2024 Indicators: SST's, MSLP, Shear, SAL, Steering, Instability (Day 16+ Climate Models)

[al78]

It's finally up.
https://twitter.com/philklotzbach/status/1831185547861114940
Link at https://tropical.colostate.edu/Forecast/2024_0903_seasondiscussion.pdf
Copied from the executive summary/abstract:

Thank you for the heads-up! Will enjoy the read in the morning (well, the part of the morning that includes daylight )

They are doing everything but raising the white flag, they are throwing out the same ideas we have already been hearing for a few weeks now, but honestly, they are educated guesses at best. It will take far more analysis than anything that can be done during the season and we may never see complete answer. This season will affect yearly forecasts for the foreseeable future, expect something very conservative next year regardless of what their analysis leads them to put out. It's embarrassing to the research community, and those looking for funding will have some serious explaining to do for the next round. See something, say something for the rest of the season, keep looking at models but until you see something actually developing, there isnt anything regardless of model agreement.

If that attitude is widespread I find it very disappointing. If anything, a major forecast bust should increase the incentive for further research to reduce the chance of it happening again. In the UK in October 1987 our Met Office failed to predict an extremely damaging billion pound loss windstorm and they were heavily vilified for it. That forecast bust, however, led to further research on cyclogenesis and extreme winds and the phenomena known as sting jets was discovered, and now forecasters know what to look for in a developing windstorm to identify the formation of a sting jet and the likelihood of extreme near-surface gusts.

https://theconversation.com/sting-jet-t ... inds-85620

Ultimately meteorology is not an exact science and expecting superb predictions all the time is unrealistic. Forecasts are probabilistic by nature, the deterministic forecast can be viewed as the most-likely outcome, but inherent uncertainty means the actual outcome may be better or worse than predicted, the probability decreasing the further away from the deterministic forecast you go. With the 2024 hurricane season forecasts, even though all agencies were predicting a hyper-active season, there was never a zero probability of an above-average but not hyper-active, or even a near average season, it is just these outcomes were much less likely given the known teleconnections prior to peak season. If I see the same Nino state and tropical Atlantic SSTs next year and we have a hurricane in the MDR in June/July I will almost certainly make the same prediction as I did this year, and I will make the same statement in the confidence/uncertainties section of the forecast document that unpredictable intra-seasonal factors may result in a less active season.

[toad strangler]

For those keeping score on ACE this weirdo season.. CREDIT: Weather Tiger .... The model as fallen off to ABOVE NORMAL best chance from hyperactive.

[Spacecoast]

EPS Weekly for Oct showing that 'October' pattern.....

Coincidentally...

[Teban54]

 https://x.com/dmorris9661/status/1831796309034221830



Several Euro weeklies follow in the thread. The 4th week seems particularly interesting, as it not only shows a very late CV season, but also tracks that are much further south than you'd expect for late September:

 https://x.com/dmorris9661/status/1831796309034221830

[LarryWx]

EPS Weekly for Oct showing that 'October' pattern.....
https://i.ibb.co/9cYXgXQ/ecprobb.jpg
Coincidentally...
https://i.ibb.co/jrjVr8W/clim.jpg

The mean ACE prog for that week, Sep 30-Oct 6, is for a whopping 160% of 2004-2023 climo! That’s the highest % for any week in quite awhile. That equates to an ACE that week of 15, which is just one below the 2004-23 averaged ACE at the peak week of 9/9-15. The week prior (Sep 23-29) also is progged at 15 (120% of climo). So, this run is essentially predicting the equivalent of peak climo during a period who’s actual climo is already well under peak climo.

[LarryWx]

Followup: CPC Aug NAO came in at +0.63, about where I expected it. So, despite that other version of Aug NAO being at a record high for it (over +3!), this one was only moderately positive. Many have been much higher with the Aug record high way up at +1.97.

https://www.cpc.ncep.noaa.gov/products/ ... scii.table

[Teban54]

CPC has also released their analysis of the Intertropical Front (ITF) position during August 21-31. The western ITCZ is mostly in line with climo now, though the eastern ITCZ remains anomalously north (and parts of it actually shifted further north compared to August 11-20).

[gatorcane]

Ironically, the disturbance over Mali/Mauritania looks better than anything we have seen over the Atlantic in the past couple of weeks. I also don't recall seeing anything like this so far north in Africa before, it's not normal right?

[aspen]

Ironically, the disturbance over Mali/Mauritania looks better than anything we have seen over the Atlantic in the past couple of weeks. I also don't recall seeing anything like this so far north in Africa before, it's not normal right?

https://i.postimg.cc/900kGpN7/goes16-vis-swir-eatl.gif

I remember the Euro was showing a disturbance in late Aug/early Sept quite similar to what we’re seeing right now, being anomalously far north into the Sahara. It’s ridiculous how far north the ITCZ/AEJ is.

[Ubuntwo]

Ironically, the disturbance over Mali/Mauritania looks better than anything we have seen over the Atlantic in the past couple of weeks. I also don't recall seeing anything like this so far north in Africa before, it's not normal right?

It is associated with a huge batch of 6-sigma PWAT anomalies over the Sahara, so no, this is not normal.

[REDHurricane]

Ironically, the disturbance over Mali/Mauritania looks better than anything we have seen over the Atlantic in the past couple of weeks. I also don't recall seeing anything like this so far north in Africa before, it's not normal right?

It is associated with a huge batch of 6-sigma PWAT anomalies over the Sahara, so no, this is not normal.
https://i.imgur.com/bkCCPUw.png

For context, the probability of a 6-sigma event occurring (in a normal distribution) is somewhere around 1 in 500 million according to the interwebs

[USTropics]

I can't share the graphics since its ongoing research, but we have a professor here at FSU (Dr. Wing) who is currently on a field mission in the eastern Atlantic. Her research group is releasing various daily soundings from a ship in tropical waves/convection to assess the vertical profile. I can tell you (especially around the 3rd/4th week of August) some of the mid-upper level air soundings are astonishing (as in, large presence of dry air and terrible lapse rates).

[aspen]

We’re a week into September with no imminent development on the horizon, and models keep pushing back any significant TC activity. I think now it’s safe to say we’re confidently in historic bust territory. While this probably won’t be among the lowest-ACE seasons by virtue of having Beryl, this will likely be the biggest bust in Atlantic history relative to the forecasts being put out.

I think the totals may be 7-11 NS, 3-5 H, 1-2 MH, and 70-100 ACE once all is said and done. While this exceeds 2013 in every metric except NS, it’s a far cry from the numerous 20+ NS and hyperactive ACE forecasts. I do expect we’ll see at least a few more storms this season, but probably not any significant peak in activity like in a normal ASO.

Edit: and I just noticed the models ticked up this morning and the wave we’ve been watching for 2 weeks might actually develop soon, my bad lol. Still not expecting much more than 100-110 ACE, though.

[REDHurricane]

We’re a week into September with no imminent development on the horizon, and models keep pushing back any significant TC activity. I think now it’s safe to say we’re confidently in historic bust territory. While this probably won’t be among the lowest-ACE seasons by virtue of having Beryl, this will likely be the biggest bust in Atlantic history relative to the forecasts being put out.

I think the totals may be 7-11 NS, 3-5 H, 1-2 MH, and 70-100 ACE once all is said and done. While this exceeds 2013 in every metric except NS, it’s a far cry from the numerous 20+ NS and hyperactive ACE forecasts. I do expect we’ll see at least a few more storms this season, but probably not any significant peak in activity like in a normal ASO.

Still way too early, my friend. I'd be willing to bet semi-significant money that the Atlantic will reach 100 ACE, even if the season ends up being a bust overall... it would be legitimately shocking if the same Atlantic that produced Beryl in June goes the entirety of September/October/November producing less than 45 ACE total, like I get the conservative outlook but it really only would take one or two more decent hurricanes to exceed 45 ACE, and let's remember that the hurricanes don't care about our human calendar-based expectations of how a normal year should play out. It's certainly possible that you're right (and for the sake of Atlantic coastal areas I hope you are), but I feel like this might end up being one of those comments that people pull up after the season is over to illustrate the pitfalls of assuming that present conditions predict future performance. There are still 7 weeks left in September/October plus all of November, and we're entering a weak La Niña in a tropical Atlantic + Caribbean/Gulf that's still hitting record or near-record SSTs and OHC -- as we have witnessed time and time again in previous seasons, things can and often do change very quickly when these kinds of conditions are in place.

[Teban54]

We’re a week into September with no imminent development on the horizon, and models keep pushing back any significant TC activity. I think now it’s safe to say we’re confidently in historic bust territory. While this probably won’t be among the lowest-ACE seasons by virtue of having Beryl, this will likely be the biggest bust in Atlantic history relative to the forecasts being put out.

I think the totals may be 7-11 NS, 3-5 H, 1-2 MH, and 70-100 ACE once all is said and done. While this exceeds 2013 in every metric except NS, it’s a far cry from the numerous 20+ NS and hyperactive ACE forecasts. I do expect we’ll see at least a few more storms this season, but probably not any significant peak in activity like in a normal ASO.

Edit: and I just noticed the models ticked up this morning and the wave we’ve been watching for 2 weeks might actually develop soon, my bad lol. Still not expecting much more than 100-110 ACE, though.

If anything, there's a significantly increased chance that we won't be looking at an empty TWO map on September 10. I'd even say we'll probably have at least two entities on the map, if not two TCs.

[Hammy]

Now that I've figured out how to both find the wind (rather than just pressure map) and also the expanded view on pivotal, it looks like the CFS is showing potentially 12 storms roughly, through early October, and this doesn't seem like it's out of the question now that the model signal is there that the issues are finally beginning to resolve.

Interestingly, while it doesn't show the current GFS solution (more than likely given the real time monsoon trough is causing issues for all the models--especially a lower resolution one like the CFS)--it shows a nearly identical, but stronger, scenario so that particular run setting up near the end of September

[Cachondo23]

We’re a week into September with no imminent development on the horizon, and models keep pushing back any significant TC activity. I think now it’s safe to say we’re confidently in historic bust territory. While this probably won’t be among the lowest-ACE seasons by virtue of having Beryl, this will likely be the biggest bust in Atlantic history relative to the forecasts being put out.

I think the totals may be 7-11 NS, 3-5 H, 1-2 MH, and 70-100 ACE once all is said and done. While this exceeds 2013 in every metric except NS, it’s a far cry from the numerous 20+ NS and hyperactive ACE forecasts. I do expect we’ll see at least a few more storms this season, but probably not any significant peak in activity like in a normal ASO.

Edit: and I just noticed the models ticked up this morning and the wave we’ve been watching for 2 weeks might actually develop soon, my bad lol. Still not expecting much more than 100-110 ACE, though.

1 more MH for the rest of the season?

[Hammy]

We’re a week into September with no imminent development on the horizon, and models keep pushing back any significant TC activity. I think now it’s safe to say we’re confidently in historic bust territory. While this probably won’t be among the lowest-ACE seasons by virtue of having Beryl, this will likely be the biggest bust in Atlantic history relative to the forecasts being put out.

I think the totals may be 7-11 NS, 3-5 H, 1-2 MH, and 70-100 ACE once all is said and done. While this exceeds 2013 in every metric except NS, it’s a far cry from the numerous 20+ NS and hyperactive ACE forecasts. I do expect we’ll see at least a few more storms this season, but probably not any significant peak in activity like in a normal ASO.

Edit: and I just noticed the models ticked up this morning and the wave we’ve been watching for 2 weeks might actually develop soon, my bad lol. Still not expecting much more than 100-110 ACE, though.

The models have been showing imminent development (within five days) for the last couple. The bolded is a fair estimate for the rest of the season but I highly doubt this is going to be the season total.

The 20+ numbers and peak ACE forecasts always seemed unachievable once we went all of July without any new storms--any extreme high or low forecast I've always doubted.

[Hurricane2022]

Inb4 the switch flip was just delayed by 20 days and then from this next GOM system we're going to see the Atlantic producing hurricanes in an absurd hurry until December

[Teban54]

Within the last 24 hours, we have three concurrent orange or cherry AOIs, two concurrent invests that were newly declared, as well as GFS and Euro runs with significant hurricanes.

The first thing this reminds me of is the classic Captain Barbossa's Tropical Cyclone Timeline. So here's my attempt at a 2024 edition (based on Category5Kaiju's version earlier):


1. June 1st: Everyone is excited about the upcoming season. Many are anticipating upcoming action later in the month, but most know that the real action will most likely start in August.

2. June 30th: A Category 4 hurricane rampages through the MDR. Many are absolutely stunned at the sight.

3. July 2nd: That Category 4 hurricane is now a Category 5 hurricane in the Eastern Caribbean. Many begin to greatly worry about the future of the season.

4. July 15th: Lots of SAL is present in the Atlantic basin. However, most people are not surprised by this, as they were expecting it, althouh a select few see nothing in the models and begin to question if hyperactivity is on the table after all.

5. July 28th: Atlantic is still slow. Dry, stable air is present in the tropics. However, models are beginning to suggest things will be changing within a few days.

6. August 15th: Models show nothing in the near-future (other than Ernesto). Many are becoming skeptical about the season amounting to anything significant.

7. August 23rd: Normally, there should be multiple invests in the Atlantic and conditions are rapidly beginning to change. But this year the Atlantic fell asleep, as Ernesto was gone and nothing else was on the horizon. Models still show nothing. There are long debates about whether conditions will change or not.

8. September 3rd: Somehow, the Atlantic is still dead. No storms seem likely to form (aside from a failed model storm) leading up to the climo peak. Experts and fans start desperate attempts at explaining why that's the case, and CSU had to issue a special discussion explaining why the Atlantic is quiet. Many are calling the season a bust and think it will finish like 2013, while some still expect a heavily back-loaded season.

9. September 7th: There are multiple invests in the Atlantic and conditions are rapidly beginning to change. The models begin to show cyclogenesis. Many quickly change their minds about a quieter season (?). (Typically on August 23rd)

Will the following happen?

10. ???: Some experts continue to doubt signs of the Atlantic awakening. These experts issue outlooks that support original ideas of a quieter season. (Typically on August 24th)

11. ???: There is now at least one active TC. There is a potential that at least one TC could become a hurricane. Many people appear shocked by the increased activity. (Typically on August 31st)

12. ???: Several TCs have already formed and dissipated. A few who suggested that the season would be quiet now state that they always knew the Atlantic would spring to life. (Typically on September 30th)

13. ???: The last storm probably has dissipated by this point. Many look back at the season and state that they are surprised with the outcome. (Typically on November 30th)


(Aside: I found last year's discussions about Captain Barbossa's timeline. Of course, people were saying "2023 isn't a normal year because El Nino". We know how that turned out.)