Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 400 AM EDT Mon Jul 28 2025 Valid 12Z Mon Jul 28 2025 - 12Z Wed Jul 30 2025 ...Derecho likely over portions of the Northern Plains/Upper Midwest today... ...Excessive rainfall concerns shift from Northern Plains and Upper Midwest today south to North/Central Plains and Middle Mississippi Valley on Tuesday... ...Dangerous, heatwave underway across the Southeast U.S. this week... Thunderstorms are expected to develop late this afternoon before congealing into a derecho by early this evening over parts of eastern South Dakota. This derecho is then expected to move east-southeastward into parts of southern Minnesota and northern Iowa. A moderate risk (level 4/5) of severe thunderstorms is in effect for portions of eastern South Dakota into southwestern Minnesota. Several wind gusts in excess of 75 mph, a few line-embedded tornadoes and instances of severe hail are also probable, according to the Storm Prediction Center. There's also a heavy rainfall component to the derecho threat today. High rain rates over saturated soils should lead to scattered to isolated instances of flash flooding over portions of the Northern Plains into the Upper Midwest. A slight risk (at least 15% chance) of excessive rainfall is in effect for parts of eastern South Dakota into southern Minnesota and northern Iowa as a result. While the severe weather threat diminishes on Tuesday, the excessive rainfall threat does not. Tuesday night storms propagating from the Northern High Plains to the Lower Missouri Valley could produce some high rain rates over sensitive surfaces. A slight risk of excessive rainfall is in effect from southeastern Montana through parts of northeastern Wyoming, western South Dakota, much of Nebraska and western Iowa. Extreme heat is expected to continue across much of the Southeast and this week, with the most dangerous combination of high temperatures and humidity occurring through Wednesday. Heat levels will be dangerous for anyone without adequate cooling or hydration. High temperatures will soar into the upper 90s to low 100s, with heat index values ("feels like" temperatures) surpassing 110--115 degrees. Several major metropolitan areas--including Raleigh, Charlotte and Orlando are expected to experience Extreme HeatRisk, with over 18 million people impacted at the peak today. Kebede Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php