2023 Global Model Runs Discussion (Out thru day 16)

[DorkyMcDorkface]

This is a bit of a ways out but I am honestly more interested in this MDR signal the GEFS is latching on to; it's been there the past few runs. A tropical wave is obviously a much more realistic pathway to cyclogenesis than the spurious Venezuelan vorticity the GFS is always obsessed with this time of year. For that reason, I feel more confidence in other models possibly sniffing this out in the near future. With the current SSTs I'd say an early season MDR TD/TS is within the realm of possibility. We'll see.
https://i.ibb.co/SK0q8Yc/90668154-2.gif

The GFS actually isn't developing this from a spurious vorticity associated with the CAG, it's origins are related to a TW that is expected to depart the coast of Africa here shortly. You can follow this in the 700mb vort signature from the latest GFS run below (roughly highlighted the wave axis in pink in the animation below):

https://i.ibb.co/wd8WNhc/gifmaker-me.gif

The difference in the models is the upper-level features and steering pattern. The GFS has a sharp trough that extends all the way down towards the Yucatan peninsula (highlighted in pink below). This has multiple impacts: (1) displaces the subtropical high towards the northeast (highlighted in orange), (2) erodes the western periphery of the high pressure area, (3) reduces zonal flow in the Caribbean, and (4) provides the necessary "lift" for this tropical wave to exit the Caribbean towards the GOM.

https://i.imgur.com/OdkCd1I.png

Compare this to last night's 00z ECMWF run at the same time frame, and you can see the high pressure is oriented more E to W and extends further west, there is only a weak signature of a trough over CONUS that doesnt extend nearly as far south, and the zonal flow in the Caribbean carries the wave vort signature through Central America and into the EPAC.
https://i.imgur.com/KzJfZYL.png

I stand corrected, thanks for the clarification. I suppose it is just years of false alarms from the GFS that have me skeptical. I still remain so however because it continues to be the only model showing this scenario.

[Europa non è lontana]

I don't think it's unreasonable for people to be skeptical of the GFS given its history of false alarms in this exact region and that no other model as of the 12z runs has this wave developing into an Atlantic TC, as far as I know.

[wxman57]

No one is paying attention to the Last GFS?

With the Euro and CMC both showing nada (except maybe in the EPAC), not really.

The CMC is a joke, and the Euro only has a TC forming when it's already been named for a solid 24 hours.
Let's just wait and see.

Look at the upper-level patterns in each model, not the surface. The upper-air patterns in the Euro and CMC are nothing like the GFS, which is why the GFS is developing a Caribbean storm and they are not. Euro is indicating East Pac development, which is probably right.

[USTropics]

I don't think it's unreasonable for people to be skeptical of the GFS given its history of false alarms in this exact region and that no other model as of the 12z runs has this wave developing into an Atlantic TC, as far as I know.

Models are just tools at the end of the day, it's up to the forecaster to understand and use them properly. Past ~7 days, ensembles can given us a better understanding/picture of what type of pattern we see evolving (and where we should give more credence). One reason to remain skeptical is the run to run consistency from the ECMWF ensembles in the evolving pattern. Typically when the ECMWF ensembles are this consistent it lends to more credibility.

ECMWF ensemble trend:


Meanwhile, the GFS ensembles have been a bit more fluid with its depiction and orientation of the trough from run to run:


The CMC ensembles in the past few runs have also trended towards more ridging in the NW Caribbean/GOM, which lends more credence to the ECMWF ensemble solutions:


The type of pattern the ECMWF and CMC ensembles show (with more ridging and a less pronounced trough) would indicate to me development would be more concentrated in the EPAC. As someone said earlier, this doesn't preclude development occurring in both basins, but it's likely the GFS is overdoing the trough in its long range forecast.

[cycloneye]

Levi is spot on.

 https://twitter.com/TropicalTidbits/status/1667621150497849344

[wxman57]

GFS still has a completely different surface and upper level pattern at day 10. Euro an Canadian have a similar 850mb and 200mb pattern.

[cycloneye]

Euro ensembles have a MDR signal.

[OuterBanker]

Just goes to show you that if you wait long enough the GFS will target you.

https://www.dropbox.com/s/8la2iflpz84pz ... 0.png?dl=0

Let's see, started in the Bahamas, Naples, NOLA, TX, Mx, this morning Cancun 18z today cat 3 on the OBX.

But, I have to admit that without the GFS it would be God awful boring.

[tiger_deF]

I'm still fairly sure that the storm is a phantom, but unlike most typical phantoms the timeline hasn't been pushed too far back since the storm popped up a week ago. Plus, there is some GEFS support now as well.

[Kingarabian]

Imo this early on, only way the GFS solution makes sense is IF it did not show EPAC development. So unless it drops the EPAC system, it's hard to believe.

[MetroMike]

Imo this early on, only way the GFS solution makes sense is IF it did not show EPAC development. So unless it drops the EPAC system, it's hard to believe.

The EPAC system was very weak or non exsistent on the 18Z run ICYMI.

[Teban54]

Unless I'm mistaken (which I jolly well might), the 0z GFS seems to bury the first Caribbean system into Yucatan and briefly BoC, then develop a second system, blow it up and send it towards FL.

Could be a sign towards "correcting" the trajectory of the system and more ridging.

[LarryWx]

Unless I'm mistaken (which I jolly well might), the 0z GFS seems to bury the first Caribbean system into Yucatan and briefly BoC, then develop a second system, blow it up and send it towards FL.

Could be a sign towards "correcting" the trajectory of the system and more ridging.

Although this is by my count the 23rd straight GFS run (going back to the 12Z run on June 5th) with a TC in the W Caribbean from this, it appears to me to be the first of those 23 without it getting to TS+ strength in the W Caribbean as this appears to only be a TD per soundings before moving into Belize.

[AtlanticWind]

EURO has a disturbance heading for the Islands in latest run.

[Category5Kaiju]

Guys let's stop focusing on the major Gulf hurricane that the GFS keeps blowing up; there's a new sheriff in town with support from multiple models

 https://twitter.com/OSUWXGUY/status/1667855014050627584

[wxman57]

EURO has a disturbance heading for the Islands in latest run.

Tracking the 850mb vorticity backwards, it has a feature moving off the coast of Africa tomorrow. It's a bit early for development east of the islands. Shear is too high. Something like that would have to be monitored more closely as it moves to the western Caribbean in about 13 days. It would probably cross Central America and go into the East Pac.

[LarryWx]

Like the 6Z GFS, the 12Z GFS has a strong TS developing in the W Caribbean before going inland into the Yucatan. It is the 3rd one in a row moving W into the Yucatan. This now makes 25 GFS runs in a row with a W Caribbean TC that forms within a day of 6/18. Is this W Car TC for real or not? The longest streak of GFS runs in a row that I can recall that turned out to be fake was 30 something.

El Niño seasons with +1.3+ in ASO since the late 1800s have had TCs form in mid to late June in the W Caribbean or Gulf more often than not fwiw. Of course, even if that occurs this season, too, it doesn't have to be from the one the GFS has been developing. It could be from something as late as 12 days later.

[Hypercane_Kyle]

GFS ensemble support remains quite strong.

[wxman57]

Perhaps the GFS can set a new record for the most consecutive runs showing a phantom storm? I saw mentioned a few pages back that the GFS has done well in the West Pacific. Uh, no, it hasn't. We forecast cyclones worldwide and watch the model runs very closely. It is constantly developing phantom storms in every basin. If it's alone in its prediction, it is best to ignore the GFS. I think that the GFS is having trouble with the upper-air pattern beyond 5-7 days. As a result, it is generating this phantom Caribbean/Gulf storm.

[wxman57]

The GFS is like a slot machine. Each run has a different solution, but that solution is not matched by other models.