Path & Speed
A tropical cyclone’s movement is mainly determined by the surrounding wind flows that steer it. The air in which the tropical cyclone is embedded is a constantly moving and changing "river" of air. Other features in that flow, such as high and low pressure systems, can greatly alter the speed and the path of the cyclone. In turn, it can modify the environment around the storm.
In the animation below, you can investigate how changes in position of lows, highs, and a hurricane itself can affect the path of the hurricane.
Some tropical cyclones follow a fairly straight course, while others loop and wobble along their path. For example, in 2004, Hurricane Jeanne (below) moved northward through the eastern Bahamas as a tropical storm and looked as if it might recurve harmlessly back out to sea. However, over the next few days it intensified while making a clockwise loop, before making landfall in Florida as a major hurricane.
Hurricane Jeanne (2004)
These changeable paths can be difficult to forecast, and they have important consequences for hazards. Typically, a tropical cyclone’s forward speed averages around 15 mph (24 km/h). However, some tropical cyclones stall, often causing devastatingly heavy rain. For example, Tropical Storm Allison (2001) moved slowly over eastern Texas and dumped over 30 inches (76 cm) of rain in Houston, causing extremely damaging flooding (see figure below). Others can accelerate to more than 60 mph (97 km/h). Hurricane Hazel (1954) hit North Carolina on the morning of 15 October; fourteen hours later it reached Toronto, Canada where it caused 80 deaths.
Storm total precipitation, Tropical Storm Allison (2001)