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

[Hypercane_Kyle]

Feels eerily reminiscent to last year.... early Category 5, followed by lull at peak season before a chaotic late-September/October.

[cycloneye]

 https://x.com/frontierfcst/status/1961121576687919302

[Travorum]

Feels eerily reminiscent to last year.... early Category 5, followed by lull at peak season before a chaotic late-September/October.

Including a wave after that early Category 5 that initially looks like it has potential to develop into something serious only to bust due in part due to the storm in front of it overperforming.

[cycloneye]

 https://x.com/DylanFedericoWX/status/1961156185752494304

[Hurricaneman]

 https://x.com/DylanFedericoWX/status/1961156185752494304

I have a feeling it’s going to be nasty from mid September into mid October based on it seems like this year is seemingly similar to last year

[Category5Kaiju]

With what's being talked about currently, it really hammers down the idea of how extraordinary 1933 was. Looking at that season's timeline, this was a highly active Atlantic hurricane season that also pretty much had no major lulls in activity.

[Hypercane_Kyle]

With what's being talked about currently, it really hammers down the idea of how extraordinary 1933 was. Looking at that season's timeline, this was a highly active Atlantic hurricane season that also pretty much had no major lulls in activity.

https://upload.wikimedia.org/wikipedia/en/timeline/skfl16tnbwtp0n3pko8zknzjko5xd5h.png

What's crazy is that 1933 was almost certainly much more active than that. It probably had more named storms than 2020.

[lsuhurricane]

Thought this was a really good observation by Cantor and certainly a key factor that will impact the remainder of the season. A more northern ITCZ really benefits the Gulf and Caribbean especially as the MJO rotates back.

 https://x.com/yconsor/status/1960438858799309132

[psyclone]

Mid September to mid October is vastly more scary than mid August to mid September. In the past a dead looking Atlantic at the end of August would trigger plenty of season cancel posts....but not anymore...we're on to this pattern. Beware the late season chicanery. The Gulf and Caribbean continue to build OHC. Something will probably happen...most likely after 9-10 peak climo

[cycloneye]

September CANSIPS has positive NAO.

 https://x.com/WorldClimateSvc/status/1962531384062329129

[LarryWx]

There’s an unusually large disagreement between GEFS and EPS regarding the MJO as they almost couldn’t be further apart!

1. GEFS heads for less threatening MC/W Pac (at low amp) pretty quickly and is on phase 6/7 border on 9/15 (supported by CMC).

2. Euro ens stuck mainly in phase 2, the most dangerous phase for Conus H hits in JAS (supported by JMA).


I may be forgetting but I can’t recall ever seeing this degree of disagreement between these two! I don’t have a good feel for which will verify more closely but of course it could end up between the two.

[chaser1]

There’s an unusually large disagreement between GEFS and EPS regarding the MJO as they almost couldn’t be further apart!

1. GEFS heads for less threatening MC/W Pac (at low amp) pretty quickly and is on phase 6/7 border on 9/15 (supported by CMC).

2. Euro ens stuck mainly in phase 2, the most dangerous phase for Conus H hits in JAS (supported by JMA).


I may be forgetting but I can’t recall ever seeing this degree of disagreement between these two! I don’t have a good feel for which will verify more closely but of course it could end up between the two.

How close to the circle was the EURO MJO forecast going well into September? That and, how accurate (or off) was the EURO forecast for late August?

Just to add, I'd personally lean toward the model indicating a higher amplitude which would imply (to me) a greater level of confidence and suggesting that MJO forecast should play a bigger factor. On the other hand, I would interpret differeing model solutions but with each of them straddling the circle (low amplitude), to be suggestive of the MJO playing a very muted enhancement of tropical cyclone activity & development. Hmmm, that could suggest not much action for the near term

[LarryWx]

There’s an unusually large disagreement between GEFS and EPS regarding the MJO as they almost couldn’t be further apart!

1. GEFS heads for less threatening MC/W Pac (at low amp) pretty quickly and is on phase 6/7 border on 9/15 (supported by CMC).

2. Euro ens stuck mainly in phase 2, the most dangerous phase for Conus H hits in JAS (supported by JMA).


I may be forgetting but I can’t recall ever seeing this degree of disagreement between these two! I don’t have a good feel for which will verify more closely but of course it could end up between the two.

How close to the circle was the EURO MJO forecast going well into September? That and, how accurate (or off) was the EURO forecast for late August?

Just to add, I'd personally lean toward the model indicating a higher amplitude which would imply (to me) a greater level of confidence and suggesting that MJO forecast should play a bigger factor. On the other hand, I would interpret differeing model solutions but with each of them straddling the circle (low amplitude), to be suggestive of the MJO playing a very muted enhancement of tropical cyclone activity & development. Hmmm, that could suggest not much action for the near term

1. Euro and GFS ensemble means are of pretty similarly low amps in week 2 overall.

2. Great Q and fortunately I saved the two forecasts from Aug 15! GEFS did way better for the endpoint (8/29) and was almost spot on. It had forecasted 8/29 to be barely inside the circle in phase 5. It ended up being only a little further inside the circle in 5! In contrast, the EPS forecasted 8/29 to be well within the circle in phase 1.

Assuming this is a decent indication of what may be ahead for the MJO, I now have to give a bit of an advantage to GEFS over EPS. In other words, I’m now thinking the actual 9/15 will likely end up closer to today’s GEFS than today’s EPS. Does that sound logical?

[Stratton23]

activity should pick up after the 12th or so, I really seriously doubt this quiet period lasts for september

[LarryWx]

There’s an unusually large disagreement between GEFS and EPS regarding the MJO as they almost couldn’t be further apart!

1. GEFS heads for less threatening MC/W Pac (at low amp) pretty quickly and is on phase 6/7 border on 9/15 (supported by CMC).

2. Euro ens stuck mainly in phase 2, the most dangerous phase for Conus H hits in JAS (supported by JMA).


I may be forgetting but I can’t recall ever seeing this degree of disagreement between these two! I don’t have a good feel for which will verify more closely but of course it could end up between the two.

How close to the circle was the EURO MJO forecast going well into September? That and, how accurate (or off) was the EURO forecast for late August?

Just to add, I'd personally lean toward the model indicating a higher amplitude which would imply (to me) a greater level of confidence and suggesting that MJO forecast should play a bigger factor. On the other hand, I would interpret differeing model solutions but with each of them straddling the circle (low amplitude), to be suggestive of the MJO playing a very muted enhancement of tropical cyclone activity & development. Hmmm, that could suggest not much action for the near term

Wow, what a massive fold by GEFS to EPS in today’s MJO forecast! Whereas the EPS is similar to yesterday’s idea of not going to the right side (MC), GEFS abandoned the typical counterclockwise path that it had yesterday through MC and then to 6/7. Today, it remains in 2 through 9/11 and then crawls “backwards” up to 1 followed by 8 as of 9/16 all mainly inside the circle (i.e., low amp). The EPS is very similar as it also ends up in low amp 8.

[chaser1]

There’s an unusually large disagreement between GEFS and EPS regarding the MJO as they almost couldn’t be further apart!

1. GEFS heads for less threatening MC/W Pac (at low amp) pretty quickly and is on phase 6/7 border on 9/15 (supported by CMC).

2. Euro ens stuck mainly in phase 2, the most dangerous phase for Conus H hits in JAS (supported by JMA).


I may be forgetting but I can’t recall ever seeing this degree of disagreement between these two! I don’t have a good feel for which will verify more closely but of course it could end up between the two.

How close to the circle was the EURO MJO forecast going well into September? That and, how accurate (or off) was the EURO forecast for late August?

Just to add, I'd personally lean toward the model indicating a higher amplitude which would imply (to me) a greater level of confidence and suggesting that MJO forecast should play a bigger factor. On the other hand, I would interpret differeing model solutions but with each of them straddling the circle (low amplitude), to be suggestive of the MJO playing a very muted enhancement of tropical cyclone activity & development. Hmmm, that could suggest not much action for the near term

Wow, what a massive fold by GEFS to EPS in today’s MJO forecast! Whereas the EPS is similar to yesterday’s idea of not going to the right side (MC), GEFS abandoned the typical counterclockwise path that it had yesterday through MC and then to 6/7. Today, it remains in 2 through 9/11 and then crawls “backwards” up to 1 followed by 8 as of 9/16 all mainly inside the circle (i.e., low amp). The EPS is very similar as it also ends up in low amp 8.

That's interesting Larry. I'd be interested to hear a couple of our Forum Meteorologists chime in with their interpretation of this.

As I see it, the MJO weak signal is clearly not suggestive of any near to mid term amplification during what would typically be the Atlantic basin's most prolific period for tropical cyclone activity. I'm NOT suggesting that the NHC's "30/70" forecast for the E. Atlantic wave will be a bust. What I am thinking however is that the GFS might in fact be a bit quick to develop and deepen our next eventual T.S. This sort of feels like the anticipation and evolution of how Fernand eventually developed (in terms of time). My other take-away is this season has not been prolific and minus any shot of caffeine that the MJO might inject into the Atlantic basin, leads me to think that we could well end up riding through September with only 2 or 3 named storms without any major impact to any significant population centers (dependant of course on the track & development of our current E. Atlantic TW).

[MarioProtVI]

 https://x.com/AndyHazelton/status/1963980757417799798



So far it seems like this season is behaving a lot like 2007, with one strong hurricane surrounded by a bunch of weak short-lived tropical storms, while conditions are struggling even at peak with subsidence across the tropical Atlantic while systems struggle to form or get strong there. I’ve seen a lot of people say that mid-month the MJO should make things more favorable, but with how things are right now I am very skeptical about that. Should the 2007-like behaviors/pattern continue some of the forecasts will need to be adjusted down quite a bit.

[LarryWx]

 https://x.com/AndyHazelton/status/1963980757417799798



So far it seems like this season is behaving a lot like 2007, with one strong hurricane surrounded by a bunch of weak short-lived tropical storms, while conditions are struggling even at peak with subsidence across the tropical Atlantic while systems struggle to form or get strong there. I’ve seen a lot of people say that mid-month the MJO should make things more favorable, but with how things are right now I am very skeptical about that. Should the 2007-like behaviors/pattern continue some of the forecasts will need to be adjusted down quite a bit.

Thanks. Fwiw, the MJO forecasts are centered on favorable phases through Sept 19th. In contrast, 2007 MJO was in less favorable MC to W PAC phases Sept 7-Oct 7.

[Teban54]

I'll repeat what I said in the 91L discussion thread earlier...

The last time someone asked identical questions was in 2024 at a similar time of the year, when pre-Francine failed to form east of the Lesser Antilles as modeled (but eventually formed in the Gulf).

Helene and Milton came after that, as well as two other MHs.

[CyclonicFury]

While I still expect activity to pick up in the back of half of September, there's an increasing chance we go the entire first 10 days (or perhaps longer) of September without a single tropical cyclone. That has to be extremely rare. Two years in a row, we've seen an uncharacteristic lull near the peak of the season. Unlike last year though, we've seen practically no Gulf activity except the weak, short-lived Barry in late June. Erin has been the only hurricane so far. 2025 is on pace to have the latest second hurricane in the NATL since 2013.