TROPICAL DEPRESSION, TROPICAL STORM AND HURRICANE- WHAT IS THE DIFFERENCE?

By: Patricia Cermignano

Do you know the difference between a tropical depression, a tropical storm and a hurricane? As we approach peak hurricane season, we wanted to take the time to describe the differences between these seasonal weather-related terms so you have a better understanding of what to expect should any of these storms move into your area.

Tropical Depression

A tropical depression is when a low-pressure area is adjoined by thunderstorms and produce a spherical or circular wind flow. The wind speed during a tropical depression is below 39 MPH, but typically tends to range anywhere from 25-35 MPH.

Tropical Storm

A tropical depression is upgraded to a tropical storm when the wind speed increases to anywhere between 39-73 MPH. It is at this stage that the cyclonic shape begins to form and when a storm receives a name.

Hurricane

A tropical storm gets upgraded to a hurricane when the wind speed increases to more than 74 MPH. Meteorologists use the Saffir-Simpson Hurricane Scale to categorize and rate the intensity of the hurricanes in the Atlantic based on wind. The five categories are as follows:

  • Category 5- Wind (MPH) >156
  • Category 4- Wind (MPH) 131-155
  • Category 3- Wind (MPH) 111-130
  • Category 2- Wind (MPH) 96-110
  • Category 1- Wind (MPH) 74-95