Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 324 PM EDT Sat Apr 28 2018 Valid 00Z Sun Apr 29 2018 - 00Z Tue May 01 2018 ...Rain and mountain snow possible across the Western U.S. with severe weather chances increasing through the weekend across the High Plains... ...Record lows possible across the Midwest on Sunday morning... An expansive upper level system shifting slowly eastward through the Western U.S. will bring mainly light to moderate rain and mountain snows in the highest elevations to much of the Northwest and into the northern Rockies. A gradual cooling trend will continue through the weekend underneath the upper low, while daytime high temperatures ahead of it could be 10 to 20 degrees above normal across parts of the Plains states. Return moisture ahead of this system will also increase chances for showers and thunderstorms across the southern Rockies and adjacent High Plains this weekend and into early next week. The Storm Prediction Center is highlighting a marginal to slight risk for severe thunderstorms Sunday and into Monday along and east of a dryline which sets up by Sunday afternoon across the southern and central High Plains. On the backside of the dryline, warm and dry conditions will expand the elevated to critical fire weather threat across the Four Corners states where red flag warnings and fire weather watches are in effect. Meanwhile in the East, a cold front pushing off the Atlantic Coast this evening may bring some scattered showers to parts of the Northeast. This front will usher in a chilly airmass by Sunday which could mean light snow showers for the lower Great Lakes and central Appalachians. Much of the country east of the Plains will see below normal temperatures on Sunday, with record lows possible across parts of the Midwest on Sunday morning. Santorelli Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php