The graphic from the NWS below shows the huge geographic extent of the flooding. If the symbol is yellow, orange, red or purple, that flood gauge is in flood or near flood.
Here is the rainfall for the 24-hours ending at 7 o'clock this morning.
More rain is forecast the next five days but the heaviest will be outside the worst-stricken areas with the exception of south Texas.
And, yes, there is a risk of tornadoes later today and tonight. The (brown) significant risk area extends from St. Louis and Memphis to Shreveport and Tyler.
AccuWeather.com and other sources for local warnings.