135 FXUS01 KWBC 280727 PMDSPD Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 326 AM EDT Fri Aug 28 2026 Valid 12Z Fri Aug 28 2026 - 12Z Sun Aug 30 2026 ...There is a Slight Risk (level 2/5) of severe thunderstorms over parts of the Northern Plains/Great Basin on Friday... ...There is a Slight Risk (level 2/4) of excessive rainfall over parts of the Southern Mid-Atlantic/Southeast on Friday... A quasi-stationary front will move off the Northeast Coast overnight Friday. At the same time, the southern part of the boundary continues from the Southern Mid-Atlantic to the Lower Mississippi Valley through Saturday night. Near and south of the front, showers and thunderstorms will develop over the Southern Mid-Atlantic to the Southeast and Central/Eastern Gulf Coast through Sunday morning. Moisture-rich air and the nearby front will contribute to showers and thunderstorms producing heavy rain over parts of the Southern Mid-Atlantic/Southeast on Friday. Therefore, the WPC has issued a Slight Risk (level 2/4) of excessive rainfall with these thunderstorms over parts of the Southern Mid-Atlantic/Southeast. The associated heavy rain will create mainly localized areas of flash flooding, with urban areas, roads, small streams, and low-lying areas being the most vulnerable. A front extending from the Northern High Plains southwestward to Northern California will remain quasi-stationary through Saturday morning, when a reinforcing boundary will strengthen the front. Showers and thunderstorms will develop over the Great Basin and into the Northern Plains, with a strong diurnal component from late afternoon into late evening Friday and Saturday. Moreover, monsoonal moisture will produce showers and thunderstorms with moderate to heavy rain over parts of the Southwest from late Friday afternoon into late Saturday evening. The WPC has issued a Marginal Risk (level 1/4) of excessive rainfall over parts of the Southwest. The associated heavy rain will create localized areas of flash flooding, affecting areas that experience rapid runoff with heavy rain. Furthermore, upper-level impulses will produce showers and thunderstorms over parts of the Northern Plains/Upper Mississippi Valley on Friday and the Upper Mississippi Valley into the Upper Great Lakes on Saturday and Sunday. In addition, weak onshore flow and upper-level energy will help produce rain over parts of the Pacific Northwest on Friday and Saturday. Ziegenfelder Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php Extreme Heat Key Messages available at: https://www.wpc.ncep.noaa.gov/key_messages/LatestKeyMessage_1.png $$