What separates hyperactive and record-breaking seasons?

[AlphaToOmega]

There are many factors that govern hurricane season activity: SST patterns, shear patterns, air humidity, velocity potential anomalies, and steering just to name some. With very few exceptions, we generally have a good idea if a hurricane season is going to be above-average, average, or below-average before. As we start to get further into the season, we might be able to tell if a season is going to be above-average or hyperactive. However, it is difficult to tell if a season is going to be hyperactive or record-breaking. By "record-breaking", I mean seasons in the same league as 2005 and 2020. By "hyperactive", I mean seasons such as 1995 and 2010.

Sometimes conditions in "hyperactive" seasons can seem even more favorable than those in "record-breaking" seasons. For instance, the SST pattern of 2010 seemed much more favorable than the one in 2005 (warmer MDR, much stronger La Nina and -PDO). That raises the question: Are there conditions that separate "hyperactive" and "record-breaking" seasons? If so, what are they? If not, is having a record-breaking season just a matter of really bad luck?

[abajan]

A long-tracking MDR storm in July (like Elsa) may be an important indicator, according to what Dr. Klotzbach states in this video:

[youtube]https://youtu.be/dK6SNnrrHJ0[/youtube]

[AlphaToOmega]

A long-tracking MDR storm in July (like Elsa) may be an important indicator, according to what Dr. Klotzbach states in this video:

https://youtu.be/dK6SNnrrHJ0

That explains 1933 and 2005 but not 2020. What conditions separate 1933, 2005, and 2020 from everything else?

[tolakram]

What do you mean by record breaking? Number of storms is inconsequential due to improved identification and naming standards. ACE, while imperfect, would a better standard for records and the long trackers are what really rack up the ACE. Still, imperfect, as any metric will be.

[AlphaToOmega]

What do you mean by record breaking? Number of storms is inconsequential due to improved identification and naming standards. ACE, while imperfect, would a better standard for records and the long trackers are what really rack up the ACE. Still, imperfect, as any metric will be.

Either storms, hurricanes, major hurricanes, or ACE
Any of those could be considered "record-breaking", does not matter

[abajan]

A long-tracking MDR storm in July (like Elsa) may be an important indicator, according to what Dr. Klotzbach states in this video:

https://youtu.be/dK6SNnrrHJ0

That explains 1933 and 2005 but not 2020. What conditions separate 1933, 2005, and 2020 from everything else?

I would have to view the video again, but I think Dr. Klotzbach said that whenever there was a long-lived storm in July which formed in the MDR, that season ended up being very active. That's not to say that every hyperactive year had such a storm.

[Teban54]

A long-tracking MDR storm in July (like Elsa) may be an important indicator, according to what Dr. Klotzbach states in this video:

https://youtu.be/dK6SNnrrHJ0

That explains 1933 and 2005 but not 2020. What conditions separate 1933, 2005, and 2020 from everything else?

I would have to view the video again, but I think Dr. Klotzbach said that whenever there was a long-lived storm in July which formed in the MDR, that season ended up being very active. That's not to say that every hyperactive year had such a storm.

2008 had long-tracking July MDR major Bertha, yet it fell just short of the official hyperactive definition. (Its impact definitely felt hyperactive though.)

[Kingarabian]

Cool neutral during ASO probably.

[Category5Kaiju]

To be honest, I personally do not think that it is possible to predict whether a season will be hyperactive versus "record-breaking" at least based on your definition of what that is. For example, 2010 had insanely warm sst anomalies in the MDR and based on that alone one could easily believe that that season could have extreme instability throughout the basin that would even dwarf 2005 in activity levels, yet that did not materialize, and mid-level dry air was a main issue for not allowing the season to reach its true potential. 2005 was in a cool neutral state by the time infamous Dennis and Katrina occurred and not even in a weak La Nina, which I would think many people would think would need to be present for a season to go into overdrive. 2020 was the most active year NS wise but did not feature a single Cat 5 and lacked many long tracking storms despite the very warm sst anomalies in the MDR.

In all, my point is that while the definition of a hyperactive year is pretty straightforward, among these hyperactive years, I feel the term "record-breaking" is more appropriate to apply in more localized contexts rather than in an overall context as one hyperactive year could feature a unique, mind-blowing record for a particular event over other hyperactive years. For example, while 2005 may have had the most major hurricanes and 4 Cat 5s in one season (MH count tied with 2020), its ACE score was only second highest, with the highest being from 1933 that featured 6 MHs and 2 Cat 5s. Then you could look at 2004 as a "record-breaking" year for Florida, where it was struck by 4 powerful storms in only 2 months and with that season also featuring Ivan, the highest ACE-producing Atlantic storm. Then again, you could look at 2017 as "record-breaking" in how it was able to generate all of its hurricanes consecutively, with Harvey being the costliest Atlantic storm (tied with Katrina) and Irma maintaining Cat 5 strength for one of the longest time periods recorded in the basin. And then you could look at 1998 with Mitch being one of the deadliest storms ever in the basin, and so forth.