CHICOPEE, Mass. (WWLP) – With Dorian in the Atlantic, it helps to know how hurricanes form.
Hurricanes need very specific ingredients to form. One important one is wind. In Atlantic hurricanes, wind from Africa over the Atlantic evaporates water from the ocean surface, then it turns into vapor and rises.
That creates unstable air. As this air rises, the vapor cools, and condenses into droplets, forming towering clouds.
As evaporation and condensation continue, the cloud gets taller, when eventually, wind will circulate around a central point, think of water draining from your bathtub.
Tropical cyclones, the generic name for hurricanes and tropical storms, need warm, moist air to fuel themselves, which means they also need warm ocean water of at least 80 degrees.
As the thunderstorm grows higher, air at the top of the cloud heats up, increasing the air pressure and causing winds to move outward from the top.
Down below at the surface, this causes a pressure drop, which in turn, creates more thunderstorms. Winds in the storm spin up and turn in a circular motion.
When these winds hit 25 to 38 miles per hour, the storm is considered a tropical depression. When the wind speed reaches over 39 miles per hour, it’s then considered a tropical storm.
If the storm continues to strengthen, with winds over 74 miles per hour, it is officially a hurricane. Hurricanes weaken when they hit land because they no longer have warm water to fuel them.