Caution: Tornado Crossing
(Part 1 of 5) Yes, Dorothy, we're back in Kansas. This classic prairie tornado formed less than 30 seconds before crossing this lonely gravel section road in northern Kansas. Right as it did, the condensation funnel first touched ground -- although the tornadic circulation probably was fully down just before. We had turned west on this road after seeing amazingly fast rising and sinking motions suddenly form around what had been a ragged wall cloud. The clear slot is classic supercell structure, formed as sinking air evaporates cloud material and wraps around the mesocyclone. The rotating slice of sinking air really is part of the mesocyclone, and is called the occlusion downdraft. The occlusion downdraft is a small part of the thunderstorm's entire rear-flank downdraft (RFD), which extends well away from the mesocyclone.
5 SSW Stockton KS (15 May 99), looking W