Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 319 AM EST Fri Dec 01 2017 Valid 12Z Fri Dec 01 2017 - 12Z Sun Dec 03 2017 ...Heavy snow over the Northern Cascades... ...Snow possible over the Southern Cascades and Northern Rockies... ...Heavy rain possible over parts of the Northwest Coast... The upper-level pattern has a generally west to east flow regime through Saturday when the flow pattern becomes more amplified over the Pacific Northwest. Embedded in the fast upper-level flow, weak disturbances over the Southeast will aid in producing scattered rain over the area through Saturday evening. In the meantime, an upper-level disturbance over the Northeast will move eastward out over the Western Atlantic by Friday evening. Rain will develop over parts of New England that will begin to taper off by Friday afternoon and end by Friday evening. Meanwhile, upper-level energy over Northern Rockies will move eastward to the Great Lakes while intensifying. The energy will produce areas of rain and snow over parts of the Upper Great Lakes overnight Friday into Saturday that will move into Eastern Canada by Saturday evening. Additionally, weak embedded upper-level impulses will aid in producing rain over the Pacific Northwest Coast and snow over the higher elevations of the Northern Rockies on Friday morning. On Friday, upper-level troughing will begin to move onshore over the Pacific Northwest that will slowly increase as an upper-level low comes onshore over the Northwest on Saturday afternoon into evening. Weak onshore flow will also accompany the upper-level troughing. As the troughing moves onshore, the snow level will lower over the Pacific Northwest. Rain and higher elevation snow will develop over the Pacific Northwest through Saturday evening. On Saturday, the rain will being to move into Northern California with the precipitation extending inland to the Northern Rockies by Saturday evening. Snow will develop over the higher elevations of Northern/Central California into parts of the Sierras Saturday evening into Saturday night. Snow will also develop over parts of the Northern Rockies by Saturday evening. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php