Hurricane Dorian: What dictates a hurricane's strength?

There are many ways to categorize a hurricane.

The storm's central pressure is one way. The height of its storm surge is another. How much rain it drops is another. And, of course, the strength of its wind is another. But what causes a hurricane to strengthen or weaken? The answer is simple enough, but multifaceted.  In order for a tropical wave or disturbance to organize and become a tropical system, ocean water temperatures need to be above 80 degrees, and the wind aloft needs to be light. If those favorable conditions persist, then the system progresses to the hurricane stage. As that storm approaches places where we live, or have family or property, then interest in the storm's strength really heightens.

There are many factors that impact whether that hurricane will strengthen or weaken, or remain in a steady state. The most obvious is the ocean temperature, and it's more than just the surface temperature…we meteorologists look at the upper ocean's heat content. If the storm moves over cooler waters, then there will be some weakening.  Conversely, warmer ocean waters are like throwing gasoline on a fire. Warmer waters mean that more water vapor evaporates up into the storm, which is then turned into rain. But there's more to that story: Condensation releases energy…and that's energy added to the hurricane's system. What becomes especially interesting is if a hurricane becomes stationary. When that happens, cooler water from deep below the ocean surface upwells, and a cooler pool of water can form underneath the hurricane, which can weaken it.  In fact, sometimes, a tropical system moving over the same path as a previous hurricane encounters these areas of cooler water, which can affect their own development.

In order for a tropical wave or disturbance to organize and become a tropical system, ocean water temperatures need to be above 80 degrees, and the wind aloft needs to be light. If those favorable conditions persist, then the system progresses to the hurricane stage. As that storm approaches places where we live, or have family or property, then interest in the storm's strength really heightens.

There are many factors that impact whether that hurricane will strengthen or weaken, or remain in a steady state. 

https://www.clickondetroit.com/weather/hurricane-dorian-what-dictates-a-hurricanes-strength