We cover a lot of storm chasing here on Jalopnik, mainly because of the insane super-vehicles the scientists use. That's not to say that the video they sometimes shoot becomes awe-inspiring in its own right, like the view from inside a tornado or this super cell over Texas.
Shot by storm chaser Mike Olbinski, a disciple of the late Tim Samaras, near the Texas-Oklahoma border, the spinning rotation is not actually indicative of a tornado about to form, although it is possible. The mechanics are a bit more complex, according to Wired Science:
The rotating, barrel-like “wall cloud” that hangs beneath the cloud ceiling is the column through which supercell storms “breathe in” hot, humid air, creating a powerful rotating updraft, says NASA Goddard Space Flight Center atmospheric scientist Anthony Didlake.
“Generally in the Great Plains, you have southerly winds bringing warm, moist air from the Gulf of Mexico near the surface, and westerly winds bring cooler, drier air off of the Rockies,“ Didlake said. The angle at which these forces collide is what sets off the eddy-like spin of the supercell.
The fast movement of the clouds along with the brief flashes of lightning remind me of the motherships from Independence Day. Even if I knew for certain that the storm would not produce a tornado, I'd probably be running the other way.
Although that could just be my astraphobia.