During its entire life from its pre-T.D. formative stages through now, Ernesto has been ebbing and flowing between tightening up and looking more impressive, and not being able to sustain that and instead struggling to be anything more than an energetic tropical wave.
Today, it’s decidedly in the latter mode, in fact the latest aircraft recon which is investigating the storm has had a hard time finding any westerly winds, which are necessary for a “closed” circulation, an essential characteristic of a tropical cyclone, and the convection is quite ragged, and there’s a low cloud swirl — what “center” there is — “exposed” on visible satellite imagery.
So Ernesto has characteristics of a tropical wave, and is looking more like that than a tropical storm at the moment. No doubt the National Hurricane Center is debating whether to down-classify it or keep it as a tropical storm; they’ve kept it as a t.s. for now.
This makes its future strength even iffier than typically-difficult tropical cyclone intensity forecasts. Dry air might be one culprit for Ernesto’s struggles (though that doesn’t seem to fully explain it), and there’s more dry air in its path. Eventually getting its act together and becoming a hurricane can’t be ruled out, but first it has to survive this phase of difficulty.
One thing that the system does have is size, with heavy rainbands extending far to the north of the “center.” They have brushed Puerto Rico and Hispaniola, and if they hold together are headed more squarely for Jamaica along with gusty winds.
Partly due to Ernesto having not cranked up in intensity, the track forecast seems more certain now, with more of a southerly route being taken, i.e. rather than heading toward the northern part of the Yucatan, instead going toward the southern part or even scraping the coast of Honduras.
So, even if the storm recovers, it’ll then weaken again as it moves across a thick stretch of land, and could bury itself over land or barely make it out into the Bay of Campeche. Thus, while it’s conceivable that something makes it far enough north to affect south Texas, between its future track over land in the meantime and an overall relatively southerly route which puts it farther from the influence of mid-latitude troughs, a strong system hitting the U.S. seems like a very low probability at this point.