Will the 2023 Atlantic hurricane season have a typical Nino shutdown, or will it have significant activity in Oct/Nov?

[CyclonicFury]

IMO, the looming question for the final activity of the 2023 Atlantic hurricane season (and whether it reaches hyperactive status or not) comes down to how much activity we see in October and November. While El Nino is bordering strong territory, this El Nino has been anything but normal, with the Atlantic having 13 named storms already and likely to have its third major hurricane (Lee) in a few days and possibly end September with 100+ ACE.

Historically, moderate-strong El Nino years often end earlier and have below normal ACE during October and November, as upper-level westerlies suppress tropical cyclogenesis in the Caribbean and MDR. However, there are some exceptions. 1994, an El Nino year, had two hurricanes in November, Florence and Gordon. 2009 had Hurricane Ida in the Caribbean. 2014 had Hurricanes Fay and Gonzalo in October, the latter of which resembled a Cape Verde storm despite being so late in the season. 2015 had Hurricane Kate over the western Atlantic.

The typical Nino shear has not been present this year, which would suggest there could potentially be some windows for Caribbean/Gulf activity late in the season. However, 2004 was also an active season that had low Caribbean/MDR shear and it ended up having very little activity in October/November. Going to be interesting to see what happens.

[Teban54]

This reminds me of people on social media who claimed that El Nino will shut down the Atlantic for the entire September, so if we didn't see activity in early August, the season would be a bust.

Yet, we're looking at a real chance of the strongest storm ever in the open Atlantic.

[ChrisH-UK]

I don't think it will.

Now why, it's not really a El Nino where the Atlantic is colder than the Pacific. The reality is both the Atlantic and the Pacific are hot the temperature difference between the two is more like a neutral year. This with the heat has reduced the trade winds and the shear that it creates which we have been seeing. So as this isn't the typical El Nno season but a Hot Neural season I think we could get some late season activity.

[LarryWx]

It looks like it was closer to a typical Nino shutdown than the other way around. ACE for storms forming Oct-Nov and with nothing in site right now has been only 16.6 vs the 1991-2020 normal of ~28. Only 2 NS/1H/0MH formed, which compares to ~4 NS/2H/1MH normal for all of Oct and Nov.
So, El Niño appears to win Oct-Nov!