Short Range Weather Forecast

A long-duration winter storm will impact the Northwest through the weekend.

Short Range Weather Forecast

Long Duration Winter Storm for the Pacific Northwest; Heavy Rains in the Southeast and Hawaii

A long-duration winter storm will impact the Northwest through the weekend. The coastal ranges and lower elevations of the Cascades will have moderate to heavy rain, and periods of heavy snow will impact many mountain passes. Scattered storms and heavy rains may produce localized flash flooding across the central Gulf Coast into the Southeast and Hawaii.

...Multi-day winter storm will impact travel in the Northwest with significant mountain snow and heavy rain...

...Unsettled weather forecast across the eastern third of the country with heavy rain potential along the Gulf Coast and Southeast, while wintry weather is expected from parts of the Midwest and Great Lakes to northern New England...

Meteorological winter is off to a fast start across much of the Northwest, Great Basin, and Rockies as plentiful moisture streams inland from the Pacific Ocean over at least the next few days. The specific region seeing the most impacts from heavy mountain snow and heavy rain will be the Pacific Northwest, where a strong atmospheric river is expected to wallop the region on Sunday after continuous instances of moderate precipitation  today and Saturday. Total rainfall amounts through this weekend are expected to approach 5 to 10 inches along the coastal ranges of western Washington and Oregon, with several inches of rain also expected for places such as Portland, OR and Seattle, WA. Heavy snow likely adding up to at least a few feet is expected across the Cascades, including many mountain passes. Travel will be difficult to hazardous due to both heavy snow and blowing snow. Snow levels are expected to increase by Saturday night and throughout the day on Sunday, leading to heavy rain on top of recent snowfall throughout the Cascades. This combination of heavy rain and snowmelt on Sunday will likely produce minor to moderate river flooding.

Heavy snow potential will also extend into the mountainous terrain of the  Great Basin and Rockies as leftover moisture transport continues to slide eastward from the Pacific. Heavy snow is likely to reach into several mountain ranges from Idaho and Montana to Colorado. The highest peaks are forecast see as much as 1 to 3 feet of snow. Winter Storm Warnings and Winter Weather Advisories have been issued for areas most likely to see impactful and/or hazardous snowfall.

An increasing southwesterly jet stream over the eastern U.S. will allow for unsettled and mild weather to overspread the region during the first weekend of December. An initial system is forecast to progress from the Midwest to the Great Lakes by Saturday as another developing system right on its heels enters the Great Lakes on Sunday. Overall, light rain is expected across the Ohio Valley, Appalachians, Northeast, and Mid-Atlantic. However, elevated atmospheric moisture content and instability may lead to locally heavy rainfall and thunderstorms along the Gulf Coast today. This threat of heavy rainfall then pushes farther north into the Southeast on Saturday ahead of a central U.S. upper trough. Farther north, wintry weather is expected on the northern periphery of the precipitation shield as cold air remains in place due to a stretched out high pressure system extending into southeast Canada. Mostly light and localized snowfall is expected from parts of eastern Iowa to the Lower Peninsula of Michigan through tonight. Heavier snow is possible across northern New England on Monday, where modest probabilities (40-60%) for greater than 4 inches of snow exist between northern New Hampshire and northern Maine.

Elsewhere, mostly dry conditions are expected across the central and southwestern United States. Below average temperatures are also anticipated to be confined to the central Plains and West through the beginning of the weekend, with above average temperatures throughout the remainder of the CONUS.