Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 353 PM EDT Fri Jul 21 2023 Valid 00Z Sat Jul 22 2023 - 00Z Mon Jul 24 2023 ...There is a Slight Risk of excessive rainfall over New England, Southern Plains to Southern Appalachians, and Southern High Plains on Friday... ...There is a Slight Risk of severe thunderstorms over parts of New England, Lower Mississippi Valley to the Southeast, and southern High Plains... ...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 Texas... A front and low pressure over New England will create showers and thunderstorms through Saturday evening. The showers and thunderstorms will produce heavy rain. Therefore, the WPC has issued a Slight Risk of excessive rainfall over parts of New England through Saturday morning. The associated heavy rain will create mainly localized areas of flash flooding, with urban areas, roads, and small streams the most vulnerable. In addition, the system will produce showers and severe thunderstorms. Therefore, the SPC has issued a Slight Risk of severe thunderstorms over parts of New England through Saturday morning. The hazards associated with these thunderstorms are frequent lightning, severe thunderstorm wind gusts, hail, and a few tornadoes. On Saturday, the threat of excessive rainfall and severe thunderstorms will end over New England. Furthermore, a front extending from the Southeast westward to the Southern Plains will produce showers and thunderstorms with heavy rain over parts of Oklahoma eastward to northwestern Georgia. Therefore, the WPC has issued a Slight Risk of excessive rainfall over parts of the Southern Plains/Lower Mississippi/Tennessee Valleys and Southern Appalachians through Saturday morning. The associated heavy rain will create mainly localized areas of flash flooding, with urban areas, roads, and small streams the most vulnerable. Similarly, the front will produce showers and severe thunderstorms. Therefore, the SPC has issued a Slight Risk of severe thunderstorms over parts of the Southern Plains/Lower Mississippi/Tennessee Valleys and Southern Appalachians through Saturday morning. The hazards associated with these thunderstorms are frequent lightning, severe thunderstorm wind gusts, hail, and a minimal threat of tornadoes. Moreover, upper-level energy over the Southern High Plains will create showers and thunderstorms with heavy rain over parts of eastern New Mexico. Therefore, the WPC has issued a Slight Risk of excessive rainfall over parts of the Southern High Plains through Saturday morning. The associated heavy rain will create mainly localized areas of flash flooding, with urban areas, roads, and small streams the most vulnerable. Additionally, the energy will produce showers and severe thunderstorms over parts of New Mexico. Therefore, the SPC has issued a Slight Risk of severe thunderstorms over parts of the Southern High Plains through Saturday morning. The hazards associated with these thunderstorms are frequent lightning, severe thunderstorm wind gusts, hail, and a minimal threat of tornadoes. On Saturday, the front extending from the Southeast to the Southern Plains moves southward over the Gulf Coast States. The system will continue to produce showers and thunderstorms. However, the threat of excessive rainfall and severe thunderstorms reduces slightly to a Marginal Risk of excessive rainfall and severe thunderstorms. The hazards for excessive rainfall will be moderate to heavy rain, creating localized areas of flash flooding, affecting areas that experience rapid runoff with heavy rain. The hazards associated with these thunderstorms are frequent lightning, strong to severe thunderstorm wind gusts, hail, and a minimal threat of tornadoes. Also, on Saturday, an area of upper-level energy will move across the Upper Mississippi Valley and the Central Plains, producing showers and strong to severe thunderstorms. Therefore, the SPC has issued a Marginal Risk of severe thunderstorms over parts of the Upper/Middle Mississippi Valley and Central Plains from Saturday into Sunday morning. The hazards associated with these thunderstorms are frequent lightning, strong to severe thunderstorm wind gusts, hail, and a minimal threat of tornadoes. On Sunday, showers and thunderstorms continue to develop along the front over the Gulf Coast States, producing moderate to heavy rain. Therefore, on Sunday, the WPC has issued a Marginal Risk of excessive rainfall over parts of the Central/Eastern Gulf Coast and parts of the Southeast. The associated heavy rain will create localized areas of flash flooding, affecting areas that experience rapid runoff with heavy rain. 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 parts of California, Nevada, Idaho, eastern Oregon, Arizona, southwestern New Mexico, eastern third of Texas, Louisiana, southern and eastern counties of Arkansas, most of Mississippi, Alabama, southern half of 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. Ziegenfelder Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php