They must form in high humidity regions at least 5 degrees from the equator because the Coriolis effect is crucial to their initial rotation.
When two of these are near each other, the Fujiwhara effect occurs, resulting in their centers orbiting around a point in between the two systems. Their formation is aided by upper-level speed divergence in the vicinity of the jet stream coupled with weak surface convergence. They must form in high humidity regions at least 5 degrees from the equator because the Coriolis effect is crucial to their initial rotation. These systems are classified by winds reaching a 12 on the Beaufort scale. For 10 points name these tropical storm systems that contain areas of low pressure and warm circulation, an example of which sees a calm at its center or "eye."
When two of these are near each other, the Fujiwhara effect occurs, resulting in their centers orbiting around a point in between the two systems.
tropical cyclone [or hurricane; cylonic vortex; typhoon; tropical storm until mentioned; tropical depression; prompt on partial answers of any of these; do not accept “low pressure center” or “tropical wave”]