Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 359 AM EDT Wed Aug 13 2025 Valid 12Z Wed Aug 13 2025 - 12Z Fri Aug 15 2025 ...Scattered showers and thunderstorms to persist across the eastern U.S. into the Deep South with heavy rain possible today into tonight across the southern Appalachians... ...Strong to severe thunderstorms are forecast for portions of the northern Plains late Wednesday and into the upper Midwest Thursday to early Friday... ...Heat is building across the central High Plains as HeatRisk is forecast to locally reach extreme level in portion of central Florida... Over the next couple of days, a series of cold fronts is forecast to advance from the Midwest and across the Great Lakes toward the eastern U.S. Ahead of the cold fronts, a large area of warm and moist air already present across the eastern U.S and into Deep South will be an ingredient for scattered showers and thunderstorms that are expected to be most active from late afternoon into the evening hours. Heavy rain can be expected to accompany the stronger storms through the next couple of days in these areas. The most favorable region for heavy rain to occur will be across the southern Appalachians today into tonight as a plume of tropical moisture is forecast to lift northeast from the central Gulf Coast toward the higher terrain in the southern Appalachians ahead of an upper-level trough. In fact, the Weather Prediction Center has maintained a Slight Risk (level 2/4) of excessive rainfall for today and tonight for this area. Meanwhile, a low pressure system is taking shape cross southwestern Canada and into the northern Rockies with a warm front lifting northward across the northern Plains. The dynamics of this system will raise the threat of heavy showers and thunderstorms across the northern Plains, especially from South Dakota into northern Nebraska where there the Storm Prediction Center has highlighted a Slight Risk (level 2/5) of severe thunderstorms with a concern for damaging wind gusts and isolated areas of large hail. As the warm front advances eastward and then collides with a cold front pushing in from the Canadian prairies, the severe weather threat will then head further east across the upper Mississippi Valley on Thursday and into Friday morning. Cooler temperatures behind this cold front will allow for temperatures to gradually trend below normal across the northern High Plains and especially the Northwest U.S. for the latter part of the week. This will bring a break from the heatwave that portions of the Intermountain West have been experiencing as well. However, the same hot weather that has been over the West will shift east out into the central Plains and the Midwest late this week. This will bring a couple of days with high temperatures reaching well into the 90s to locally over 100 degrees into the High Plains. Across the Northeast where it has been hot lately, temperatures are forecast to gradually cool down as a threat of showers and thunderstorms arrives just ahead of the cold front. Across northern Florida, a slight increase of heat and humidity is enough to raise HeatRisk to extreme levels on Thursday and Friday as the Bermuda High builds westward into the Sunshine State. Kong/Orrison Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php