Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 148 AM EST Tue Dec 11 2018 Valid 12Z Tue Dec 11 2018 - 12Z Thu Dec 13 2018 ...Heavy rain and mountain snow expected for the northwestern U.S. and relatively uneventful for most of the central and eastern states... An active weather pattern will remain in place across the Pacific Northwest over the next couple of days, with a relatively strong Pacific cold front affecting the region on Tuesday. This will result in widespread moderate to heavy rain and mountain snows inland across Washington and Oregon. This moisture is expected to spread across the northern Great Basin and northern Rockies by Tuesday night and into Wednesday morning. The higher elevations of the northern Cascades may see snowfall accumulations up to two feet, and 6 to 18 inches possible for portions of the northern Rockies. After a brief lull across the Pacific Northwest, another frontal system will approach late Wednesday, bringing another round of potentially heavy rain and mountain snow to the region. Across the north-central part of the nation, a low pressure system will cross the Great Lakes and portions of the Northeast through Tuesday, bringing scattered areas of snow showers. A weak cold front is expected to cross the central and northern plains on Tuesday, with some scattered and relatively light precipitation possible into Wednesday across portions of the northern plains and the Midwest states. A new surface low develops across the western High Plains Wednesday night and this will begin advecting Gulf of Mexico moisture northward by Thursday morning across the southern plains, with showers and some thunderstorms developing. The contiguous U.S. will be largely cut off from any significant incursions of arctic air masses during the short range forecast period, and high temperatures through the middle of the week are expected to range from 5 to 15 degrees above average across much of the central U.S. The East Coast should remain seasonably cool with temperatures up to 10 degrees below average, although temperatures will slowly moderate some by Wednesday. D. Hamrick Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php