Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 326 PM EST Sat Dec 19 2020 Valid 00Z Sun Dec 20 2020 - 00Z Tue Dec 22 2020 ...There is a Slight Risk of excessive rainfall over parts of the Pacific Northwest... ...Rain and thunderstorms spread across the Southern Plains while light snow spreads across the Upper Midwest into the Northeast... A front moves into the Pacific Northwest accompanied by a stream of moisture will help produce rain and higher elevation snow across the Pacific Northwest into the Northern Intermountain Region. The WPC has issued a Slight Risk of excessive rainfall over parts of the Pacific Northwest through Tuesday. The Heavy rain associated with the system will produce mainly localized scattered areas of Flash Flooding where urban areas, roads, and small streams will be the most vulnerable to Flash Flooding. Besides, despite relatively high snow levels, snow is likely at higher elevations of Washington's Cascades and toward the Northern Rockies. Snow amounts through Monday morning are likely to be over a foot in the Cascades, with 12 to 18 inches in the Northern Rockies, Sawtooth Mountains/Bitterroots, and the Wind River Mountains/Tetons. Additionally, high winds are a threat across the Northern Rockies toward Northern and Central High Plains through Sunday afternoon with the strong westerly flow. Farther south, an Elevated Risk of fire weather is in place for Southern California, where low relative humidity exists. A front will move eastward from the Great Lakes to the Central Gulf Coast will dissipate overnight Saturday, giving way to a front forming just offshore of the Eastern Seaboard on Sunday. Precipitation should move west to east across much of the Central and Eastern U.S. through Monday associated with these fronts and as Gulf of Mexico moisture streams northward. Rain is expected in the Middle/Lower Mississippi Valley, Tennessee Valley, Lower Ohio Valley, and Southeast. Some thunderstorms are possible across Texas and Louisiana. To the north over the Upper Great Lakes to the interior Northeast, snow or mixed precipitation is forecast. Snow amounts should generally be a couple of inches or less. Additionally, temperatures across the Northern High Plains will be 10 to 25 degrees above average on Sunday. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php