Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 249 AM EST Thu Dec 28 2017 Valid 12Z Thu Dec 28 2017 - 12Z Sat Dec 30 2017 ...Freezing rain possible over parts of the Pacific Northwest with snow in the Cascades and northern Rockies... ...Light snow for the northern Plains along with continuing lake effect snow... ...Chance for mixed precipitation across parts of the Southeast... The Pacific Northwest and the Intermountain West will remain in a persistent wet pattern into the weekend and beyond. An approaching low pressure system will usher in a robust plume of moisture that will result in Widespread coastal rain, a mix of rain/freezing rain at the lower elevations of Washington and Oregon and snow in the higher elevations of the Cascades and Northern Rockies. Heavy snow is expected in this regime - Numerous Winter Storm Warnings, Winter Weather Advisories and Winter Storm Watches are in effect from Washington to Montana. Light snow will spread across the Dakotas and Upper Midwest today as a clipper system passes through. As this system approaches the upper Great Lakes it will ramp up the lake effect snow production for that region. As the system moves eastward on Friday--lake effect snow will also ramp up for the lower Great Lakes. With Arctic air residing over a majority of the Northeast, as well as the West Virginia spine of the Appalachians, Wind Chill Advisories and Warnings are in effect. A wavy front in the Gulf of Mexico along with upper level energy sweeping across the Southeast will spread moisture across the Gulf Coast states. A shallow layer of cold air dammed against the Appalachians will allow for mixed and/or freezing rain to occur for portions of Georgia and the Carolinas over the next few days. Further west, light showers can be expected across the central Gulf coast. See WPC's winter weather products for more information. Campbell Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php