2024 Atlantic Hurricane Season

[GaWx]

12Z EPS: notable uptick in members active with this E Atlantic AEW vs earlier runs.

[WxWatcher007]

11 minutes ago, GaWx said:

12Z EPS: notable uptick in members active with this E Atlantic AEW vs earlier runs. Primary US threat leans to E coast on this run.

We’ll see if it holds but this should test my theory that we haven’t seen much traction in the basin recently because everything is too far north and it’s killing waves before they have a chance. 

There’s still plenty of SAL and stability in the eastern MDR, but something further south should be able to overcome it with enough time in a low shear/high SST environment. 

[GaWx]

47 minutes ago, WxWatcher007 said:

We’ll see if it holds but this should test my theory that we haven’t seen much traction in the basin recently because everything is too far north and it’s killing waves before they have a chance. 

There’s still plenty of SAL and stability in the eastern MDR, but something further south should be able to overcome it with enough time in a low shear/high SST environment. 

 I’m currently thinking 2/3 chance of a TCG by next week. Due largely to this AEW, I expect the first uptick  (as long as I’ve been tracking this daily) on the Euro Weeklies, especially for the week of 9/2-8. Probably some uptick on 9/9-15 as well just due to the end of this.

[wkd]

I'm trying to locate the thread about the 2024 hurricane predictions.  I can't remember what I posted. Any help?

[GaWx]

36 minutes ago, GaWx said:

 I’m currently thinking 2/3 chance of a TCG by next week. Due largely to this AEW, I expect the first uptick  (as long as I’ve been tracking this daily) on the Euro Weeklies, especially for the week of 9/2-8. Probably some uptick on 9/9-15 as well just due to the end of this.

 Surprisingly to me, today’s Euro Weeklies had no uptick in the mean ACE progs. These are based on today’s 0Z extended EPS. Had they been based on today’s 12Z instead, I’m confident there would have been an uptick. They stayed the same for weeks 1-3 and had a slight down tick for week 4. 

 Regardless, the maps showing the areas with enhanced chances of TC strike suggest for weeks 3-4 (9/9-22) the highest chance in and near the SE US for any run since I started following these daily. Also, week 3 has the highest chance of any run for the corridor SE to PR.

[GaWx]

8 minutes ago, wkd said:

I'm trying to locate the thread about the 2024 hurricane predictions.  I can't remember what I posted. Any help?

15/9/4

[GaWx]

8PM TWO from NHC:

 

Central Tropical Atlantic:
An area of low pressure could form in the central portion of the 
Tropical Atlantic in a few days. Thereafter, environmental 
conditions appear generally favorable for some slow development of 
this system by this weekend into early next week as it moves 
westward to west-northwestward at 10 to 15 mph.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 7 days...low...20 percent.

[yoda]

4 hours ago, wkd said:

I'm trying to locate the thread about the 2024 hurricane predictions.  I can't remember what I posted. Any help?

 

 

[Windspeed]

Excellent thread by Kaylan Patel covering the quiet August stretch. He includes the abnormally strong monsoonal trough latitudinally displacing WAM/ITCZ like we have also discussed and also mentions a stable upper troposphere over the MDR. He mentions the +NAO and SPH placement tapping SAL. But I do like his play-by-play of the resulting pattern here:

In short it goes like this.
1) Have an active WAM/Tropical Wave train
2) Shift them north through a Monsoon Trough
3) Have them exit Africa at 20N directly into SAL/Stable Air
4) Enhanced trades from the TW push that stable air directly into MDR and into southern TWs
5) Repeat!
Other factors that could've been the reason include.
-Too strong TEJ and way too strong westerly trades
-ENSO transition not properly taking effect
-Stability issues in the upper levels due to abnormal warmth
-All of the above?

He also alludes to the EPS and GEFS showing the monsoonal trough weakening. These are all topics we've covered above but a nice succinct thread here. Just to show a lot of discussion ongoing across SM by the pros and further implications that the quiet period may be closing.

[Windspeed]

A vigorous AEW should be exiting south of the Cabo Verdes by Wednesday. This disturbance is at a lower latitude and has intensified over the past 24 hours. The cyclonic spin is quite noticeable beyond a typical mesoscale feature and may already have an organized low. Based on its look and latitude, it has my attention. Note that the image was sourced from Meteosat and not GOES to get a better perspective of the wave at 5°W to avoid distortion.

[Seminole]

2 hours ago, Windspeed said:

A vigorous AEW should be exiting south of the Cabo Verdes by Wednesday. This disturbance is at a lower latitude and has intensified over the past 24 hours. The cyclonic spin is quite noticeable beyond a typical mesoscale feature and may already have an organized low. Based on its look and latitude, it has my attention. Note that the image was sourced from Meteosat and not GOES to get a better perspective of the wave at 5°W to avoid distortion.

Nothing to write home about behind that wave though.  

[Supercane]

As Windspeed alluded to in the post above, the NAO has been mostly positive since mid-June. The impact of this can be seen in the SSTA pattern, with the warmest SSTAs concentrated in the subtropics between Newfoundland and the Azores, and cooler SSTAs along the Canary current and in the far north Atlantic. This is not exactly a classic +AMO pattern and began to take shape in June, concurrent with the NAO flipping positive:

 

 

I still fully expect activity to pick up in September and October and for the season to finish above the long-term average. But the signs in June began pointing toward a more modest season (rather than one of the most active on record), and the ongoing lull reinforces that likelihood.

[GaWx]

26 minutes ago, Supercane said:

As Windspeed alluded to in the post above, the NAO has been mostly positive since mid-June. The impact of this can be seen in the SSTA pattern, with the warmest SSTAs concentrated in the subtropics between Newfoundland and the Azores, and cooler SSTAs along the Canary current and in the far north Atlantic. This is not exactly a classic +AMO pattern and began to take shape in June, concurrent with the NAO flipping positive:

 

 

I still fully expect activity to pick up in September and October and for the season to finish above the long-term average. But the signs in June began pointing toward a more modest season (rather than one of the most active on record), and the ongoing lull reinforces that likelihood.

Here is fwiw a copy of some excerpts from a post I made on 4/7/24 regarding the extremely bullish April CSU forecast:

“I see a pretty clear pattern when they’ve gone very active in April:

2. NS days: They’re predicting 115. Prior to this the highest they predicted in April was 85-95 (four times). All four of those progs ended up too high. The highest actual of those four was only 58 and they averaged a whopping 40.5 too high!

3. # H: They’re predicting 11. The prior highest predicted in April was 9 (six times). All of those 6 progs ended up too high by an average of 3.

7. ACE: They’re predicting 210. The prior highest predicted in April were 160-183 (five times). Of these five, all progs ended up too high with even the closest still being 34 too high! The five averaged a whopping 85.8 too high!

Conclusion: If I were a betting man, I’d short CSU’s April ‘24’s forecast overall, especially NS Days, # H, and ACE.”

 

[CurlyHeadBarrett]

40 minutes ago, Supercane said:

As Windspeed alluded to in the post above, the NAO has been mostly positive since mid-June. The impact of this can be seen in the SSTA pattern, with the warmest SSTAs concentrated in the subtropics between Newfoundland and the Azores, and cooler SSTAs along the Canary current and in the far north Atlantic. This is not exactly a classic +AMO pattern and began to take shape in June, concurrent with the NAO flipping positive:

 

 

I still fully expect activity to pick up in September and October and for the season to finish above the long-term average. But the signs in June began pointing toward a more modest season (rather than one of the most active on record), and the ongoing lull reinforces that likelihood.

Define "more modest"

[ldub23]

25 minutes ago, GaWx said:

Here is fwiw a copy of some excerpts from a post I made on 4/7/24 regarding the extremely bullish April CSU forecast:

“I see a pretty clear pattern when they’ve gone very active in April:

2. NS days: They’re predicting 115. Prior to this the highest they predicted in April was 85-95 (four times). All four of those progs ended up too high. The highest actual of those four was only 58 and they averaged a whopping 40.5 too high!

3. # H: They’re predicting 11. The prior highest predicted in April was 9 (six times). All of those 6 progs ended up too high by an average of 3.

7. ACE: They’re predicting 210. The prior highest predicted in April were 160-183 (five times). Of these five, all progs ended up too high with even the closest still being 34 too high! The five averaged a whopping 85.8 too high!

Conclusion: If I were a betting man, I’d short CSU’s April ‘24’s forecast overall, especially NS Days, # H, and ACE.”

 

You were wise. GFS says the  first  low  is  0/0 now but  it  does develop another  one that will recurve  400 miles east  of Bermuda. I still think the ATL will produce several biggies  in oct/nov but  300-400 miles east  of  bermuda is where they will likely  go.

[Retrobuc]

1 hour ago, GaWx said:

Here is fwiw a copy of some excerpts from a post I made on 4/7/24 regarding the extremely bullish April CSU forecast:

“I see a pretty clear pattern when they’ve gone very active in April:

2. NS days: They’re predicting 115. Prior to this the highest they predicted in April was 85-95 (four times). All four of those progs ended up too high. The highest actual of those four was only 58 and they averaged a whopping 40.5 too high!

3. # H: They’re predicting 11. The prior highest predicted in April was 9 (six times). All of those 6 progs ended up too high by an average of 3.

7. ACE: They’re predicting 210. The prior highest predicted in April were 160-183 (five times). Of these five, all progs ended up too high with even the closest still being 34 too high! The five averaged a whopping 85.8 too high!

Conclusion: If I were a betting man, I’d short CSU’s April ‘24’s forecast overall, especially NS Days, # H, and ACE.”

 

To me the CSU forecast was always too bullish and it seems to have become a game of groupthink after that.  You should always be cautious when forecasts for anything are 4-6x higher than the highest point.

[Supercane]

2 hours ago, GaWx said:

Here is fwiw a copy of some excerpts from a post I made on 4/7/24 regarding the extremely bullish April CSU forecast:

“I see a pretty clear pattern when they’ve gone very active in April:

2. NS days: They’re predicting 115. Prior to this the highest they predicted in April was 85-95 (four times). All four of those progs ended up too high. The highest actual of those four was only 58 and they averaged a whopping 40.5 too high!

3. # H: They’re predicting 11. The prior highest predicted in April was 9 (six times). All of those 6 progs ended up too high by an average of 3.

7. ACE: They’re predicting 210. The prior highest predicted in April were 160-183 (five times). Of these five, all progs ended up too high with even the closest still being 34 too high! The five averaged a whopping 85.8 too high!

Conclusion: If I were a betting man, I’d short CSU’s April ‘24’s forecast overall, especially NS Days, # H, and ACE.”

 

The retrospectives will be interesting. In defense of CSU and the other agencies, if I had released a seasonal forecast in April or May, I would have likely predicted a very hyperactive season based on how the SSTA pattern was at the time (and also knowing the El Nino was dissipating). However, my ACE forecast model (which predicted an ACE of "only" 154 this year) was purposefully released in the first week of July, because often it's not until June that the contours of a season become apparent. This year is a good example of that, having a very favorable SSTA pattern in the Spring which was significantly disrupted by a +NAO in June. A much more dramatic flop occurred in 2013, and the opposite trend occurred in 2004. Also, the evolution of ENSO tends to be more clear by June and after the Spring barrier.

That said, CSU and TSR both released forecasts in early July and still called for an ACE of 230 and 240, respectively, so their methodologies obviously differ. It's far too early to make any definitive claims about how this season will progress or grade how anyone performed, but I'm enjoying the discussion about what is causing this long lull. Trying to understand unexpected events like this are how the science of forecasting is improved.

[Supercane]

2 hours ago, CurlyHeadBarrett said:

Define "more modest"

Above average, but below 200 ACE.

[GaWx]

1 hour ago, Supercane said:

The retrospectives will be interesting. In defense of CSU and the other agencies, if I had released a seasonal forecast in April or May, I would have likely predicted a very hyperactive season based on how the SSTA pattern was at the time (and also knowing the El Nino was dissipating). However, my ACE forecast model (which predicted an ACE of "only" 154 this year) was purposefully released in the first week of July, because often it's not until June that the contours of a season become apparent. This year is a good example of that, having a very favorable SSTA pattern in the Spring which was significantly disrupted by a +NAO in June. A much more dramatic flop occurred in 2013, and the opposite trend occurred in 2004. Also, the evolution of ENSO tends to be more clear by June and after the Spring barrier.

That said, CSU and TSR both released forecasts in early July and still called for an ACE of 230 and 240, respectively, so their methodologies obviously differ. It's far too early to make any definitive claims about how this season will progress or grade how anyone performed, but I'm enjoying the discussion about what is causing this long lull. Trying to understand unexpected events like this are how the science of forecasting is improved.

My ACE forecast that day at another BB’s season contest (it’s still there) was 176. That was based on CSU’s April ACE forecast ending up 34+ too high when they were very aggressive with ACE per the analysis I had done that I just linked too. They predicted 210 in April. 210-34=176. 

[Kevin Reilly]

4 hours ago, Supercane said:

As Windspeed alluded to in the post above, the NAO has been mostly positive since mid-June. The impact of this can be seen in the SSTA pattern, with the warmest SSTAs concentrated in the subtropics between Newfoundland and the Azores, and cooler SSTAs along the Canary current and in the far north Atlantic. This is not exactly a classic +AMO pattern and began to take shape in June, concurrent with the NAO flipping positive:

 

 

I still fully expect activity to pick up in September and October and for the season to finish above the long-term average. But the signs in June began pointing toward a more modest season (rather than one of the most active on record), and the ongoing lull reinforces that likelihood.

 

4 hours ago, Supercane said:

As Windspeed alluded to in the post above, the NAO has been mostly positive since mid-June. The impact of this can be seen in the SSTA pattern, with the warmest SSTAs concentrated in the subtropics between Newfoundland and the Azores, and cooler SSTAs along the Canary current and in the far north Atlantic. This is not exactly a classic +AMO pattern and began to take shape in June, concurrent with the NAO flipping positive:

 

 

I still fully expect activity to pick up in September and October and for the season to above the long-term average. But the signs in June began pointing toward a more modest season (rather than one of the most active on record), and the ongoing lull reinforces that likelihood.

Here is the NAO throughout the summer some highs some lows but nothing really too locked in though.  Looking forward we are moving neutral then negative should be interesting to see what changes we see in the coming weeks.  I like to call this period where we go from predominately positive to neutral to negative a time of chaos when it comes to the models for mid latitude systems, I am not sure how that translates though to the tropical Atlantic.

 

However, I do remember how negative the NAO was when Sandy came rolling up from Eastern Jamaica to wreak havoc up the mid-Atlantic seaboard. 

Interesting times ahead as we move towards fall and winter for sure!

In regard to winter the SST Delaware points NE have my attention for winter storms!

[Stormchaserchuck1]

I don't think it's because of the +NAO the season has been slow. The clues came in May-July when the east coast, US was super dry, and the cap was not breaking for anything, despite very hot temperatures. That seemed to be a pattern that carried across the Atlantic. 

Also, two years ago we had 14 NS during a La Nina, so that was a trend break. There was expected to be a pretty strong La Nina for the hurricane season this year, and what we have is Neutral, so all that's really going for it is the warm SSTs and you know that that is a very general factor. It doesn't look like Weak La Nina conditions will develop for the 2nd half of the season, although the subsurface ENSO is in Weak-Nina range. 

[GaWx]

41 minutes ago, Stormchaserchuck1 said:

I don't think it's because of the +NAO the season has been slow. The clues came in May-July when the east coast, US was super dry, and the cap was not breaking for anything, despite very hot temperatures. That seemed to be a pattern that carried across the Atlantic. 

Also, two years ago we had 14 NS during a La Nina, so that was a trend break. There was expected to be a pretty strong La Nina for the hurricane season this year, and what we have is Neutral, so all that's really going for it is the warm SSTs and you know that that is a very general factor. It doesn't look like Weak La Nina conditions will develop for the 2nd half of the season, although the subsurface ENSO is in Weak-Nina range. 

But we’re already weak Niña per RONI.

[thunderbolt]

18 minutes ago, GaWx said:

But we’re already weak Niña per RONI.

RONI?      

[jburns]

On 8/26/2024 at 4:19 PM, wkd said:

I'm trying to locate the thread about the 2024 hurricane predictions.  I can't remember what I posted. Any help?

I pinned it for now. Someone let me know when you want it to disappear.

[GaWx]

14 minutes ago, thunderbolt said:

RONI?      

Relative ONI, which adjusts ONI based on average global tropical SST anomalies. Right now those are so warm that RONI is over 0.5C colder than ONI. The equivalent RONI is down to ~-0.7, which is weak Niña.

[GaWx]

 

[CurlyHeadBarrett]

I’m this close to giving up 

[GaWx]

20 minutes ago, CurlyHeadBarrett said:

I’m this close to giving up 

[GaWx]

 I don’t think it was a good idea to pin the contest thread and no others. This one is way busier and the contest won’t end for several months. Or at least pin this one and the other current tropical threads as well.

 Other opinions?

[CurlyHeadBarrett]

7 minutes ago, GaWx said:

Why?