Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 324 PM EST Sun Dec 20 2020 Valid 00Z Mon Dec 21 2020 - 00Z Wed Dec 23 2020 ...Higher elevation snow and a Slight Risk of excessive rainfall over parts of the Northwest... ...Rain for parts of the Southeast and Southern Mid-Atlantic while a couple of rounds of light mixed precipitation or snow affect the Midwest to Northeast... Onshore-flow streams Pacific moisture into the Northwest that will slowly weaken after the next front comes onshore on Monday evening. The WPC has issued a Slight Risk of excessive rainfall over parts of the Pacific Northwest through Monday. The heavy rain associated with the system may produce scattered flooding areas where urban areas, roads, and small streams will be the most vulnerable. The heavy rain may also produce landslides and debris flows. Despite relatively high snow levels, snow will develop in higher elevations of the Northwest. The Washington Cascades can expect an additional 1 to 2 feet of snow. At the same time, the Northern Rockies, Sawtooth Mountains/Bitterroots, and Wind River Mountains/Tetons could see 6 to 12 inches of snow with locally higher amounts through Tuesday morning. Snow levels will lower by Monday night into Tuesday as an upper-level trough and cold front move in. Farther south, an Elevated Risk of fire weather is in place for Southern California through Monday morning, where low relative humidity exists. A developing area of low pressure off the Southeast Coast will help produce showers and a few thunderstorms over parts of the Southeast and Southern Mid-Atlantic Coast through Monday. Farther north, weak upper-level energy will help create rain and snow across parts of the Lower Great Lakes and the Northeast, with the snow generally totaling an inch or so. In addition, an area of low pressure over the Northern Plains will move eastward to the Mid-Atlantic, and the associated front will dissipate by Tuesday morning. The system will produce rain and snow over parts of the Northern Plains that will move into the Great Lakes/Ohio Valley by Monday afternoon. Overnight Monday, the system will produce light snow over parts of Eastern Ohio Valley/Central Appalachians and Lower Great Lakes that will slowly taper off on Tuesday. Elsewhere, temperatures will be 10 to 20 degrees above average over parts of the Northern High Plains into parts of the Upper Midwest. 5Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php