Tropical Storm Bret has had a good day for itself, strengthening a bit and taking on a more aesthetically pleasing look on satellite.
The sun sets on Bret on Wednesday evening. Bret is a formidable tropical storm with 65 mph winds. (Tropical Tidbits)
Bret has some good thunderstorms near its center, but it is still clearly fighting some shear. Most of the forecast has not changed for that reason, so we will take a quick look at what to expect in the islands over the next few days.
One-sentence summary
Bret is a moderate to strong tropical storm that will bring waves, some gusty winds, and locally heavy rain to central portions of the Lesser Antilles tomorrow and Friday.
Bret’s impacts
Wind shear is expected to keep Bret from further intensifying much. Yes, there is a chance that Bret could become a top-end tropical storm or category one hurricane briefly tonight or tomorrow. But given the environment around the storm, this is not the most likely scenario. Bret will maintain a due west or west-northwest course, which brings it on track to enter the Caribbean probably near Barbados or St. Lucia. Since Bret is a rather large storm (tropical storm force winds extend out 105 miles from the center), impacts will be felt far from Bret’s center.
Bret is still expected to plow west across the islands in the vicinity of Barbados, St. Lucia, or Martinique, with impacts felt a couple islands away on either side of those goalposts. (NOAA)
As of early Wednesday evening, here’s a rundown of watches and warnings:
Tropical Storm Warning (TS conditions likely within 36 hours): St. Lucia, Martinique Tropical Storm Watch (TS conditions possible within 48 hours): Barbados, Dominica, and St. Vincent and the Grenadines
The strongest winds will probably be on the north side of the storm, so places like Barbados, St. Lucia, Martinique, and Dominica will likely see the strongest gusts. While there could be some locally strong winds south of there, Bret will likely be a bit lopsided. Stronger winds may impact the Windward Islands from St. Vincent and the Grenadines south to Grenada on the backside of the storm Friday into early Saturday. Overall, while wind impacts are something to prepare for in the islands, they are not considered too serious at this point.
Some fairly substantial swells will be possible on the coast of the central and southern islands. Waves may be as high as 8 to 12 feet per forecasts from the Barbados Meteorological Services. This will lead to erosion, rip currents, and dangerous surf.
Rainfall will also be an issue as Bret pushes through. Thankfully, it continues to move at a healthy clip, so that limits just how much rain may fall, but that does not mean it won’t come with some issues. Roughly 3 to 6 inches will be possible, especially along and north of the track. Isolated amounts of up to 7 or 8 inches are certainly possible.
Updated forecast rain totals from the ECMWF model show a band of 4 to 6 inches from Barbados through St. Lucia and St. Vincent. Isolated higher amounts will be possible, with a general 1 to 3 inches on either side of that band. (Weathernerds.org)
Some flash flooding is possible, but again, we’re fortunate that this is moving along quickly.
Bret is still expected to degenerate into an open wave once in the Caribbean as it encounters some extremely potent wind shear. Confidence in that outcome should be considered above average.
We will have another update for you around 7 AM CDT Thursday morning.
Good morning. Tropical Storm Bret continues to churn west in the Atlantic, working its way toward the Caribbean. It’s very clearly running into some challenges that are impeding it from strengthening a whole lot at this point, and it has about 24 to 36 hours left before those challenges get even more difficult to fend off.
Tropical Storm Bret should peak in intensity sometime today or tomorrow before running into some serious hurdles in the Caribbean. Tropical Storm Watches are posted for several Caribbean islands. (NOAA)
One-sentence summary
Tropical Storm Bret, ragged as it looks this morning, could bring heavy rain and tropical storm conditions to several islands in the Lesser Antilles tomorrow before steadily weakening once it enters the Caribbean.
Happening now: Bret feeling the thorns of the rose
Besides Bret, we continue to watch Invest 93L, which has an 80 percent chance of developing over the next several days. More on that below. First, let’s walk through our main item.
Tropical Storm Bret
As of the 5 AM advisory, Bret is a moderately strong tropical storm with 60 mph winds. Tropical Storm Watches have been posted for Barbados, Dominica, Martinique, and St. Lucia. Those should be adjusted or expanded later today.
Bret is clearly fighting off some shear and dry air this morning as it works west. (Tropical Tidbits)
The environment around Bret is a bit tough right now. There is about 20 to 40 knots of westerly wind shear zipping across the northern quarter of Bret’s circulation. In the satellite loop above, you can see how ragged the northern half of Bret looks compared to the southern half, and that’s likely due to wind shear. On the northwestern side of Bret, there is a bit of dry air as well. Because of Bret’s size (it’s got a fairly large circulation), it can’t quite fend that off completely. In fact, Bret’s size may be working against it some, as it is being exposed to more adversity than a smaller storm might be.
Wind shear is impacting Bret to the north right now, and it will only get worse as Bret moves into the Caribbean. (Tropical Tidbits)
So to summarize: Bret is an acceptable tropical storm by June standards for sure, but it is dealing with some dry air and a good bit of wind shear that will probably cap Bret’s intensity and trend it weaker as it moves into the Caribbean. An Air Force reserve hurricane hunter aircraft is expected to investigate Bret today to get a better idea of what’s happening out there.
From here, Bret’s track is pretty straightforward. Virtually all of the hurricane models and global models and ensembles are in good agreement that Bret will basically track due west or just north of due west into the Caribbean, somewhere between about Dominica and St. Vincent, and near or just north of Barbados. Because of Bret’s size, many of the Leeward and Windward Islands will experience heavy rain and some version of tropical storm conditions. Because of Bret’s speed, those conditions will probably pass relatively fast.
Virtually all models have Bret degenerating into a depression by Saturday. Its remnants should continue west toward Central America, bringing some locally heavy rain along the way.
Forecast rainfall from the European model suggests about 1 to 4 inches across the southern Lesser Antilles, with the heaviest rain likely in Barbados, St. Lucia, and St. Vincent. Depending on the exact intensity and track, this could shift a bit north or south. (Weathernerds.org)
Rain totals are expected to be on the order of 1 to 4 inches from Bret due to its speed and disorganization as it tracks through the islands. Max rain totals will probably occur somewhere between Martinique and Grenada. For Puerto Rico, the Virgin Islands, and Hispaniola minimal direct impacts are expected, though seas could be a bit choppy.
Invest 93L
Meanwhile, we continue to watch Invest 93L behind Bret.
Invest 93L has a good deal of thunderstorms with it this morning, but it remains fairly disorganized. (Tropical Tidbits)
It still needs a bit of work before we start seriously considering this for upgrade status to a depression. But, it’s certainly got a good bit of storms with it, which doesn’t hurt. At this point, 93L is expected to turn northwest as it comes west, passing north of the islands and out to sea. It too will likely have a window to develop before it hits wind shear that overwhelms it and leads to weakening. Something to keep tabs on but nothing to worry much over at this time.
The medium range (days 6-10): Ain’t no party like an MDR party
The main development region (MDR) of the tropical Atlantic is more on fire than Stockton & Malone in NBA Jam (though I was more of a Barkley/Majerle guy myself). Behind Bret and 93L lies another tropical wave that will make an effort to develop in the medium range. Whether it does or does not is TBD, but even the fact that we’re talking about three systems in late June in the deep tropics is virtually unheard of. This next wave may be a bit too far south to really get going, but we’ll see.
Fantasyland (beyond day 10): Some pattern shuffling in the U.S. & Atlantic?
At this time, we don’t believe any systems will become notable in the day 10 to 15 timeframe, but there may be a little reason to watch some things. The pattern in the Atlantic, as well as high pressure responsible for extreme heat over Texas and Mexico are helping to direct traffic either out to sea or toward Central America as weak disturbances. But once we get into the day 10 to 15 timeframe, the pattern may change some. We will detail what that means in the coming days, but to reiterate, we have nothing specific to watch beyond day 10 right now.
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.
There are two robust disturbances in the Atlantic and a third wave emerging off Africa. While the Caribbean and Gulf are quiet, the Atlantic looks more like late August or September. (College of DuPage)
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.
At least one, if not both of Invest 92L and 93L will develop in the central or eastern Atlantic this week. (NOAA)
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.
Invest 92L is fairly close to becoming a depression it would seem. (Weathernerds.org)
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 92L and 93L are likely to be initially sheltered from dry air due to their small sizes. As 92L develops and grows, the dry air to the north and west may eventually pose issues but for the next couple days, it should be good to go. (Tropical Tidbits)
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?
Wind shear may inhibit 92L more than 93L initially, but both systems will have to fight some shear off over their life cycles. (Tropical Tidbits)
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.
Invest 92L will probably organize over the next 3 or 4 days before eventually hitting an inflection point, where a strong storm would turn out to sea and a weaker one would trek into the Caribbean. (Weathernerds.org)
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.
The heaviest rainfall from 92L will depend on the exact track and intensity. For now it looks manageable, but we’ll watch this through the week. (Weather Bell)
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.
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.
Odds of development have ticked up to about 50 percent over the next several days for the disturbance in the Atlantic. (NOAA)
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.
A very robust tropical wave for June has emerged off the coast of Africa and will be our candidate for development over the next week. (Weathernerds.org)
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.
On Monday evening, the center of the disturbance should be located a bit less than halfway between Africa and the Caribbean islands. (Tropical Tidbits)
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.
The European ensemble splits into two camps with weaker outcomes tracking toward the Caribbean and stronger ones into the open Atlantic north of the islands. (Weathernerds.org)
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.
