Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 221 AM EST Mon Dec 29 2014 Valid 12Z Mon Dec 29 2014 - 12Z Wed Dec 31 2014 ...Temperatures will be 20 to 30 degrees below average over the Northern/Central Plains... ...Snow is forecast for the interior Western U. S.... Cold high pressure over Western Canada will drift south over the next few days to be centered over the northern Plains. This high will force a front southward over the Intermountain Region to Southern California and Southwest US by Tuesday morning. The combination of cold temperatures and breezy conditions has led to the issuance of wind chill advisories over much of the northern Plains today. Weak upslope flow will aid in producing light snow over the Northern/Central Rockies, Great Basin, and the Central high Plains Monday. The upper-level energy will aid in producing snow over the ranges of southern California, the southwest, and southern Rockies mid week. Cooling temperatures result in snow reaching valley areas in southern Nevada Tuesday night and Wednesday, possibly including the city of Las Vegas, NV. A cold front over the southeast to the Lower Mississippi Valley will sink southeastward to the Florida peninsula by Tuesday morning. Moisture pooling along the boundary will aid in producing rain over the southeast to Florida and the southern Mid-Atlantic. Elsewhere, lake effect snow showers are expected in the lee of the Great Lakes through Tuesday. Petersen Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php