Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 355 AM EST Wed Nov 19 2014 Valid 12Z Wed Nov 19 2014 - 12Z Fri Nov 21 2014 ...Temperatures will remain below normal from the Great Plains to the Eastern Seaboard... ...Impressive snowfall totals will continue to add up downwind of the Great Lakes... An anomalous upper trough carved out over the eastern half of the Nation will keep temperatures below normal from the Great Plains to the Atlantic coast. Within the frigid airmass...heavy snow bands will continue to set up downwind of the Great Lakes where Arctic air will be ushering in over relatively warmer lake waters. Lake effect snows should wane a bit ahead of a clipper system sliding out of the Upper Midwest on Wednesday...but activity will ramp up again as the system lifts into Canada Thursday morning. The clipper will also bring another blast of Arctic air and the possibility for light snow showers in the central Appalachians. Precipitation will be on the increase out West as an upper ridge breaks down and a series of Pacific systems move onshore. The systems should weaken while moving inland...keeping any significant totals confined to the upslope side of the terrain of the Pacific Northwest and Northern California. Warmer air moving in over a dense cold airmass could lead to freezing rain for portions of Washington and Oregon. In the higher elevations of the Cascades and Sierra Nevada range...temperatures should stay low enough to support accumulating snows. Across the southern tier...return flow from the Western Gulf will bring moisture and the chance for showers into Texas and the Lower Mississippi Valley on Thursday. Scattered shower activity will also be a possibility across the southern tip of Florida the next few days. Gerhardt Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php