Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 1214 AM EDT Sun Apr 29 2018 Valid 12Z Sun Apr 29 2018 - 12Z Tue May 01 2018 ...Rain and mountain snow possible across the West... ...Severe weather chances increasing through Monday across the Plains... ...Record lows possible across the Midwest/Great Lakes this morning... An expansive upper level system shifting slowly eastward through the West 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 the Western system will increase chances for showers and thunderstorms across the southern Rockies and adjacent High Plains Sunday into Tuesday. The Storm Prediction Center is highlighting an increasing risk for severe thunderstorms Sunday into Tuesday along and east of a dryline during the afternoon and evening hours. 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 today 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 this morning. The Southeast will be high and dry under the aegis of high pressure. Roth/Santorelli Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php