By Bruce W. Ford, President of Clear Science, Inc.
Pattern detection is the key to developing a keen sense of what, within our global atmosphere, is connected and how. With a tool like our ACAF-DSS and CliDaaS (Climate Data as a Service), we can do this very quickly and efficiently. This is an example of what I like to call a 20-minute study...so, it's not exhaustive, but telling and worthy of additional study.
In looking at NOAA Data Explorer as last month's (April 2024) sea surface temperature anomaly (SSTA) we see:
Most of the world's oceans are above normal, and significantly so. The oceans are HOT!
Also, what I'm seeing in the news are reports of high numbers of destructive tornados on outbreak days plaguing the central portion of the country. If you flew domestically in April, you were probably impacted by the havoc these days wreaked on air travel. I suspected the warm oceans and our tornado woes are related, but let's quickly look into history (our best indicator of the future) and see if my suspicion is substantiated.
(Spoiler alert...they are related!)
Here is the SSTA pattern I'm going to quickly look into history for:
I quickly found only 3 recent years that resembled this SSTA pattern and they were 2022, 2020 and 2011.
What did the spring (April) tornado season look like in those cases? Switching to CliDaaS...
In 2022, average number of tornados on a 'tornado day' or an 'outbreak day' was about 5 storms higher than the long term average.
In 2020, the difference between the average tornado day and April of 2020 was 10 storms!
Finally, that difference grows to 22 storms over the average tornado day in 2011!
To satisfy my own curiosity, I looked back to 1970 to 2023 and these three years lead all other years (significantly so) in terms of the quantity of the departure between the long term average of tornados on a 'tornado day' and those Aprils of 2022, 2020 and 2011. These were the leaders.
That said, there is a significant link between the placement of positive SSTA anomalies and our spring tornado season.
Further, if you carefully look at the April 2024 SSTA anomalies, they are somewhat higher than any of the three model years I selected. To me this means that when the statistics are calculated for April 2024 in terms of tornados, we may well see record breaking tornados in terms of number per outbreak day, intensity, injuries and deaths.
SSTAs do not change quickly in a slow-moving ocean environment. (Slow moving as compared to the atmosphere.) We can expect those SSTA to persist will into summer and perhaps beyond.
My next question was: Would history, using these three years...2022, 2020 and 2011, support the prediction of a busy hurricane season?
Here is July-August-September-October tropical cyclone tracks for each of those years:
Yes, indeed. Those model years support an active hurricane season!
My predictions:
I expect a high-activity hurricane season in the North Atlantic
I expect the Gulf of Mexico to be active early in the season (June)
The primary formation regions between Africa and the Caribbean will also be active and for a significant portion of the season, we can expect a train of tropical cyclones moving west. These trains may be interrupted briefly by dust plumes moving off of Africa which suppress the convection needed to get a TC forming.
The table is also set for sub-tropical storm formation (these form north of the tropical regions), but these usually don't post much of the threat to the U.S. East Coast. Still, I expect 2-3 of these.
Simply put, a warm ocean provides the fuel (heat) that a tropical cyclone needs to form. It WILL NOT steer it...the atmosphere does that. Other factors have to be in place for it to form as well, such as favorable (low) sheer, outflow and so on. Not only that, but early in this hurricane season (perhaps for the entire season), where storms tend to be steered has warm water waiting, thus fuel (heat) for intensification.
Conclusion: Batten down the hatches, America.
On a side note: This is kind of a gloomy outlook, but there is a glimmer of positivity to be had. Tropical cyclones are at their core heat distribution mechanisms. They serve a purpose of moving oceanic heat from the Equator toward the poles. A busy hurricane season could potentially ease the equatorial marine heat wave in the North Atlantic and potentially return our weather to more normal patterns.
Additionally, all of this I have described is happening as the global environment is shifting from El Nino (generally fewer and less intense North Atlantic hurricanes) to La Nina (more and stronger North Atlantic hurricanes). Looking to the 2025 hurricane season, we can expect fully developed La Nina conditions. Distributing oceanic heat during this season could help us next year. A fully developed La Nina (2025) with exceptionally warm waters would make for an even more dangerous hurricane season in 2025.
My earnest hope is that we don't get beat up too bad in 2024.
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