Ed DunhamAdministrator
(Former Meteorologist & CFHC Forum Moderator (Ed Passed Away on May 14, 2017))
Sun Jul 06 2008 12:23 AM
Re: Question about Storm Formation - July 3rd, 2008 incident

From your description it seems like you viewed the rotating base of a mesocyclone. Mesocyclones are thunderstorms, sometimes massive ones, where the entire thunderstorm (or most of it) achieves rotation. They are often precursors of funnel clouds/tornadoes that form within the mesocyclone itself and this rotating collar cloud can be very close to the ground. It projects downward, often dramatically, from the base of the thunderstorm.
Cheers,
ED



Note: This is NOT an official page. It is run by weather hobbyists and should not be used as a replacement for official sources. 
CFHC's main servers are currently located at Hostdime.com in Orlando, FL.
Image Server Network thanks to Mike Potts and Amazon Web Services. If you have static file hosting space that allows dns aliasing contact us to help out! Some Maps Provided by:
Great thanks to all who donated and everyone who uses the site as well. Site designed for 800x600+ resolution
When in doubt, take the word of the National Hurricane Center