After a day with seemingly nothing to discuss yesterday, we’re returning to our familiar pattern of weak systems impacting parts of the Pacific Northwest, as well as parts of the East Coast. The southern fringe of a Pacific storm will bring rain and mountain snow to Washington today, while a cold front will help spark showers across parts of the Mississippi and Ohio river valleys.
The national overview map for today highlights our two areas of precipitation potential, as well as the very quiet pattern that will dominate the rest of the nation today. Rain and mountain snow across Washington and far NW Oregon will be of moderate intensity and low impact for everyone not travelling through the high passes today. If you are headed up and over the Cascades, watch for high elevation wintry weather and slippery roads due to the snowfall. Otherwise, it’s another rainy day in Seattle.
The cold front across the East will be similarly benign, and the ECMWF’s synoptic composite (what’s that and how do I use it?) shows why. While a decent theta-e (theta-e is a measure of heat/moisture) gradient is observed (note the shading contrasts from orange to green), there is little upper level support for the front, which will limit its ability to lift air parcels far and fast enough for impactful weather. The only upper level jet of significance is north of the border, where moderate snowfall is expected. The black lines show only a minor/gradual dip near the front, indicating weakness in the upper level energy available in the region. As a result, look for some light to moderate showers along the front today, but no significant impacts are expected due to that lack of upper level support.
Elsewhere across the country today, quiet weather is expected.
For more information on your local forecast: https://weather.us/
For more information on the local forecast for ME/NH: https://forecasterjack.com/2017/11/30/increasing-clouds-today-8/