Tropical Wave in Bay of Campeche (Is Invest 91L)

[MarioProtVI]

Euro completely dropped this AOI.

Edit: Massive downtick on 12z Euro ensembles vs 00z. Yeah this things getting its chances lowered at 8 lmao.

[Ubuntwo]

Euro completely dropped this AOI.

Edit: Massive downtick on 12z Euro ensembles vs 00z. Yeah this things getting its chances lowered at 8 lmao.

It’s a 20%, that’s an 80% chance of no development within 7 days. Still looking like roughly 20% of ensemble members onboard within 7 days on GEFS and EPS, so I suspect they will hold it for now.

[mantis83]

Euro completely dropped this AOI.

Edit: Massive downtick on 12z Euro ensembles vs 00z. Yeah this things getting its chances lowered at 8 lmao.

things are hostile out there in the atlantic!

[Teban54]

GEFS member low pressure counts (±2, out of 31):

• 12z 8/27: 9 (29%)
• 6z 8/27: 14 (45%)
• 0z 8/27: 9 (29%)
• 18z 8/26: 19 (61%)
• 12z 8/26: 17 (55%)
• 6z 8/26: 19 (61%)
• 0z 8/26: 16 (52%)
• 18z 8/25: 10 (32%)
• 12z 8/25: 14 (45%)

EPS member low pressure counts (±3, out of 51):

• 12z 8/27: 14 (27%)
• 6z 8/27 (out to 144 hrs only): 20 (39%)
• 0z 8/27: 25 (49%)
• 18z 8/26 (out to 144 hrs only): 27 (53%)
• 12z 8/26: 34 (67%)
• 0z 8/26: 22 (43%)
• 12z 8/25: 11 (22%)

Both ensemble models have fewer members than earlier runs, but still enough for a 20% chance of development.

There may be a little bit more than what meets the eye, though. On 12z GEFS, the members that do develop are by far more concentrated than earlier runs, with 4-5 strong members in a singular tight cluster near the Lesser Antilles here:



I did a bit of digging and traced it back to around 120-144 hrs. It appears that 12z GEFS is much slower but further south than previous runs - but that's still not all. Looks like since 0z 8/26 (when the uptick started), the ensemble members can be split into two clusters, the "west blob" and "east blob". On this run, the west blob only has 1 member that still has a TC, but support for the east blob seems virtually unchanged.



Why the difference between the two blobs, I don't know. Additionally, Euro ensembles are much further west at the same 144 hrs (with some members already in NE Caribbean), so such a distinction is nowhere close to being set in stone.

On the other hand, the current appearance of the disturbance does look like there are two lobes of convection stretched out E-W, with the eastern one being a bit more prominent. It also seems to have been able to sustain convection for longer than earlier discussions would make you believe, while looking more convectively active and less sheared than most disturbances in this region have been this season.

[MarioProtVI]

18z GFS and ensembles dropped this completely and now this practically has no model support anymore. Expect a lowering at 8 and removal pretty quickly by tomorrow.

[Iceresistance]

18z GEFS only has 2 members developing this
EDIT: Forgot image

https://s10.gifyu.com/images/So4xb.png

[cycloneye]

No change or best known as cut and paste.

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 PM EDT Tue Aug 27 2024

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

Central Tropical Atlantic:
An area of low pressure could form in the central portion of the
Tropical Atlantic in a few days. Thereafter, environmental
conditions appear generally favorable for some slow development of
this system this weekend into early next week as it moves westward
to west-northwestward at 10 to 15 mph.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 7 days...low...20 percent.

$$
Forecaster Beven

[WeatherBoy2000]

18z GFS and ensembles dropped this completely and now this practically has no model support anymore. Expect a lowering at 8 and removal pretty quickly by tomorrow.

They only have it 20% in seven days, the nhc is never very quick to remove AOIs like these because there's always the chance model support comes back around on them. I think it'll be at least another 12-24 hours before they decide to do anything.

[SconnieCane]

18z GFS and ensembles dropped this completely and now this practically has no model support anymore. Expect a lowering at 8 and removal pretty quickly by tomorrow.

They only have it 20% in seven days, the nhc is never very quick to remove AOIs like these because there's always the chance model support comes back around on them. I think it'll be at least another 12-24 hours before they decide to do anything.

Yeah, if they bit on every model change they'd be constantly adding/removing AOIs and it'd be pointless.

[Teban54]

Convection has increased further as we head into the night. However, GFS seems to show this increase in convection on its recent runs, yet thinks it doesn't matter. We'll see.

I also wonder if the recent backing off is because the wave is overwhelmed by the one behind it.

[cycloneye]

 https://x.com/AndyHazelton/status/1828616843487035876

[Teban54]

GEFS member low pressure counts (±2, out of 31):

• 12z 8/27: 9 (29%)
• 6z 8/27: 14 (45%)
• 0z 8/27: 9 (29%)
• 18z 8/26: 19 (61%)
• 12z 8/26: 17 (55%)
• 6z 8/26: 19 (61%)
• 0z 8/26: 16 (52%)
• 18z 8/25: 10 (32%)
• 12z 8/25: 14 (45%)

EPS member low pressure counts (±3, out of 51):

• 12z 8/27: 14 (27%)
• 6z 8/27 (out to 144 hrs only): 20 (39%)
• 0z 8/27: 25 (49%)
• 18z 8/26 (out to 144 hrs only): 27 (53%)
• 12z 8/26: 34 (67%)
• 0z 8/26: 22 (43%)
• 12z 8/25: 11 (22%)

For record-keeping purposes:

• 18z GEFS: 4 (13%), a further drop from earlier runs (as others have noted)
• 18z EPS (out to 144 hrs only): 15 (29%), roughly similar to 12z

[Stratton23]

00z GEFS uptick in support again

[WaveBreaking]

Looks better this morning

[aspen]

Operational global models are not thrilled this morning and have shifted focus to a wave coming off of Africa in about 4-5 days. However, the 00z ICON shows this wave making it into the Caribbean, so perhaps some development later is possible if it frees itself from the monsoon trough.

[WaveBreaking]

Hint of an MLC or a vort max this sunrise.

[Teban54]

GEFS member low pressure counts (±2, out of 31):

• 6z 8/28: 9 (29%)
• 0z 8/28: 9 (29%)
• 18z 8/27: 4 (13%)
• 12z 8/27: 9 (29%)
• 6z 8/27: 14 (45%)
• 0z 8/27: 9 (29%)
• 18z 8/26: 19 (61%)
• 12z 8/26: 17 (55%)
• 6z 8/26: 19 (61%)
• 0z 8/26: 16 (52%)
• 18z 8/25: 10 (32%)
• 12z 8/25: 14 (45%)

EPS member low pressure counts (±3, out of 51):

• 6z 8/28 (out to 144 hrs only): 21 (41%, some may not be TCs)
• 0z 8/28: 11 (22%)
• 18z 8/27 (out to 144 hrs only): 15 (29%)
• 12z 8/27: 14 (27%)
• 6z 8/27 (out to 144 hrs only): 20 (39%)
• 0z 8/27: 25 (49%)
• 18z 8/26 (out to 144 hrs only): 27 (53%)
• 12z 8/26: 34 (67%)
• 0z 8/26: 22 (43%)
• 12z 8/25: 11 (22%)

Curiously, recent runs of both GEFS and EPS seem to start showing some members starting tracking in the Caribbean, Gulf, and/or north of Greater Antilles, as I mentioned in the global models thread. It's unclear whether they're showing this wave developing later down the road or something else.

Either way, there's still enough support to keep this at 20% for now.

[TomballEd]

Hint of an MLC or a vort max this sunrise.

https://i.imgur.com/3VRwt5p.gif

Between this and remaining model support (see Tehan), this system is still worthy of a 7 day 20% lemon. That means 80% it never becomes a TC, I do think there is a chance it waits until the W. Caribbean to develop, which could make it a Gulf threat.

[AutoPenalti]

This could be a case of models playing catch up to real time developments, seems to be failing at initializing the convection properly.

[Stratton23]

ICON 12z starts to develop this system again in the central caribbean with stout ridging to its north