Weather across America

(NATIONAL) Heavy lake-effect snow downwind from Lakes Erie and Ontario, snow over the Southwest and Southern Rockies, a Slight Risk of excessive rainfall over parts of the Central Gulf Coast, and a Marginal Risk of severe thunderstorms over parts of the Central Gulf Coast and Florida.

A front extending from Maine over the Western Atlantic, coming back onshore over the Southeast, and stretching across the Gulf Coast on Sunday will slowly move southward across Florida by Monday evening. A wave of low pressure on the boundary over the Central Gulf Coast moves eastward to the Southeast by Monday. The circulation around the low will pull moisture off the Gulf of Mexico, aiding in the production of showers and thunderstorms with heavy rain over parts of the Central Gulf Coast. 

Therefore, the WPC has issued a Slight Risk (level 2/4) of excessive rainfall over parts of the Central Gulf Coast through Monday 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 thunderstorms will be strong to severe along parts of the Central/Eastern Gulf Coast. 

Therefore, the SPC has issued a Marginal Risk (level 1/5) of severe thunderstorms over parts of the Central/Eastern Gulf Coast through Monday morning. The hazards associated with these thunderstorms are frequent lightning, severe thunderstorm wind gusts, and a minimal threat of tornadoes and hail. On Monday, the threat of excessive rainfall ends over the Gulf Coast. 

However, the threat of showers and strong to severe thunderstorms moves over Florida. Therefore, the SPC has issued a Marginal Risk (level 1/5) of severe thunderstorms over parts of Florida from Monday into Tuesday morning. The hazards associated with these thunderstorms are frequent lightning, severe thunderstorm wind gusts, and hail, with a minimal threat of tornadoes. 

By Tuesday, the showers and thunderstorms move off the southern tip of Florida as the front moves offshore. Meanwhile, upper-level energy over the Upper Midwest into the Northeast will aid in creating lake-effect snow downwind from the Great Lakes, with moderate to heavy snow downwind from Lakes Erie and Ontario through Tuesday evening. Additionally, moderate snow will develop over the higher elevations of the Northeast, with snow showers over parts of the Ohio Valley and the Central Appalachians through Tuesday afternoon. 

Moreover, an upper-level low over the Four Corners Region will produce snow and lower-elevation rain over parts of the Southwest and Southern Rockies, lingering through Tuesday. Furthermore, a second front moving south and eastward from Central Canada will move over parts of the Northern Plains/Upper Mississippi Valley on Monday afternoon, moving to the Great Lakes by Tuesday. The system will produce light snow over parts of the Upper Mississippi Valley overnight Monday and of the Upper Great Lakes on Tuesday.