Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 258 PM EST Fri Dec 09 2016 Valid 00Z Sat Dec 10 2016 - 00Z Mon Dec 12 2016 ...Wintry weather expected for portions of the Pacific Northwest... ...Heavy snow possible across portions of the central and northern Rockies and Intermountain West... ...Lake effect snows expected to continue downwind of the Great Lakes... A winter storm system will impact much of the western states through the weekend, bringing widespread precipitation from the West Coast to the Northern/Central Rockies. Most areas will have snow; however pockets of rain and freezing rain may be possible at the lower elevations where colder air has settled. Numerous winter storm warnings and advisories are in effect from Washington/Oregon to central Montana/Wyoming/Colorado; with high wind warnings for central Wyoming and wind advisories along and east of the Sierras. Across the Cascades, heavy snow is possible. An Arctic frontal boundary draped across the interior west, along with the approaching Pacific frontal system, will continue to generate produce widespread snow today and tonight across portions of the northern Rockies and Intermountain West, spreading into the central Rockies on Saturday. Heavy snow is possible across these areas, particularly at higher elevations. Areas of snow are also possible on Saturday across the northern plains and the Midwest as a series of upper-level disturbances pass overhead, and a surface frontal zone strengthens east of the Rockies. Lake effect snows will continue today and Saturday downwind of the Great Lakes, as cold Canadian air streams across the relatively warm waters of the lakes. Snow may be heavy over localized areas, with gusty winds also possible. Campbell Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php