MEMPHIS, Tenn. (WMC) - Tropical funnels are similar to cold air funnels but differ from funnel clouds that form in supercell thunderstorms. Supercells can produce the more typical tornado which most of us are familiar with during strong storms.
Tropical funnels form in environments where you have high humidity and windy conditions. These type of funnel clouds form quickly and usually dissipate after just a few minutes. Funnel clouds are caused by vertical stretching of vorticity. Vorticity can be thought of as “spin” in the atmosphere, and is usually produced by wind shear.
As vorticity is stretched vertically, the area of rotation gets smaller and the spinning air speeds up. The more common funnel clouds from supercell thunderstorms have the same process overall, however with tropical funnels the process is on a smaller/slower scale. This leads to these funnel clouds having shorter life-cycles and much weaker wind speeds.
Tropical air funnel clouds are usually pretty high in the sky and can look pretty frightening. Tropical funnels are usually small and weak due to the slower rotation than that of a classic supercell type storm. The good news is that they don’t usually make it down to the ground. On rare occasions they can produce winds of up to 70 mph, but typically there is minimal to no damage.
In addition, one important thing of note is that a tornado does not exist until the rotation is in contact with the base of the cloud and reaches the ground. If it has no contact with the ground, it is considered a funnel cloud.