Tropical Wave in Central Atlantic (Is Invest 91L)

[LarryWx]

This MDR wave ranks up with the precursors to Bonnie, Fiona, and Ian as regards the amount of MDR convection and it appears to have some organization. Thus I think its chances of resulting in a TC at some point are rather high though predicting later destinations (IF TCG occurs at some point) whether CA, CONUS, both, and/or other places (including a sharp recurve east of the CONUS with or without landfall elsewhere) is quite a challenge to say the least at this very early pre-TC stage. Just think about how difficult Ian was to predict just two days out from FL as a very strong hurricane! My favorite model of late, the UKMET, currently doesn't have TC genesis from this at 0Z though it is often conservative.

[skyline385]

This MDR wave ranks up with the precursors to Bonnie, Fiona, and Ian as regards the amount of MDR convection and it appears to have some organization. Thus I think its chances of resulting in a TC at some point are rather high though predicting later destinations (IF TCG occurs at some point) whether CA, CONUS, both, and/or other places (including a sharp recurve east of the CONUS with or without landfall elsewhere) is quite a challenge to say the least at this very early pre-TC stage. Just think about how difficult Ian was to predict just two days out from FL as a very strong hurricane! My favorite model of late, the UKMET, currently doesn't have TC genesis from this at 0Z though it is often conservative.

UKMET has been the hidden gem this season for track forecasts. With Ian, it actually did better than TVCN and OFCL (Official NHC track) for up to 96 hours which is an amazing feat imo.

Now as for the current wave, 12Z ICON fails to develop anything before it slams into CA.

[LarryWx]

This MDR wave ranks up with the precursors to Bonnie, Fiona, and Ian as regards the amount of MDR convection and it appears to have some organization. Thus I think its chances of resulting in a TC at some point are rather high though predicting later destinations (IF TCG occurs at some point) whether CA, CONUS, both, and/or other places (including a sharp recurve east of the CONUS with or without landfall elsewhere) is quite a challenge to say the least at this very early pre-TC stage. Just think about how difficult Ian was to predict just two days out from FL as a very strong hurricane! My favorite model of late, the UKMET, currently doesn't have TC genesis from this at 0Z though it is often conservative.

UKMET has been the hidden gem this season for track forecasts. With Ian, it actually did better than TVCN and OFCL (Official NHC track) for up to 96 hours which is an amazing feat imo.

Now as for the current wave, 12Z ICON fails to develop anything before it slams into CA.

 Fwiw, the 12Z GFS at hour 48 (near 54W in the MDR) along with the 6Z are the two most active runs of that model with this at that location. So, its subtle trend suggests it may be just now starting to catch onto it.

[tolakram]

Careful with the hero model analysis. If a model has a bias that happens to match a situation it will look like the best model ever, only to fail miserably with the very next storm. We've seen this with the UKmet before, and other models.

[tropicwatch]

Convection is basically maintaining and 925/850mb vorticity continues to increase.

[LarryWx]

Careful with the hero model analysis. If a model has a bias that happens to match a situation it will look like the best model ever, only to fail miserably with the very next storm. We've seen this with the UKmet before, and other models.

Indeed! All models are very imperfect. The UKMET, while it did great with Ian and Irma, has also stunk to high heaven with others.

Meanwhile, the 12Z CMC, often a horrible model like it was with Ian, is by far the strongest CMC run with this yet in the E Caribbean. Even models with poor records can give us worthy hints.

[Iceresistance]

Fooey! ASCAT has missed this twice!

[jconsor]

How much troughiness is left in the E. US after day 10 may play a role if this possible TC slows down and hangs around long enough in the W. Caribbean or over C. America.

 https://twitter.com/yconsor/status/1576578823461535745




 https://twitter.com/yconsor/status/1576605040785076224

[aspen]

The last few ICON runs turn this into Bonnie 2.0. It stays very close to South America, doesn’t develop until it reaches the SWCar, takes a slight southward shift, and makes landfall as a TS.

[skyline385]

Careful with the hero model analysis. If a model has a bias that happens to match a situation it will look like the best model ever, only to fail miserably with the very next storm. We've seen this with the UKmet before, and other models.

Indeed! All models are very imperfect. The UKMET, while it did great with Ian and Irma, has also stunk to high heaven with others.

Meanwhile, the 12Z CMC, often a horrible model like it was with Ian, is by far the strongest CMC run with this yet in the E Caribbean. Even models with poor records can give us worthy hints.

Agreed, I remember in 2020 the UKMET's west bias got many systems consistently off track. That's why consensus models like TVCN exists, to account for biases between models. However, this year UKMET has performed excellent so credit where it's due. Here is track verification for Earl, Fiona and Ian. You can see its performance in the range up to 96 hours.



As for the current wave, 12Z GFS seems to keep a broad area of circulation failing to form a vortmax this run similar to ICON. With CMC starting to show hints of TCG, there is a possibility that this changes.

[LarryWx]

The 12Z UKMET, like its prior runs, has no TC genesis formally noted. But as I said, it is often conservative with TCG and thus often misses genesis. If it ever shows TCG for this, that would be noteworthy to me.

Meanwhile, the 12Z CMC fwiw has a hurricane in the central and western Caribbean. This is by far its strongest run with this yet.

[weeniepatrol]

12z Canadian

[LarryWx]

The 12Z GEFS as measured by both the mean precipitation and the individual members looks to me to be about the most active GEFS run yet in and near the eastern Caribbean.

[ColdMiser123]

The latest run of the GEFS shows the split in potential track outcomes that was discussed with me & jconsor earlier in the thread, you can see two camps, one due west likely central America bound, and the other, farther northeast track, that sees the opportunity to travel NW for a period of time thanks to the weakness from the trough associated with the remnants of Ian.

If I had to assign odds, I would give the group going into central America an 80% chance, with the northeast group a 20% chance. Will depend heavily on how strong this gets in the short term.

[skyline385]

Decent outflow combined with an increase in 850mb vorticity

[cheezyWXguy]

12z gefs has a pretty strong signal for this system through 5 days, breaks into two tightly clustered camps by the end



Edit: coldmiser beat me to it. Also, gif doesn’t work for some reason unless you click on it? Weird

[cycloneye]

it has an outflow already?

[weeniepatrol]

The 12Z GEFS as measured by both the mean precipitation and the individual members looks to me to be about the most active GEFS run yet in and near the eastern Caribbean.

[Iceresistance]

it has an outflow already?

https://i.imgur.com/nv2Owj9.gif

Yes, I believe that it's what this season is featuring: Excellent outflow before the storm even develops. Which is allowing them to become stronger and faster with less wind shear.

skyline385 mentioned it before.

Decent outflow combined with an increase in 850mb vorticity

[Teban54]

Went to bed with someone wondering in the models thread why people aren't paying attention yet.

Woke up to its own thread with 3 pages

Unlike Fiona and Ian in their early stages, shear isn't a problem.