Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 302 PM EST Thu Feb 11 2016 Valid 00Z Fri Feb 12 2016 - 00Z Sun Feb 14 2016 ...Heavy lake effect snow possible downwind of Lakes Erie and Ontario... ...Arctic air mass expected to spread into much of the eastern U.S. by Saturday... ...Heavy rain and snow possible in the Pacific Northwest... A vast portion of the eastern states will have much colder temperatures through the weekend as a series of arctic air surges through. Cold air flowing over the open waters of the Great Lakes will result in lake effect snows, primarily in the favored areas downwind of the Lakes. Through Sunday morning, some areas downwind of Lakes Erie and Ontario may receive up to a foot of additional snowfall. Northwest Pennsylvania and the western half of New York have Lake Effect Snow Warnings and Advisories in effect. Snowfall amounts of 5 to 10 inches are possible for the same time period across portions of Michigan downwind of Lakes Superior and Michigan. Portions of the Upper Midwest will have temperatures 20 to 30 degrees below average on Friday in the wake of a cold front. The surge of Arctic air is expected to reach the Mid-Atlantic and Northeast by Friday night/Saturday morning. Well-below normal temperatures for mid-February will persist through the weekend from the Upper Midwest/West to the Mid-Atlantic/Northeast. Light snow will be possible on along the northern/central Appalachian range, as well as, coastal North Carolina. A cold front will sweep through portions of the Great lakes, Ohio Valley and Northeast bringing snow primarily to Maine by Saturday. Southeast Maine is forecast to receive the highest snowfall, with total accumulations near a foot. An upper-level disturbance and a lingering stationary frontal boundary will bring light precipitation to the northern plains today. A mixture of rain and snow will be possible, with sleet or freezing rain for mixed in for some areas. Locally heavy rain, with snow falling at the highest elevations, will be possible over the Olympics and the Washington Cascades today and tonight as a frontal system approaches the Pacific Northwest. Snow levels will fall through the day on Friday as the frontal system pushes inland. Additional snowfall is expected along the Cascades and the Olympics in the wake of the front. This system will also spread rain and snow into the northern Intermountain West into Saturday as it moves inland. Campbell Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php