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

[TallyTracker]

We had our first cold front of the year hit the Gulf Coast at the end of August. Our lows dropped to the low-mid 60s. It’s warmed back up so but overall it’s looking and feeling more like a fall pattern here. I noticed too the northern Gulf water temps are now at or slightly below average now. Can’t speak for the whole basin, but the pattern here is more like October than early September.

[psyclone]

we're headed for peak season on 9-10 where we have a 90% historical probability of a named storm in the basin...and this year looks like a 10% year where there is no storm. It's remarkable how dead it is. there's no season cancel posts because it just seems people have moved on. Very odd but after last year...im good with the tranquility.

[Teban54]

Here's my long-standing question about dry air.

When people talk about dry air in general indicator threads like this, the impression is typically: "dry air exists in the MDR = nothing can form, MDR cancelled". Yet, I look at archives of dry air imagery, major hurricanes in the MDR are often right next to pockets of mid-level dry air, which can even be in the dead center of MDR.

The loop below shows, at their peak intensity: Lorenzo 2019, Teddy 2020, Sam 2021, Lee 2023, Beryl 2024, Kirk 2024, and Erin 2025. All were Cat 4/5s in or next to the MDR, and you can see dry pockets (red) next to all of them, often well within the MDR.

[TomballEd]

I certainly wouldn't say complete season cancel. Late September/October will produce at least one SW Gulf or Caribbean storm, and Ian, Laura and Michael type high major storms seem more common than they used to. They'll be some subtropical trash between Bermuda and the Azores that will be named, that happens every year.

Euro seeing slightly above average ACE starting around the Equinox, which would perhaps fit my late September/early October storms Caribbean storm or storms. Although TC probabilities may be suggesting the Euro sees another CV/Atlantic MDR storm that likely recurves. Note BoC probs however. Past 10 days the 0Z Euro ensembles starts suggesting some support for storms either side of Central America. The GFS ensembles and the most recent Op GFS would support that as well, although Euro weeklies ACE seem to suggests the real CAG stuff is beyond the 16 day range. Or, the GFS family would be in the 0-16 day thread and the Euro family would be in the Day 16+ thread.

[tolakram]

Dry air can prevent formation but once the engine is running it doesn't matter unless wind shear pushes that dry air into the core.

91L had a pocket, missed it, poofed. According to the posts on this forum the Atlantic has suffered from dry air and stability for the last 20 years.

[HurricaneRyan]

I wouldn't season-cancel just yet.

2022 and 2024 gave us Ian and Helene respectively in late September so Mother Nature can easily shut you up when she wants to.

[chaser1]

In Joe Bastardi's free Saturday summery video he was making comparisons with last year mid to late September with the MJO placement in 2024 and this years predicted placement along with similar pressure placements.
Very similar moisture in the western basin also.
Seems any threats for the conus will come from the western basin and not the MDR.
Shall see if this pans out.

I would actually be very curious to go back in time and compare last years MJO for September '24 and this year for myself. I don't specifically recall if last year's MJO was rather muted (close to or within the circle) or significantly more heightened?

Yes if you watch Joe's video from Saturday he shows the MJO from late September last year and it was more muted but over South America and the conus.
This year’s MJO forecast looks to be less muted and centered over the western basin also.

Thanks! That would lead me to think that mid level humidity issues will be soon moistened up in about a week or so

[LarryWx]

In Joe Bastardi's free Saturday summery video he was making comparisons with last year mid to late September with the MJO placement in 2024 and this years predicted placement along with similar pressure placements.
Very similar moisture in the western basin also.
Seems any threats for the conus will come from the western basin and not the MDR.
Shall see if this pans out.

I would actually be very curious to go back in time and compare last years MJO for September '24 and this year for myself. I don't specifically recall if last year's MJO was rather muted (close to or within the circle) or significantly more heightened?

Highly impactful hurricanes while MJO inside circle (all or much of)
-‘24: Debby (most incl. when strongest), Francine, Milton
-‘23: Idalia
-‘22: Fiona, Ian
-‘20: Eta (most incl. when strongest)
-‘19: Dorian (5 of its days including when strongest)
-‘17: Harvey (most of incl. almost entire time was H), Irma, Maria
-‘16: Hermine, Nicole (almost all)
-‘10: Igor (most of), Karl
-‘08: Paloma (all but last day when weakened to TS/TD)
-‘05: Katrina
-‘03: Fabian (nearly all), Juan
-‘99: Floyd
-‘98: Mitch
-‘96: Fran (most incl. nearly entire time it was TS+)
-‘95: Marilyn (most of), Opal
-‘93: Emily
-‘92: Andrew (most including entire time it was an H)
-‘91: Grace/perfect storm
-‘88: Gilbert (most of incl. at strongest)
-‘85: Elena
-‘75: Eloise

So, 30 of the most impactful hurricanes on land since 1975 (excluding 1978 because no MJO available) were inside the circle at least during when they had their biggest impact. That’s out of 84 quite impactful hurricanes overall for the same period. So, 30/84 is 36%.

So, the data’s not saying inside is more conducive than or even as conducive as outside. Rather, it’s saying that very bad storms can be during inside MJO and that was the case for these 30. Note some of the most notorious are in those 30 like Gilbert, Andrew, Mitch, Katrina, Harvey, Irma, Maria, Dorian, Eta (in Honduras), and Ian.

Of the 30 highly impactful hurricanes that occurred when inside the circle, 9 reached cat 5: Gilbert, Andrew, Mitch, Katrina, Irma, Maria, Dorian, Ian, and Milton. There have been a total of 23 highly impactful hurricanes that peaked as a cat 5 since 1975. That means that 9/23 or 39% of those were when the MJO was inside.

Link to MJO history:
http://www.bom.gov.au/climate/mjo/#tabs=Monitoring

[Stratton23]

EPS/ GEFS agree on a strong MJO rotation outside the circle into phases 8/1 in the atlantic and maybe staying their for a while, should be a matter of time before models wake up and see this, I seriously doubt the rest of the season is this quiet , as always stay vigilant on the gulf coast and SE US, it only takes one storm to be a bad season for many and we got plenty of time left for that to happen

[FireRat]

Yeah, 2025 is a tricky season and could very well blow up around 9/25 and into the rest of the Fall.
Backloaded season makes more sense, like last year and 2022. 2001 also comes to mind.
Really will depend on that MJO.