Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 312 AM EST Thu Dec 17 2015 Valid 12Z Thu Dec 17 2015 - 12Z Sat Dec 19 2015 ...Heavy rain possible over the Pacific Northwest Coast into parts of Northern California... ...Heavy snow possible for the higher elevations of Idaho... ...Freezing rain possible for parts of interior Washington State and Oregon... A front extending from the a Lower Great Lakes to Central/Eastern Gulf Coast will move eastward off most of the East Coast by Friday morning. Showers and thunderstorms will develop along and ahead of the boundary over parts of the Southeast into the Eastern Gulf Coast that will move the Southeast Coast overnight Thursday. The showers and thunderstorms will come to an end over Eastern Florida by Friday evening. In addition, rain will develop along the front from the Lower Great Lakes to the Southern Mid-Atlantic on Thursday morning that will move off most of the East Coast by Friday morning. In the wake of the system, lake effect snow will develop downwind of the Great Lakes Thursday evening into Friday evening. Meanwhile, strong onshore flow ahead of the next Pacific system will stream moisture into the Pacific Northwest that will aid in produce rain over the Pacific Northwest Coast into parts of Northern California through Friday. Warm air will move inland ahead of the system that will rise snow levels over the interior Northwest into parts of the Northern Rockies through Friday morning. Cold air trapped in valleys will aid in producing rain/freezing rain over parts of Washington State and parts of Oregon through Thursday evening. Rain and higher elevation snow will develop over parts of the interior Northwest into parts of the Northern Rockies through Thursday. As the next front moves onshore over the Northwest on Friday, snow levels will lower and snow with lower elevation rain will develop over parts of the interior Pacific Northwest to the Northern Rockies. Elsewhere, upper-level energy over the Central Rockies will move to the Tennessee Valley by Thursday evening. The energy will trigger rain and higher elevation snow over parts of the Central Rockies into parts of the Central Plains through Thursday evening. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php