The mid-Atlantic disturbance is organizing as it heads toward the Caribbean
Tropical Disturbance #1 is not now expected to develop. It will move into the Caribbean as just a moisture surge.
Tropical Disturbance #2, on the other hand, has developed on the southern edge of the Saharan dust plume, so it has access to dust-free air on at least two sides. It’s already showing rotation and some organization.
The National Hurricane Center has designated the system Potential Tropical Cyclone Five, which allows watches and warnings to be issued for land areas – in this case some of the eastern Caribbean islands. A “potential tropical cyclone” is the technical name for a system that could develop into a tropical depression on tropical storm by the time it gets to land.
In this case, we’ll get Tropical Storm Elsa if the peak winds are estimated to be 40 mph or higher. If Elsa forms, which is likely, it will be the earliest “E” storm on record, even beating last year.
Atmospheric conditions appear conducive for organization and strengthening, so people in the eastern Caribbean islands need to stay aware. The system is forecast to move through the islands into the Caribbean Sea on Friday.
If you are looking at the computer forecast models online, always bear in mind that the computer simulations are much less accurate when systems are disorganized or just developing like this one. So don’t read too much into them. The key point is that conditions appear to support development of the system in the short term.
Looking past the potential development point, the future track of the system depends to a large degree on how strong it gets. Since that is unknowable, the possible tracks through the weekend and into next week appear to range from Mexico to near Florida.
Also, the computer forecast models significantly disagree on how strong the system will be in the Caribbean. The system is forecast to be south of Cuba on Sunday, July 4. We should have a better idea before then if Florida might be involved early in the week.
Over the weekend, a big dip in the jet stream will be moving through the northeastern U.S. The question is, will that dip nudge the tropical system north, or does is miss? It’s just too early to know.
Plan to stay informed over the holiday weekend in case we have to take action.