Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 253 AM EST Sun Dec 20 2020 Valid 12Z Sun Dec 20 2020 - 12Z Tue Dec 22 2020 ...Heavy rain/flooding potential, snow in higher elevations, and high winds are all threats in the Northwest... ...Rain expected for the Southeast today while a couple of rounds of light mixed precipitation or snow affect the Midwest to Northeast... A persistent and strong moisture plume from the Pacific Ocean (atmospheric river) and a meandering front will continue to affect the Northwest over the next couple of days with potentially heavy precipitation. In coastal and lower elevations of the Pacific Northwest, multi-day rain totals of multiple inches could lead to flooding, and Flood Watches and Slight Risks of excessive rainfall are in place. Urban and small stream flooding are threats, as are landslides and debris flows. Despite relatively high snow levels, snow is forecast in higher elevations of the Northwest. The Washington Cascades can expect an additional 1 to 2 feet of snow while 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 are expected to come down by Monday night into Tuesday as an upper-level trough and cold front come in. Additionally, given the strong westerly flow, high winds are a threat across the Northern Rockies into northern and central portions of the High Plains today. Farther south, an Elevated Risk of fire weather is in place for Southern California, where low relative humidity exists. Rain showers and possibly a few thunderstorms are forecast for the Southeast today near a developing low pressure/frontal system. Rainfall amounts should be generally light, other than isolated totals of an inch or so over Florida. Farther north, ahead of another dissipating frontal system, rain and/or snow are possible across the Lower Great Lakes region and the Northeast today, with snowfall totals generally a couple of inches or less. Then, another surface low should move across the Northern Plains/Upper Midwest today and into the Great Lakes Monday, which should spread another round of light snow to those regions. Snow totals may be enhanced a bit across the Central Appalachians and downwind of Lake Ontario. Temperature-wise, close to the entire contiguous U.S. will see above normal temperatures today and Monday, with the exception of parts of the Eastern Seaboard today. The most anomalous temperatures are expected across the Northern/Central Plains, with temperatures 15 to 25 degrees above normal. Tate Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php