Funnel cloud vs. tornado
The difference between a funnel cloud and a tornado is very tenuous. It was pushed by the NWS in decades past but the emphasis on the distinction is now considered counterproductive (and somewhat erroneous) for several reasons. Many times there is a strong surface circulation (thus tornado) without full condensation, many times visibly indicated only by swirling debris. Many large tornadoes (such as multiple-vortex bowl type) during periods of their lifetime have continuous damaging circulation(s) at the ground only indicated by occasional suction vortices' condensation and swirling debris. Other tornadoes, particularly in arid areas, have no visible funnel. As a general guideline, if a funnel cloud extends at least half way to the ground, there very likely (but not certainly) is a strong circulation at the surface (tornado). Emphasis should be on debris swirl at the surface, not condensation.
The actual idea that developing tornadoes descend, sometimes indicated by (descending) funnels, is erroneous; in actuality the vortex forms at about the same time at various heights --at the surface from tightening of vorticity (with plausible exceptions that aren't yet known). It should be noted that tornadogenesis is complex and can transpire in infinite ways. The visible funnel mostly occurs as pressure drops enough for condensation, and this is easier accomplished higher up giving the impression of a descending funnel. Spotters are now trained to be very observant of the surface under funnels and rotating wall clouds (and to a lesser extent in general, since quite a few tornadoes form without a preceding funnel or wall cloud; and other things of interest at the surface may be missed if one only monitors the cloud base).
The classic conception of a tornado is *the funnel* (which remember is incorrect); distinctions are difficult and prone to error. The conception of funnels as incipient tornadoes and as a separate phenomenon is incorrect and is strongly discouraged. Emphasis on funnel clouds (and condensation in general) invites a lot of confusion and mistakes; wind constitutes the tornado.
Funnel clouds and tornadoes from the perspective of the vortex rather than the visible condensation are (kinematically, dynamically, and morphologically) nearly the same thing. Also worth noting is that there is an assortment of funnel varieties; for example, so called "shear funnels" are not of the same process and will not become tornadoes. Even (details of) the tornado itself is tenuous (thus further complicating funnel clouds); whilst there is a largely agreed upon general definition of a tornado, there has never been (extensive) peer review delineating a definition. Tornadoes and tornadogenesis are becoming more and more complex than previously believed.
Given all of this, I have added funnel clouds to the tornado category. Funnel clouds having its own article is fine, however, some of the funnel clouds are actual tornadoes and are mislabeled. Issues I've raised need to be addressed with any text in the articles. Skyodyssey 21:20, 15 December 2005 (UTC)