2023 hurricane season update: Competing signals
MIAMI -- As we move into the peak months of tropical activity there are several signals that we continue to monitor to see how the season will unfold.
While every season is different, this year there is a higher amount of uncertainty. Out of all the factors that determine a season's activity there are two battling it out. Let's go over those.
El Niño and Wind Shear. It has developed in the eastern Pacific and is forecast to persist through the approaching peak of the Atlantic hurricane season in September.
This pattern has far-reaching global impacts but for our purposes we pay close attention to the wind shear it can create across the western Atlantic basis.
Tropical systems can only take a certain amount of shear before they are weakened by it. If there is enough shear present, a hurricane seedling wouldn't ever get a chance to develop.
However, El Niño shear does not cover the entire Atlantic basin. There will be plenty of real estate with low shear and any organizing storms will take advantage of that.
If a storm were to reach hurricane strength before passing through an area of high shear, say in the western Caribbean, it can fight off a certain amount of it as we've seen in years' past.
Sea Surface Temperatures. Most of the tropical Atlantic has seen record warm sea surface temperatures.
This is fuel for a tropical system and the warmer the water the stronger they can become.
The energy source for hurricanes is latent heat.
This comes from evaporation off the ocean surface. As the warm, moist air rises and cools, the process of condensation releases heat. This heat warms the surrounding air and can then in turn cause even more water to evaporate.
This creates our self-sustaining "heat engine" that fuels a hurricane. So, this year's extreme warmth in the tropical Atlantic is a very favorable environment for tropical development. Will it be enough to overcome El Niño-caused shear?
We just don't know; this is why it's a particularly difficult forecast. In the 2022 season we did not have competing signals.
They all pointed to a hyperactive season and yet it was below average. Then Ian hit, underscoring that it only takes one to make it a very bad season.
So, an El Niño decreases Atlantic hurricane activity but an extremely warm Atlantic increases hurricane activity. The winner will determine what kind of season we have in 2023.
We are in hurricane country here in South Florida and whether we get hit or not this year we have to prepare just the same every year.
