Bryan Norcross: Watching for tropical development in the Caribbean or Gulf late in the week

Updated at 9:30 a.m. ET on Sept. 30, 2024

A tropical disturbance that tracked across the Caribbean is interacting with a broad low-pressure system over Central America. Computer forecasts indicate that a tropical depression or tropical storm could form and head into the Gulf of Mexico later this week. The National Hurricane Center has the odds in the medium range that an organized system will develop.

None of the various computer forecast models show the Gulf storm becoming extra-strong. Certainly not a repeat of Hurricane Helene. But we always have to allow for all possibilities when the system in question hasn't even developed.

On the current consensus schedule, an identifiable low-pressure system will have developed in the western Caribbean by Wednesday and have moved into the Gulf by the weekend. Its effect on land would come about a week from now.

The macro weather features that will steer the disturbance or possible eventual storm are weaker and not as well-defined as those pushing Helene north. As a result, the subtleties in the flow pattern make a big difference, which means the various predictions seem to change every day. We have the basic layout of the pattern that will direct the storm, but not the details.

A bubble of high pressure over the Bahamas and Cuba should initially steer the system north and into the Gulf. A weak dip in the jet stream is forecast to cover the western Gulf over the weekend, which could deflect the system to the northeast or east, but there is not much consensus on the specific timing and track.

For now, everybody on the Gulf Coast from Louisiana to Florida should stay informed.

The atmospheric pattern is forecast to be reasonably conducive for the storm to develop and strengthen, at least briefly. By late in the weekend and early next week, there is a strong consensus that a cold front will move south and hostile upper-level winds will cover the northern Gulf and surrounding areas.

The questions are: How far north does the system track, and how strong does it get before the hostile wind regime arrives about Sunday? If the system stays in the middle of the Gulf, might it avoid the hostile upper winds and track toward Florida in an environment somewhat more conducive to strengthening?

We'll see what shape the system is in when it forms in the Caribbean. At that point, much like when Helene was developing, the forecasts will hopefully come into better agreement. Until then, expect the various predictions to jump around.

Out in the Atlantic, Tropical Storm Isaac and Tropical Depression Joyce will dissipate in the next few days. New Tropical Depression Twelve is forecast to organize and strengthen into a powerful hurricane this week. It will likely get the name Kirk and head into the open ocean.

The disturbance in the far eastern Atlantic is at a low latitude, so it might slip under the various dips in the jet stream that have been turning the other storms north. Nothing will happen fast. The system wouldn't reach the general vicinity of the Caribbean islands, if it ever does, until mid- to late next week.

This system has a good chance of eventually becoming a hurricane as well. It looks like it will develop before the Gulf system – if that one ever organizes – and get the name Leslie. The name after that is Milton.

Original article source: Bryan Norcross: Watching for tropical development in the Caribbean or Gulf late in the week