Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 349 PM EDT Fri Jun 27 2025 Valid 00Z Sat Jun 28 2025 - 00Z Mon Jun 30 2025 ...There are Heat Advisories and a few Extreme Heat Warnings 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 Saturday and Sunday... With the ridge aloft weakening the spatial extent of the excessive heat has shrunk down to the Middle/Lower Mississippi Valley and the Ohio/Tennessee Valleys and will continue reducing into the weekend. 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. Afternoon high temperatures are expected to return to seasonal normal for late June. For Saturday and Sunday, high temperatures in the 80s to lower 90s are forecast for much of the eastern half of the country. Meanwhile a surface low pressure system will track from the Upper Midwest to the Northeast by Sunday with a secondary wave tracking from the Northern High Plains to the Upper Mississippi Valley. Showers and severe thunderstorms will develop along and ahead of the associated front over parts of the Northern/Central Plains. SPC has issued a Slight Risk (level 2/5) of severe weather for portions of the Northern/Central Plains into the Upper Mississippi Valley through Sunday 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. 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. Elsewhere, 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. 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. Farther east showers and thunderstorms will develop over parts of the Lower Great Lakes to the Northeast as the front advances through the area. The Ohio Valley southward to the Gulf Coast, daytime heating and ample moisture will produce showers and thunderstorms over the region. Upper-level impulses are forecast to produce light rain through Saturday evening along the International border from Washington to Montana. Campbell/Ziegenfelder Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php