The Cuban meteorologist José Rubiera published an analysis on his YouTube channel this Friday, warning that the remnants of tropical storm Dolly —now downgraded to an open tropical wave— could reform by the beginning of next week in an area that includes the Bahamas, northern Cuba, southern Florida, and the northern Gulf of Mexico.
The analysis arrived on the same day that the INSMET issued its last official notice about Dolly, ruling out the possibility of the system redeveloping as a tropical entity.
Rubiera, without contradicting that diagnosis for the short term, emphasized the need to remain vigilant regarding the medium term.
Why did Dolly stop being a tropical storm?
Tropical storm Dolly formed on Thursday, August 27 with maximum sustained winds of 65 km/h, but it deteriorated to a remnant low within hours upon encountering an environment described by the meteorologist as "completely hostile."
Rubiera explained the mechanism of weakening: "It crossed over an ocean buoy, and that buoy did not encounter west winds. For there to be a closed circulation, there must be west winds from the south, east winds from the north, and so on to create the circular motion of the winds. Without encountering west winds, it indicates that it is an open tropical wave."
That factor was compounded by the presence of extremely dry air: "The dry air was trapped here. There was no way for it to escape. That’s why it might weaken even more as it approaches the Lesser Antilles."
The third obstacle was a vertical wind shear of enormous intensity: "There is strong vertical air shear, strong winds in the upper atmosphere. 80, 90, 100 km/h acting on the system and decapitating it. It cannot develop here."
To all of this, a translation speed of 41 km/h was added, which is too high for any tropical system to become organized.
What are the conditions that could favor reformulation?
As a tropical wave, the remnants of Dolly were located on Friday about 1,580 km east of the Lesser Antilles.
Rubiera outlined the trajectory leading to a potential reorganization: showers and storms in the Lesser Antilles this Sunday, reaching Puerto Rico and the Virgin Islands Sunday afternoon, and arriving in the Dominican Republic Monday morning.
It is precisely after crossing Hispaniola where the numerical models show something significant: the trail of cloudiness is interrupted and reappears in the Bahamas and the Gulf of Mexico, which Rubiera interprets as a sign of possible reorganization.
The meteorologist contrasted the destructive conditions that Dolly faced with those she would encounter in that area:
"The sea temperature is a bit higher than here. The air is dry throughout this area, and there is very weak vertical shear with the wind. This means that there are very good conditions here, and the translation speed decreases significantly."
With that combination —sea temperature above 30 °C, almost nonexistent shear, and lower movement speed—, Rubiera was straightforward:
"In the area from the north of the Dominican Republic to the Bahamas, northern Cuba, Florida, the Gulf of Mexico, and this part of the Atlantic, there could be regeneration of the system, and a reformulation of Dolly could occur by early next week."
A warning with nuances, not a certainty
Rubiera was careful not to present this scenario as inevitable.
"I’m not saying it happens, I’m saying there are models that are at least suggesting it, and I believe that the logic of the processes indicates that there are better conditions for development there," he warned.
This position contrasts with that of INSMET, which, in its latest advisory on Dolly, stated that "throughout its path, atmospheric conditions will remain unfavorable, so the system is not expected to achieve any tropical development again."
The National Hurricane Center of the United States assigned a probability of nearly 0% in 48 hours and only 10% in seven days for the development of the remnants.
Rubiera announced that, although there are no regular programs this Saturday or Sunday, he will maintain the watch.
"Although we're not going live on Saturday and Sunday, we’ll keep it in mind, and if something comes up, we would then air a special program," he concluded.
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