Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 339 AM EDT Thu Jul 19 2018 Valid 12Z Thu Jul 19 2018 - 12Z Sat Jul 21 2018 ...There is a slight risk of severe thunderstorms over parts of the Middle Mississippi Valley... ...Heavy rain possible over parts of the Ohio Valley... ...Heavy rain possible over parts of the Southeast Coast and the Eastern Gulf Coast... A quasi-stationary front extending from the Southeast Coast westward to Tennessee Valley will aid in producing showers and thunderstorms over the region through Friday evening. In addition, a developing upper-level low over the Northern Plains will move roughly eastward to the Upper Mississippi Valley/Great Lakes by Friday evening into Saturday morning. The energy will aid in producing showers and thunderstorms over parts of the Northern Plains into the Middle Mississippi Valley that will move eastward to the Upper Mississippi Valley/Great Lakes and the Ohio/Tennessee Valleys while expanding into parts of the Central Appalachian and the Southern Mid-Atlantic by Friday evening. Meanwhile, monsoonal moisture and daytime heating will aid in producing showers and thunderstorms over parts of the Southwest/Great Basin and the Central/Southern Rockies through Friday evening, too. The showers and thunderstorms will have the greatest areal coverage during the late afternoon into the late evening on Thursday and Friday. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php