Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 356 AM EDT Sun May 22 2016 Valid 12Z Sun May 22 2016 - 12Z Tue May 24 2016 ...There is a slight risk of severe thunderstorms over the Plains... ...Heavy rains possible over parts of the Northern Rockies... A developing upper-level low over the Lower Great Lakes will move roughly southeastward to off the Mid-Atlantic Coast by Monday evening. The system will produce rain over parts of the Lower Great Lakes/Central Appalachians to the Mid-Atlantic/Southern New England on Sunday morning expanding into the Northeast and the Southern Mid-Atlantic by Sunday afternoon through Sunday evening. Overnight Sunday, the rain will continue over parts of the Mid-Atlantic through Monday evening. A second deeper upper-level low over the Northern Rockies slowly move into Southern Saskatchewan Canada by Monday evening. The storm will produce rain and highest elevation snow over parts of the Pacific Northwest/Northern California eastward to parts of the Northern/Central Rockies through Monday evening. Moisture from the Western Gulf of Mexico will move northward over the Plains that will move into parts of the Upper Mississippi Valley/Upper Great Lakes by Monday. The moisture will aid in producing showers and thunderstorms over the Plains Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php