The unmarked photograph below is one I snapped of a tornado in Carson County, NE of Amarillo. To the weather novice it is jut s a cool picture of a twister but to a storm spotter it is a portrait of the mechanics that come together to make up a tornado.
Click on each picture to get an enlarged view.
I've also posted labeled versions of the same picture, highlighting areas that are of interest to storm spotters.
Especially of note is the "dry notch" caused by the Rear Flanking Downdraft AKA RFD. Many storm spotters have noticed this clear area forming just prior to the spawning of a tornado. The RFD is composed of winds rushing down behind the storm, forced down by slamming into the jet-stream high above. Once the RFD hits the ground it spreads out with some of the winds possibly enhancing the wind divergence (and thus spin) in the storm
Other features of note are the "Beaver Tail" a jet of moist air feeding into the updraft adding even more fuel to the fire metaphorically speaking. The Beaver Tail can be see on the right side of the photo (click on the picture to enlarge) as a cloud formation leading into the wall cloud.