A funnel cloud or (rarely) a small, relatively weak tornado that can develop from a small shower or thunderstorm when the air aloft is unusually cold (hence the name).They are much less violent than other types of tornadoes. Winds often accelerate as they enter a confluent zone, resulting in speed divergence which offsets the (apparent) converging effect of the confluent flow.Air that descends an elevated plain and consequently warms and dries.
The structure typically is most pronounced on the leading edge of the updraft, while drier air from the rear flank downdraft often erodes the clouds on the trailing side of the updraft.
Includes winter storm conditions of sustained winds or frequent gusts of 35 mph or more that cause major blowing and drifting of snow, reducing visibility to less than one-quarter mile for 3 or more hours.
An area of low pressure around which winds blow counterclockwise in the Northern Hemisphere.
Also the term used for a hurricane in the Indian Ocean and in the Western Pacific Ocean.
In Australia, it is described as atmospheric circulations that rotate clockwise in the southern hemisphere, and anti-clockwise in the northern hemisphere.