Cyclone
- This article is about the meteorological phenomenon. For other uses of the term see Cyclone (disambiguation).
In meteorology, a cyclone can refer to one of several different meteorological phenomena. Due to ambiguity most weather forecasters avoid using the term cyclone without a qualifying term.
The term normally refers to a wind and rain storm associated with a region of atmospheric low pressure. The cyclonic winds rotate around a common center. Rotation is counter-clockwise in the northern hemisphere, or clockwise in the southern hemisphere. The storms are termed Hurricanes, typhoons or tropical cyclones, depending where they form and how strong they are.
Tropical cyclones with maximum sustained surface winds of less than 17 m/s (34 kt, 39 mph) are called a tropical depression.
Once the tropical cyclone reaches winds of at least 17 m/s (34 kt, 39 mph) they are typically called a tropical storm and assigned a name.
If winds reach 33 m/s (64 kt, 74 mph), then they are called a hurricane.
In North America, a tornado may also be called a cyclone. This usage has gone out of favour in recent years as professional weather forecasters have avoided using the term in this way.
See also
