Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 400 PM EDT Sat Jul 22 2023 Valid 00Z Sun Jul 23 2023 - 00Z Tue Jul 25 2023 ...There is a Marginal Risk of excessive rainfall over parts of the Southeast to the Central Gulf Coast... ...There is a Slight Risk of severe thunderstorms over parts of the Central Plains and Central Gulf Coast to the Southeast... ...Excessive Heat Warnings and Advisories from parts of California, the Northern Intermountain Region, Southwest, and the Great Basin; a second area from the Southeast to the Western Gulf Coast... ...There are Air Quality Alerts over parts of the Upper Mississippi Valley... A front extending from the Southeast westward to the Southern Plains will produce showers and severe thunderstorms over parts of the Southeast to the Central Gulf Coast. Therefore, the SPC has issued a Slight Risk of severe thunderstorms over parts of the Southeast to the Central Gulf Coast through Sunday morning. The hazards associated with these thunderstorms are frequent lightning, severe thunderstorm wind gusts, hail, and a minimal threat of tornadoes. The showers and thunderstorms will also produce moderate to heavy rain over parts of the Southeast to the Central Gulf Coast. Therefore, the WPC has issued a Marginal Risk of excessive rainfall over parts of the Southeast to the Central Gulf Coast through Sunday morning. The associated heavy rain will create localized areas of flash flooding, affecting areas that experience rapid runoff with heavy rain. Moreover, upper-level energy over the Central Plains will create showers and severe thunderstorms over parts of the Central Plains. Therefore, the SPC has issued a Slight Risk of severe thunderstorms over parts of the Central Plains through Sunday morning. The hazards associated with these thunderstorms are frequent lightning, severe thunderstorm wind gusts, hail, and a minimal threat of tornadoes. Additionally, there is an increased threat of hail two inches or greater over western Kansas. Furthermore, upper-level energy over the Southwest to Southern High Plains will create showers and thunderstorms with moderate to heavy rain over parts of the Southwest eastward to the Central/Southern High Plains. Therefore, the WPC has issued a Marginal Risk of excessive rainfall over parts of the Southwest eastward to the Central/Southern High Plains through Sunday morning. The associated heavy rain will create localized areas of flash flooding, affecting areas that experience rapid runoff with heavy rain. On Sunday, showers and thunderstorms will continue along a front over the Gulf Coast to the Southeast, with troughing extending into the Mid-Atlantic, creating moderate to heavy rain. Therefore, the WPC has issued a Marginal Risk of excessive rainfall over parts of the Central Gulf Coast to the Southeast and northward into the Mid-Atlantic from Sunday into Monday morning. The associated heavy rain will create localized areas of flash flooding, affecting areas that experience rapid runoff with heavy rain. Moreover, upper-level energy trapped underneath and upper-level high over the Southwest will create showers and thunderstorms with moderate to heavy rain over parts of the Southwest. Therefore, the WPC has issued a Marginal Risk of excessive rainfall over parts of the Southwest from Sunday into Monday morning. The associated heavy rain will create localized areas of flash flooding, affecting areas that experience rapid runoff with heavy rain. On Monday, showers and thunderstorms will develop over parts of the Mid-Atlantic/Northeast, Upper/Middle Mississippi Valley, and Southwest. Meanwhile, upper-level high over California/Great Basin/Southwest and upper-level ridging into parts of the Southeast, bringing hot high temperatures and low temperatures not cooling off much overnight, which have contributed to Excessive Heat Warnings and Heat Advisories over portions of California, Nevada, Idaho, eastern Oregon, and Arizona and a second area over part the Western Gulf Coast, southern Louisiana, southern Mississippi, southern Alabama, southern Georgia, and Florida. In addition, the upper-level ridge/high has also contributed to a dangerous, long-lived, and record-breaking heat wave that will continue over the Southwest this weekend, particularly in the low desert areas, with triple-digit high temperatures extending northward into the Central Great Basin. Temperatures next week are forecast to remain hot but return closer to average. Additionally, oppressive heat and humidity are expected to create widespread 105-115 degree heat indices across the Mid-South, Southeast, and Gulf Coast through early this weekend. Relief arrives by Sunday for most areas as a cold front approaches the northern Gulf Coast. Take the heat seriously and avoid extended time outdoors. Temperatures and heat indices will reach levels that would pose a health risk to anyone without effective cooling and/or adequate hydration. Nighttime temperatures will provide very little relief. Heat is the leading weather-related killer in the U.S. Lastly, smoke from wildfires in Central Canada will reduce air quality over parts of the Upper Mississippi Valley prompting Air Quality Warnings over the area. Ziegenfelder Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php