Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 235 AM EST Wed Dec 31 2014 Valid 12Z Wed Dec 31 2014 - 12Z Fri Jan 02 2015 ...Temperatures will be 20 to 30 degrees below average across the Southern High Plains... ...Snow for Southern/Central Rockies and Mogollon Rim... Cold high pressure over the Southern Plains will slowly modify as the high slowly moves eastward to the Central Gulf Coast by Thursday evening. Upslope flow associated with the flow around the high will aid in producing light snow and areas of sleet over parts of the Southern High Plains through Thursday morning. Rain will also develop over parts of the Lower Rio Grande Valley on Wednesday into Thursday. As the high moves out of the Plains, moisture from the Gulf of Mexico will overrun the cold air producing light to moderate rain over parts of the Lower Mississippi Valley by Thursday evening. In addition, an area of showers and thunderstorms will develop along the Western Gulf of Mexico on Thursday evening as well. Meanwhile, upper-level low over the Southern California will move eastward to the Southern Rockies and begin to weaken by Thursday evening. The system will produce snow over parts of the Southwest/Great Basin that will move into parts of the Southern/Central Rockies by Thursday morning. Additionally, rain will develop over the lower elevations over the Southwest on Wednesday. The snow will taper off to a small area over parts of the Central Rockies by Thursday evening. Elsewhere, upper-level energy will contribute to the development of light snow over parts of the Great Lakes on Wednesday. A front moving southward out of South-Central Canada will move into parts of the Upper Midwest on Thursday. The system will produce snow over parts of the Northern Plains into the Upper Mississippi Valley on Thursday morning that will move into the Great Lakes to the Northern Appalachians by Thursday evening. Also, an old boundary over Florida will aid in producing light rain over parts of Florida through Thursday evening. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php