Share this article:
A return of storms to the northwestern United States will deliver drenching rain and wintry travel hazards this week.
“An atmospheric river of moisture originating near the tropics in the West Pacific Ocean will stretch across the Pacific and help fuel heavy rain across the Northwest through Wednesday,” according to AccuWeather Meteorologist Jordan Root.
Weather-related delays to ground and air travel can be anticipated.
Along the coast, there will be the risk of flash and urban flooding, strong winds, mudslides and continuing erosion. Farther inland, travel problems will result from snow, ice and rain.
The track of the storms will bring milder conditions and rain with some exceptions along the Interstate 5 corridor of the Northwest.
Rainfall generally totaling 2 to 4 inches will otherwise soak Portland, Oregon, and the other cities along Interstate 5 including Seattle and Olympia, Washington, and Salem and Eugene, Oregon.
Widespread flash flooding will threaten places along the coast and the western slopes of the northern Cascade Mountains, where rainfall should total 4-8 inches. Some rivers and streams may overflow their banks.
However, many of the rivers in western Washington are running at their lowest levels since the end of the summer, according to the National Weather Service in Seattle.
Northwestern US interactive radar
Snowplow clipped by tractor-trailer plummets off 300-foot cliff
Weekly wrap-up: Police issue tickets after motorists abandon vehicles in Oregon snow; Storms bust northern California drought
The rain will be windswept at times. The strength of the winds toward midweek could lead to sporadic tree damage and power outages along the coast. Seas will build as the winds howl, threatening to cause beach erosion.
Snow levels will rise well above the mountain passes early this week, meaning motorists traveling through Snoqualmie Pass along Interstate 90 will face water on roads and reduced visibility from downpours and fog instead of a snow-covered highway.
“This will not be a big snow event for the Cascades except for the highest peaks as snow levels will rise to between 7,000 and 7,500 feet on Tuesday,” AccuWeather Senior Meteorologist Dan Baker said.
Several hours of freezing rain can be enough to cause dangerous travel and power outages from Portland, Oregon, eastward through the Columbia River Gorge along I-84.
Motorists venturing east of the Cascades will face a significant hazard due an extended period of ice in the valleys of northern Oregon and southern Washington.
Travel will be treacherous around Ellensburg and Wenatchee, Washington. Slippery roads and sidewalks may persist for a few hours after the air temperature rises above freezing. In these areas, a significant buildup of ice is likely with extensive power outages.
The risk of ice will extend to Pendleton, Oregon, as well as along Interstate 90 to Spokane, Washington, and into western Montana, before an eventual changeover to rain.
Wintry weather may become more extensive over the Northwest by this weekend.
“The jet stream (a fast-moving river of air along which storms travel) will take a dip across the West during midweek and will help bring colder air farther south,” Root said. “That will lower snow levels and allow snow to pile up across the Cascades later in the week.”
Periods of rain, albeit not as heavy as earlier in the week, will continue to dampen the Interstate 5 corridor late this week.
While dry weather will hold across California early this week, the second half of the week will turn stormy.
Comments that don't add to the conversation may be automatically or manually removed by Facebook or AccuWeather. Profanity, personal attacks, and spam will not be tolerated.
The intense record heat baking the south-central United States is expected to get trimmed back early this week, but a sweep of refreshing air is not on the horizon.
This weekend’s rainstorm was only the start of an abnormally wet pattern that will elevate the flood risk in the eastern United States into the end of the month.
Despite NASCAR moving up the start time of the Foxwoods Resort Casino 301, rain has hung on and delayed the race at Loudon, New Hampshire.
Yet another round of severe weather is threatening the southeastern United States to close out this weekend.
The remainder of July will be dominated by a resurgence of heat across the northwestern United States.
An uptick in monsoon rainfall is expected to heighten the flood threat across eastern and northern India this week.
A deadly heat wave is expected to continue into early week across Japan.