Low pressure developing over the western Caribbean Sea (Is Invest 97L)

[TomballEd]

Looks like this unmarked disturbance in EPac will be why this ends up being nothing more then a sloppy system - it interacts with the CAG enough to keep the AOI very broad and weak. Models seem to be shifting towards this now with a notable downtrend in intensity among ensemble members. Seems like September could go with a single major (I do not have expectations for the MDR storm given GFS is the only one showing anything remotely strong there and it tends to be overzealous there). Good for GoM people as it’ll likely be nothing more then a typical June tropical storm setup (thinking Cindy 2017-like). The curse of 2024 continues…

https://media.discordapp.net/attachments/783987504071573517/1287101254358536192/msfc.gif?ex=66f051f4&is=66ef0074&hm=8a24f8ca188552094922d67c786eaa62b910c676d53e6753467744e43f2d5a69&

Too soon for that call, I see a member in the 930s, likely an outlier. But I see enough systems in the 950's and 960's, a system as strong as a Cat 3 is possible. I expect a Cat 1 or Cat 2, which probably gets somewhat maintained as it approaches the strong shear by the strong W-lies and SW-lies that will aid the evacuation of air and create extra lift before the shear can push dry air into the system.

What reliable models are showing the low CAT3 hurricane? I have not seen one. Thanks!

See the use of the word 'ensembles', which are a better guide than the operational when the operational is 'guessing' where the low forms. See a few posts back, I linked the GFS ensembles

Edit- I used the actual word 'ensembles' a few posts back. I'm not the kind of guy that gets excited about the Korean or NAVGEM model.

Second edit to add There is a 930s ensemble member, a solid Cat 4, but one of 30 ensembles doesn't a decent amateur forecast make. I was focusing on the 950s's and 960's mb ensemble members.

[3090]

Too soon for that call, I see a member in the 930s, likely an outlier. But I see enough systems in the 950's and 960's, a system as strong as a Cat 3 is possible. I expect a Cat 1 or Cat 2, which probably gets somewhat maintained as it approaches the strong shear by the strong W-lies and SW-lies that will aid the evacuation of air and create extra lift before the shear can push dry air into the system.

What reliable models are showing the low CAT3 hurricane? I have not seen one. Thanks!

See the use of the word 'ensembles', which are a better guide than the operational when the operational is 'guessing' where the low forms. See a few posts back, I linked the GFS ensembles

Edit- I used the actual word 'ensembles' a few posts back. I'm not the kind of guy that gets excited about the Korean or NAVGEM model.

But what models support a CAT3? I have not seen one model support a CAT3!

[Ubuntwo]

What reliable models are showing the low CAT3 hurricane? I have not seen one. Thanks!

See the use of the word 'ensembles', which are a better guide than the operational when the operational is 'guessing' where the low forms. See a few posts back, I linked the GFS ensembles

Edit- I used the actual word 'ensembles' a few posts back. I'm not the kind of guy that gets excited about the Korean or NAVGEM model.

But what models support a CAT3? I have not seen one model support a CAT3!

He said ensembles. That is, there are individual cat-3 EPS and GEFS members in spite of no reliable operational models supporting that solution. So while the current model prog would not support a major hurricane, a few tweaks here and there to the setup could. It's not the most likely outcome but it's not ruled out just yet.

[DunedinDave]

There’s a chance the center actually hits somewhere around Appalachicola or Panama City but the whole west coast of Florida gets the nasty rain from all this….which stinks because we don’t need anymore rain. One sprinkle at this point will flood my street.

[Steve]

So assuming these 4 models upper patterns are blended, we would have a storm landfalling in the 990s coming in between N and NNE then getting sucked back NW into the trough. GFS gets the farthest east inland before getting drawn in. Last couple days we’ve been looking at a more likely landfall late next weekend or Monday. Now everything is moved up to end of next week and weaker. Still looks to be an event but more of a nuisance than a major threat. Landfall would be between Grand Isle and Destin.

Quite concerned for the rainfall potential in these set ups, particularly if it slows down over land, which doesn’t appear to be the case. That would be a nightmare. Very large, disorganized system seems to be the “trend”, which I use loosely. But there does appear to be some sort of consolidation within the models. Lots of variables and tomorrow is a new day with more data.

Thing is though is that most of the models string out the rainfall pretty far before moving the low up into the conus low where there is notable precip in FL GA AL MS AR TN and LA. Super soaker event is mostly confined to specific areas. Let’s look at the 10 day (240 hour) precip where we have it.

CMC - heaviest rain belt is 1-2 feet along the MS/AL border for 200 miles or so inland and Escambia Co FL.
https://www.tropicaltidbits.com/analysi ... 112&fh=240

GFS - lesser amounts than CMC but Gulf/Wakulla/Franklin Counties and then again along the Chattahoochee River (AL/GA border). Later into SE Missouri.

https://www.tropicaltidbits.com/analysi ... 112&fh=240

ICON is the farthest west and only shows out to 7.5 days. But it has the 1-2 feet across central Arkansas and nominal amounts associated with the landfall.

https://www.tropicaltidbits.com/analysi ... 112&fh=180

ECAI (though 6z) has the least amount of rainfall and is more associated with the landfall. So some 6-8” across SE LA


https://www.tropicaltidbits.com/analysi ... 100&fh=240

[Ubuntwo]

12z model roundup:
GFS - 988mb large TS into Panama City. Pulled north very quickly with limited time to organize.
Euro - 991mb TS into Pensacola. Somewhat similar to the GFS but with a slower trough causing land interaction with the Yucatan.
ICON - 999mb elongated trough into SE Louisiana. Similar to the CMC.
CMC - 994mb elongated trough into Mobile. Elongated due to the 500mb cutoff low digging down into Texas.
UKM - 999mb TS in the north central Gulf, run ends before landfall.

Some agreement on intensity, at least?

[Blown Away]

12z GEFS… Continue the E shifts, GFS operational W of most of the GEFS… NHC doesn’t seem to be leaning on GEFS for now with their potential area pointing towards Panama City to New Orleans, for now…

[ROCK]

Sigh…The current global “operational” model runs lol show big pile of stretched out crap. Maybe it will change once there is something to look at other than a few clouds in Carib.

[TomballEd]

What reliable models are showing the low CAT3 hurricane? I have not seen one. Thanks!

See the use of the word 'ensembles', which are a better guide than the operational when the operational is 'guessing' where the low forms. See a few posts back, I linked the GFS ensembles

Edit- I used the actual word 'ensembles' a few posts back. I'm not the kind of guy that gets excited about the Korean or NAVGEM model.

But what models support a CAT3? I have not seen one model support a CAT3!

The best initial data possible is given to the Op Model. But perfect initialization is impossible. So that model run with random small tweaks in the initial conditions, especially before an actual LLC forms, on average, produce a better forecast. Only a fool gets excited by something hour 300 on the GFS op if not ensemble supported, because unintentional errors in data fed the operational model can generate huge errors at longer time range. I respect Environment Canada and ECMWF for not running their op models beyond 240 hours, where very small initialization errors can result in major errors in the model prediction.

Thank You for coming to my TedT alk.

Two finger typing will be the death of me.

[TomballEd]

See the use of the word 'ensembles', which are a better guide than the operational when the operational is 'guessing' where the low forms. See a few posts back, I linked the GFS ensembles

Edit- I used the actual word 'ensembles' a few posts back. I'm not the kind of guy that gets excited about the Korean or NAVGEM model.

But what models support a CAT3? I have not seen one model support a CAT3!

The best initial data possible is given to the Op Model. But perfect initialization is impossible. So that model run with random small tweaks in the initial conditions, especially before an actual LLC forms, on average, produce a better forecast. Only a fool gets excited by something hour 300 on the GFS op if not ensemble supported, because unintentional errors in data fed the operational model can generate huge errors at longer time range. I respect Environment Canada and ECMWF for not running their op models beyond 240 hours, where very small initialization errors can result in major errors in the model prediction.

Thank You for coming to my TedT alk.

Two finger typing will be the death of me.

My understanding is Euro ensembles are run at the same resolution as the op Euro, or there is, in effect, a 360 hour op Euro, But nobody grabs that one ensemble member and treats it like the op.

[ConvergenceZone]

12z model roundup:
GFS - 988mb large TS into Panama City. Pulled north very quickly with limited time to organize.
Euro - 991mb TS into Pensacola. Somewhat similar to the GFS but with a slower trough causing land interaction with the Yucatan.
ICON - 999mb elongated trough into SE Louisiana. Similar to the CMC.
CMC - 994mb elongated trough into Mobile. Elongated due to the 500mb cutoff low digging down into Texas.
UKM - 999mb TS in the north central Gulf, run ends before landfall.

Some agreement on intensity, at least?

Yep, unless conditions in the Gulf somehow change, Tropical Storm seems the most likely scenario now, and Thank God for that. But let's hope it's a minimal tropical storm. But even if so, as mentioned before, the rain can still end up fairly bad depending upon where the convective blobs setup. All we can do is hope for the best as far as the rain is concerned.

[Janie2006]

Sopchoppy? That’s a place with one of the more interesting histories.

Really? Elaborate?

[Dalek voice] Explain! Explain!! [/Dalek voice]

[toad strangler]

2024 post-Beryl:
1. Models show a strong hurricane impacting the U.S. “This will be the big one!” everyone thinks.
2. Models become increasingly unenthusiastic and the system either fails to form or is sloppier than expected.
Not saying this is a guaranteed outcome with this one, but I’m leaning towards it.

I don’t think there’s been a pervasive mindset that this was gonna be a big one. There’s been evidence since the beginning that this might not come together being CAG origin

[psyclone]

We've had 2.5 to close to 4 feet of rain here in the last 2 months. We sure don't need any more water. Toppling trees from a saturated soil state and high water table is a legit concern...along with urban and river flooding. I'm expecting peninsular Florida to get sauced pretty good even if the system passes by to our west. Most TC's are water storms with water rather than wind as the primary hazard. A large slack and wet storm system is a significant hazard in the eastern gulf region...even more so with the exceedingly wet antecedent conditions...and that extends to sea state and tide/wave action as well. We are pre-beat...and could use a break. I'm continuing to wish cast a cold front

[Spacecoast]

There is a 930s ensemble member, a solid Cat 4, but one of 30 ensembles doesn't a decent amateur forecast make. I was focusing on the 950s's and 960's mb ensemble members.

I don't see many 950's / 960's . I count 2, (maybe 3) <970mb members on WxNerds. Which is about 10%.
Dependent upon whether you use Pivotal / Weathernerds, or TT ens member pressure level centers (TT has notably lower pressure levels).
Incidentally, those same members have a high normalized spread σ. Visualized on TT by the (eye catching) deep orange shading. This signifies significant deviation from the ensemble mean pressure level, which shows a C1 intensity.


"The ensemble spread is a measure of the differences between each ensemble member and is represented by the standard deviation with respect to the ensemble mean. Small spread indicates lower uncertainty, large spread indicates higher uncertainty. Spread usually, but not always, increases with forecast range. Spread refers to the uncertainty of the values of a parameter but it does not necessarily refer to the flow patterns - small differences in gradients or phase of the general flow that has been forecast by members can induce significant differences among corresponding values of forecast parameters." Source : ECMWF

[Woofde]

2024 post-Beryl:
1. Models show a strong hurricane impacting the U.S. “This will be the big one!” everyone thinks.
2. Models become increasingly unenthusiastic and the system either fails to form or is sloppier than expected.
Not saying this is a guaranteed outcome with this one, but I’m leaning towards it.

Those are exactly my thoughts as well. This season just doesn't seem to have "it". I don't know what "it" is, just that everything seems to be being held back.

It's insane to juxtapose this season and a season like 2020. At their face value they had similar setups, but something underlying which I haven't seen anyone cleanly pin yet is holding this season's storms back.

Maybe this one will be different...

[Steve]

Sigh…The current global “operational” model runs lol show big pile of stretched out crap. Maybe it will change once there is something to look at other than a few clouds in Carib.

lol Rock but most of us are okay with something more minimal.

[TomballEd]

There is a 930s ensemble member, a solid Cat 4, but one of 30 ensembles doesn't a decent amateur forecast make. I was focusing on the 950s's and 960's mb ensemble members.

I don't see many 950's / 960's . I count 2, (maybe 3) <970mb members on WxNerds. Which is about 10%.
Dependent upon whether you use Pivotal / Weathernerds, or TT ens member pressure level centers (TT has notably lower pressure levels).
Incidentally, those same members have a high normalized spread σ. Visualized on TT by the (eye catching) deep orange shading. This signifies significant deviation from the ensemble mean pressure level, which shows a C1 intensity.


"The ensemble spread is a measure of the differences between each ensemble member and is represented by the standard deviation with respect to the ensemble mean. Small spread indicates lower uncertainty, large spread indicates higher uncertainty. Spread usually, but not always, increases with forecast range. Spread refers to the uncertainty of the values of a parameter but it does not necessarily refer to the flow patterns - small differences in gradients or phase of the general flow that has been forecast by members can induce significant differences among corresponding values of forecast parameters." Source : ECMWF

I looked 6 hour by 56 hour on TT. I didn't say there were a lot, I said there were enough. I am the last person screaming 'the Gulf is boiling, this is a Cat 5 for sure'. In fact, I am now on enemies lists when pointing out a poster when the 'weenie' every posts More ensemble members are TS and Cat 1 than anything else, I'm not going back two pages, but I think I said I expected a Cat 1 or a Cat 2.

[Woofde]

2024 post-Beryl:
1. Models show a strong hurricane impacting the U.S. “This will be the big one!” everyone thinks.
2. Models become increasingly unenthusiastic and the system either fails to form or is sloppier than expected.
Not saying this is a guaranteed outcome with this one, but I’m leaning towards it.

I don’t think there’s been a pervasive mindset that this was gonna be a big one. There’s been evidence since the beginning that this might not come together being CAG origin

It's been waning recently, but not long ago there was very solid ensemble support (It was 96% of EPS developing If i remember correctly) and strong operation runs, just like Francine really. Ironically enough we are approaching that preinvest thread's number of posts.

[TomballEd]

To the people whose every post is 'this is a Cat 5 for sure, the Gulf is boiling' (or use the Korean or other obscure model) to support these assertions, thank you. Not seeing your posts is a kindness.