I always come back to this image from NCAR when seeking to introduce the idea that predictability is a function of the scale of the event. Individual thunderstorms have low practical and inherent predictability; we simply cannot *reliably* predict when and where they will occur beyond a few hours.
Based on some of the reactions and comments I am absorbing by average people and elected officials, I think there needs to be a serious explanation and lesson on what the limits of predictability are for floods like the one in Texas.