Weather across America

(NATIONAL) A Marginal Risk of excessive rainfall over parts of the Mid-Atlantic to the Central Gulf Coast, a Slight Risk of severe thunderstorms over parts of the Southern Appalachians and western Carolinas, excessive heat warnings and advisories across the US, and 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 western North/South Carolina. Therefore, the SPC has issued a Slight Risk of severe thunderstorms over parts of the Southern Appalachians and western Carolinas through Monday morning. The hazards associated with these thunderstorms are frequent lightning, severe thunderstorm wind gusts, and a minimal threat of tornadoes and hail. 

The showers and thunderstorms will also produce moderate to heavy rain over parts of the Mid-Atlantic to the Central Gulf Coast. Therefore, through Monday morning, the WPC has issued a Marginal Risk of excessive rainfall over parts of the Mid-Atlantic to the Central Gulf Coast. The associated heavy rain will create localized areas of flash flooding, affecting areas that experience rapid runoff with heavy rain. Additionally, on Sunday, upper-level energy over the Northern/Central Plains will create showers and thunderstorms over parts of the Northern/Central Plains.  

Furthermore, upper-level energy over the Southwest will create showers and thunderstorms with moderate to heavy rain over parts of southern Nevada, Arizona, and far western New Mexico. Therefore, the WPC has issued a Marginal Risk of excessive rainfall over parts of the Southwest through 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 continue over parts of the Mid-Atlantic/Northeast, creating moderate to heavy rain. Therefore, the WPC has issued a Marginal Risk of excessive rainfall over parts of the Mid-Atlantic/Northeast from Monday into Tuesday 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 and moisture over the Midwest will create showers and thunderstorms with moderate to heavy rain over parts of the Midwest. Therefore, the WPC has issued a Marginal Risk of excessive rainfall over parts of the Middle Mississippi Valley from Monday into Tuesday morning. The associated heavy rain will create localized areas of flash flooding, affecting areas that experience rapid runoff with heavy rain. 

Further, upper-level energy trapped under the upper-level high over the Southeast will create showers and thunderstorms with moderate to heavy rain over parts of Utah, southern Nevada, and Arizona. Therefore, the WPC has issued a Marginal Risk of excessive rainfall over parts of the Southwest and Great Basin from Monday into Tuesday morning. The associated heavy rain will create localized areas of flash flooding, affecting areas that experience rapid runoff with heavy rain.  

On Tuesday, showers and thunderstorms over the Southwest will expand northeastward into the Central/Southern Rockies, developing areas of Moderate to heavy rain over parts of the Southwest, Central/Southern Rockies, and Great Basin. Therefore, on Tuesday, the WPC has issued a Marginal Risk of excessive rainfall over parts of the Southwest, Central/Southern Rockies, and Great Basin. 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 will bring hot high temperatures and hot low temperatures that will contribute to areas not cooling off overnight, which have contributed to Excessive Heat Warnings and Heat Advisories over portions of California, the Northern Intermountain Region, Southwest, Northern Plains, southern third of Texas, the southern tip of Florida and the Great Basin. 

In addition, moisture moving into the Southwestern portion of the country has reduced the areal coverage of the Excessive Heat Warnings and Heat Advisories. 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.