Flood watches issued as soaking storm moves over Southern California

Frequent storms that have affected the Pacific Northwest over the past few months have ended the drought in much of western and central Washington and northwestern Oregon. In California, much of the state is still in the throes of a long-term drought, but the Golden State has been getting needed relief in December.

In the central Sierra Nevada, storms this month have deposited yards of snow. In the Donner Summit area of Lake Tahoe, California, more than 17 feet of snow has fallen, resulting in a new December record. The old December snowfall record of 179 inches was last set in 1970. This snowfall and more that follows during the winter will go a long way toward filling rivers and reservoirs in the region when spring arrives.

Nearly 80% of California, including Los Angeles County, is currently dealing with extreme drought conditions, according to the U.S. Drought Monitor, a figure which is down from 83% at the start of November.

The percentage of the state in exceptional drought, the most intense classification of drought, dropped from 28.27% to 23.11% from Dec. 14 to Dec. 21 and is down from about 37% in mid-November.

Farther south, drought conditions are less intense in parts of San Diego County where moderate drought conditions exist, according to the weekly report.

Regardless of drought classification, much more rainfall is needed in the state in order to help eat away at the drought, and AccuWeather forecasters say that more precipitation is on the way.

"A potent storm is bringing more rain to the Southwest this week, impacting major cities such as Los Angeles and San Diego," said AccuWeather Meteorologist Jessica Storm.

It has been a wet December in much of Southern California. For example, after just 4.81 inches of rain total between January and November, Downtown Los Angeles has received 6.89 inches of rain in December alone. Despite the wet month, the city is still experiencing a rainfall deficit for the year.

"As the year comes to a close, Los Angeles has reported only 82% of its average rainfall for 2021 as much of California is experiencing extreme drought," stated Storm.

Rain has not fallen since Sunday in Los Angeles, but that short break is about to come to an end.

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"The heaviest rain is expected to fall in the Los Angeles basin from Wednesday night into Thursday, with a total of 1-3 inches," said Storm.

Not only will rain douse Los Angeles and San Diego, but locally heavy rain is also expected in locations where wildfires raged this past summer and fall. This will raise the risk for flash flooding and debris flows in any burn scar areas where heavy rain falls over a short period of time.

"Those who live near recent burn areas should take some time ahead of the rain to make a plan and be ready to evacuate if needed," said Storm.

A flood watch is currently in place for cities including Anaheim, Riverside and Newport Beach.

In the mountains, colder air will cause precipitation to fall in the form of snow. This could bring snow to parts of Interstate 5, although that heaviest snow should fall above areas 4,500 feet in elevation.

"Anyone traveling through the mountains should keep a winter kit in their car for possible emergencies, and cars should be cleared of snow and ice before getting on the road," said Storm.

In the highest elevations, 1-2 feet of snow are possible. This will continue to increase the snowpack, which will melt in the spring and provide a boost to the low reservoir levels. However, the snow will make travel difficult through the mountains and passes.

By the end of the week, precipitation will move into Utah, Colorado, Arizona and western New Mexico. This will bring beneficial rain to locations such as Phoenix and Tucson, Arizona. Snow will fall in Flagstaff, Arizona, and northward to Salt Lake City. The same storm is likely to produce a 2,700-mile-long swath of accumulating snow and travel disruptions from the mountains of Southern California and northern Arizona to the Great Lakes and the eastern provinces of Canada during the New Year's weekend, AccuWeather Senior Meteorologist Alex Sosnowski said.

Following this storm, several dry days are in store for California. However, below-normal temperatures will lead to the potential of a frost or a freeze in some of the valleys of the state. Sacramento could drop to or below freezing on both Friday night and Saturday night.

Precipitation is expected to return to Northern and Central California by Monday or Tuesday, but dry weather may continue in Southern California until the middle of next week.

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