Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 355 AM EDT Sat May 21 2016 Valid 12Z Sat May 21 2016 - 12Z Mon May 23 2016 ...There is a slight risk of severe thunderstorms over parts of the Northern High Plains and the Southern High Plains... ...Heavy rain possible along the Mid-Atlantic Coast and parts of the Northern Rockies... An upper-level low over the Ohio Valley will intensify as the low moves southeastward to the Southern Mid-Atlantic by Sunday evening. The system will produce rain over parts of the Lower Great Lakes into the Northern Mid-Atlantic on Saturday morning that will continue through Sunday evening. Rain will also move into parts of Southern New England by Saturday evening and into the Northeast on Sunday. In addition, showers and thunderstorms will develop over parts of the Southern Ohio Valley into the Southern Mid-Atlantic and the Southeast on Saturday morning that will move off most of the Southeast Coast by Sunday morning while continuing over parts of the Southern Mid-Atlantic through Sunday evening. Meanwhile, a much larger and deeper upper-level low over the West Coast will slowly move northeastward to the Northern High Plains by early Sunday while move just over the U. S./Canadian Boarder near the Northern High Plains by Sunday evening. Rain and highest elevation snow will develop over parts of the Northwest and Northern California through Sunday evening. Rain with embedded thunderstorms will develop over parts of the Northern Rockies into the Northern High Plains on Saturday with a day time heating Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php