Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 327 AM EDT Fri Jun 27 2025 Valid 12Z Fri Jun 27 2025 - 12Z Sun Jun 29 2025 ...There are Heat Advisories across much of the Ohio/Tennessee Valleys and Middle /Lower Mississippi Valley... ...There is a Slight Risk of excessive rainfall over parts of the Central Appalachians and northern Mid-Atlantic on Friday... ...There is a Slight Risk of severe thunderstorms over parts of the Northern/Central Plains and Great Lakes on Friday and the Upper Mississippi Valley and Northern/Central Plains on Saturday... Upper-level ridging weakens from the Ohio Valley to the Southeast on Friday, resulting in a reduced area of Heat Advisories over the east. The most extreme heat is expected to subside to temperatures more typical of late June by Friday night and remain so throughout this upcoming weekend. For Saturday and Sunday, high temperatures in the 80s to lower 90s are expected across the region. This heat level can be dangerous to anyone without effective cooling and/or adequate hydration, especially those engaging in lengthy outdoor activities. Heat-related illnesses increase significantly during extreme heat. Wear lightweight and loose-fitting clothing. Take action when you see symptoms of heat exhaustion and heat stroke. Additionally, a wave of low pressure over the Upper Midwest on Friday will move eastward to the Northeast Coast by Sunday morning. On Friday, a second wave moves from the Northern High Plains to the Upper Mississippi Valley by Sunday. With the Northern High Plains low, showers and severe thunderstorms will develop along and ahead of the associated front over parts of the Northern/Central Plains. Therefore, the SPC has issued a Slight Risk (level 2/5) of severe over parts of the Northern/Central Plains through Saturday morning. The hazards associated with these thunderstorms are frequent lightning, severe thunderstorm wind gusts, hail, and a few tornadoes. However, there will be an increased threat of severe thunderstorm wind gusts of 65 knots or greater and hail two inches or greater over the area. In addition, the wave of low pressure over part of the Great Lakes will produce showers and severe thunderstorms. Therefore, the SPC has issued a Slight Risk (level 2/5) of severe over parts of the Great Lakes through Saturday morning. The hazards associated with these thunderstorms are frequent lightning, severe thunderstorm wind gusts, hail, and a few tornadoes. Another area of showers and thunderstorms will develop heavy rain over parts of the Central Appalachians and northern Mid-Atlantic. Therefore, the WPC has issued a Slight Risk (level 2/4) of excessive rainfall over parts of the Central Appalachians and northern Mid-Atlantic through Saturday morning. The associated heavy rain will create mainly localized areas of flash flooding, with urban areas, roads, small streams, and low-lying areas the most vulnerable. Moreover, showers and thunderstorms will develop on Friday over parts of the Ohio/Tennessee Valleys, the Central Gulf Coast, and the Southeast. On Saturday, a front moving across the Northern Plains and Upper Mississippi Valley will produce showers and severe thunderstorms over parts of the Upper Mississippi Valley and the Northern Plains. Therefore, the SPC has issued a Slight Risk (level 2/5) of severe thunderstorms over parts of the Upper Mississippi Valley and the Northern Plains from Saturday through Sunday morning. The hazards associated with these thunderstorms are frequent lightning, severe thunderstorm wind gusts, hail, and a few tornadoes. Furthermore, on Saturday, showers and thunderstorms will develop over parts of the Lower Great Lakes to the Northeast as a front moves across the area. Furthermore, from the Ohio Valley southward to the Gulf Coast, daytime heating and ample moisture will produce showers and thunderstorms over the region. Meanwhile, upper-level impulses will produce light rain from Friday to Saturday evening along the U.S./Canadian border from Washington State to Montana. Ziegenfelder Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php