Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 407 AM EDT Mon Apr 20 2015 Valid 12Z Mon Apr 20 2015 - 12Z Wed Apr 22 2015 ***Large low pressure system over the Great Lakes*** ***Snow likely for parts of the Upper Midwest*** ***Scattered rain and snow showers for the Rockies*** A large upper level low over the Upper Midwest and Great Lakes for the beginning of the work week will be a key player in the weather expected for the eastern U.S. through Tuesday. An occluded surface low currently over the Great Lakes is forecast to lift northward into Canada, and the associated cold front will continue moving east and exit the East Coast by Tuesday morning. In terms of sensible weather impacts, widespread rain is expected ahead of the warm front from the Mid-Atlantic to New England, and rainfall amounts could easily exceed an inch for many areas. Farther to the south in the warm and humid airmass, strong thunderstorms are a possibility on Monday from Virginia to the Gulf Coast. On the west side of the large surface low, unseasonably cold weather is expected for the Upper Midwest along with some late-season snow showers. For the western U.S., expect some isolated to scattered showers to develop over parts of the Rockies and the Sierra Nevada range each afternoon, with snow showers for the highest elevations. Dry weather is expected for the California coast and into the Desert Southwest. Hamrick Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php