First major storm of the season could impact West Coast next week – AccuWeather.com/en/

The first week of November across the Pacific Northwest has proven to be much more active than conditions throughout October. A parade of storms have been sweeping through the area since the middle of last week with this storm train moving inland through Tuesday evening.

In the first week of November, locations like Seattle and Portland, Oregon, have already observed much higher amounts of precipitation than the monthly totals recorded for the entire month of October. Seattle has totaled just over 4 inches since the beginning of November, while Portland recorded rainfall amounts near the 4-inch mark, with additional rain falling across the region through Tuesday afternoon.

In western Washington and Oregon, relatively dry conditions over the summer put some locations on track for below historical average rainfall in 2023. As a result, a stretch of wet weather during the first week of November was the first notable period of rain of 2023 .several sites since the spring.

For example, residents of Redding, California, have not observed a three-day consecutive rainy period since May 4-6, while records from San Francisco show that the last rainy period occurred from May 1-4.

In Medford, Oregon, the last notable period of rain occurred April 21-23. During the summer months of June 1 to September 1, only 0.72 inches of rain was recorded in Medford, approximately 57% of the historical average during that period, and rain fell only intermittently.

Late week rain to moisten the coast

A respite of rain and mountain snow will arrive Tuesday night into Wednesday across the Northwest as a high pressure area expands in the sky. However, this short period of dry weather won’t last long, with another strong cold front on track to move inland by Thursday.

As the front approaches the Washington and Oregon coast Wednesday night and into early Thursday, offshore wind strength will increase significantly. Meteorologists urge boaters, especially inexperienced sailors and those operating small vessels, to be careful during this time, as winds can peak at 30 to 40 mph and waves can rise to dangerous levels.

Rain will be mainly concentrated along the coast from British Columbia to northwestern California from Thursday into Thursday evening. Following recent rounds of heavy rain, some locations may be more vulnerable to additional rainfall and flooding may be more likely.

Get your AccuWeather forecast

Rainfall totals are expected to range from 0.25 to 0.75 inches along the foothills of the Cascades and the Coastal Range where frontal tracks are onshore Thursday. Locally higher totals of about 1.00-1.25 inches can occur along the western slopes of the Olympic Mountains.

Cold air will accompany the storm and allow snowflakes to fall across the high terrain of the Olympic Mountains, Cascades and parts of Idaho’s northern Rockies.

“As is often the case when storms or cold fronts swing across the Cascades, snow levels tend to rise as the front approaches and then fall as the feature moves away from the area,” AccuWeather Senior Meteorologist Alex Sosnowski explained.

Snow levels in the Washington Cascades may rise to about 3,500 feet as this front approaches, and then may drop to about 3,000 feet, Sosnowski added. Motorists traveling through passes in Washington state may experience some travel disruption as a slush layer of up to a few inches of snow spreads across the high terrain. Forecasters say the highest peaks across the North Cascades could handle up to 3-6 inches of snow.

Looking Ahead: Another stormy period next week

Next week, additional rain and mountain snow chances will sweep across the West, this time likely to reach further south than recent storms.

Plunging southward into the jet stream could bring heavy rain to parts of California, Nevada and Utah as well as the Pacific Northwest. This shift in the pattern southward could provide a chance for the first major storm of the season across parts of California.

Although it’s still several days away, there’s growing concern among AccuWeather meteorologists that heavy rain, gusty winds and heavy mountain snow could hit full force next week.

“Heavy rain and gusty winds are expected along the central and northern California coasts. There could be periods of rain and some winds on the Southern California coast and western Oregon. “It is likely Heavy snow is measured in feet in parts of the Sierra.

Get the free ACCUWEATHER app

The heavy rainfall this storm could bring to the area could have a positive impact on wildfire risk over the next month or so.

“This (pattern) should pretty much put a lid on the fire season in central and northern California for the remainder of 2023,” Pastelok said.

Continue to monitor AccuWeather.com for updates on the developing storm next week.

Want the next level of security, without ads? Get advanced, hyper-local severe weather alerts when you subscribe to Premium+ on the AccuWeather app. AccuWeather™ Alerts are requested by our meteorologists who monitor and analyze dangerous weather risks 24/7 to keep you and your family safe.