Going off of purely convective trends, it seems like the system is wanting to consolidate further SSW than may have been initially forecasted. Such a scenario, were it to actually pan out, has some interesting implications on the future track and strength of TD26/Delta.
A starting location further SSW than initially anticipated leads to a few different changes in the
short-term (for the sake of this post, I'm considering this duration to be between now and its closest approach to/landfall on Cuba):
1) This creates more of a separation between the center of the developing system and the PV streamer that is currently imparting some northeasterly shear;
2) This also sets the storm more on an angle to mostly avoid the relatively dry air that sits north of Jamaica and on most of Cuba; (both of these first two points could lead to a greater intensification trend sooner)
3) The storm is also slightly further away from the prevailing southeasterly flow, which could also mean a slightly slower motion, giving it a couple of extra hours over the extremely warm NW Caribbean waters;
4) Such a shift in starting location could mean that TD26/Delta may ultimately avoid a landfall on western Cuba, though there's still a good chance this happens.
All of these factors could lead to a stronger system in the short-term, which could allow for the development of a more robust inner core thanks to the factors above and less land interaction.
However, such a scenario also leads to a slightly more unfavorable environment in the
mid-term (post-Cuba until Gulf landfall):
1) A storm that is on the southern edge of the cone would be sheared more by the outflow of Gamma as it approaches and passes through the Yucatan Channel;
2) This track would also be more prone to the steering influence of Gamma, which could drag it further westward before it's allowed to move north;
3) It's displaced further from the anticyclone that is forecast to establish itself in the eastern Gulf of Mexico;
4) Such a location could allow the southwesterly flow aloft in the western Gulf of Mexico to disrupt the core of the system more, which could induce a greater weakening trend as it approaches landfall.
There's still a lot up in the air about TD26, but there's a few general statements that we can probably be assured are going to be true; first, this is likely to be a developing storm at or near hurricane strength as it passes near/over the Cayman Islands and Western Cuba; second, it will likely be a strengthening/growing hurricane in the southern Gulf of Mexico in an area of relatively favorable conditions, so something stronger than what is currently forecast is certainly not out of the question; third, a combination of shear and lower SSTs will likely induce a weakening trend as it approaches land, but this is unlikely to occur soon enough to induce enough weakening to reduce the storm to below hurricane strength. Therefore, there's a very good probability that we're looking at a significant hurricane strike on a region that is already weary from having to deal with other threats from this year and years prior.
As of right now, the NHC currently predicts a significant event for both Cuba and the Gulf Coast, and there's not much reason to not trust that forecast or evidence indicating that this will not be the case.
In terms of historical analogs, I think there's three good storms to pick from in terms of impacts as sort of reasonable estimates for the level of impact that can be expected in the US (all 3) and for Cuba (the latter two) -
Nate 2017 (low to mid-end event),
Lili 2002 (mid-end event for the US, mid to upper-end for Cuba), and
Gustav 2008 (high to max potential for US and Cuba). Now, it's worth noting that these are not the only possible solutions (or even range of solutions) for TD26; these just provide the best relative range that can probably be expected with the storm as it approaches both Cuba and the United States. Something like
Ida 2009 cannot be ruled out for Cuba (or even the US Gulf Coast) in terms of impacts, but this seems to be unlikely based upon model guidance and the forecasted synoptic environment.
One last thing; I feel that it's important to point out that
I am not a certified meteorologist (yet) nor do I work at the NHC. I know that many of you are already aware of this, but when preparing for this storm, listen to your local mets and officials, and make sure to heed the warnings of the NHC - they're the best in the world at what they do, after all. If there are any errors, feel free to point them out; I'll fix them when I can. Stay safe everyone, since the 2020 hurricane season doesn't seem like it wants to go quietly. See you all in the morning.
