Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 323 AM EST Mon Dec 22 2014 Valid 12Z Mon Dec 22 2014 - 12Z Wed Dec 24 2014 ***Developing storm system across the eastern U.S. this week*** ***Periods of rain and mountain snow for the northwest U.S.*** ***Showers and thunderstorms for the Gulf Coast states*** The upper level pattern for the beginning of the week will feature a building ridge over the southwest U.S. and a developing trough over the Central Plains and Midwest states. A well-defined closed low is expected to form across the middle Mississippi Valley by Monday evening. This will be the focus for unsettled weather over the Northern Plains and Upper Midwest where wintry precipitation is forecast, with several inches of snow from South Dakota eastward into Minnesota and northern Michigan. Given the strong upper level trough setting up over the central part of the country, a well defined cold front will advance eastward in time with showers and storms developing along and ahead of it. Some of these thunderstorms may become strong to severe along the Central/Eastern Gulf Coasts on Tuesday. A few rumbles of thunder are also possible from Tennessee to Virginia as the warmer air lifts northward. Out West, a brief break in the weather is expected for Monday across the Pacific Northwest before another system brings more rain and mountain snow to the region on Tuesday. Snow showers are also in the forecast for the central and northern Rockies as the current storm system moves farther east. Hamrick Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php