Snow, Flood-Fatigued West To Be Pounded By Another Atmospheric River Event Next Week

Linda Lam
Published: January 14,2017
Another atmospheric river event is expected to take aim at the West Coast by midweek, bringing more locally heavy rain and mountain snow.
The active pattern that has brought flooding and prolific snow will return next week, after a brief break that will last through this weekend. A weak upper-level ridge of high pressure will allow mainly dry conditions to persist through the weekend, along with slightly warmer temperatures.
Then, a weather pattern change will lead to a southward plunge of the jet stream developing over the eastern Pacific, guiding a series of low pressure systems into the West next week, beginning with the Pacific Northwest on Monday.

Setup midweek that will bring heavy rain and snow to the West.

Heavy rain and snow is possible as a strong jet stream with a long plume of moisture, or an atmospheric river, is expected to take aim at the West coast once again in the Tuesday through Thursday timeframe.
(MORE: What Is an Atmospheric River)
The forecast details will change given that we are several days away from the next round of precipitation so be sure to check back with weather.com for updates.

Tuesday

Tuesday's Forecast

• Wet and windy weather will stretch from western Washington into far northern California beginning Monday night.
• Snow levels will rise up to 6,000  to 8,000 feet in the Cascades, resulting in snowmelt. This snowmelt combine with any heavy rainfall will increase the chance for flooding.
• Freezing rain is possible in the Columbia River Gorge and Upper Hood River Valley Monday night into Tuesday. Cold air trapped in other areas of eastern Washington, eastern Oregon and western Idaho could also lead to some icy conditions.

(FORECAST: Seattle | Medford, Oregon | Boise, Idaho)

Wednesday

Wednesday's Forecast

• Moderate to heavy rain and snow will spread farther south and east across California, likely reaching as far south as Southern California by Wednesday night.
• Snow will spread into parts of the inter-mountain West and Rockies.
• Snow levels will remain high in the Cascades and above 7000 feet in the Sierra.
• Windy conditions are also expected.

(FORECAST: San Francisco | South Lake Tahoe | Portland, Oregon)

Thursday

Thursday's Forecast

• Showers will continue in California and the Northwest.
• Heavy snow is also expected in the West and snow levels will lower to between 2000 and 4000 feet in the Cascades and Sierra.
• Winds will be gusty once again, especially along the coast and into parts of Southern California.

Friday

• Another strong low pressure system may approach the West Coast.
• This could result in additional bouts of heavy rain, mountain snow and strong winds.

(FORECAST: Sacramento | Reno, Nevada | Los Angeles)
Contrasting with last week, heavy rainfall of at least 3 inches is expected below snow level in western Washington and western Oregon, as well as parts of northwest California.
Snow in the higher elevations will also easily pile up to 1 to 2 feet.

Rain and Snow Forecast

Water levels on rivers and streams will likely have receded by the time this next round of rain moves in, but due to the saturated soil any heavy rain will bring the risk of flooding, especially in areas that saw flooding this past week.
There is also concern for rain falling on areas of existing heavy snowpack, including in the Portland, Oregon, metro area, where up to 15.5 inches of snow fell from Winter Storm Jupiter.
The good news is that this active weather pattern will continue to help improve drought conditions. Most of northern California is no longer in drought, but central and southern California still need substantial rain and snow to bring an end to the drought.
(MORE: Storms End Drought in Much of Northern California)

MORE: Flooding in California and Nevada (PHOTOS)