Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 330 AM EST Sun Dec 21 2014 Valid 12Z Sun Dec 21 2014 - 12Z Tue Dec 23 2014 ...Active weather across the northwestern U.S... ...Frontal boundary across the Gulf will bring showers and thunderstorms for several days in the Southeast... An atmospheric river is continuing to transport a plethora of moisture into the Pacific Northwest and the Intermountain West. This will transpire into heavy rains, especially along the coast, and orographic driven heavy snow across the Cascades and Rockies. A pacific front that has begun to move across northwestern Washington will keep pushing eastward across the region which will maintain active weather during Sunday and Monday. There is concern for flash flooding on Sunday along the coast of Washington, Oregon, and northern California (see the WPC excessive rainfall product for more detail). In addition, the WPC winter weather desk has indicated that snowfall amounts between 1 to 2 feet along the northern and central Rockies, in addition to the Cascades, is possible on Sunday and into Monday. As the front moves into the central U.S. by Monday night, expect lingering showers and snow showers across the Intermountain West. A stalled stationary front across the Gulf of Mexico and the Atlantic is bringing showers and thunderstorms to the Southeast. As the front pushes north as a warm front, precipitation will spread across the Texas coastline eastward toward the coastline of the Carolinas. By Sunday night, light to moderate showers and thunderstorms will concentrate along the Florida panhandle. This band of moderate precipitation will move eastward across northern Florida on Monday. By Monday night and into Tuesday, showers can be expected across the East Coast and most of Florida. For the most part, temperatures will stay slightly above normal for the western half of the country during the short term period. Portions of the southern Plains, Southeast, and East Coast can expect slightly cooler than normal temperatures. Fanning Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php