Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 414 AM EDT Sat Jun 18 2016 Valid 12Z Sat Jun 18 2016 - 12Z Mon Jun 20 2016 ...There is a slight risk of severe thunderstorms over parts of the Upper Midwest into the Northern High Plains... ...Heavy rain possible over parts of the Upper Mississippi Valley/Upper Great Lakes... ...Heavy rain possible along parts of the Central Gulf Coast... A front extending from the Upper Mississippi Valley/Upper Great Lakes roughly southwestward to parts of the Great Basin/Northern Intermountain Region will have a few waves of low pressure move along the boundary through Monday. Showers and thunderstorms will develop along and near the boundary from parts of the Northern High Plains to the Upper Mississippi Valley that will expand into parts of the Upper Great Lakes/Upper Mississippi Valley by Saturday evening. As the second wave moves eastward from the Northern Intermountain Region, showers and thunderstorms will extend from the Upper Great Lakes/Upper Mississippi Valley to the Northern High Plains through Sunday morning. On Sunday, the showers and thunderstorms will extend from the Upper Mississippi Valley to the parts of the Central Plains. Meanwhile, onshore flow off the Pacific will stream moisture into the Northwest through late Sunday morning when the onshore flow ends. The onshore flow will aid in producing rain over parts of Northern California into the Pacific Northwest ending by Sunday morning. In addition, a dissipating front over the Eastern Gulf Coast will aid in focusing showers and thunderstorms over parts of Florida and the Eastern Gulf Coast through Monday. Additionally, upper-level energy over the Central and Western Gulf Coast along with flow off the Western Gulf of Mexico will aid in producing showers and thunderstorms over the region through Monday, too. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php