A major and widespread severe thunderstorm and tornado outbreak is now underway across the Ohio and Tennessee Valleys and parts of the Deep South. There have already been reports today of tornadoes and baseball-sized hail across southwest Illinois and northern Alabama and the worst is yet to come as the daytime heating continues to intensify. The overall atmospheric setup continues to suggest very dangerous conditions this afternoon and evening across this large part of the country. To begin with, a strong and intensifying low pressure system is currently located over southern Illinois and it is pulling slowly towards the Great Lakes. Additionally, very warm and humid air is being funneled northward from the Gulf of Mexico by this low into the Midwest and Deep South at the same time cold air is barreling southeastward across the central Plains. In fact, it is snowing hard right now across northern Missouri, eastern Iowa and southeastern Wisconsin. The highest risk for severe thunderstorms and tornadoes over the next few hours (1-4PM central time) will be across southwestern Indiana, western Kentucky and western Tennessee so be prepared to take cover in those areas. This storm system will weaken before it begins to affect the Mid-Atlantic region early this evening; nonetheless, we’ll experience periods of rain, some of which can be heavy at times, gusty winds and possible thunderstorms right through tomorrow morning. Colder air follows tomorrow’s cold frontal passage to begin the new week with temperatures on Monday some twenty degrees colder than tomorrow’s expected highs.