bay City News Service reporter Eli Walsh, Bay Area News Group reporter Paul Rogers, Associated Press reporter Olga R. Rodriguez, and The Sacramento Bee.

A pedestrian walks by Wilford's in downtown Napa with the Napa river visible as the rain continues fall on Tuesday. The Bay Area woke up to another significant bout of rain and wind on Tuesday morning.

A pedestrian using an umbrella crossed the street in downtown Napa as rain continued to fall on Tuesday. The Bay Area woke up to another significant bout of rain and wind, including bursts of small hail.

A pedestrian crosses train tracks in downtown Napa as the rain continues fall on Tuesday. The Bay Area woke up to another significant bout of rain and wind on Tuesday morning.

Storm clouds hang over First Presbyterian Church in downtown Napa as the rain continues fall onTuesday. The Bay Area woke up to another significant bout of rain and wind on Tuesday morning.

Valerie Bez and her dog Maggie walk down the sidewalk in downtown Napa as the rain continues fall on Tuesday. The Bay Area woke up to another significant bout of rain and wind on Tuesday morning.

A pedestrian using an umbrella walks along the sidewalk in downtown Napa as the rain continues fall on Tuesday. The Bay Area woke up to another significant bout of rain and wind on Tuesday morning.

Pedestrians using an umbrella cross train tracks downtown Napa as the rain continues fall on Tuesday. The Bay Area woke up to another significant bout of rain and wind on Tuesday morning.

The First Presbyterian Church spire is seen reflected in a puddle in downtown Napa as the rain continues fall onTuesday. The Bay Area woke up to another significant bout of rain and wind on Tuesday morning.

A tree is seen reflected in a puddle in downtown Napa as the rain continued to fall earlier this week.

A pedestrian using an umbrella walked along a downtown Napa sidewalk Jan. 10, in the midst of a lengthy chain of rainstorms that swept through Northern California during the first half of the month.

Yountville town employees worked to contain flooding at Hopper Creek, which spilled over into the Oak Circle neighborhood Monday morning. The latest atmospheric river to enter the Bay Area brought more than 2 inches of rain to many parts of Napa County.

A pedestrian paused to look at a flooded street after Hopper Creek in Yountville spilled over on Monday.

The Mira Winery vineyard is seen flooded in Napa on Monday. The latest atmospheric river brought more rain and high winds to the Napa Valley causing some flooding and power outages.

A flooded section of Washington Street is seen in Yountville on Monday. The latest atmospheric river brought more rain and high winds to the Napa Valley causing some flooding and power outages.

A car passes along a flooded section of Washington Street in Napa on Monday. The latest atmospheric river brought more rain and high winds to the Napa Valley causing some flooding and power outages.

Pedestrians pare seen walking across a foot bridge above Hopper Creek which spilled over and flooded the Oak Circle neighborhood in Yountville spilled over on Monday. The latest atmospheric river brought more rain and high winds to the Napa Valley causing some flooding and power outages.

People walk along the Napa River and take photos in Napa as the river approaches flood level on Monday. The latest atmospheric river brought more rain and high winds to the Napa Valley causing some flooding and power outages.

People stood on the banks of the Oxbow Commons flood bypass near the Napa River on Monday.

A person takes photos of the Napa River from Oxbow Commons in Napa as the river approaches flood level on Monday. The latest atmospheric river brought more rain and high winds to the Napa Valley causing some flooding and power outages.

A Pedestrian walks along the Napa River through Oxbow Commons in Napa as the river approaches flood level on Monday. The latest atmospheric river brought more rain and high winds to the Napa Valley causing some flooding and power outages.

People are seen near police tape and restrictive signs erected to keep people from entering Oxbow Commons in Napa as the river approaches flood level on Monday. The latest atmospheric river brought more rain and high winds to the Napa Valley causing some flooding and power outages.

People are seen crossing the First Street bridge in downtown Napa as the Napa river approaches flood level on Monday. The latest atmospheric river brought more rain and high winds to the Napa Valley causing some flooding and power outages.

A crew works to open the Oxbow Commons flood gates Thursday after closing the Napa River downtown spillway the day before. Authorities planned to shut the gates again Saturday ahead of new Bay Area storms expected to raise the river level north of the city past 23 feet by Tuesday, less than two feet below flood stage.

A pedestrian walks toward Oxbow Commons after the flood gates were reopened less than 24 hours after being closed in Napa on Thursday. The city plans to close them again on Saturday as another band of significant rainfall heads towards the North Bay.

A Napa City employee is seen collecting fallen debris in Kennedy Park caused by strong winds which accompanied the most recent storm to slam into the Bay Area on Thursday.

People are seen taking photos of the Napa River from Oxbow Commons on Thursday. The Oxbow Commons flood gates were reopened on Thursday, but city officials say they will be closed again on Saturday as another wave of storms are suppose to hit the Bay Area.

The Napa Golf Course in Kennedy Park is seen flooded on Thursday.

Spectators watched as crews worked to close the Oxbow Commons flood gates on Wednesday while a powerful storm began passing through the Bay Area.

A pedestrian using an umbrella walked past a sign warning of a flooding hazard at Oxbow Commons in Napa on Wednesday.

People gathered near the Napa River on Wednesday, before authorities closed the Oxbow Commons flood gates to turn the linear park into a flood relief channel during a major Bay Area storm.

Leif Bryant a technician with the flood control district cleans dirt from the rivets of the Oxbow Commons Flood Gates near McKinstry Street in Napa on Wednesday. The flood gates will close today in anticipation of the major storm scheduled to hit the Bay Area starting Wednesday afternoon.

A pedestrian walks through Oxbow Commons in Napa on Wednesday. The Commons will be closed later today when the flood gates are closed in anticipation of the major storm scheduled to hit the Bay Area starting Wednesday afternoon.

Signs warning of a flooding hazard at Oxbow Commons are seen in Napa on Wednesday. The Commons will be closed later today when the flood gates are closed in anticipation of the major storm scheduled to hit the Bay Area starting Wednesday afternoon.

A view of the Oxbow Commons as the rain falls in Napa on Wednesday. The Commons will be closed later today when the flood gates are closed in anticipation of the major storm scheduled to hit the Bay Area starting Wednesday afternoon.

A pedestrian walking across the First Street Bridge looks down at Oxbow Commons in Napa on Wednesday. The Commons will be closed later today when the flood gates are closed in anticipation of the major storm scheduled to hit the Bay Area starting Wednesday afternoon.

Spectators gather in a steady rain to watch crews work to close the Oxbow Commons flood gates in Napa on Wednesday as a powerful storm slams into the Bay Area.

A spectator braves the rain to get video of crews woringk to close the Oxbow Commons flood gates in Napa on Wednesday as a powerful storm slams into the Bay Area.

Spectators gathered in a steady rain to watch crews work to close the Oxbow Commons flood gates in Napa on Wednesday evening, as a powerful storm bore down on the Bay Area.

Crews work to close the Oxbow Commons flood gates in Napa on Wednesday as a powerful storm slams into the Bay Area.

A crew worked to open the Oxbow Commons flood gates before noon Thursday in downtown Napa. The city and the Napa County flood control district plan to close them again Saturday afternoon ahead of another expected storm in the Bay Area.

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