Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 356 AM EDT Wed Aug 17 2022 Valid 12Z Wed Aug 17 2022 - 12Z Fri Aug 19 2022 ...There is a Slight Risk of excessive rainfall over parts of the Southern Rockies and Southwest through Thursday morning... ...There is a Slight Risk of excessive rainfall over parts of Southwest and a second area over parts of the Southeast from Thursday into Friday morning... ...There is a Slight Risk of excessive rainfall over parts of the Lower Mississippi Valley/Central Gulf Coast through Thursday morning... ...There is an Excessive Heat Watch and Heat Advisory over parts of the West Coast through Friday... Monsoonal moisture and upper-level energy moving out of the Central Rockies will aid in producing diurnal showers and thunderstorms with heavy rain over parts of Colorado and New Mexico. Therefore, the WPC has issued a Slight Risk of excessive rainfall over parts of the Southern Rockies through Thursday 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, an upper-level low over parts of North-Central Mexico will continue to move eastward while weakening through Friday. Ample moisture and upper-level energy will aid in producing showers and thunderstorms with heavy rain over southern Arizona, southern New Mexico, and far western Texas. Therefore, the WPC has issued a Slight Risk of excessive rainfall over the Southwest near the U. S./Mexican border into far western Texas through Thursday morning. The associated heavy rain will create mainly localized areas of flash flooding, with urban areas, roads, and small streams the most vulnerable. On Friday, the energy and moisture will aid in producing showers and thunderstorms with heavy rain over southern Arizona and southwestern New Mexico. Therefore, the WPC has issued a Slight Risk of excessive rainfall over the Southwest near the U. S./Mexican border from Thursday into Friday morning. The associated heavy rain will create mainly localized areas of flash flooding, with urban areas, roads, and small streams the most vulnerable. Meanwhile, a weak front extending from the Southeast roughly westward to the Southern Plains and upper-level impulses will produce showers and thunderstorms, with heavy rain over parts of Mississippi and Alabama. Therefore, the WPC has issued a Slight Risk of excessive rainfall over parts of the Lower Mississippi Valley/Central Gulf Coast through Thursday 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, as the waves of low-pressure move along the front on Thursday, tropical moisture will aid in producing showers and thunderstorms over the Gulf Coast States into the Southeast. Therefore, the WPC has issued a Slight Risk of excessive rainfall over parts of the Southeast from Thursday into Friday morning. The associated heavy rain will create mainly localized areas of flash flooding, with urban areas, roads, and small streams the most vulnerable. Elsewhere, upper-level ridging will build into California and the Northwest, allowing temperatures to rise into the mid-to-upper hundreds over parts of California, prompting an Excessive Heat Watch and Heat Advisories over the Sacramento and San Joaquin Valleys through Friday. As the upper-level ridging builds over the Northwest, temperatures climb into the upper nineties to low hundreds over the interior Northwest, prompting Excessive Heat Watch and Heat Advisories over the region into Friday. Additionally, record-breaking relatively high low temperatures will contribute to areas not cooling off overnight, which will also contribute to the effects of heat. Ziegenfelder Graphics are available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php