Atmospheric river storm approaches California, Pacific Northwest; 1st week of fall to see rain

The arrival of an atmospheric river storm to California will coincide with the first week of fall. 

The National Weather Service said a low pressure system will help push the atmospheric river into the Bay Area and Northern California from the Pacific Northwest at the beginning of the week, bringing rain chances mostly in the North Bay. 

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While fall begins on the West Coast late Friday night, the earliest chances of rainfall would appear to begin early Monday morning. The approaching atmospheric river is expected to bring heavy rain and strong winds to Washington, Oregon, and the upper portion of Northern California.

The weather service said rainfall could reach half an inch per hour at times, accompanied by gusty southerly winds increasing ahead of the system.

ALSO READ: What is an atmospheric river, and what causes it? 

In the Bay Area, while most of the rain is expected in the North Bay, light showers could extend as far south as the Santa Clara Valley. As of Friday morning, the chance of Santa Rosa receiving rain early Monday morning was 45%, with rain more likely in the afternoon, the weather service said.

Winds around 15 mph are expected with the arrival of the storm system, with gusts up to 20-25 mph possible over the North Bay, according to the weather service.

Rain is also expected to fall in the Sacramento Valley, mostly north of the capital.

During the next few days, temperatures should continue to be cooler than normal, with daytime highs in the mid to upper 70s inland and the low 60s along the coast.

Lows are expected to range from the upper 40s to mid 50s, according to the weather service.

In:
• Atmospheric River
• Oregon
• California
• Washington