No offense at any of these suggestions, but this tornado was not necessarily something easily spotted until it was already past. The rain was coming down in sheets and the tornado, itself, seemed to be rain-wrapped and most of the folks that were seeing it were from the south looking north at it, correct? While tornados in this area are not as common as further north up the 'alley,' taking precaution is always a good idea because any storm in the midwest has the potential to turn severe. For every 'turn around and don't drown,' my momma used to say, 'don't look at the sky and wonder why (as in why are things swirling around in the air?) --go hide.' Useful advice when our neighborhood got hit many years ago.
As far as sirens go, they can be okay, but having grown up with them they are sometimes hard to hear over storm noise etc. In rural areas, battery operated weather radios may be an alternative.
*Edit to add--I love that movie, Dufflepud....