Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 303 AM EST Mon Dec 21 2015 Valid 12Z Mon Dec 21 2015 - 12Z Wed Dec 23 2015 ...Bad weather expected to continue over the northwestern quadrant of the nation... ...Above normal temperatures are forecast to return to the eastern U.S. along with increasing rain chances... The next two days will be featured with a progressive flow pattern aloft that will result in rapidly moving shortwave disturbances from west to east across the northern U.S. In addition, ridging aloft and at the surface is expected to develop over the eastern U.S., with little in the way of any arctic air intrusions. A series of storm systems will continue to move eastward across the eastern Pacific Ocean and then towards the Pacific Northwest. A strong Pacific storm system will cross the West Coast Monday afternoon with coastal rain and heavy mountain snow, with the greatest amounts likely over the Cascades and northern Rockies where amounts in excess of one foot are likely at the highest elevations. A slightly weaker system is forecast to affect the region late on Tuesday with another round of precipitation. Temperatures are forecast to begin moderating to above normal levels to start out the new work week. The cold surface high that was associated with the cold and breezy conditions along with lake effect snow over the weekend has moved offshore. This is resulting in large-scale southwesterly flow to develop that will raise temperatures and advect moisture northward from the Gulf of Mexico. As a result, widespread showers and a few thunderstorms are likely ahead of a frontal boundary that is expected from the southern Plains to the Ohio Valley. Hamrick Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php