Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 331 AM EDT Mon Jul 26 2021 Valid 12Z Mon Jul 26 2021 - 12Z Wed Jul 28 2021 ...There is a Slight Risk of excessive rainfall over parts of the southern Mid-Atlantic into the Southern Appalachians and over parts of the Great Basin and Southern California through Tuesday morning... ... There is a Slight Risk of severe thunderstorms over parts of the Upper Midwest through Tuesday morning... ...Excessive Heat Warning over parts of Idaho and eastern Oregon and the Northern High Plains; Heat Advisory over parts of the Lower Mississippi Valley/Southern Plains... Monsoonal moisture is on the decrease over the Southwest and moving into Southern California. As upper-level energy migrates over the region aiding in producing showers and thunderstorms, and some will produce heavy rain over the Great Basin and Southern California through Tuesday. Therefore, the WPC has issued a Slight Risk of excessive rainfall with these thunderstorms. The associated heavy rain will create mainly localized areas of flash flooding, with urban areas, roads, and small streams the most vulnerable through Tuesday morning. However, the excessive rainfall threat will continue to lessen from Monday into Tuesday as the monsoonal moisture decreases. Furthermore, scattered showers and thunderstorms will continue over the Southwest, Central/Southern Rockies, and Great Basin on Tuesday and Wednesday. A front extending from the Northeast Coast to the southern Mid-Atlantic across the Ohio Valley into the Northern Plains will slowly dissipate and move off the Mid-Atlantic Coast by Tuesday evening. Nonetheless, very moist air will pool along the boundary producing showers and thunderstorms, some with heavy rain, along and near the front over Mid-Atlantic into the Ohio/Tennessee Valleys and the Central/Southern Appalachians on Monday. Therefore, The WPC has issued a Slight Risk of excessive rainfall with these thunderstorms. The associated heavy rain will create mainly localized areas of flash flooding, with urban areas, roads, and small streams are the most vulnerable through Tuesday morning. The excessive rainfall threat will lessen on Tuesday into Wednesday, yet showers and thunderstorms will continue over the Southeast to Southern Plains. Meanwhile, a front over the Northern High Plains will move eastward to the Upper Midwest and merge with a front moving southward from Central Canada. The boundary will continue to move east across the Great Lakes into the Northeast by Tuesday morning while sinking into the Mid-Atlantic by Wednesday. The system will produce showers and thunderstorms over the Upper Midwest on Monday. The showers and thunderstorms will move across the Great Lakes into the Northeast on Tuesday into Wednesday. The dynamics associated with these thunderstorms will be strong enough to produce severe weather on Monday. Therefore, the SPC has issued a Slight Risk of severe thunderstorms over parts of the Upper Midwest through Tuesday morning. The hazards associated with these thunderstorms are frequent lightning, severe thunderstorm wind gusts, hail, and a few tornadoes. The severe thunderstorm threat will continue over parts of the area on Tuesday into Wednesday. Over the Northwest, there is an Excessive Heat Warning over parts of Idaho, eastern Oregon, and the Northern High Plains, where temperatures rise into the 100s through Monday. The 100s will move into Northern Plains, Northern High Plains, and the Midwest on Tuesday and Wednesday. Furthermore, Heat Advisories are currently in effect for portions of the Lower Mississippi Valley and parts of the Southern Plains. Moreover, an Excessive Heat Warning affects the Kansas City metro area. Additionally, several regions have Air Quality Alerts due to wildfires over the Northwest into the Northern Rockies. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php