Speaker Notes:

• The Rear Flank Downdraft (RFD) is the clearing slot on the back side of the supercell thunderstorm. This is formed by upper level winds interacting with the updraft of the thunderstorm, and being forced downward.

• Researchers think the RFD is a key component to the formation of tornadoes. This downward motion of air helps bring the rotation from the cloud down to the ground. In fact some studies suggest if an RFD is observed, then a tornado is likely and it will be a large tornado.

• RFD’s are rare in this part of the country.