Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 357 PM EDT Fri Aug 24 2018 Valid 00Z Sat Aug 25 2018 - 00Z Mon Aug 27 2018 ...There is a slight risk of severe thunderstorms over parts of the Middle Mississippi Valley... An upper-level low over the Upper Mississippi Valley/Upper Great Lakes will move eastward to Quebec by Sunday. The system will produce showers and thunderstorms over parts of the Upper/Middle Mississippi Valley and Upper Great Lakes/Western Ohio Valley that will move eastward to the Lower Great Lakes into the Ohio Valley by Sunday. In addition, tropical moisture and weak upper-level impulses will aid in developing showers and thunderstorms over parts of the Southeast/Eastern Gulf coast through Sunday. Meanwhile, a front extending from the Northern High Plains southwestward into the Great Basin will move eastward to the Upper Great Lakes/Upper Mississippi Valley southwestward to the Central Plains by Sunday. The system will aid in producing showers and thunderstorms over the Northern High Plains that will move into parts of the Upper Great Lakes/Upper Mississippi Valley southwestward into the Central Plains by Sunday. A second front will develop over parts of the Northern Rockies/Northern Intermountain Region on Saturday afternoon that will extend into parts of the Northern High Plains by Sunday. The energy associated with the boundary will aid in producing light rain over parts of the Pacific Northwest on Saturday afternoon into Sunday morning. Showers and thunderstorms will develop along and near the front overnight Saturday into Sunday. Elsewhere, upper-level energy over the Arizona/Mexican border will move northeastward to the Central High Plains by Sunday. The energy and monsoonal moisture will aid in producing showers and thunderstorms over parts of the Southwest/Great Basin and the Central/Southern Rockies through Sunday. The showers and thunderstorms will have the greatest areal coverage during the late afternoon into the late evening on Friday and Saturday. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php