Pattern Shift Likely to Bring Much-Needed Rain, Snow to Parts of California, the West Into Next Week

 Linda Lam

Published: March 5, 2021

Multiple rounds of much-needed rain and mountain snow will push into California through early next week as a weather pattern change develops along the West Coast.

Southern California saw rain, thunderstorms and mountain snow from an initial system that moved into the Southwest on Wednesday. On Thursday, rain and snow from that system fell in parts of Utah, northeastern Arizona, northern New Mexico into southern Wyoming, eastern Colorado and the Central Plains.

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This wetter pattern will continue and become more widespread for parts of California and the interior West into next week. Here's the latest on what to expect.

Wetter Pattern

The next system is arriving in the Pacific Northwest and Northern California coasts.

Rain will stretch from western Washington and western Oregon into Northern California into Saturday, with snow in the higher elevations.

A southward dip in the jet stream will then take hold along the West Coast next week, and multiple disturbances will bring the chance for more rain and mountain snow to parts of California and the Northwest.

Additional rounds of rain and mountain snow will spread across California Monday into Wednesday.

Tuesday's Forecast

Most areas outside of the Pacific Northwest can expect light to moderate rain and snow over the next week or so, although heavier precipitation may develop from parts of southwestern Oregon into portions of Northern California. However, a major storm does not appear likely.

However, there is the "potential for significant amounts of rain along with mountain snow down to perhaps as low as 3,000 feet," the National Weather Service in Los Angeles notes for next week.

Snow and Rain Outlook

There are signs for above average precipitation in parts of the Southwest into mid-March. In Southern California and parts of the interior West, the chance of precipitation is higher than average through next weekend, according to NOAA's Climate Prediction Center.

Along with the increase in precipitation, cooler than average temperatures will accompany this pattern change for most of the West next week.

Precipitation Outlook

Much-Needed Precipitation

Winter (December-February) was drier than usual for most locations west of the Rockies.

Two-thirds of the region was in drought when fall began, and drought conditions have grown and intensified. About 80% of the West is in drought and 20% of the region is in exceptional drought, the highest category, according to the U.S. Drought Monitor.

Current snow water equivalents (estimate of the water content in the snowpack) are below average through the Sierra Nevada mountains, Utah, western Colorado, Arizona and New Mexico, as shown in the red, orange and yellow areas on the map below. Locations shaded in green are close to average. Blue areas are above average.

Statewide snowpack in California was just 61% of the average for March 2, according to a survey from the Department of Water Resources.

Snowmelt during the summer and early fall is important in the West because it recharges reservoirs and rivers.

The storm track this season has brought plentiful moisture into the Northwest, but California and the Southwest have not received as much compared to average.

A wetter pattern will bring beneficial moisture to California and the Southwest. Concerns for flooding and debris flows are lessened because a strong storm is not anticipated.

Status of snowpack in the West, expressed as a percent of the average water content of snow, as of March 1, 2021.

The Weather Company’s primary journalistic mission is to report on breaking weather news, the environment and the importance of science to our lives. This story does not necessarily represent the position of our parent company, IBM.

The Weather Company’s primary journalistic mission is to report on breaking weather news, the environment and the importance of science to our lives. This story does not necessarily represent the position of our parent company, IBM.