Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 256 PM EST Sat Dec 10 2016 Valid 00Z Sun Dec 11 2016 - 00Z Tue Dec 13 2016 ...Heavy snowfall expected to continue for the higher elevations of the Northwest... ...Snow will continue to spread from the Midwest today into the Northeast by Sunday... An arctic frontal boundary draped along the higher terrain of the Intermountain West and the Rockies continues to keep below normal temperatures locked in across much of the Northwest U.S. and into the Northern Plains. This boundary will interact with moisture streaming inland off the Pacific to produce heavy snowfall in the higher terrain of the Pacific Northwest, the Intermountain West, and the northern and central Rockies and High Plains. Heavy rain will also be possible in the lower terrain and along the Pacific Northwest Coast. The rain and snow across the Northwest is expected to continue through the weekend as a series of upper level disturbances move through aloft. Farther east, an upper level shortwave ejecting into the Plains will help to spin up a low pressure system at the surface this evening. Snowfall to the north and east of the low this afternoon from the Northern Plains to the Middle Mississippi Valley will continue to expand into the Midwest and Great Lakes tonight and eventually the Northeast and New England by tomorrow. Winter storm watches, warnings, and winter weather advisories are in effect across parts of the Midwest and the Lower Great Lakes where 4 to 10 inches of accumulating snow is possible. To the south of the snow area, from the Mississippi Valley to the Deep South and Mid-Atlantic, widespread moderate to heavy rain is possible on Sunday as a cold front traverses the region. Santorelli Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php