Final answer:
Hurricane forecasts use measurements of wind speeds to predict the potential impact of the storm. The energy relates to the cube of wind velocity, while categories are based on minimum wind speeds. Measurements involve calculations and observations of the system's rotations, vorticity, and the effects of Earth's rotation.
Step-by-step explanation:
Hurricane forecasts often refer to wind speeds measured by various meteorological instruments and techniques. One key aspect of these measurements is understanding that the wind speeds are highest near the eye of the hurricane and that the energy of a storm increases dramatically with the wind speed, following a cubic relationship. These winds develop over warm ocean waters and are part of a larger system involving rapid air movement, heavy rains, and rotational cyclonic patterns due to the Earth's rotation. Forecasters use this data to predict hurricane strength, direction, and potential damage.
Wind speeds can be approximated by calculations such as speed equals distance divided by time, using the storm’s circumference and rotation period. For example, a storm with a diameter of 400 km rotating once every 24 hours would yield a wind speed at the edge of the storm of about 52 km/h. More sophisticated models also consider factors such as relative vorticity, the conservation of angular momentum, and differences in air pressure to make more comprehensive predictions.
A hurricane’s category rating is based on its minimum wind speed, which helps to determine the potential for damage. As hurricanes move over land, the friction with the surface reduces wind speeds, altering the impact compared to over open water.