332 FXUS01 KWBC 051959 PMDSPD Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 358 PM EDT Wed Aug 05 2026 Valid 00Z Thu Aug 06 2026 - 00Z Sat Aug 08 2026 ...Western heat wave expands into the Intermountain West, Rockies, and the central/southern Plains through the end of the week... ...Unsettled and stormy weather continues for portions of the Southwest and much of the eastern half of the U.S. the next few days... ...Poor air quality remains in place for parts of the Pacific Northwest, Great Basin, Intermountain West, and the Rockies... The dome of high pressure which brought an extended heat wave to the Western U.S. the last several days will gradually amplify across the Great Basin, Four Corners, and Southwest through Friday into Saturday. In response, increasingly hot weather will expand eastward through the Intermountain West, Rockies, and the central/southern Plains, with high temperatures surging well into the 90s and 100s. Widespread moderate to major HeatRisk is likely. A wavy frontal boundary stretching from the southern Plains to the Midwest to the Northeast will foster the development of scattered showers and thunderstorms across much of the eastern U.S. the next few days. Along and south of this boundary, southerly flow will supply a steady stream of Gulf moisture. This moisture when combined with strong daytime heating will lead to elevated instability and the potential for high rainfall rates. If storms are slow-moving or repeatedly train over the same areas, isolated to scattered flash flooding will be possible, especially for low-lying, poor drainage, and urban areas. Another front pushing into the Upper Midwest and western Great Lakes on Friday could also spark a few strong to marginally severe thunderstorms across the Upper Mississippi Valley. Additionally, monsoonal moisture will likely produce daily showers and thunderstorms with the threat of locally heavy rain and isolated flash flooding over parts of the Southwest during the afternoon and evening hours through the end of the week. Ongoing fires across parts of the Pacific Northwest, Great Basin, Intermountain West and the Rockies will continue to produce large plumes of dense and persistent smoke the next several days. As a result, air quality will likely remain poor for parts of these regions through the end of the week. Air quality alerts remain in effect, highlighting the potential for adverse health effects for people who are particularly sensitive to poor air quality. This includes children, the elderly, and persons with respiratory problems. Miller Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php $$