Mushroom

Mushroom - [Slang], a thunderstorm with a well-defined anvil rollover, and thus having a visual appearance resembling a mushroom.
USA Immigration Services ...

Mushroom - A thunderstorm with a well-defined anvil rollover, and thus having a visual appearance resembling a mushroom.

With the cotton thread cut off the top part of the cyclone (like you cut off the head of a mushroom). Put the it back and show how the top part of the cyclone turns in the opposite direction to the bottom.

Anvil rollover - [slang] a circular or semicircular lip of clouds along the underside of the upwind part of a back-sheared anvil, indicating rapid expansion of the anvil. See cumuliform anvil, knuckles, mushroom.

often implies a very strong updraft and a high severe weather potential.
NOAA National Weather Service - Cite This Source - This Definition
Browse Related Terms: Anvil, Anvil Dome, Anvil Rollover, CB, CBMAM, Cumuliform Anvil, Knuckles, Mushroom, ...

cumulus-type clouds (rather than the more typical fibrous appearance associated with cirrus). A cumuliform anvil arises from rapid spreading of a thunderstorm updraft, and thus implies a very strong updraft. See anvil rollover, knuckles, mushroom.

clouds (rather than the more typical fibrous appearance associated with cirrus). A cumuliform anvil arises from rapid spreading of a thunderstorm updraft, and thus implies a very strong updraft. See anvil rollover, knuckles, and mushroom.

See anvil rollover, knuckles, mushroom.Cumulus(Abbrev. CU) - detached clouds, generally dense and with sharp outlines, showing vertical development in the form of domes, mounds, or towers.

fungi Molds, mildews, yeasts, mushrooms, and puffballs, a group of organisms that lack chlorophyll and therefore are not photosynthetic. They are usually nonmobile, filamentous, and multicellular.

See also: Horizon, Thunder, Storm, Thunderstorm, Stability