Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 406 AM EDT Tue May 23 2017 Valid 12Z Tue May 23 2017 - 12Z Thu May 25 2017 ...There is a slight risk of severe thunderstorms over parts of the Southeast and the southern tip of Texas... ...Heavy rain possible over parts of the Southern Appalachians/Southern Mid-Atlantic... ...Heavy rain possible over parts of Southeast... A developing upper-level low over the Upper Mississippi Valley will slowly move southward to the Middle Mississippi and Tennessee Valleys by Wednesday evening. An old boundary extending from the Mid-Atlantic southwestward to the Central Gulf Coast will aid in developing showers and thunderstorms from the Southern Mid-Atlantic to the Central Gulf Coast that will extend from the Southern Mid-Atlantic to the Southeast by Tuesday evening. The showers and thunderstorms will generally move off the Mid-Atlantic/Southeast Coast overnight Tuesday. A front associated with the upper-level low will aid in producing rain over parts of the Upper/Middle Mississippi Valley and the Upper Great Lakes on Tuesday morning. The rain will transition into showers and thunderstorms by Tuesday afternoon over parts of the Upper Great Lakes to Middle Mississippi Valley and the Southern Plains that will move to the Great Lakes/Ohio Valley and the Central Appalachians/Southeast by Wednesday evening. Meanwhile, Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php