Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 328 AM EDT Wed Apr 28 2021 Valid 12Z Wed Apr 28 2021 - 12Z Fri Apr 30 2021 ...There is a Moderate risk of excessive rainfall over parts of the Middle/Lower Mississippi and the Southern Plains... ...There is a Slight risk of severe thunderstorms over parts of the Southern Plains and the Lower Great Lakes through Thursday morning... ...There is a chance for record-breaking hi-low temperatures over the East and below-average temperatures over the Southern Rockies/Southwest into the Central High Plains... A slow-moving front extending from the northern Mid-Atlantic westward to Michigan, then southwest to the Central/Southern Plains will inch eastward off the Northeast/Mid-Atlantic Coast by Friday. The southern part of the boundary will extend from the Southeast to the Central/Western Gulf Coast on Friday. Showers and thunderstorms will develop along and ahead of the front from the Middle Mississippi Valley eastward to parts of the Northeast. The SPC has issued a Slight risk of severe thunderstorms over the Lower Great Lakes through Thursday morning. The main hazards with the severe thunderstorms are frequent lightning, severe thunderstorm wind gusts, hail, and a few tornadoes. Additionally, showers and thunderstorms will develop along and ahead of the front over parts of the Central/Southern Plains. The SPC has issued a Slight risk of severe thunderstorms over parts of the Southern Plains through Thursday morning. The main hazards with the severe thunderstorms are frequent lightning, severe thunderstorm wind gusts, hail, and a few tornadoes. There is a 10% or greater probability of two-inch hail over parts of south-central Texas. The thunderstorms will produce heavy rain from parts of the Ohio Valley to the Southern Plains. The WPC has issued a Moderate risk of excessive rainfall over parts of the Middle/Lower Mississippi and the Southern Plains through Thursday morning. The heavy rain associated with the thunderstorm will produce numerous areas of flash flooding over this region. Many streams may flood, potentially affecting larger rivers. The severe threat will lessen somewhat on Thursday as showers and thunderstorms continue along and ahead of the boundary. The showers and thunderstorms will continue to develop along and ahead of the front through Friday morning. In the warm sector, south of the front, there is a chance for record-breaking hi-low temperatures over the East on Wednesday into Thursday. Meanwhile, under the upper-level low over the Four Corners Region rain and higher elevation snow will develop over parts of the Central/Southern Rockies and the Southwest on Wednesday, ending on Thursday morning. Additionally, under the upper low, temperatures will be 10 to 15 degrees below average on Wednesday. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php