Severe storms may erupt from Oklahoma to Minnesota Monday afternoon and into Monday night.
Rising temperatures and humidity across the mid-Atlantic will have it feeling like the end of June.
Slow-moving showers and storms will bring heavy rain and flooding potential.
Heavy rain returning to the northern Plains will generate a renewed flood threat for the Red River.
More than 20 tornadoes were reported by the National Weather Service with hundreds of hail and wind reports Sunday afternoon through Sunday night.
Several tornadoes touched down from Oklahoma to Iowa, including near Wichita, Kan., and Oklahoma City, on Sunday.
Severe storms may erupt from Oklahoma to Wisconsin on Monday as the storm system that spawned several tornadoes across the Plains on Saturday and Sunday shifts slowly to the east.
Normal snowfall for the month of May is 13 cm (5 inches), according to Environment Canada (EC).
A slow-moving storm resulted in a week of below-normal temperatures that will likely continue into the week.
Smoke from fires in the Yucatan Peninsula will continue to affect parts of Texas and Louisiana for the first part of the week.
Despite advancements in tornado warning systems, 60 people die each year from tornadoes. This raises the question: why do people ignore tornado warnings?
Niagara, Ontario (1996)
During a showing of the movie "Twister" at a local drive-in, a real twister struck. There was some flying debris, but nobody was hurt.
Ft. Myers, FL (1985)
A hospital and several homes were evacuated due to brush fires.
Tornado has 70 mile long track that ends in Kansas City suburb. 48 people died.