Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 417 AM EST Sat Dec 14 2013 Valid 12Z Sat Dec 14 2013 - 12Z Mon Dec 16 2013 ...Heavy snows and freezing rain possible for the Northeast and northern Mid-Atlantic states this weekend... The same storm system that brought a wintry mix of precipitation to portions of the Midwest on Friday will begin sliding into the Eastern U.S. this weekend. The main surface low with this complex storm will quickly lift from the Tennessee to Ohio Valley on Saturday...before a new low rapidly deepens off the Delmarva coast late Saturday/early Sunday and becomes the dominant feature. An influx of Gulf and Atlantic moisture will continue to fuel widespread precipitation with this system. Heavy rains and thunderstorms will be possible with the associated cold front pushing through the southern tier. Farther north...an arctic airmass in place will complicate precipitation types across the Ohio Valley...northern Mid-Atlantic states...and Northeast. Precipitation should start off as snow in many locations...before changing over to a mix of freezing rain and rain as the arctic air gradually erodes. To the north and west of the transition zone...heavy snows are expected to develop and should result in a wide swath of moderate accumulations over Western Pennsylvania and into interior New England. Conditions should quickly clear out across the Eastern U.S. on Sunday as the deepening surface low races into the Canadian Maritimes and the trailing cold front clears the Atlantic coast. Elsewhere across the Nation...upper energy dropping southeastward from Canada should help ignite light snow showers across the Great Lakes Saturday and Sunday. Light snows will also be possible ahead of a warm front pushing eastward through the Dakotas late this weekend. Upper ridging should keep weather quiet across much of the Western U.S...with the exception of the Pacific Northwest and Northern Rockies...which could see some light shower activity as a Pacific system moves inland over British Columbia. Gerhardt Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php