The Eyewall

One look at the satellite image over the Atlantic this morning, and it’s sensible to ask what month it is currently. Even when one factors in the idea that we’ve been able to name more small storms in recent years, this is a bit ridiculous.

Thankfully, both systems of note in the Atlantic will probably have relatively short shelf-lives, but folks in the Lesser Antilles, Virgin Islands, and Puerto Rico should monitor the progress of these systems.

One-sentence summary

Two disturbances in the Atlantic, Invest 92L and Invest 93L have been given 100 percent and 40 percent chances (respectively) of developing this week and could become depressions or named storms in the coming days.

Happening now: Investment prospectus

Two invests means two systems to discuss, so let’s take a look at their futures.

Invest 92L

Looking at Invest 92L this morning closer in on satellite, it’s pretty clear that this is almost ready to go.

After struggling for a couple days, the thunderstorms seem to have consolidated and there is a noticeable “spin” to the disturbance. This is likely going to become a depression not long after we publish this post.

Over the next couple days, the question becomes how much better organized 92L gets. Let’s look first at atmospheric moisture tomorrow evening.

Both systems are highlighted above, but looking at 92L specifically, it looks good into Tuesday evening, with ample moisture and dry air off to the north and west and far enough away for now to prevent problems for development.

What about wind shear?

I don’t think that shear will be prohibitive to 92L, but it may keep it from intensifying as much as some models have been saying. By tomorrow evening, it’s dealing with a fair bit of shear “in the neighborhood” but perhaps not enough to keep it from becoming a tropical storm.

So where will this system go? Obviously, that’s the $10,000 question. We have enough clues in the data to make a decent call of at least what to watch and when to watch it for planning purposes in the Lesser Antilles, Virgin Islands, and Puerto Rico. If we use the GFS ensemble as a guide, we can see that 92L’s intensity is likely to “peak” in about 72 to 96 hours, or on Wednesday/Thursday. When you run 30+ different versions of the model to generate the ensemble, you get the map below.

From this point, the GFS ensemble at least takes stronger outcomes more north into the open Atlantic while weaker ones (with 1 or 2 exceptions) track into the Caribbean. It’s notable that all the European ensemble members (not shown) keep 92L weaker and track it into the Caribbean. But I prefer using the GFS ensemble as a guide, as it opens up a wider array of options for us to see right now.

Beyond day 3 or 4, it seems likely that whatever 92L becomes is going to run into a good bit of northerly shear and some broader dry air that could lead to it becoming less organized. This is why we believe that if it makes it to the islands or Caribbean, it will likely do so as a tropical storm and rain producer, certainly not without hazards but something a little less extreme for late June. But we’ll have a good idea by midweek of what this does and who it impacts.

If we look at the European ensemble mean for rainfall over the next 7 days, we can see a corridor of locally heavy rain that moves into the Lesser Antilles, with Guadeloupe through St. Lucia being in the heaviest rain. Depending on intensity and exact track, that “bullseye” could shift north or south a bit. For now, the ensemble mean prints out 1 to 4 inches of rain, but there could be some locations that see more and some flooding concerns, again depending on track and intensity, a picture that should become clearer later this week.

Invest 93L

From the maps above, it’s clear that Invest 93L is going to be in a slightly more intriguing environment for development. Much like 92L, how well organized this gets will lead to some track outcome, with a better organized disturbance likely turning northwest before the Caribbean and a less organized one likely following 92L to the west and into the islands. I want to see more of how 92L behaves before worrying much about 93L, and besides 92L is the more immediate system to watch for the islands.

The medium range (days 6-10): More to come?

It seems funny that for the last 2 weeks the GFS operational model has been all about the western Caribbean and yet it’s the Atlantic that’s off to the races. There are some signs in the models that a third disturbance emerging off Africa may be something that could develop over the weekend or next week. Much like 92L and 93L, it seems unlikely it will become a big deal but this meteorologist can’t recall a busier late June in the deep Atlantic in recent memory, if ever. Of course, record warm water temperatures in the Atlantic likely mean record-type outcomes, despite El Niño.

Fantasyland (beyond day 10): Calmer?

As of right now, a cursory glance at operational models and ensembles seems to indicate that things may begin to quiet down some heading into July. We’ll see.

Follow our social media for any updates should 92L develop today.

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Otherwise, we’ll be back with you on Tuesday morning.

Good afternoon. We hope everyone is having a great Father’s Day—here in Houston I am enjoying some time with the family but this face-melting heat and humidity is something else. The situation is little different out across the Atlantic tropics, where sea surface temperatures are at or near record levels for this time of year. And lo and behold, the warm tropics are producing uncharacteristically robust activity for mid-June. Hence this post on a holiday weekend.

An area of interest, known for now as Invest 92L, has continued to show signs of organization today as thunderstorm activity increases and it passes through an area of relatively low wind shear. As a result, the National Hurricane Center now gives the system a 90 percent chance of becoming a tropical depression or tropical storm in the next two days. In all likelihood, we’re looking at Tropical Storm Bret by early next week. In other words, I’d bet on Bret. Sorry for the dad joke, but today is Father’s Day you know.

This tropical system should continue to have a reasonably favorable environment for strengthening into the middle part of next week as it continues to track westward across the tropical Atlantic, toward the Windward Islands. After that? Well, if the storm continues trucking westward it will eventually face more hostile conditions. This means that a tropical storm could move into the Eastern Caribbean Sea by Thursday or so, but then likely weaken. The other scenario is that the storm begins to turn more northerly before entering the Caribbean Sea. Along this path the tropical system would find more favorable conditions, but should spin harmlessly out in the ocean.

The bottom line is that if you’re in (or traveling to) the Windward or Leeward Islands—basically from the Virgin Islands all the way south to Barbados—it’s worth keeping an eye on this system. I don’t think anything too troublesome is coming, but the Atlantic is very warm so it’s worth monitoring. As for other parts of the Atlantic basin, including the United States, this probably is not anything more than a curiosity. We’ll have bigger fish to fry later this season, no doubt.

It appears that we pretty clearly have our next item to watch on the docket out in the Atlantic, so most of today’s post will be devoted to that. Let’s jump right in.

One-sentence summary

Development is becoming increasingly more possible in the eastern Atlantic, an extremely rare occurrence this early in the season.

Happening now: Slow Atlantic development possible

The National Hurricane Center has bumped up the chances of development with the tropical wave off Africa to 50 percent over the next week as it marches west across the Atlantic. This remains exceptionally far east for this early in the season.

If we take a look at a satellite loop off Africa (which feels really weird to type in mid-June), we see a truly robust looking wave moving west. This looks much more like August than June, likely speaking to the exceptionally, record warm water temperatures in the eastern Atlantic.

The system remains an open wave at this point, but it will likely be declared an “invest” sometime this weekend or by early next week. Any development over the next 3 days would be slow. By days 4 and 5 (bringing us to Monday and Tuesday), we could see some consolidation in the open Atlantic east of the Caribbean islands.

The system will be steered basically due west around the base of high pressure in the central Atlantic. Development will likely be sluggish as it fends off some shear and dry air in the neighborhood. But it seems plausible that a slow, steady attempt at development will occur through Tuesday. Which takes us to…

The medium range (days 6-10): Watching how well-organized the Atlantic system can get

As this disturbance makes its way toward the islands, again, we expect development to be sluggish but generally in the direction toward organization. Here’s where it gets tricky. Any future track of this disturbance will probably be contingent on how strong it gets. In other words, the stronger the system is, the more likely it is to begin gaining latitude. The weaker and more disorganized it is, the farther south it will track.

We can see this nicely illustrated when looking at how the European ensemble is handling things. By day 8, next Friday, there are two pretty clear camps showing up. Remember, we use ensembles to get a realistic spread of outcomes by tweaking a model a bunch of different ways and re-running it 30 to 50 times. In the Euro ensemble, we run it 51 times. We aren’t looking for the answer key, but we are looking for information we can use to inform our forecast analysis. In this case, we have what we need.

In this situation, ensemble members that blow up the system (tracks in yellow or orange) take it more north and northwest into the open Atlantic. Ensemble members that keep the system on the weaker side (blue or green tracks) take it west into the Caribbean and toward the islands. And you can see that weaker outcomes outnumber stronger outcomes by a modest but notable margin.

So, we know that as this develops, we need to be watching intensity, as a stronger system will turn northwest faster. A weaker one will proceed toward the islands, putting them at risk for some impacts, hopefully not too significant. In that instance, the storm would probably gradually weaken beyond the islands as it encounters a more hostile wind shear environment closer to the US.

For now, if you are in the Caribbean, continue to monitor the situation. You have plenty of time to watch and hopefully it never becomes a big deal. We’ll keep you posted throughout.

Fantasyland (beyond day 10):

The good news is that aside from this system in the Atlantic, there is not much else to discuss. Yes, the GFS keeps springing noise on us in the Caribbean. No, we still don’t think it will amount to anything. For now, the only other action should be in the Pacific.

As of now, we’ll plan to check back in on Monday, but if the Atlantic disturbance does begin to organize more effectively than expected, we’ll join you Sunday for an update.

The tropics remain quiet in the near-term and more interesting a bit farther out in time, though with no real concerns to any specific place at this time. If you missed it yesterday, we published our first real in depth piece which discussed the story of the Gulf of Mexico in recent years and what it does (and doesn’t) tell us about the future.

One-sentence summary

Over the next 7 to 10 days, the most interesting area to watch will be in the middle of the Atlantic and toward the Lesser Antilles, where there is perhaps a low chance of lower-end development.

Happening now

Over the next few days, we don’t expect much of anything to occur. If you look at a satellite image of the Atlantic, there’s nothing of note. Yes, there are storms off Florida and the Southeast coast, but they remain extremely disorganized. By next week, the circled area of thunderstorms over Africa may try to slowly begin developing as it moves across the middle of the Atlantic.

But, that’s more of a medium range story, so let’s shift to that section.

The medium range (days 6-10): An odd area to watch in June

If you look at a map of where June storms form at the end of the month, historically, you are not really looking east of the islands.

Through 2015, there had been one that developed in the same general area we’ll watch next week. Since 2015, we have added three more, so we’re either getting better at identifying systems that far east or this is a new phenomenon.

None of these storms became particularly large, though Elsa did become a category 1 hurricane and caused over $1 billion in damage, becoming notable also for being the first hurricane in years to hit Barbados.

Editor’s Note: As of 8 AM ET, the National Hurricane Center designated this as an area to watch over the next week, with 20% odds of development.

As we go into next week, that wave highlighted above near Africa will move into the Atlantic. Both the GFS and European models show it trying to develop, slowly, in between Africa and the Lesser Antilles. If we look at the European model in about 6 to 7 days, we can see a pretty clear signal about 10,000 feet up just east of the islands.

Interestingly, the GFS model has a similar situation shown. Ensemble guidance seems to validate this with a fairly weak ensemble mean signal and about 50 percent of individual ensemble members showing development. The maps shown here today are from deterministic, operational models, as they have a clearer signal we can highlight. But meteorologically, we are looking closer at the ensemble guidance, which gives us 30 to 50 different outcomes and allows us to blend together a more nuanced picture of development chances, which are elevated but by no means a lock.

So what to make of this if you live in the islands? Well, you should monitor this. I think there’s enough signal on the models right now that makes it clear that, at the least, some sort of robust disturbance is going to approach later next week. It may not organize, it may turn before getting there, or it may come through as a tropical system. We just don’t know at this point. Would it be a big storm? Probably not, given the time of year, dust in the area, and some (a lot of?) wind shear as well.

So, if you live in the Lesser Antilles or Virgin Islands or Puerto Rico, this is worth monitoring but probably not worth getting too worked up about. It’s a definite oddball given where it could develop relative to the calendar. But it seems likely that it will have some hurdles to face to become a defined tropical entity. We’ll keep watching and have more tomorrow.

Fantasyland (beyond day 10): Still noisy, still not super impressed

The Atlantic system will probably disperse at some point in this timeframe, so we could see unsettled weather in the Caribbean. We are continuing to watch the western Caribbean for some noisier conditions but we remain unimpressed with the odds of any organized development in this timeframe.