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  • Writer's pictureBryan Norcross

Unusual June disturbance speeding across the Caribbean while the Gulf system is trying to organize

Tropical Disturbance #1, which we have followed across the tropical Atlantic, has now entered the Caribbean. It is flying toward the west, just north of the Venezuelan coast, and will move through the ABC islands today – first coming across Bonaire, then Curaçao, and finally Aruba.

The National Hurricane Center is designating this system Potential Tropical Cyclone Two as part of their protocol for issuing tropical storm warnings for the islands. Winds of 40 mph have been measured in the storm, so they are ready to name it Bonnie if it ever fully organizes. Even with the fancy name, however, it is still just a tropical disturbance.

This is quite unusual for June. Only once before in the record book, in 1933, has a tropical system come near these islands this early in the season. Technically, of course, this one won’t count in the future, unless it is able to organize enough to officially become Tropical Storm Bonnie. But the records are still indicative of how unusual it is to have any tropical system track this far south.

The disturbance still has a slight chance of becoming Tropical Storm Bonnie today. The atmospheric conditions are supportive. But systems that are moving super quickly have a harder time acquiring a full circulation. Since the whole system is zooming to the west at about 30 mph, the winds on the bottom side of the attempted circulation would have to be stronger than that to get going.

Imagine a system that is standing still and has a donut of 40 mph winds circulating counterclockwise around the center. Now move the system to the west at, say, 25 mph. Winds at the top of the donut get accentuated (40 + 25 = 65 mph) because they are going in the same direction as the movement. But on the bottom side, the winds get canceled down to a net of 15 mph. Since this speedy system isn’t very strong, getting bottom side winds going has been a challenge.

On the projected track, the northern coastlines of Venezuela and Colombia are just ahead. Even though the disturbance should slow down a bit as the steering flow weakens, dry air feeding into the system off the land will likely limit significant development. Although, if it tracks just far enough offshore, and slows down sufficiently, Bonnie could still form.

Once the system clears the South American land mass late tomorrow or early Friday, development appears likely over the extreme southwestern Caribbean. This means that southern Nicaragua is projected to be impacted by a stronger system.

Interestingly, what should be Bonnie by then is forecast to move across the thinnest part of Central America and emerge into the Pacific, though as a weaker system. Assuming it acquires a circulation over the Caribbean and maintains it across the landmass, it would still be called Bonnie if it redevelops over the Pacific Ocean.

In the Gulf, there is a broad area of low pressure off the coast of south Texas, which is drifting toward shore. I’m labeling it Disturbance #2. Heavy thunderstorms are associated with the system, but they are not organized around the circulation. There is a decent chance that the disturbance will organize enough to be designated a tropical depression before it comes ashore about Friday.

Whether it organizes or not, the main threat with this system is the heavy rain it will drag over the Texas coast tomorrow and Friday. This system combined with an old front will keep rain going over the rest of the northern Gulf coast through the weekend.

Coastal Texas is having a drought, so the rain will be beneficial if it doesn’t come too fast.

Out in the Atlantic, Tropical Disturbance #3 is just a blob of moisture. It is projected to reach the Caribbean islands late Friday into the weekend. Its odds of development are fairly low, but in any case, it will likely bring gusty tropical rainstorms to the islands.

This disturbance will likely take a more northerly track than its better developed cousin Tropical Disturbance #1. This means that the northeastern Caribbean islands including Puerto Rico and the Virgin Islands will likely be affected.

Stay informed on the potentially affected islands to be sure the system doesn’t quickly organize into something more threatening.

Hopefully, Mother Nature will take its typical late June/early July break after this. But we’ll see. Nothing obvious is on the horizon.


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