2023 Indicators (SST, SAL, MSLP, Wind shear, Steering, Instability) and Day 16+ Models

[gatorcane]

Whereas ACE/# of storms were far above any other El Niño season of this strength on record thanks to the record warm Atlantic, there has still so far been out of the numerous storms only one TC that moved W or WNW west of 74W. That’s largely because of a very weak mean Bermuda high, which is common with El Niño or oncoming El Niño seasons. So, regarding storm tracks, El Niño was still very much in charge.

Exactly. Early indicators before the season started strongly suggested the kind of tracks we saw. El Niño not only kept the Caribbean and Gulf quiet, but kept all of the storms away from the CONUS and islands for the most part. Idalia was the one surprise and happened to hit a narrow window of favorable Gulf conditions and track into the Big Bend of Florida but other that, season behaved as expected.

[REDHurricane]

Whereas ACE/# of storms were far above any other El Niño season of this strength on record thanks to the record warm Atlantic, there has still so far been out of the numerous storms only one TC that moved W or WNW west of 74W. That’s largely because of a very weak mean Bermuda high, which is common with El Niño or oncoming El Niño seasons. So, regarding storm tracks, El Niño was still very much in charge.

Exactly. Early indicators before the season started strongly suggested the kind of tracks we saw. El Niño not only kept the Caribbean and Gulf quiet, but kept all of the storms away from the CONUS and islands for the most part. Idalia was the one surprise and happened to hit a narrow window of favorable Gulf conditions and track into the Big Bend of Florida but other that, season behaved as expected.

To supplement your point, here is the November 2022 CanSIPS forecast for ASO 2023 -- not 100% accurate by any means, but it did get the general pattern mostly correct:


For comparison, here is the November 2023 CanSIPS forecast for ASO 2024 -- note the significant increase in Caribbean activity versus what we've seen this season:



Last November's CanSIPS forecast anomalies for Sept. 2023 vs. actual -- pretty spot-on with the dry Caribbean/Gulf of Mexico + wet subtropical Atlantic as well as global SSTs:




Plus the most recent CFS Monthly run for August 2024 (as far out as it goes) because why not:

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Can we say for sure that the currently strong CanSIPS signal for next year means that the 2024 season will be substantially more active than 2023 because last year's CanSIPS ended up underestimating this season's activity? Of course not. That said, at the moment all signs are pointing to the 2024 season being just as, if not more, favorable for TC development in the Caribbean/Gulf compared to this year, so it'll be very interesting to look at which way the climate model forecasts trend as we go through winter into next spring.

[Teban54]

Bumping the 2023 indicator thread because of this tweet that shows how anomalous the season was, specifically in terms of having favorable upper-level winds over the MDR (-ve y-axis) despite an El Nino (+ve x-axis).

As a side note, the plot also shows that years with warm MDR SSRs (red dots) generally have weaker upper-level winds, even when holding ENSO fixed. So even though a boiling ocean won't produce many storms if the wind shear is strong, the boiling ocean itself typically correlates with lower shear.
 https://x.com/AndyHazelton/status/1778071880013926653