- This very peculiar cloud column appeared in Warrenton, Va., on Wednesday, Sept. 28, 2011. (Kathy)
Hey folks: Technically I'm on vacation, so I am putting the ball in your court today. ABC7 viewer Kathy sent this photo yesterday to senior meteorologist Bob Ryan, wondering what in tarnation it could be. She says:
I took this picture from my back porch in Warrenton, Va. [on Wednesday] about 7:00 p.m.... We did see some rotation in the clouds. There was rain and wind before we saw it, and then more rain and wind after. It was not raining when I took the pictures, but it was very windy and the clouds were moving very fast.
The weather guys here are on the case, but feel free to hop down to the comments section with your informed explanations, total shots in the dark or wacky UFO conspiracies. This column of air will not go unexamined! I will check back in on Monday. (And that's the Blue Ridge and Skyline Drive about 20 miles in the distance, if you were wondering.)
BOB RYAN ADDS: The picture was not taken by Dorothy and I don't think it is a tornado. Here's the definition - according to the Glossary of Meteorology (AMS 2000), a tornado is "a violently rotating column of air, pendant from a cumuliform cloud or underneath a cumuliform cloud, and often (but not always) visible as a funnel cloud." Well it sure looks like a tornado and Kathy did see some rotation but it was not "violently rotating". A shower had just passed and if you look closely you can see some fog in the low spots and even a few plumes of fog that look like wisps of smoke. The air was damp/humid with a relative humidity of almost 100% and so I think what we are seeing is an updraft or rising column of air creating the clouds above that is rotating a bit and enough to lower the air pressure and form what my colleague Doug Hill called a "moist updraft". Updrafts that form those puffy cumulus clouds do have rotation as all air does on our rotating earth. Remember seeing a hawk or eagle soaring in a circle in the air? They are rising on a slowly rotating updraft.
I also sent the picture to a couple of friends at the local NWS forecast office, one of whom studied under my friend Howie Bluestein one of the great tornado researchers, and they don't think it really could be called a tornado either. But it is something and a great photo. Maybe we just call it a scary moist updraft. What do you think?