Just saw this thread and am not going to read all the suggestions. So what I have to say has probably already been said. If so, sorry for being repetitive.
During our 14+ yrs of full timing we ran into this numerous times. Having come from an area with frequent tornado watches and warnings, it was pretty easy to recognize well ahead the general conditions favorable to tornados. Upon check in, ask the cg manager where to go in the event of a tornado warning. Most cgs have an area map included in their checkin package. Write down the name of the county you are in and the adjoining county names at the appropriate sides or corners of the map. Have the host locate the nearest hospital on the map (good place to ride out a warning if the cg doesn't have a shelter). Knowing what counties are on what sides of you can help you track local radio reports of weather movement. Have a good radar app on your smart phone and know how to read it and, of course, have an emergency weather radio.