Is the 1951-2020 climatology even useful for hurricane seasons at this point?

[WalterWhite]

Since 2016, the tropical Atlantic has always had above-average SSTs during the peak season. Additionally, we are able to detect more short-lived tropical or subtropical storms than in the past. Both of these factors have led to Atlantic hurricane seasons being almost invariably above-average (and invariably not below-average) since 2016 relative to the 1951-2020 climatology in both storm count and ACE. This above-average activity is certainly present in La Niña seasons (2016, 2017, 2020, and 2021), cool-neutral seasons (2024), warm-neutral seasons (2019), and even El Niño seasons (2018 and 2023). If the NHC keeps naming short-lived tropical storms (as they should) and if the tropical Atlantic continues to be above-average every hurricane season, should we expect every hurricane season in the near future to be above-average relative to this climatology in both storm count and ACE? And if so, is the 1951-2020 climatology even useful at this point?

The reason NOAA updates their climatology is to reflect a changing climate. For hurricane seasons, it has the additional effect of reflecting improvements to satellite technology. Does the 1951-2020 climatology hide the obvious fact that satellite technology has dramatically improved within the past view decades, allowing us to detect more nameable storms? Does the 1951-2020 climatology hide the fact that, due to the tropical Atlantic being warmer than average every peak season, it is highly unlikely for an Atlantic season to have a below-average ACE at this point?

[FireRat]

The way things are now, I think it might be good to use a rolling 10-15 year average following each season, at least until it becomes apparent that we enter a new inactive era like pre-1995.

For example, 2024 would look at the 2012-2023 average, 2025 would look at the 2013-2024 average and so on.

Another idea is maybe better a 30 year average, so it accounts for all the 1995+ seasons.

[TheDreamTraveler]

I don't think it's useful anymore. Also there was a meteorologist I really trust who was theorizing recently that the massive increase of aerosols around the 1930s through the 1980s might have actually massively reduced the amount of hurricanes that could form or strengthen because it was keeping a cap on warming SST's. Look at the 2020 reduction in shipping lane aerosols and how SST's increased DRASTICALLY the past few years since then in response. Basically his theory is that the inactive periods in the 1900's might have not been as inactive as we thought and instead were stunted by our use of aerosols keeping atlantic SST's cooler. It's an interesting theory that does make a bit of sense in hindsight now that we know more about how impactful aerosols are on ocean temps.

[WalterWhite]

The 2016-2024 averages (assuming no storms form after Sara) are 19 storms, 9 hurricanes, 4 major hurricanes, and 150 ACE. Given that, because we are naming systems that would not have even been detected 30 years ago and that the Atlantic is consistently warm, these averages feel like much better benchmarks than the 1951-2020 averages.

[WalterWhite]

The 2016-2024 averages (assuming no storms form after Sara) are 19 storms, 9 hurricanes, 4 major hurricanes, and 150 ACE. Given that, because we are naming systems that would not have even been detected 30 years ago and that the Atlantic is consistently warm, these averages feel like much better benchmarks than the 1951-2020 averages.

If we were to apply the NOAA thresholds to these averages, we would get these results:

1. Extremely active (>165% of average): >248 ACE, >31 storms, >15 hurricanes, >7 major hurricanes
2. Slightly above-average (120%-165% of average): 180-248 ACE, 23-31 storms, 11-15 hurricanes, 5-7 major hurricanes
3. Average (71.4%-120% of average): 107-180 ACE, 14-22 storms, 6-10 hurricanes, 3-4 major hurricanes
4. Below-average (<71.4% of average): <107 ACE, <14 storms, <6 hurricanes, <3 major hurricanes

[al78]

The 2016-2024 averages (assuming no storms form after Sara) are 19 storms, 9 hurricanes, 4 major hurricanes, and 150 ACE. Given that, because we are naming systems that would not have even been detected 30 years ago and that the Atlantic is consistently warm, these averages feel like much better benchmarks than the 1951-2020 averages.

If we were to apply the NOAA thresholds to these averages, we would get these results:

1. Extremely active (>165% of average): >248 ACE, >31 storms, >15 hurricanes, >7 major hurricanes
2. Slightly above-average (120%-165% of average): 180-248 ACE, 23-31 storms, 11-15 hurricanes, 5-7 major hurricanes
3. Average (71.4%-120% of average): 107-180 ACE, 14-22 storms, 6-10 hurricanes, 3-4 major hurricanes
4. Below-average (<71.4% of average): <107 ACE, <14 storms, <6 hurricanes, <3 major hurricanes

Extremely active category seems too high to me here, as to break it requires at least near record breaking activity and 2005 barely exceeded it. Surely that should be classed as exceptional activity, and calling a 248 ACE season slightly above average feels even more of an understatement to me.