Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 221 AM EST Fri Feb 12 2016 Valid 12Z Fri Feb 12 2016 - 12Z Sun Feb 14 2016 ...Lake effect snowfall to continue downwind of the Great Lakes Friday into Saturday... ...The coldest air mass of the season expected to impact Eastern U.S. this weekend... ...Rain and snow expected to spread across the Northwest on Friday and into the Northern Plains and the Upper Midwest by Saturday... A cold front sweeping across the Great Lakes will continue to allow for moderate to locally heavy lake effect snowfall the next few days. An additional 6 to 10 inches of snow may be possible in the favorable downwind areas of the Great Lakes as westerly and northwesterly flow across the lakes results in very localized heavy snow bands. Winter weather advisories and Lake Effect snow warnings are in effect into Saturday. At the same time, a weak area of low pressure will move off the South Carolina coast this morning which is expected to bring some light snow or freezing rain accumulations to portions of eastern North Carolina on Friday. The low is forecast to move well off the Eastern U.S. coastline, but may still clip coastal Maine with up to a foot of snow. Strong surface high pressure nudging into the Central U.S. today will allow for temperatures 10 to 20 degrees colder than normal to continue across the Northern Plains and into the Midwest. The cold front sweeping into the Great Lakes however, will usher an even colder airmass into the Eastern U.S. by Saturday. Afternoon high temperatures as much as 20 to 30 degrees below normal are likely across portions of the Ohio Valley, Mid-Atlantic, and the Northeast this weekend. A strong pressure gradient in the wake of the low off the Northeast coast will also bring gusty winds to these same areas which could create dangerously cold overnight wind chills. A frontal boundary moving into the Northwest today will bring locally heavy rain and higher elevation snows to the Pacific Northwest and portions of the Intermountain West throughout the weekend. As the upper level energy moves into the High Plains Saturday afternoon, snow will spread into the Northern Plains, and eventually the Upper Midwest by Sunday. Relatively light accumulations of up to half a foot could be possible across the eastern Dakotas into portions of western Minnesota. Santorelli Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php