A storm system will dive southward from the Northwest to the Southwest into early this week, bringing rain, mountain snow and a shot of chilly air.
A parade of storm systems have brought much-needed rain to parts of the Northwest since Friday and will continue to do so through Sunday.
Rain amounts across Washington ranged between 1 to as much as 4 inches across the state, including Olympia, Tacoma and Seattle since Friday. Quillayute, Washington, received over 4.5 inches of rain while 5.5 inches of rain fell at Stampede Pass.
Portland, Oregon, has received over 2 inches of rain since Friday.
While the rain ruined some outdoor Halloween plans across the Northwest, the rain was a welcome sight as much of the region lies in a severe or extreme drought, according to the U.S. Drought Monitor.
Aside from the heavy rain, strong winds battered the region since Friday. Winds gusted between 50 and 70 mph at times in areas with this storm.
Rain will continue across the Northwest to end the weekend. As cooler air dives in, snow levels will drop significantly from between 7,000 and 8,000 feet on Friday into Saturday to about 4,000 feet on Sunday.
According to AccuWeather Meteorologist Michael Doll, "The passes above 5,000 feet through the Washington Cascades will be slippery and snow covered into Sunday night."
"As snow levels fall toward 4,000 feet late Sunday, those planning on traveling through Stevens Pass, Cayuse Pass and White Pass, should be prepared for worsening driving conditions, he added.
Accumulating snow will develop across the Cascades of Washington and Oregon; the Bitterroot Mountains of Idaho; and the Cabinet Mountains and Lewis Range of Montana.
"There could be as much as 6 inches of snow down to 4,000 feet by Monday morning," Doll said. "Snowqualmie Pass along Interstate 90 will likely stay wet with precipitation falling as rain through tonight."
Travel could become dangerous at times along the passes in Washington and western Montana.
Rain, along with falling leaves, could produce slick spots on roadways.
In addition to the slick roads, there is the potential for mudslides and other debris on the roadways. The bulk of the mudslide risk will be along the western slopes of the Cascades.
Drivers should slow down through any wet roadway to reduce the risk for hydroplaning.
Use AccuWeather Minutecast® for the minute-by-minute precipitation forecast for your area. Mobile users can also use their GPS location.
The storm system causing this weather will drop southward from the Northwest to the Southwest bringing rain into much of California.
By Monday, rain and mountain snow will build into Nevada and California. Wet weather will also develop across southern Idaho into northern Wyoming.
There will still be the threat for a spotty shower across the Northwest on Monday, but it won't be as heavy as the rain over the last three days.
Cities such as San Francisco, Los Angeles and Fresno, California, and Reno, Nevada, will deal with wet weather heading into the new workweek.
Heavy snow will fall across the Sierra Nevada as snow totals could exceed 6 inches through Monday.
Similar to the Northwest, any rain will be beneficial to the extreme drought across the Southwest.
By Tuesday, the storm will move into the central Rockies with more rain and accumulating mountain snow.
This storm system will also be responsible for bringing a shot of chilly air to the western U.S. through at least midweek.
According to AccuWeather Senior Meteorologist Alex Sosnowski, "In the West, temperatures early this week will range from 5 to 10 degrees below normal during the first two weeks of November."
By Tuesday, high temperatures will be held into the 40s from Billings, Montana, to Seattle; Salt Lake City; Flagstaff, Arizona; and Reno, Nevada.
Los Angeles may fail to reach 70 F for the first time since May 26, 2015.
Parts of the West haven't seen temperatures this low since last spring.
While the chilly air blasts the western U.S., a warmup will take place across the eastern U.S..