Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 359 AM EDT Tue Apr 21 2015 Valid 12Z Tue Apr 21 2015 - 12Z Thu Apr 23 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 at the start of the period will be a key player in the weather expected for the eastern U.S. through Wednesday. An occluded surface low currently over Ontario is forecast to remain nearly stationary over the next couple of days, and this will be close to the upper-level low. In terms of sensible weather impacts, improving weather is expected from the southeast coast to New England as the cold front exits the coast and takes the bad weather along with it. 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. A secondary cold front is progged to sweep through the Ohio Valley and reach the East coast by Wednesday night, and a prolonged stretch of cooler than normal temperatures is expected behind this front. 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. Hamrick Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php