ATL: Ex-INVEST 91L - Models

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AutoPenalti
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Re: ATL: INVEST 91L - Models

#41 Postby AutoPenalti » Thu Sep 04, 2025 11:40 am

I am a little confused with this feature at around 90W... is this just a short-wave low or is this originated from the GOM?

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Re: ATL: INVEST 91L - Models

#42 Postby BobHarlem » Thu Sep 04, 2025 11:49 am

Makes it to the Bahamas with a stronger ridge.

Image

Image

The 12z Canadian still curves north before the Caribbean, but is southwest of the 0z.
Last edited by BobHarlem on Thu Sep 04, 2025 11:51 am, edited 1 time in total.
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Re: ATL: INVEST 91L - Models

#43 Postby AutoPenalti » Thu Sep 04, 2025 11:50 am

This is going to get nasty, that ridge is too strong...
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Re: ATL: INVEST 91L - Models

#44 Postby TampaWxLurker » Thu Sep 04, 2025 11:51 am

Moving WNW thru the Bahamas at 288 hours out, pressure up to 990mb. Dry air and shear doing a number on it.
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Re: ATL: INVEST 91L - Models

#45 Postby Pelicane » Thu Sep 04, 2025 11:51 am

That is a very unusual cutoff low. Forms in the SE, dips down nearly into the gulf (and presumably picks up a wave with it), and then goes north into the Midwest. Tons of ridging traps it.
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Re: ATL: INVEST 91L - Models

#46 Postby LAF92 » Thu Sep 04, 2025 11:52 am

AutoPenalti wrote:This is going to get nasty, that ridge is too strong...

The only consolation is the pressure is rising hopefully it gets shredded
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Re: ATL: INVEST 91L - Models

#47 Postby chaser1 » Thu Sep 04, 2025 11:53 am

AutoPenalti wrote:I am a little confused with this feature at around 90W... is this just a short-wave low or is this originated from the GOM?

https://i.imgur.com/BVy0udX.gif


With a front draped across South/Central Florida, a deep southwesterly flow is already bending surface winds from the southwest. Then, a 1009 low appears around 204 hrs over Yucatan and it quickly moves NE and deepens to 1006 mb south of W Cuba. The whole mess moves north with that weak LLC coming into the Florida W Coast. The LLC appears to dissipate but the larger mid level low moves northwest into the N GOM

Edit/ Correction-
It appears that once the LLC moves north into W Coast Florida.... it is actually a seperate mid level short wave that drops south (or cuts off) originating from the S. Plains. So, there's a couple things going on here.
Last edited by chaser1 on Thu Sep 04, 2025 11:58 am, edited 1 time in total.
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Re: ATL: INVEST 91L - Models

#48 Postby IcyTundra » Thu Sep 04, 2025 11:55 am

This run might be GOM bound with that ridge to the north building westward. With how slow this will be moving we will be watching this system for possibly up to 2 weeks.
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Re: ATL: INVEST 91L - Models

#49 Postby AutoPenalti » Thu Sep 04, 2025 11:57 am

Weakens considerably compared to the 06z

Image
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Re: ATL: INVEST 91L - Models

#50 Postby TampaWxLurker » Thu Sep 04, 2025 11:58 am

Landfall hour +312, middle Keys, pressure 989/995 between last 2 frames.
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Re: ATL: INVEST 91L - Models

#51 Postby BobHarlem » Thu Sep 04, 2025 11:58 am

Landfall middle/upper Florida Keys. (Islamorada/Tavernier)
Image

Then Naples/Marco Island
Image
Last edited by BobHarlem on Thu Sep 04, 2025 12:02 pm, edited 1 time in total.
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Re: ATL: INVEST 91L - Models

#52 Postby Pelicane » Thu Sep 04, 2025 12:01 pm

GEFS still seems unimpressed, although there was a bit of a shift south.
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Re: ATL: INVEST 91L - Models

#53 Postby IcyTundra » Thu Sep 04, 2025 12:03 pm

12Z GEFS only has a handful of members developing but the ones that do take it through the islands. I think the small vortex that could develop for 91L is giving the GEFS issues because of its low resolution
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Re: ATL: INVEST 91L - Models

#54 Postby kevin » Thu Sep 04, 2025 12:04 pm

Landfall occurs after +300 hours. Of all the variables, models are often worst with shear forecasts. So whether this'll be a TS or a MH at that stage is highly uncertain. I expect future runs to vary from a weak TS to a high-end MH. What today's models do show with more certainty is a more southern short-term track which as a result places the islands (and potentially the SE CONUS) at a higher risk. If it forms, 91L will likely be a hurricane when it reaches the islands. What state it'll be in by the time (and if) it reaches the US is very dependent on potential landfalls and many other factors. Still it's just one model cycle for an invest. Everyone from the Caribbean to Newfoundland should keep an eye on this one.
Last edited by kevin on Thu Sep 04, 2025 12:07 pm, edited 1 time in total.
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Re: ATL: INVEST 91L - Models

#55 Postby BobHarlem » Thu Sep 04, 2025 12:06 pm

exits Florida around Melbourne, somehow stronger (granted that path does take it over Lake O). Looks like another landfall is possible. (edit: Myrtle Beach, Delmarva, and then long island) East coast Rider, effectively.
Image
Last edited by BobHarlem on Thu Sep 04, 2025 12:22 pm, edited 4 times in total.
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Re: ATL: INVEST 91L - Models

#56 Postby SFLcane » Thu Sep 04, 2025 12:08 pm

All fun in games with this dollar store version of Irma but that fact we have gotten to this point is a little nerve recking if it sticks .
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Re: ATL: INVEST 91L - Models

#57 Postby Stratton23 » Thu Sep 04, 2025 12:13 pm

12z GEFS isn’t aggressive, but definitely shifted south, with a couple members very far south , like just north of SA, interesting days ahead with this one
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Re: ATL: INVEST 91L - Models

#58 Postby MEANINGLESS_NUMBERS » Thu Sep 04, 2025 12:17 pm

TampaWxLurker wrote:Landfall hour +312, middle Keys, pressure 989/995 between last 2 frames.


I don't think they even bring in the lawn furniture for 995 down there.
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Re: ATL: INVEST 91L - Models

#59 Postby IcyTundra » Thu Sep 04, 2025 12:17 pm

Stratton23 wrote:12z GEFS isn’t aggressive, but definitely shifted south, with a couple members very far south , like just north of SA, interesting days ahead with this one


GEFS runs at a lower resolution than the GFS. It is looking like this is going to be a pretty small system. I am skeptical of the lack of development from most GEFS members to say the least.
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Re: ATL: INVEST 91L - Models

#60 Postby LAF92 » Thu Sep 04, 2025 12:19 pm

It feels like the GFS operational and ensembles are completely lost.
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