Thanks to Nancy Olson for sending in a photo of a funnel cloud near New Windsor, Illinois. It occurred on Sunday afternoon under a rapidly developing cumulus cloud.
And yes, funnel clouds like these can happen without any rain or thunderstorm activity. Quite simply, a funnel like this is a product of the tremendous upward movement of air within the cloud. As that air moves upward, it produces a cyclonic twist under the base of the cloud…much like what happens if you pull the plug on a bathtub.
Usually, these funnels only grow to about 100 feet down from the base of the cloud. Very rarely do they ever touch the ground. Conditions will be similar across Eastern Iowa and Western Illinois today.
-Meteorologist Eric Sorensen
