Heavy lake-effect snow downwind from Lakes Erie and Ontario; snow overthe Southwest/Southern Rockies.There is a Slight Risk of excessive rainfall over parts of the CentralGulf CoastThere is a Marginal Risk of severe thunderstorms over parts of theCentral Gulf Coast and Florida.A front extending from Maine over the Western Atlantic, coming backonshore over the Southeast, and stretching across the Gulf Coast on Sundaywill slowly move southward across Florida by Monday evening. A wave of lowpressure on the boundary over the Central Gulf Coast moves eastward to theSoutheast by Monday. The circulation around the low will pull moisture offthe Gulf of Mexico, aiding in the production of showers and thunderstormswith heavy rain over parts of the Central Gulf Coast. Therefore, the WPChas issued a Slight Risk (level 2/4) of excessive rainfall over parts ofthe Central Gulf Coast through Monday morning. The associated heavy rainwill 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 theCentral/Eastern Gulf Coast. Therefore, the SPC has issued a Marginal Risk(level 1/5) of severe thunderstorms over parts of the Central/Eastern GulfCoast through Monday morning. The hazards associated with thesethunderstorms are frequent lightning, severe thunderstorm wind gusts, anda 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 movesover Florida. Therefore, the SPC has issued a Marginal Risk (level 1/5) ofsevere thunderstorms over parts of Florida from Monday into Tuesdaymorning. The hazards associated with these thunderstorms are frequentlightning, severe thunderstorm wind gusts, and hail, with a minimal threatof tornadoes. By Tuesday, the showers and thunderstorms move off thesouthern tip of Florida as the front moves offshore.Meanwhile, upper-level energy over the Upper Midwest into the Northeastwill aid in creating lake-effect snow downwind from the Great Lakes, withmoderate to heavy snow downwind from Lakes Erie and Ontario throughTuesday evening. Additionally, moderate snow will develop over the higherelevations of the Northeast, with snow showers over parts of the OhioValley and the Central Appalachians through Tuesday afternoon.Moreover, an upper-level low over the Four Corners Region will producesnow and lower-elevation rain over parts of the Southwest and SouthernRockies, lingering through Tuesday.Furthermore, a second front moving south and eastward from Central Canadawill move over parts of the Northern Plains/Upper Mississippi Valley onMonday afternoon, moving to the Great Lakes by Tuesday. The system willproduce light snow over parts of the Upper Mississippi Valley overnightMonday and of the Upper Great Lakes on Tuesday.