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

[Ivanhater]

18Z GEFS ensemble shows a definite uptick from 12Z, clustering in the NW Car at 162 hours, roughly similar to the 18Z op run

Can you post an image?

[TomballEd]

[TomballEd]

As the 12Z GFS (and most 12Z models) did not signify a weak system that heads W on their own, a single model run, neither does the 18Z GFS and its ensemble members doesn't mean a strong system will cross Cuba and menace the Eastern Gulf. It is till too far out in time.

[Stratton23]

Big big increase by the 18z GEFS

[Steve]

Can someone tell me the difference between ensembles and operational models in a sentence or two please. I have been on S2k for 20 years and there is still so much to learn IMO.

Super basic is that Ensembles are x number of runs with slightly different tweaks to account for atmospheric differences.

https://www.weather.gov/about/models

In more simplistic terms, picture a baseball team. The "team" itself would be the "operational model", verses each of the individual players would represent the ensemble members. On any baseball team, some batters might tend to hit farther, or hit more to the right... or left. Some are stronger while others are less so. Each baseball player is unique and each ensemble member as well (with some that apply higher/lower degree of track or strength influence). Throw them all into a pot and what is congealed would ultimately be your operational model outcome.

I apologize if that oversimplies or misses the mark as an analogy.

It’s pretty close except the operational isn’t the same thing as ensemble mean.

[Stratton23]

TomballEd that may be true, but you have to factor in that the 12z models incorrecty or did not get the waves active convection correct, now the 18z run is closer to what is actually happening , might not be a strong system, but it also will probably be more consolidated than the 12z runs

[Frank P]

Until the NHC comes out with their 7-day forecast track for a particular storm threat, I take all model runs with a sip or two of Crown, and really don't start any serious preps until about 4-5 days out.. Everything beyond 7 days is entertainment but within the 3-day forecast, should I be in one, all preps are complete, and the copious amounts of Crown go up exponentially! Cheers

[TomballEd]

TomballEd that may be true, but you have to factor in that the 12z models incorrecty or did not get the waves active convection correct, now the 18z run is closer to what is actually happening , might not be a strong system, but it also will probably be more consolidated than the 12z runs

I get that, but I'm not biting on the 18Z 'Happy Hour' GFS until the 0Z models start coming. Looks like darn near half the ensemble members have a significant TC in the Gulf. I'm not counting the 1011 or 1013 mb members.

On ensemble models- the best possible initial data is fed to the op model. But measurement errors and the fact that the entire atmosphere is not measured at all points by observations, soundings and remote sensing, the model is run 30 or 50 times, each new run with something tweaked in the data. Especially at longer times frames, the ensembles give an sense of what the solutions can be. The global models are not initialized the same way, so at longer range, multi-model consensus usually gives the best results. NHC forecasters may dismiss individual models or ensemble families if they think there is an issue, but the tend to use the consensus of the models.

Anyway, waiting for 0Z runs.

[Frank P]

A majority of the 18Z GFS ensemble members are west of the operational.

[Teban54]

A majority of the 18Z GFS ensemble members are west of the operational.

That's a very distinctive change from just about every run prior to this, when GEFS members were usually well east of the operational.

[otowntiger]

I bet the 00Z is back to a weak low hitting the Yucatan again

We can watch the system the next couple of days and see if the models have been handling it well or not. If the vorticity becomes more established, the models will latch on

I too would bet on another wild swing toward a very mild system tonight, and continued wild swings for the next several days with all the models. I would not be surprised if the ultimate outcome of the system in real life ends up being rather insignificant. And the same goes for if it is.

[TomballEd]

A majority of the 18Z GFS ensemble members are west of the operational.

That's a very distinctive change from just about every run prior to this, when GEFS members were usually well east of the operational.

Anyone have access to the control run? The control run determines how much the reduced resolution affects an identically initialized to the op ensemble.

[Frank P]

Will post the18z GEFS ensemble tracks when completed.

[Ivanhater]

Eh, operational looks pretty centered amongst the ensembles. The further east ensembles make landfall sooner, then weaken. There were even a couple split off east of Florida. The western solutions look stronger as time goes on as those become dominant

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[floridasun]

it wait and see we seen before we see cat 5 going to miami and change going to south cuba or alone cuba coast line

[cycloneye]

Near the Lesser Antilles and Caribbean Sea:
Shower activity associated with a tropical wave located several
hundred miles east of the Lesser Antilles has become a little
better organized since yesterday. Slow development is possible
as the disturbance moves westward and reaches the Lesser
Antilles on Monday. Later next week, the disturbance is expected
to move across the central and western Caribbean Sea, where
conditions could become more conducive for development, and a
tropical depression could form during that time.
* Formation chance through 48 hours...low...10 percent.
* Formation chance through 7 days...medium...40 percent.

[Frank P]

Eh, operational looks pretty centered amongst the ensembles. The further east ensembles make landfall sooner, then weaken. There were even a couple split off east of Florida. The western solutions look stronger as time goes on as those become dominant https://uploads.tapatalk-cdn.com/20240831/f01367d7bacee9fc38b5807ff5960bbb.jpg

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Yeah I might have to wait and see the actual tracks of each member to see if the west had a majority, hard to tell off the Tidbits site... Weathernerds has the tracks but still running...
Thru hour 180 I count ~9 for east and ~9 for west... not final yet so will have to see, I just need one more west for a majority but its not significant in the grand scheme of things... just hard to tell each individual members on Tidbits...

[Ivanhater]

18Z GFS Ensembles at 186 hrs

Operational looks down the middle at this point

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[Category5Kaiju]

Up to 10% of formation within the next two days.

[SFLcane]