Warning: file_put_contents(): Only -1 of 122 bytes written, possibly out of free disk space in /srv/users/newsbrig/apps/thehamdenjournal/public/wp-content/plugins/wp-optimize/includes/class-wp-optimize-htaccess.php on line 136

Warning: file_put_contents(): Only -1 of 122 bytes written, possibly out of free disk space in /srv/users/newsbrig/apps/thehamdenjournal/public/wp-content/plugins/wp-optimize/includes/class-wp-optimize-htaccess.php on line 136
Downpour coming to Sacramento as another atmospheric river hits California. Here’s when – The Hamden Journal

Downpour coming to Sacramento as another atmospheric river hits California. Here’s when

Already well above its historic average for December, there’s plenty more rain coming to Sacramento to end 2022 — and to kick off 2023 — as a strong atmospheric river headlines another batch of storms set to pound Northern California in the coming days.

Sacramento could get about three-quarters of an inch of rain Friday, intensifying in the evening. A downpour is expected Saturday, with between 1-2 inches possible, National Weather Service forecasts show.

Parts of the Sacramento Valley could get up to 4 inches between those two days, forecasts show, with up to 7 inches anticipated in the foothills and 9 inches of precipitation in parts of the Sierra Nevada mountains.

Those amounts prompted the weather service to issue a flood watch, in place from 4 p.m. Friday through 4 a.m. Sunday for the vast majority of Northern California, including the entire Sacramento Valley, all of the Bay Area, the Sierra Nevada foothills and northern portions of the San Joaquin Valley.

Water is released at Nimbus Dam on the American River on Friday. The operation of Folsom Dam upstream shifted to flood control operations on Thursday to make space in the reservoir for inflows from the expected major storm. Flows on the river were expected to increase from 8,000 cubic feet per second on Friday morning to approximately 25,000 cfs by evening – potentially causing hazardous conditions along the river and at Lake Natoma.

Drivers should be alert for difficult travel conditions, including localized roadway flooding, especially near rivers, creeks and stream.

After a sunny New Year’s Day reprieve Sunday, another storm track will likely bring rain starting Monday and continuing through at least Thursday in the capital city, with amounts not yet settled.

The end-of-year atmospheric river will likely propel Sacramento well past double its average of about 3 ½ inches for December. Downtown Sacramento had already recorded about 6 ½ inches for the month through Thursday, with nearly 2 inches of that total falling since Monday, according to the weather service.

What about Sierra snow?

Up to a foot of snow is anticipated across most of the central Sierra Nevada range, with snow levels above 7,500 feet on Friday lowering to about 4,500 feet by Saturday evening, the weather service said.

Much higher totals — up to about 4 or 5 feet of snow — could fall south of the Tahoe area, including near Carson Pass and Ebbetts Pass, according to the weather service. Chain controls and significant delays are likely for mountain travelers.

What’s an atmospheric river, again?

The current storm is the product of an atmospheric river — a long, narrow band of moisture in the atmosphere that can unleash heavy precipitation in a short time frame.

Many of California’s biggest rainstorms in recent years have been caused by atmospheric rivers off the Pacific coast, including Sacramento’s rainiest day ever in October 2021. An atmospheric river also caused the storm earlier this week in Northern California, which included howling winds in the valley and gusts above 100 mph at some mountain peaks.

A relatively new scale used to rank the intensity of atmospheric river storms, introduced in 2019 by Scripps Institution of Oceanography’s Center for Western Weather and Water Extremes, shows the coming weekend storm as a Category 3 atmospheric river across most of California and a Category 4 storm in some regions, including part of the Bay Area.

Per the scale, a Category 3 storm is a “balance of beneficial and hazardous.” Atmospheric rivers can be beneficial by helping to ease California’s drought conditions, but hazardous when they are so powerful that they create high flood risk.

A Category 4 atmospheric river storm is “mostly hazardous, also beneficial,” while a Category 5, the highest on the scale, is denoted as “primarily hazardous.”