Cool, unsettled pattern setting up over the Western states

Residents from Portland, Oregon, southward to San Francisco and Los Angeles, and inland to Salt Lake City will want to keep an umbrella handy throughout the week as showers are likely to swoop in on more than one occasion.

AccuWeather Global Weather Center – March 8, 2021 – As the calendar seemingly jumps to April across the eastern half of the nation this week, the West will be stuck in a cool and dreary pattern with rain, snow and even hail showers expected each day.

A storm system lurking just offshore Monday and Tuesday will slowly pivot southeastward and inland across California and the Southwest during the latter half of the week. Once over land, it will sit, spin and churn out days of unsettled weather.

In this satellite loop from early Monday morning, March 8, 2021, a swirl of clouds is seen off the Pacific Northwest coast. This swirl of clouds is associated with the slow-moving storm expected to bring days of unsettled weather to the West this week. (NOAA/GOES-WEST)

Rain showers at lower elevations and snow showers higher up will accompany the storm’s slow journey across the region.

The greatest risk for widespread showers and dampened outdoor plans will be Tuesday through Wednesday around San Francisco, and Wednesday through Thursday for Los Angeles and San Diego.

“Rain and snow will spread across Nevada and the Four Corners states late Wednesday and Thursday,” AccuWeather Lead Long-Range Meteorologist Paul Pastelok said.

Preceding any rain in the Desert Southwest will be gusty winds and a heightened fire danger into the middle of the week, as the air is stirred up well ahead of the storm system.

“There is not an abundance of moisture to work with and no atmospheric river to cause excessive rain with this storm,” AccuWeather Senior Meteorologist Mike Doll said.

Despite this, the cumulative effect of the showers and potential for more robust downpours could yield rainfall totals of 0.50-1.00 inch for coastal areas of California into late week. Lesser amounts are expected farther inland across the Southwest.

“West- and southwest-facing slopes in the coast ranges could receive well over an inch of rain,” Doll said.

Although most of this rainfall will be beneficial due to meager precipitation totals during the winter months and the ongoing drought, it is possible for heavier downpours to trigger localized flooding concerns, especially near burn scar areas. Motorists will want to slow down on the highways amid any downpours to reduce the risk of hydroplaning.