Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 1243 AM EST Tue Dec 20 2016 Valid 12Z Tue Dec 20 2016 - 12Z Thu Dec 22 2016 ...Cold and dry across much of the eastern U.S. and additional snow for the northern tier states... An expansive high pressure area is large and in charge across much of the central and eastern U.S. through Wednesday behind the strong cold front that exited the East Coast Sunday evening. Sunny to partly cloudy skies will be commonplace, except for some lake effect snow showers downwind of the Great Lakes. After record-breaking frigid temperatures over the past two nights, the arctic air mass is now moderating across much of the north-central U.S. It will remain seasonably cool across much of the southern U.S. over the next couple of days, with some lingering rain across parts of the coastal Southeast states and the Florida peninsula. Residents of South Florida will have the warmest temperatures since the frontal boundary will be slow to clear that region. An approaching Pacific low pressure system Tuesday morning will produce another round of rain and mountain snow to the Pacific Northwest, and some freezing rain will be possible for interior valleys where a shallow layer of sub-freezing temperatures exist. This low and trailing cold front will then track inland across the northern Rockies and bring accumulating snow to this region by Tuesday. The snow is then expected to fall over the northern Plains and Upper Midwest by Wednesday as the storm system continues progressing eastbound. D. Hamrick Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php