Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 258 PM EST Fri Dec 15 2017 Valid 00Z Sat Dec 16 2017 - 00Z Mon Dec 18 2017 ...Heavy snow possible over the Northern Cascades... ...Heavy lake effect snow possible downwind from Lakes Erie and Ontario... ...Snow possible over the Northern Rockies and parts of Southern New England Coast... Upper-level energy over Pensilvania will move eastward out over the Western Atlantic by Saturday morning. The energy will aid in producing light snow over parts of the Northern Mid-Atlantic Coast and Southern New England Coast that will end overnight Friday. In addition, another area of upper-level energy over Lakes Superior will, likewise, move eastward out over the Western Atlantic by Saturday evening. The energy will aid in producing lake effect snow downwind from the Great Lakes ending by Saturday evening. Additionally, a front over the Northern Plains into the Upper Great Lakes will also aid in developing light snow near the boundary that will lift northward into Western Ontario by late Saturday evening. Meanwhile, a strong upper-level trough moving onshore over the West Coast will move southeastward to the Northern Rockies/Southwest by Sunday. The energy will aid in producing coastal rain and higher elevation snow over the Pacific Northwest through Saturday morning. Overnight Friday, snow will develop over parts of the Northern Intermountain Region/Northern Rockies expanding into the Great Basin and streaming out into parts of the Northern/Central Plains on Saturday. The snow will begin to wane on Sunday morning over the area. More to Follow Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php