Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 357 AM EDT Mon Apr 21 2025 Valid 12Z Mon Apr 21 2025 - 12Z Wed Apr 23 2025 ...Light to moderate snow over parts of the Upper Great Lakes on Monday... ...There is a Marginal Risk of excessive rainfall over parts of the Southern Plains on Tuesday... ...There is a Slight Risk of severe thunderstorms over parts of the Central/Southern Plains on Tuesday... On Monday, a front extending from the Upper Mississippi Valley/Upper Great Lakes to the Ohio/Tennessee Valleys and Lower Mississippi Valley/Western Gulf Coast will move eastward to the Northeast/Mid-Atlantic Coast westward into the Tennessee Valley by Wednesday. Showers and thunderstorms will develop along and ahead of the boundary from the Great Lakes/Ohio Valley southwestward to the Lower Mississippi Valley/Western Gulf Coast. An area of strong to severe thunderstorms will develop over parts of the Eastern Ohio Valley. Therefore, through Tuesday morning, the SPC has issued a Marginal Risk (level 1/5) of severe thunderstorms over parts of the Eastern Ohio Valley. The hazards associated with these thunderstorms are frequent lightning, severe thunderstorm wind gusts, hail, and a few tornadoes. A second area of strong to severe thunderstorms will develop over the Tennessee/Lower Mississippi Valleys. Therefore, the SPC has issued a Marginal Risk (level 1/5) of severe thunderstorms over parts of the Tennessee/Lower Mississippi Valleys from through Tuesday morning. The hazards associated with these thunderstorms are frequent lightning, severe thunderstorm wind gusts, hail, and a minimal threat of tornadoes. On Monday, light to moderate snow will develop over the areas adjacent to the western end of Lake Superior along the northern edge of the precipitation shield. On Tuesday, as the western end of the front moves into the Mid-Atlantic, the eastern Tennessee Valley and Lower Mississippi Valley will produce showers and thunderstorms from the southern Mid-Atlantic to the Lower Mississippi Valley. Strong to severe thunderstorms will develop over parts of the southern Mid-Atlantic. Therefore, the SPC has issued a Marginal Risk (level 1/5) of severe thunderstorms over parts of the southern Mid-Atlantic from Tuesday into Wednesday morning. The hazards associated with these thunderstorms are frequent lightning, severe thunderstorm wind gusts, hail, and a minimal threat of tornadoes. Moreover, moisture streams northward over the Central/Southern Plains on Tuesday, and a dryline will form over the Southern High Plains. Showers and severe thunderstorms will develop over the Southern High Plains/Central Plains. Therefore, the SPC has issued a Slight Risk (level 2/5) of severe thunderstorms over parts of the Southern High Plains/Central Plains from Tuesday into Wednesday morning. The hazards associated with these thunderstorms are frequent lightning, severe thunderstorm wind gusts, hail, and a few tornadoes. Further, the showers and thunderstorms will produce moderate to heavy rain over parts of the Southern Plains. Therefore, the WPC has issued a Marginal Risk (level 1/4) of excessive rainfall over parts of the Southern Plains from Tuesday into Wednesday morning. The associated heavy rain will create localized areas of flash flooding, affecting areas that experience rapid runoff with heavy rain. Meanwhile, on Monday, upper-level energy over the Northern Intermountain Region will develop a front over the Northern Rockies/Great Basin that will move eastward to the Upper/Middle Mississippi Valley to the Central Plains by Tuesday evening and then dissipate. The energy will produce rain and highest-elevation snow over parts of the Northwest into the Northern Intermountain Region and the Northern Rockies. Furthermore, on Monday, a third front moving south out of Central Canada will consolidate with the dissipating front over the Upper/Middle Mississippi Valley overnight Tuesday into a boundary extending from the Upper Mississippi Valley/Central Plains into the Central Rockies. A warm front will extend from the Upper Mississippi Valley Great Lakes to the Central Appalachians, and then a cold front will develop over the Mid-Atlantic by Wednesday morning. Overnight Monday, the front will develop showers and thunderstorms over parts of the Northern Plains. On Tuesday, showers and strong to severe thunderstorms will develop along and ahead of the boundary over parts of the Upper/Middle Mississippi Valley. Therefore, the SPC has issued a Marginal Risk (level 1/5) of severe thunderstorms over parts of the Upper/Middle Mississippi Valley from Tuesday into Wednesday morning. The hazards associated with these thunderstorms are frequent lightning, hail, and a minimal threat of tornadoes and severe thunderstorm wind gusts. Ziegenfelder Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php