Too early to think about hurricanes?

 

Hurricane Idalia at Category 4 intensity, August 2023 (Source: NOAA)

Although the Atlantic hurricane season doesn’t officially get underway until June 1, a new NOAA report contains a big clue as to what kind of season it could be. There's an 83% chance El Nino conditions will dissipate by the time the hurricane season begins in June. To add to that, NOAA also indicated a greater than 60% chance of La Nina conditions developing by August 2024. That would have significant repercussions for the tropical Atlantic.

La Nina helps create ideal conditions for tropical storm formation because it is characterized by above average sea surface temperatures and a below average amount of wind shear (i.e., winds that differ in direction with altitude). The tropical Atlantic sees below average activity during El Nino events (circa 2015, 1997 and 1992). The busiest Atlantic hurricane seasons often occur during episodes of La Nina. Even ENSO neutral conditions (neither El Nino or La Nina) tend to feature more favorable conditions in the tropical Atlantic then El Nino conditions.

While the presence of La Nina or El Nino are major drivers of tropical activity, there are other factors to consider as well. The presence of atmospheric dust that sometimes travels west from central Africa into the tropical Atlantic can impact tropical storm formation. The existence of above or below average sea surface temperatures in the Atlantic Ocean Basin is also important to consider. The Atlantic Ocean Basin includes the Gulf of Mexico and Caribbean Sea. Much of the tropical Atlantic was already unusually warm at the end of February, NOAA reports. That will be important to watch as the start of the hurricane season draws closer.

Every Atlantic hurricane season since 2016 has been busier than average. However, the overall number of tropical storms and hurricanes is less important than where they develop and track. For example, this summer will be 32 years since Hurricane Andrew, which remains one of the strongest and costliest hurricanes to ever make landfall in the United States. Ironically, it was the only major hurricane in what was an otherwise quieter than average Atlantic hurricane season. 

By comparison, the 2010 Atlantic hurricane season was very active during a strong episode of La Nina. Fortunately, the United States didn’t see any direct impacts from the 12 hurricanes that developed in 2010.

Another trend that bears watching this spring is whether or not 2024 will become the ninth season in the last decade that at least one storm develops before the official June 1 start of the season. While having named storms develop early can foreshadow an active hurricane season, that isn’t always the case. Distinguished scientists at NOAA and Colorado State University will issue their forecasts for the upcoming Atlantic hurricane season later this spring.