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  • Writer's pictureBryan Norcross

Close call whether we’ll finish August without a named tropical system

There are three disturbances across the tropics, but none are primed to develop immediately. By the middle of next week, however, there’s a chance that at least one of the systems might organize into a named storm.

Disturbance #1 is hardly recognizable. It’s just a weak cluster of showers moving through the eastern Caribbean. The atmospheric environment is usually unhealthy for tropical systems in this area, and now is no exception. When it reaches the western Caribbean toward the end of next week, it might find a more conducive patch of atmosphere. But the system has to survive that long as a concentrated disturbance, which is not guaranteed.

If it does survive, the atmospheric conditions look conducive for development late next week.

Disturbance #2 has a good cluster of thunderstorms associated with it, but it is so far south in the far eastern Atlantic that it will struggle to lift north enough to move into the development area. It may well merge with Disturbance #3. But any significant cluster of thunderstorms is worth keeping an eye on.

Disturbance #3 is a large area of disturbed weather that just moved off Africa. It’s plowing ahead into the dry air, which has been covering much of the tropical Atlantic this year, but its large envelope might eventually moisten enough atmosphere to allow development. As above, it may well pull moisture from Disturbance #2.

Nothing is likely to happen immediately, but by around the middle of next week, it looks more likely that it will be able to fight off the dry air and pull itself together.

September 1st comes next Thursday, so it’s going to be a close call whether Disturbance #1 or #3 can develop in August. If it develops at all.

The National Hurricane Center is giving all these disturbances a low chance or no chance to develop in the next 5 days. But their percentages are just an estimation of the odds of a tropical depression forming, not a named storm. And 5 days will fill out August.

Right now, the odds look higher that we’ll get through August without a named storm, which would be very unusual. And never in modern times has it happened during a La Niña year in the Pacific. La Niña conditions along the equator south of Hawaii, almost always result in a weather pattern over the tropical Atlantic that is more conducive than average for systems to develop.

So what’s going on? It’s an excellent question without an obvious answer. Clearly there has been excessive dry air over the Atlantic, which has acted like a sponge taking moisture out of tropical systems. But why that’s happening and persisting is an open question. In any case, it appears likely to come to an end.

So enjoy the weekend. It’s a race to the finish between the calendar and the disturbances to see if we have a Danielle when September starts next Thursday.


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