The 2023 Atlantic Hurricane Season was no pushover. With a total of 20 named storms, seven of those hurricanes and 3 major hurricanes, it was the fourth most active season on record since 1950. And, mind you, this was despite the presence of a developing El Niño. So, with the upcoming season at the doorsteps, what can we expect over the next 5 months? Well, lets take a look at some factors we take into account when producing these forecasts:
ENSO: The strong El Niño that dominated 2023 has quickly decayed over the last few months and is being replaced by cooler waters off the coast of South America. This signals the development of a La Niña, which has been notorious for increased tropical cyclone activity across the Atlantic. While this Nina is still in its infancy, buoys along the equator reveal a very deep cold pool of water below the surface that will gradually work toward the surface through the rest of the year. Additionally, the atmosphere has begun to respond to these dramatic oceanic changes, with sinking air now developing over the Pacific and rising air supportive of widespread thunderstorms developing over the Indian Ocean.
Ensembles Support Development Of La Niña
Model predictions, showing a transition from El Niño to La Niña through 2025.
Models diverge quite a bit on the eventual peak strength of this La Niña, with a rough consensus sitting around -1C, which would take us into a “moderate” event. This could easily be conservative given the depth and magnitude of the aforementioned sub-surface waters in the equatorial Pacific, though the exact strength of the Niña doesn’t have a notable impact on activity in the Atlantic. The main takeaway here is that there will very likely be a La Niña by the time we get into the peak months of the hurricane season, which helps reduce wind shear and increase thunderstorm activity across the basin.
Current Sea Surface Temperatures (SSTs) across the North Atlantic. The black line indicates this year, while orange represents last year
Record Atlantic Warmth: Last year we saw an incredible surge of warm waters develop across the Atlantic during the summer months that skyrocketed temperatures well above levels ever observed in the modern satellite era. This allowed the Atlantic to stay quite active despite the El Nino by allowing a large-scale rising motion to develop during the peak months, which wound up producing a flurry of 13 storms between August and September! Incredibly, near-record-to-record warm sea surface temperatures (SSTs) were able to maintain themselves through the winter months and are already in the process of warming at an alarming rate across the areas we’d look to for tropical cyclone development. In fact, how these SSTs are configured is just about as favorable of a pattern as one could draw up for a very active hurricane season and is quite reminiscent of some of the most active years on record.
Sea Surface Temperature Temperatures Support A Very Busy Season
A look at SST Anomalies across the North Atlantic Ocean
Another major factor is that these very warm waters also extend quite a bit below the ocean surface, preventing storms from quickly bringing up cooler water as they move overhead. This could allow multiple storms to track over the same area without being affected by cooler waters that are typically brought to the surface after a storm passes by.
Favored Storm Tracks for the upcoming Hurricane Season
The Forecast: These factors give us higher than normal confidence in a very active to potentially hyperactive hurricane season for 2024. At this time, we’re forecasting 19 - 23 named storms, 9 - 13 hurricanes, and 4 - 6 major hurricanes. These numbers (especially the named storms) could wind up being on the lower end of things if we do see more short-lived storms like 2020. While it’s very difficult to forecast landfalls months in advance, looking at years that have a similar setup to this year can give us a rough idea of how things may play out. Those years show an area of enhanced concentration of storms in the Caribbean, with some of that activity extending north and into the Gulf of Mexico. Additionally, this season has a high chance of producing multiple long-lived hurricanes originating from Africa. While it’s tough to get these storms to track across the entire Atlantic, it’s certainly possible and something we’ll have to keep a close eye on as we get deeper into the heart of the season. As we've seen time and time again, it only takes one storm to make a hurricane season memorable!
Our Official Hurricane Season Forecast
Finally, it’s quite possible that we won’t see the Atlantic take off until around the middle of August, which is a prevalent theme in the list of similar hurricane seasons to this one. Studies have shown that there is little to no correlation between early season activity (June - July) and what the peak of the season (August - October) might produce, so certainly keep this in mind if things are relatively "quiet" over the next month or so!
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