Possible development in the Western Atlantic / GOM (Is Invest 97L)

[LarryWx]

6z GEFS are getting a little more interested in this now

Indeed, just after the least active 0Z run in awhile (only 1 member (3%) with a TC), the 6Z GEFS with 5 TCs from 31 members (16%) is the most active GEFS to this point. All 5 members landfall in the CONUS (4 E coast, 1 FL Keys and panhandle) with 3 of these 5 landfalling twice.

[Category5Kaiju]

So at least as of now the GEFS likes a more west system while the Euro likes it east. Why is this the case?

[toad strangler]

6z GEFS are getting a little more interested in this now

Indeed, just after the least active 0Z run in awhile (only 1 member (3%) with a TC), the 6Z GEFS with 5 TCs from 31 members (16%) is the most active GEFS to this point. All 5 members landfall in the CONUS (4 E coast, 1 FL Keys and panhandle) with 3 of these 5 landfalling twice.

GEFS seems to be favoring a E solution now inline with the Euro. But really, none of this matters much until an actual closed low/depression develops.

[SFLcane]

[Category5Kaiju]

https://i.postimg.cc/ydKDmTvX/IMG-1526.png

Looks like the ones that become stronger end up more east. Definitely see a fork there.

[LarryWx]

6Z EPS 144 is as active, if not more active, vs the 0Z EPS 150 regarding the C MDR wave.

[NDG]

As always is the case I can't imagine either the GFS or ECMWF being that wrong. So most likely there will be weak development out of this TW but further west where the EC shows it to be. The CMC is probably a good close consensus between them two.
But one thing for sure is that 7 days ago the GFS forecast was way off for this morning's moisture envelope with it.

[jlauderdal]

As always is the case I can't imagine either the GFS or ECMWF being that wrong. So most likely there will be weak development out of this TW but further west where the EC shows it to be. The CMC is probably a good close consensus between them two.
But one thing for sure is that 7 days ago the GFS forecast was way off for this morning's moisture envelope with it.

https://imagizer.imageshack.com/img923/3797/pNKeJJ.gif

The struggle is real with the modeling in the Tropics this season, expect more big swings until something gets going and that is a few days away.

[ChrisH-UK]

These are the waves that we are talking about.

[aspen]

Something to note about the Euro solutions is how long “future Debby” takes to make its turn to the north. It slows down a lot in that corner of the Atlantic by the Bahamas/just north of the GAs, which’ll give it a few full days over toasty 28-29C *if* this solution verifies, which would be concerning giving its proximity to the East Coast.

Alternatively, the Euro could be far too north in its track forecasts at this point. I remember it was too north with Laura, showing a track just above the GAs and possibly into Florida while the GFS was further south and ended up verifying.

[mpic]

Well, let's not lose sight of good 'ol terra-firma. Land has a tendency to "stop it from really getting going"

It only takes a Cat 1 to and Beryl proved that it would take a heck of lot more land to stop it. My area is still trying to dig out of the rubble and subsequent rains that have kept us from doing repairs.

[BobHarlem]

12z Icon ends with it in the Gulf, and this is the first time the Icon has really picked up on this area.

[LarryWx]

The 12Z ICON is its first run with a TC from this. At 180 it has a 1005 mb low moving NW in the direction of the central US GOM coast.

[chaser1]

I think part of the problem with current modeling is that we're just not looking at nearly as finite of a disturbance as will likely be the case in the weeks to come. The NHC keeps referring to the interaction between a (ITCZ) disturbance and the approaching wave. I think that the NHC is in fact more primarily focused on the approaching wave around 33W. This wave however more pronounced, appears to be quite shallow at the lower levels and although seemingly anchored by a pronounced mid-level feature, is also abutting dryer air. This north/south wave is hauling off to the west at a pretty good clip but the 850mb vorticity seems stretched out and less pronounced then the ITCZ disturbance further west around 11N & 48W. It seems to me that the NHC is sort of anticipating that the easterly wave with the further north associated broad (and dryer) mid-level feature, will "catch-up" to and pull the better established ITCZ 850mb disturbance up (north) and merge into it.

My thinking is more in-line with Aspen's take on the EURO's forecast track in general here, and this is my reasoning. Overall conditions within the Central and Eastern Atlantic are still transitioning and I still see the eastern TW being to moisture starved to develop on its own. Meanwhile, the disturbance further WSW has what I believe to be a better establish 850mb vorticity and is better "seeded" within a pocket of greater moisture (as evidenced on IR). As fast as the eastern wave would seem to be moving west, it is the associated drier mid-level feature closer to around 16N & 33N that I believe the EURO is broadly reflecting an eventual surface reflection to develop just north of PR or Hispaniola. I am a bit more skeptical on this overall scenario and equally so regarding overall development given the interaction with land. As Aspen alluded to, I think that any cyclogenesis that might occur will be driven more by the disturbance further west, as it is "influenced" (but not merged with) the approaching TW. I think that the disturbance itself could develop in the NE Caribbean but further south and west then what the EURO is projecting. My guess is that by this time tomorrow, we might begin to see NHC's cone shift further south and west as a result.

[Category5Kaiju]

The 12Z ICON is its first run with a TC from this. At 180 it has a 1005 mb low moving NW in the direction of the central US GOM coast.

Ahhh...

So the system is Gulf-bound after all.

[mpic]

Will the African dust have any notable effect on it at all? It sure hasn't prevented all the rain in the Houston area. I have had almost 10 inches in the last week.

[Michele B]

Something to note about the Euro solutions is how long “future Debby” takes to make its turn to the north. It slows down a lot in that corner of the Atlantic by the Bahamas/just north of the GAs, which’ll give it a few full days over toasty 28-29C *if* this solution verifies, which would be concerning giving its proximity to the East Coast.

Alternatively, the Euro could be far too north in its track forecasts at this point. I remember it was too north with Laura, showing a track just above the GAs and possibly into Florida while the GFS was further south and ended up verifying.

I’m thinking it has more to do with the large Bermuda high-type ridge and how strong it is once that PTS gets close enough to be influenced to either move west or curve north.

[chaser1]

Well, let's not lose sight of good 'ol terra-firma. Land has a tendency to "stop it from really getting going"

It only takes a Cat 1 to and Beryl proved that it would take a heck of lot more land to stop it. My area is still trying to dig out of the rubble and subsequent rains that have kept us from doing repairs.

I understand where you're coming from but I don't think you understood my point. Beryl developed over water. Significant land interaction can have a mitigating effect on a developing tropical cyclone as a whole. Beryl had a very significant circulation as is progressed over the Yucatan Peninsula. The disturbance(s) of discussion have not yet developed, and land interaction may just impact that process to an extent that nothing may form. If a TD does develop, there would certainly be less space to become a well-developed tropical storm or hurricane. Not saying it can't or won't happen, but that I think a clear path for this to develop into a Cat 1 hurricane is WAY far from certain.

[LarryWx]

Fwiw, the composite of tracks posted by another poster earlier in the summer suggests that the area of the CONUS from N central Gulf through FL and E coast as opposed to further W or MX/C America is at highest risk from landfalls when ASO is in weak La Nina territory. That’s where RONI ASO appears to be heading as of now.

[DunedinDave]

Most systems coming from this direction and approach do in fact curve away and with the EUROs track record, I see nothing to lead me to believe that it wont be right. It's the rare one that sneaks through but time will tell and it's still early so we will see.

Agree. I think a strong storm is more likely to go that path.

However, if it goes through the islands and is weak, it’s less likely to pull north. That’s what the ICON and GFS seems to be hinting at. It could actually get destroyed if it goes right through Haiti and the Cuban mountains.