Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 359 PM EDT Fri Aug 06 2021 Valid 00Z Sat Aug 07 2021 - 00Z Mon Aug 09 2021 ...Heavy rainfall and the chance for flash flooding continues for portions of the Southeast along a persistent frontal boundary... ...Heavy rainfall and severe storms expected from the Northern/Central Plains to the Midwest today and Saturday... ...Hot in the High Plains, poor air quality due to wildfire smoke continues in the Midwest and Intermountain West... A persistent quasi-stationary frontal boundary continues to meander across the Southeast today. An upper-level trough moving across the Southeast, as well as waves of low pressure along the boundary, will continue to promote showers and storms in the vicinity of the boundary into Saturday. There is a Marginal Risk (level 1 of 4) of excessive rainfall in effect through tomorrow from the Big Bend of Florida northward through Georgia and into the Carolinas. As the western portion the stationary front begins to dissipate and the upper-level trough moves east, the threat for heavy rain will shift northeastward into the Carolinas and southern Mid-Atlantic. A Slight Risk (level 2 of 4) of excessive rainfall is in effect for portions of eastern North Carolina and southeastern Virginia as widespread heavy rain totals between 1 to 2 inches, with locally higher amounts, may result in a few instances of localized flooding. A series of fronts as well as the next upper-level trough moving east out of the Rockies will lead to the chance for heavy rain and severe weather across the Northern Plains and the Midwest today through Sunday. A Marginal Risk of excessive rainfall is in effect for today for some instances of heavy rain through tomorrow morning ahead of a cold front across the Great Lakes. The greater threat for heavy rain and severe weather will begin further west over the Northern High Plains as a low pressure system and associated fronts moves east across the area this evening. The Storm Prediction Center has issued a Slight Risk (level 2 of 5) for severe weather for portions of northeastern Wyoming, the Black Hills of South Dakota, and northwestern Nebraska ahead of a cold front moving east out of the Rockies. High winds should be the main threat with these storms. The low pressure system will move east across the Northern/Central Plains tomorrow morning. A warm front lifting northward across the Upper Missouri and Mississippi Valleys will help advect a moist, buoyant airmass northward across the region. Numerous, organized showers and storms are expected to develop along this warm front as well as ahead of the cold front on Saturday. A Slight Risk of excessive rainfall is in effect from Saturday through Sunday morning for west-central Wisconsin, with a broader Marginal Risk in effect from the Upper Mississippi Valley southwestward into the Central Plains. Heavy rain totals of 1-2 inches, with locally higher amounts in the Slight Risk area, may pose the risk for flooding. A Slight Risk remains in effect for much of southern Wisconsin, eastern Iowa, and northwestern Illinois on Sunday as any organized storms from the previous night continue and new storms form across the region. In addition for the threat for heavy rain, the Storm Prediction Center has issued a Slight Risk for severe weather on Saturday for the threat of hail, wind, and a couple of tornadoes. Hot weather is expected to continue for the Southern and Central High Plains on Saturday, with highs in the mid-upper 90s. The heat will spread northward into the Northern High Plains on Saturday with high temperatures in the low to mid-90s likely. Air quality will remain an issue due to western wildfires across portions of the Intermountain West and upper-Midwest. Elsewhere, much below normal temperatures are expected in the Pacific Northwest and Northern Rockies behind the storm system currently moving across the Rockies and a second storm system moving east from the Pacific. High temperatures in the mid-70s will be common, with 60s possible in the Northern Rockies. There will be a warming trend in the Southeast as the persistent frontal system finally moves into the Atlantic, with high temperatures into the low 90s likely by Sunday. Putnam Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php