Why is the 2024 Atlantic hurricane season underperforming expectations?

[LarryWx]

From the suffering perspective, this inactivity is a blessing. This may be the single most interesting hurricane season of all time IMO if it plays out way below the hyper predictions by so many, including all the high powered season models.

Agree 100% on both of your points.

Nobody knows for sure the reasons, of course, as a good number of different reasons have been given. My educated guess is that it is a combination of many of the things already mentioned in this thread. My feeing is that as has been mentioned by others and myself in another thread is that the record warmth 30-45N in E Atlantic is also one of the calming factors for the E MDR.

What’s interesting is that these not as strong seasons as expected have for the most part not been well predicted publicly including reasoning by anyone as I can best recall. You’d think that there’d at least be a small minority of forecasters catching these factors in advance.

Will the next season this occurs be successfully publicly forecasted by a few? I’m not betting on it but perhaps.

[Category5Kaiju]

From the suffering perspective, this inactivity is a blessing. This may be the single most interesting hurricane season of all time IMO if it plays out way below the hyper predictions by so many, including all the high powered season models.

Agree 100% on both of your points.

Nobody knows for sure the reasons, of course, as a good number of different reasons have been given. My educated guess is that it is a combination of many of the things already mentioned in this thread. My feeing is that as has been mentioned by others and myself in another thread is that the record warmth 30-45N in E Atlantic is also one of the calming factors for the E MDR.

What’s interesting is that these not as strong seasons as expected have for the most part not been well predicted publicly including reasoning by anyone as I can best recall. You’d think that there’d at least be a small minority of forecasters catching these factors in advance.

Will the next season this occurs be successfully publicly forecasted by a few? I’m not betting on it but perhaps.

I'm starting to think that just maybe, future seasonal forecasts also consider subtropical and extratropical water temperature anomalies. It could be a subcategory of the "sst anomaly" factor that these forecasts already consider to judge how active a season may be. The warmer those areas are, the greater the chances of an underperformance relative to a season with all else equal but with the deep tropics being disproportionately warm. Perhaps going forward, warm deep tropics cannot be seen as a lock for insane levels of activity.

Also, I know it's extremely early to tell and that this would be better suited for the following year's discussion thread, but will this unusually warm extratropical pattern be an issue again in 2025? Or was it just a fluke of the last three (including this) hurricane seasons?

[Teban54]

From the suffering perspective, this inactivity is a blessing. This may be the single most interesting hurricane season of all time IMO if it plays out way below the hyper predictions by so many, including all the high powered season models.

Agree 100% on both of your points.

Nobody knows for sure the reasons, of course, as a good number of different reasons have been given. My educated guess is that it is a combination of many of the things already mentioned in this thread. My feeing is that as has been mentioned by others and myself in another thread is that the record warmth 30-45N in E Atlantic is also one of the calming factors for the E MDR.

What’s interesting is that these not as strong seasons as expected have for the most part not been well predicted publicly including reasoning by anyone as I can best recall. You’d think that there’d at least be a small minority of forecasters catching these factors in advance.

Will the next season this occurs be successfully publicly forecasted by a few? I’m not betting on it but perhaps.

I'm starting to think that just maybe, future seasonal forecasts also consider subtropical and extratropical water temperature anomalies. It could be a subcategory of the "sst anomaly" factor that these forecasts already consider to judge how active a season may be. The warmer those areas are, the greater the chances of an underperformance relative to a season with all else equal but with the deep tropics being disproportionately warm. Perhaps going forward, warm deep tropics cannot be seen as a lock for insane levels of activity.

The problem is, most of the "SST vs. ACE" correlation charts from CSU and other sources do show the correlation between subtropical SSTAs and activity -- but they're usually around zero, not negative. If there is indeed a causal effect between warm subtropics and less active seasons, it's puzzling why they don't appear on the correlation charts.

[Hurrilurker]

I don't think it's that weird because it's not an exact science and probably never will be. It's like in sports, you can have the most stacked team ever that on paper should win the championship every single year. They do win it a lot of the time, but not always. There's a hundred or a thousand little things that can derail what looks to all observers like a clear path.

[ThomasW]

The way I see it, it looks like the ITCZ has lifted north semipermanently. This is likely the result of a strong WAM and the ASW that's persisted since 2015. This means no more MDR storms until it stops because the waves exit too far north to develop, and the northward-displaced ITCZ pumps a never-ending train of dry air parcels into the MDR, killing anything that even tries to organize as far west as the Caribbean. This isn't a season predictions thread, but IMO, Beryl was our only MH.

[cycloneye]

Webb has this theory.

 https://x.com/webberweather/status/1830227580068462938

@webberweather
What really turned the tide of this season is likely originating from the extratropics. The +NAO in July namely (which is likely related to the late winter SSWE) cooled the far N Atlantic & increased the NE trades off NW Africa.

[al78]

I'm usually an extremely bullish forecaster, but the fact that recent seasons, and especially this one, have been so strange is making me wonder whether the AMO is beginning to flip. Maybe 2018 was the last positive AMO year? It would line up with 1969, another year with a Category 5 landfall on the Gulf coast, as the end of its own AMO+ era.

I heard talk of that after the 2015 season which was the third of three consecutive below-average seasons, unprecedented in the AMO active phase. Then came 2017 and that was the end of that discussion.

[al78]

I don't think it's that weird because it's not an exact science and probably never will be. It's like in sports, you can have the most stacked team ever that on paper should win the championship every single year. They do win it a lot of the time, but not always. There's a hundred or a thousand little things that can derail what looks to all observers like a clear path.

One thing to note is that seasonal forecasts are not fundamentally predicting numbers and ACE. They are predicting how favourable the large scale climate fields known to influence hurricane activity based on decades of past observations will be. This is inevitably going to result in a probabilistic assessment of the upcoming hurricane season. We can say that based on observations over the last 70 years, climate fields are (or are not) pointing towards an active or hyperactive season, but this does not mean it is 100% nailed on, and the atmosphere or ocean can throw curveballs in the form of intra-seasonal anomalies which can overwhelm the pre-season large-scale teleconnections, but historically this is rare and so has a low probability of happening. Low probability does not mean it is guarenteed never to happen, just like it is not guarenteed I will not be killed when I ride my bicycle on the road even though it hasn't happened yet (although it very nearly happened once), but it is extremely likely on any one bike ride it won't happen. The analogy with strong sports teams and success is a good one, one of the things that make sport exciting to watch is that the underdog can occasionally win, either because they play above their level and have some luck, or the strong team gets complacent and blunders.

My gut feeling (ugh) is that intra-seasonal factors have been more frequent in influencing Atlantic hurricane activity over the last 10-15 years than, say, prior to 2010 inclusive. One thing I intend to look into is how the correlations between MDR SST, trade wind anomaly and ENSO have varied since 1950 to see if there has been a drop-off in the last decade or so.

[Hypercane_Kyle]

It seems to be similar to 2013, with a lack of vertical instability due to a weird SST profile combined with ITCZ being too far north.

This season might struggle to reach 15 named at the rate we are seeing, certainly not 20. It’s September 1st, we haven’t had a storm since mid-August, and models are slipping on development every time we see a signal.

I don’t want to call it a “bust” yet because of the possibility of October shenanigans, but it’s certainly heading there.

[DorkyMcDorkface]

It seems to be similar to 2013, with a lack of vertical instability due to a weird SST profile combined with ITCZ being too far north.

This season might struggle to reach 15 named at the rate we are seeing, certainly not 20. It’s September 1st, we haven’t had a storm since mid-August, and models are slipping on development every time we see a signal.

I don’t want to call it a “bust” yet because of the possibility of October shenanigans, but it’s certainly heading there.

I'm not one to be "the boy who cried bust" either, but given the massive preseason hype stemming from the exceptionally bullish seasonal guidance and crazy numbers pretty much every agency put forth, I think it's fair to acknowledge the massive underperformance since Ernesto dissipated. Yes, this season could still very well turn out to be super backloaded (especially given ENSO) but even then that's asking for a lot of ground to be made up post-peak, especially ACE-wise as the long-tracker Cabo Verde season begins to subside.

[DunedinDave]

The Saharan dust prolly killed 4-5 potential storms at least. There was no Cape Verde season. That’s gonna crush the forecast predictions

All that’s really left now are some early cold fronts coming down and something forming off the tail end. I think we’ll get a few from that…maybe a big one sometime between mid-Sept to early Oct as a result.

[WeatherBoy2000]

The Saharan dust prolly killed 4-5 potential storms at least. There was no Cape Verde season. That’s gonna crush the forecast predictions

All that’s really left now are some early cold fronts coming down and something forming off the tail end. I think we’ll get a few from that…maybe a big one sometime between mid-Sept to early Oct as a result.

It's only September 1st, we could still a get a CV storm at any point until October, even 2013 had one CV hurricane.

[canes92]

Not a big deal. You can predict, analyze, estimate, etc but Mother Nature still does what she will do at the end of the day.

[al78]

Not a big deal. You can predict, analyze, estimate, etc but Mother Nature still does what she will do at the end of the day.

Everything ultimately has cause and effect. Mother nature is still bounded by the laws of physics. Seasons like this come down to two questions:

1. Why did the season not fit with what the teleconnections were indicating?
2. If there are answers to 1., can these additional factors be predicted in advance of peak season?

[DunedinDave]

The Saharan dust prolly killed 4-5 potential storms at least. There was no Cape Verde season. That’s gonna crush the forecast predictions

All that’s really left now are some early cold fronts coming down and something forming off the tail end. I think we’ll get a few from that…maybe a big one sometime between mid-Sept to early Oct as a result.

It's only September 1st, we could still a get a CV storm at any point until October, even 2013 had one CV hurricane.

We could but it would likely be in name only. I don’t see anything forming in forseeable future and after mid-September, anything that forms there recurves usually because of troughs coming across. In two weeks, the focus starts shifting more to the Caribbean.

[Teban54]

Just an observation, but the amount of discussions on seasonal activity and indicators appears to be inversely proportional to current organization of and model support for the 10/40 AOI. Fewer users were talking about why it was quiet, or saying the rest of the season would be trash, whenever there's an uptick on models showing the wave to become a formidable system at some point (even a short-term uptick). Conversely, if model support drops or the wave isn't organizing well, you can even have a few users explicitly linking this single system to the rest of the season and how big of a bust the seasonal forecasts are.

This is not to say that any analyses and opinions shared here and other seasonal threads are invalid just because of the outcome of one wave. But it does make you wonder: Are people's perceptions of the (rest of the) season disproportionally skewed by short-term trends?

[LarryWx]

Just an observation, but the amount of discussions on seasonal activity and indicators appears to be inversely proportional to current organization of and model support for the 10/40 AOI. Fewer users were talking about why it was quiet, or saying the rest of the season would be trash, whenever there's an uptick on models showing the wave to become a formidable system at some point (even a short-term uptick). Conversely, if model support drops or the wave isn't organizing well, you can even have a few users explicitly linking this single system to the rest of the season and how big of a bust the seasonal forecasts are.

This is not to say that any analyses and opinions shared here and other seasonal threads are invalid just because of the outcome of one wave. But it does make you wonder: Are people's perceptions of the (rest of the) season disproportionally skewed by short-term trends?

I don’t wonder about this. I know about this. That’s human nature to a large extent. Nothing unusual.

[toad strangler]

Just an observation, but the amount of discussions on seasonal activity and indicators appears to be inversely proportional to current organization of and model support for the 10/40 AOI. Fewer users were talking about why it was quiet, or saying the rest of the season would be trash, whenever there's an uptick on models showing the wave to become a formidable system at some point (even a short-term uptick). Conversely, if model support drops or the wave isn't organizing well, you can even have a few users explicitly linking this single system to the rest of the season and how big of a bust the seasonal forecasts are.

This is not to say that any analyses and opinions shared here and other seasonal threads are invalid just because of the outcome of one wave. But it does make you wonder: Are people's perceptions of the (rest of the) season disproportionally skewed by short-term trends?

IMO It goes further than nearly an entire existence of one wave. There is a noticeable tendency to change perceptions from model run to model run with a percentage of the average weather hobbyist. It’s my personal preference to judge a season once the season is over. Not barely halfway through it. But I understand the place for this type of discussion in the now.

[Woofde]

Just an observation, but the amount of discussions on seasonal activity and indicators appears to be inversely proportional to current organization of and model support for the 10/40 AOI. Fewer users were talking about why it was quiet, or saying the rest of the season would be trash, whenever there's an uptick on models showing the wave to become a formidable system at some point (even a short-term uptick). Conversely, if model support drops or the wave isn't organizing well, you can even have a few users explicitly linking this single system to the rest of the season and how big of a bust the seasonal forecasts are.

This is not to say that any analyses and opinions shared here and other seasonal threads are invalid just because of the outcome of one wave. But it does make you wonder: Are people's perceptions of the (rest of the) season disproportionally skewed by short-term trends?

Well, after almost 2 weeks of inactivity, watching the only wave with a real chance of becoming a hurricane any time soon trend further and further towards nothing does start to plant doubts in your head.

[psyclone]

The risk now is people overshooting to the downside. Anything that is extremely anomalous is unlikely to persist. The current dead streak is insanely anomalous. I'd bet it finds a way to end. Just as forecasting a record season. That too is extremely anomalous and will likely find a way to not happen. As it stands now we have 2 extremely high risk months to tiptoe through. Will nothing continue to happen? Perhaps. But that would be a crazy extreme and I'd take the opposite side of that bet. If you're in the Caribbean, central or east Gulf ...in many of those areas the highest climo risk remains ahead. We're dancing through a minefield right now but we have a long way to go and the risk of a high impact event(s) remains substantial...IMO.