THREE OUT OF THE SIX TROPICAL SYSTEMS ON THE BOARD ARE OF SPECIAL INTEREST
FROM BRYAN NORCROSS - September 12, 2020: Tropical Depression Nineteen spun up over the Bahamas a bit ahead of schedule. The center of the broad circulation has now moved over the extreme southern Florida peninsula. The weather effects are the same as if it hadn’t organized – heavy rain for South Florida today with some downpours tonight and tomorrow as well. There is potential for local flooding across the southern part of the state.
The depression is forecast to intensify once it gets over the very warm Gulf of Mexico under a reasonably supportive atmospheric pattern. Everybody on the Gulf coast from Florida to Louisiana needs to stay aware because the system could reach near hurricane strength as it tracks across the Gulf. Tropical Storm Watches are already in effect for the Florida west coast.
The steering currents are not expected to be very strong, so the storm will likely be a slow-mover meaning there could be very heavy persistent rain wherever it impacts the coast.
Already in the Gulf is little Disturbance #1. It will move toward the western Gulf ahead of the depression-turned-tropical-storm-and-maybe-hurricane. Upper-level winds are somewhat hostile ahead of the system now, so the odds are low that it can pull itself together into at least a tropical depression, but it’s not impossible. If it happens, the system could develop quickly near the Texas or Mexico coast. Stay alert.
In the central Atlantic, Tropical Storm Paulette has been maintaining its strength in spite of seriously hostile upper winds. This is evidence that it could turn into a serious hurricane when the atmosphere becomes conducive for strengthening in a day or two. The National Weather Service is forecasting Paulette to be near Bermuda on Monday as a strong Category 2 storm, which means they have to be ready for a Cat 3.
Tropical Storm Rene is barely hanging on, strolling northward in the middle of the Atlantic. It looks like it will get trapped under blocking high pressure and somewhat hostile upper winds. So for the next several days, it will exist, but only be noticeable for its possible effect on the track of Disturbance #2.
The disturbance in the eastern Atlantic that we’ve been following is Disturbance #2 today. It’s still broad and disorganized, so there are still big questions about its future.
As a general statement, the slower it organizes – meaning the weaker the system stays – the more likely it is to track toward the Caribbean islands. Conversely, if it consolidates and strengthens fairly soon, it will likely hang a right before it gets to the islands and move up into the middle of the Atlantic.
A stronger system is more likely to be able to take advantage of the pathway north created by Paulette and Rene.
The computer forecast models are not a big help because they show those possibilities and more due to the close proximity of Disturbance #3.
For now, we’ll just watch how see how this tropical mish-mash develops, and if the individual systems separate as clear individual entities. The steering currents are not especially strong, so nothing is going to happen fast. If Disturbance #2 makes it to the Caribbean islands, it wouldn’t be there until next Wednesday or Thursday on the current schedule.
Disturbance #4 appears to be in the pipeline as well. It is forecast to emerge off the African coast late tomorrow or on Monday at a low latitude, which means we have to watch it carefully. The farther south systems are, the less likely they are to turn north quickly.
There is a race underway between Tropical Depression Nineteen and Disturbance #2 to see which can become Tropical Storm Sally first. My money is on the depression.