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Dual Storms To Swipe California With Flooding Rain, Mountain Snow

There won't be any reprieve from the historically turbulent cold season in California with the end of winter.

The end of winter will not bring relief from a historically stormy cold season in California. AccuWeather meteorologists warn that twin storms early this week can deliver another round of significant precipitation, first to Northern California, then through the southern part of the state.

The first of these storms arrived Saturday evening. The rain spread across much of coastal Northern and Central California before working its way into interior sections, with moderate rain even being reported at times in cities such as Santa Rosa overnight. This particular storm will continue to deliver rain through Sunday, as the heaviest precipitation shifts inland and the system continues to drive onshore.

The flow of wind around this first storm as it tears across the Golden State will mean that the foothills of the Sierra Nevada will face an enhanced risk of heavy rainfall through the day as moist air is forced to rise across the higher terrain. This motion will also lead to heavy snowfall at higher elevations within the Sierra, where several inches of snow accumulation will be possible in spots through Sunday.

This first storm and its round of heavy rainfall are not classified as an atmospheric river, like some previous events. Despite this, any vigorous downpours could further exacerbate river flooding concerns in Northern California and any snow can make for difficult travel at times through the passes. Both, however, will continue to help improve the lingering drought in the region.

Last week’s report from the United States Drought Monitor placed roughly 36% of the state in drought, a value sharply lower from the 98% coverage that was reported in early October.

On Monday, the first storm will travel northeastward, giving California a small respite in between the two sides of the one-two punch of storms. ACCUWEATHER

The first storm will move northeastward on Monday, providing a brief reprieve for California in between the halves of the one-two punch of storms. 

The second storm appears rather quickly on Tuesday. This will bring an even more robust round of rain and mountain snow into Wednesday, including a greater risk of dangerous flooding to Southern California.

“Yet another atmospheric river event may unfold across a significant swath of California this week,” according to AccuWeather Meteorologist Mary Gilbert. Indeed, a stream of Pacific moisture is expected to burst onshore in Central and Southern California on Tuesday morning, with precipitation already ramping up in intensity as far north as the San Francisco Bay Area.

Ample availability of moisture could send rainfall amounts skyrocketing and lead to flooding issues. ACCUWEATHER

Unlike with the previous storm, a majority of the most robust tropical moisture from this event is likely to focus on Southern California, according to Gilbert, adding that ample availability of moisture could send rainfall amounts skyrocketing and lead to flooding issues.

Heavy rain is expected to affect the Los Angeles metropolitan area on Tuesday, with widespread flooding possible on streets and in poor drainage areas. As of March 18, downtown Los Angeles has picked up 24.06 inches of rain since November, a whopping 205% of their normal rainfall tally of 11.72 inches, and the upcoming rain will further boost area reservoir levels.

Heavy rain is expected to affect the Los Angeles metropolitan area on Tuesday, with widespread flooding possible on streets and in poor drainage areas. ACCUWEATHER

A bit farther west along the coast, Santa Barbara is in a similar position, having received 23.98 inches of rain since November, nearly double their typical total of 13.85 inches. This total includes the remarkable 4.22 inches of rain that fell on Jan. 9, causing numerous downed trees and power lines, landslides and washed-out roadways around Santa Barbara County in a previous atmospheric river event.

This rainfall surplus has even led to the relaxation of water restrictions in Southern California earlier this month, with this week’s rainfall serving to further reduce the strain on the area’s water supplies

“Given recent rains and saturated ground, the threshold for additional rainfall that can produce a significant risk for flooding is reduced. Creeks, streams and dry washes, especially in the higher elevations, can rise rapidly resulting in quickly escalating life-threatening flash flooding in some areas. Mudslides, rock slides and road closures may occur once again,” AccuWeather Chief Meteorologist Jonathan Porter said.

Between both storms, widespread rainfall amounts of 1-2 inches are expected across California, with some elevation areas likely to have a few inches. Some of the higher elevations in Southern California could end up with over 4 inches of rainfall through Wednesday, with an AccuWeather Local StormMax™ of 10 inches.

Rain and snow will not be the only hazards with this more powerful second storm, AccuWeather meteorologists say. Strong onshore winds will also accompany this potent disturbance on Tuesday, with gusts as high as 60 mph possible right along the coast from Point Conception through much of Ventura County and into the mountains of Los Angeles, San Bernardino and Riverside counties.

This storm’s precipitation is expected to taper off through Wednesday, with less coverage of precipitation Wednesday night before yet another storm Thursday into Friday offers an additional opportunity for too much rain and snow.

Produced in association with AccuWeather

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