2025 Indicators: SST's, MSLP, Shear, SAL, Steering, Instability (Day 16+ Climate Models)

[Teban54]

Aside, and to balance the bullishness of my previous comment:

The first 3 storms of the season generated 0.2, 0.4 and 0.8 ACE respectively. Andrea will likely be adjusted upwards in TCR, but still.

The current record holder for the lowest ACE of the first 5 storms is 2017. Could 2025 "beat" that record?

Of course, that's meaningless for seasonal activity as a whole: 2017 then produced 10 hurricanes in a row, and ranked as the 7th highest-ACE season on record.

(@cycloneye, I don't see a 2025 Global ACE thread. Perhaps we should make one?)

[LarryWx]

Chantal 2025 was named yesterday, July 5. The last iteration of the same name, Chantal 2019, didn't form until August 20.

It's kind of surprising that, despite the impression of an inactive start of the season (especially 2 weeks ago), we're still running ahead of 2019.

As a reminder, 2019 ended above average in both NS counts (18) and ACE (132). The following storm was Dorian.

Hey Teban, Good post with 2025 getting its C storm 1.5 months ahead of 2019! It also has 4 times the 2019 ACE as of July 6th.

Interestingly though, despite running well ahead of normal with already 3 NS, the ACE is still only at 1.46 vs the 1951-2024 avg of 4.12! That is lower than 46 of those 74 years.

I’ll now compare to other years since 1951 with 3+ NS by July 6th along with their ACE:

Year: NS/ACE
1954: 3/8.56
1959: 4/7.18
1968: 3/13.54
2005: 4/5.84
2012: 4/11.2
2016: 4/6.85
2017: 3/3.18
2020: 5/7.24
2021: 5/10.59
2023: 3/8.62
2024: 3/32.57
2025: 3/1.46

Note that for the 12 seasons since 1951 with 3+ NS by July 6th, 2025 has by far the lowest ACE/storm (0.49)! That easily beats the 2nd lowest, 2017’s 1.06/storm. The highest is 2024’s 10.86/storm. The avg of these 12 seasons through July 6th is ~2.8 ACE/storm.

Edit: lol, great minds think alike. While I was putting together this post, which took over an hour to calculate/compile, I see you posted something similar to this one about the very low ACE/storm.

[cycloneye]

Aside, and to balance the bullishness of my previous comment:

The first 3 storms of the season generated 0.2, 0.4 and 0.8 ACE respectively. Andrea will likely be adjusted upwards in TCR, but still.

The current record holder for the lowest ACE of the first 5 storms is 2017. Could 2025 "beat" that record?

Of course, that's meaningless for seasonal activity as a whole: 2017 then produced 10 hurricanes in a row, and ranked as the 7th highest-ACE season on record.

(@cycloneye, I don't see a 2025 Global ACE thread. Perhaps we should make one?)

Thanks for the reminder and yes, the 2025 Global ACE thread is up.

[cycloneye]

 https://x.com/BenNollWeather/status/1942229618586526086

[cycloneye]

There is good and bad news that Ben Noll highlights in his message.

@BenNollWeather
New ECMWF seasonal guidance shows anomalous rising motion over Africa during the peak of hurricane season — a pattern that can invigorate the easterly waves that go on to become hurricanes.

However, sinking air farther west in the Atlantic may suppress activity.

 https://x.com/BenNollWeather/status/1942244718072799445

[cycloneye]

Wow. Very unfavorable view here from Tyler who knows a lot about the patterns. But closer to where people live is where the activity may be.

@TylerJStanfield
This is the most sinking motion (+VP200) observed over Africa in April-May-June since 2015.

MJO phase 5-7 is favored in this current regime which is a mixed bag for subseasonal TC favorability of the Atlantic.

SW ATL and subtropics appear to be the hot spots for TCs generally

 https://x.com/TylerJStanfield/status/1942241181305290990

[Category5Kaiju]

I could be wrong, but I could've sworn that sinking air over the main Atlantic basin and rising air over Africa is the composite look for above-average, even hyperactive, seasons? Can't remember who it was exactly who shared that VP composite (probably Eric Webb or somebody like that), but I could've sworn that I saw something like that a few years ago online.

[WeatherBoy2000]

Wow. Very unfavorable view here from Tyler who knows a lot about the patterns. But closer to where people live is where the activity may be.

@TylerJStanfield
This is the most sinking motion (+VP200) observed over Africa in April-May-June since 2015.

MJO phase 5-7 is favored in this current regime which is a mixed bag for subseasonal TC favorability of the Atlantic.

SW ATL and subtropics appear to be the hot spots for TCs generally

 https://x.com/TylerJStanfield/status/1942241181305290990

Tyler claims 2000 as his closest analog to 2025.

 https://x.com/TylerJStanfield/status/1942306511167934962



An outcome like 2000 would make 2025 the second least active season of the 2020s, only behind 2022 (so far).

[Category5Kaiju]

I think cycloneye already mentioned it in the ENSO thread, but the recent July NMME model officially shows La Nina for this winter. If the trends toward a colder ENSO 3/4 region are indeed true, then perhaps that could be a sign that the Atlantic won't be as unfavorable as initially imagined?

[WeatherBoy2000]

I think cycloneye already mentioned it in the ENSO thread, but the recent July NMME model officially shows La Nina for this winter. If the trends toward a colder ENSO 3/4 region are indeed true, then perhaps that could be a sign that the Atlantic won't be as unfavorable as initially imagined?

The eps is also predicting a flip to a more sustained -nao pattern starting around the middle of the month:

 https://x.com/dmorris9661/status/1941808591146525071

[cycloneye]

Maybe a backloaded season with that NMME news?

[cycloneye]

The July run of NMME for precipitation and sst anomalys for ASO looks not so good to have an active to hyperactive rest of season, but mother nature dictates in reallity what will happen and all who live in the tropical coasts and in Caribbean must be prepared for anything.

[al78]

Most likely sea level pressure anomalies (from UK Met Office) not looking favourable for tropical cyclone activity across the Atlantic basin. From the dynamical model seasonal forecasts I have looked at, I am not seeing a very active season this year.

[cycloneye]

The ups and downs continue. Here is the up.

 https://x.com/webberweather/status/1942592168448688597



 https://x.com/webberweather/status/1942594022335472035

[WeatherBoy2000]

I think cycloneye already mentioned it in the ENSO thread, but the recent July NMME model officially shows La Nina for this winter. If the trends toward a colder ENSO 3/4 region are indeed true, then perhaps that could be a sign that the Atlantic won't be as unfavorable as initially imagined?

The eps is also predicting a flip to a more sustained -nao pattern starting around the middle of the month:

 https://x.com/dmorris9661/status/1941808591146525071

The gefs has also trended more negative. Prior runs still had many positive members, now nearly all of them go negative to some degree:

[LarryWx]

https://www.metoffice.gov.uk/images/prob_ensemble/20250601/2cat_20250601_mslp_months24_tropics_prob_public.png

Most likely sea level pressure anomalies (from UK Met Office) not looking favourable for tropical cyclone activity across the Atlantic basin. From the dynamical model seasonal forecasts I have looked at, I am not seeing a very active season this year.

I sure hope it’s nothing like last year’s horrible season. I’ve been thinking it won’t be.

But when you say “not very active”, that could still mean near the active mean of 1991-2020 (122 ACE avg). Are you thinking more like that or are you thinking less active than that?

[cycloneye]

Mr Webb continues to post important messages. Below are 4 more as a thread at X. The bottomline is things are looking bleak to put a word to have an active or even an average season. But, if we dont have the traditional CV season rolling, homegrowns may be forming and that is worrisom. As I said earlier in the thread, maybe a backloaded season closer to where people live.

 https://x.com/webberweather/status/1942606569461498197



 https://x.com/webberweather/status/1942607255612055601



 https://x.com/webberweather/status/1942607915136999916



 https://x.com/webberweather/status/1942609052292505868

[TomballEd]

Noticed on the ENSO thread that both the sub-tropical Atlantic and the sub-tropical Pacific were generally well above normal temperature wise. I'd assume this would tend to suppress activity in both basins. Note how quickly the sub-tropical North Pacific has warmed. https://www.tropicaltidbits.com/analysis/ocean/cdas-sflux_ssta7diff_global_1.png

[LarryWx]

Noticed on the ENSO thread that both the sub-tropical Atlantic and the sub-tropical Pacific were generally well above normal temperature wise. I'd assume this would tend to suppress activity in both basins. Note how quickly the sub-tropical North Pacific has warmed. https://www.tropicaltidbits.com/analysis/ocean/cdas-sflux_ssta7diff_global_1.png

Thanks, Ed. That makes sense as it tends to reduce tropical instability. But suppressed off of an extreme season, which could still be active, or suppressed off of an average season? I’ve seen no model output or well followed forecast going for anything close to quiet. 1991-2020 ACE avg is 122. The lowest I’ve seen is the latest Euro, which is near 120-125 (to me that’s still fairly active) vs it’s prior run’s 130-140.

[DorkyMcDorkface]

EPS has an intriguing signal for the first half of August in the MDR. This about lines up with the return of the MJO so it makes sense. Until then, look for subtropical/homegrown developments rather than anything notable in the deep tropics.