A low-pressure system emerging will cross the Midwest while turning northeastward and strengthening.  An enhanced threat of severe thunderstorms will peak into Tuesday across the South, especially from the lower Mississippi Valley eastward.  Despite the severe-weather threat, thunderstorms will provide much-needed rain in key drought areas, with event-total precipitation expected to reach 1 to 2 inches or more from the Mississippi Delta to the Atlantic Coast, excluding Florida’s peninsula.  Later in the week, cool air will trail the departing storm system, especially from the northern Plains into the Northeast. 

…