Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 359 PM EDT Thu May 08 2025 Valid 00Z Fri May 09 2025 - 00Z Sun May 11 2025 ...Widespread showers and storms across much of the eastern and southern U.S Friday.... ...Threat for isolated to scattered flash flooding for portions of the Mid-Atlantic and south Texas with a severe weather threat across the Tennessee Valley/southern Appalachians through Friday morning, then an isolated threat for the the Northeast and Gulf states/Southeast through Sunday morning... ...Temperatures remain below average across much of the eastern and southern U.S. while much above average expand across the north-central and western U.S.... A slow moving front, from the Northeast trailing trough the eastern states and westward across the Gulf states and Texas, will be the focus for convective development as moist Gulf return flow persists. Some of these storms have the potential to produce rainfall rates of 0.5 inch/hour or greater given the abundant moisture availability and with the slow motion expected, there will be an increased threat for isolated instances of flash flooding. WPC has a broad Marginal Risk today that covers much of the eastern third of the country as well southern Texas and extreme southeast New Mexico. Higher moisture in an airmass undisturbed by the previous days convection over south Texas will also lead to widespread storms with a locally higher threat for heavier downpours and scattered flash flooding, with a Slight Risk in effect. In addition, a couple areas of severe weather are expected. First, locally stronger winds associated with one of the upper-level waves and sufficient instability with warming temperatures ahead of the cold front will lead to a cluster of strong to severe storms from the Tennessee Valley east through the southern Appalachians. The Storm Prediction Center has introduced a Slight Risk of severe weather (level 2/5) mainly for the threat of very large hail along with damaging wind gusts. Second, an upper-level shortwave passing over the Rio Grande Valley/south Texas will bring the threat for some strong to severe storms here as well, with another Slight Risk in place for additional instances of large hail and damaging winds. The progression of this front will be slightly more progressive with the leading low as it advances north/northeast near the coast however the movement across the Southeast will be slow. This will maintain an elevated threat for isolated areas of flash flooding for the Gulf/Southeast and for the Northeast through the weekend. Elsewhere, lingering moisture along the Central/Southern Rockies and the adjacent High Plains will lead to some scattered storms today through Friday. An upper-level shortwave and accompanying surface frontal system passing from the Northern Rockies/High Plains today to the Upper Midwest Friday will bring a chance for some isolated showers. Mostly dry conditions are expect across the Plains, Midwest and the Great Basin/West Coast. The consolidating upper-trough across much of the eastern/southern U.S. while a ridge builds over the western/northern U.S. will lead to some significant variations in temperatures through the weekend. Under the troughing, below average temperatures will be felt across much of the Great Lakes/Northeast southwest through the Ohio/Middle Mississippi Valley and for the Central/Southern Plains. Daily maximums in the 50s and 60s will be common for more northern locations with 60s and 70s from the Ohio Valley southwards. Conditions along the East Coast will be a bit closer to average ahead of the approaching cold front, with highs in the 60s and 70s for the Mid-Atlantic and 70s and 80s into the Southeast. In contrast, well above average temperatures will expand in coverage across the Northern Plains/Upper Midwest and Interior West/West Coast. Forecast highs are generally in the 70s and 80s with 90s in the central California Valleys and low 100s into the Desert Southwest. Campbell/Putnam Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php