Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 330 AM EST Tue Dec 23 2014 Valid 12Z Tue Dec 23 2014 - 12Z Thu Dec 25 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 middle of the week will feature a building trough over the Central Plains and Midwest states, and another trough near the West Coast by Thursday. The central U.S. trough will dig south over the Gulf of Mexico, and result in the development of a surface low that will intensify as it lifts northward towards the Great Lakes. 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 possible from the Dakotas eastward into 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. It will also get warmer along the East Coast on Wednesday before the cold front moves through. Out West, another system is forecast to bring more rain and mountain snow to the Pacific Northwest and northern Rockies for Tuesday and Wednesday. As the cold front settles southeastward and the upper level trough axis becomes situated over the Intermountain West, rain and snow will also develop over northern California and into Nevada and Utah. Hamrick Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php