588 FXUS01 KWBC 310623 PMDSPD Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 222 AM EDT Fri Jul 31 2026 Valid 12Z Fri Jul 31 2026 - 12Z Sun Aug 02 2026 ...Risk for severe thunderstorms and heavy rainfall across the Mississippi Valley into the Great Lakes and Ohio Valley... ...Flash flooding and severe thunderstorm risk across portions of the Four Corners... ...Daily rounds of heavy downpours bring localized flash flooding risks to the Southeast... ...Dangerous heat builds across the Southwest on Friday, Intermountain West/northern High Plains on Saturday... Unsettled weather continues across the central U.S. as an upper level shortwave trough traverses southern Canada into the Upper Midwest/Great Lakes. At the surface, the cold over Northern Plains will drop southward on Friday, while a low-pressure system will continue to deepen and slowly move eastward. The frontal boundary associated with the system will extend across the Mississippi Valley into the Southern Plains, while the warm front will extend across parts of the Southeast. The slow moving boundary will interact with warm moisture and strong instability, leading to heavy rainfall that is capable of producing high rainfall rates and heavy downpours. Therefore, a Slight Risk (level 2/4) of excessive rainfall is in place over portions of the Upper Midwest into mid-Mississippi Valley and portions of the Ohio Valley, while a broad Marginal Risk highlights much of the Upper Great Lakes and Southeast for Friday. Additionally, a Slight Risk (level 2/5) of severe thunderstorms is in place for portions of the Mississippi Valley and Ozarks. On Saturday, as the system moves eastward into the Ohio/Tennessee Valley and merges with the cold front over the Upper Great Lakes, chances for showers and thunderstorms continue. With increasing instability and sufficient moisture, the risk for severe thunderstorms and excessive rainfall will shift eastward into the lower Great Lakes, Ohio/Tennessee Valley, and portions of the Southeast. These storms may also produce damaging wind gusts, isolated marginal hail, and possible tornadoes. Over the southwest, southeasterly flow continues to bring monsoonal moisture across the Four Corners, which will produce afternoon to evening thunderstorms. Slow storm motion and increasing instability will bring the potential for isolated flash flooding and severe thunderstorms, with the chance for damaging winds and hail, through Saturday. Otherwise, the upper-level ridge over Southwestern U.S. will continue to bring dangerous heat across the Southwest on Friday, and will gradually lift into the northern High Plains/Intermountain West by Saturday. Afternoon highs are expected to reach 110-120 degrees for parts of the Southwest, while the areas farther north will reach 90s to 100s. Unfortunately, overnight lows will provide little relief as temperatures are expected to remain warm. Therefore, much of western U.S. will experience widespread Major to Extreme HeatRisk conditions, which will bring concern for heat-related illness, especially for those without adequate cooling or hydration. Oudit Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php $$