Matt Lanza

The tropical Atlantic thinks it’s later July or August as Invest 95L captures our attention

Headlines

  • Invest 95L is slowly organizing in the central Atlantic.
  • There is strong model support for it to organize over the next 3 to 5 days.
  • Models differ significantly on how quickly that occurs, which has important ramifications for the longer-term outlook on 95L.
  • For now, Caribbean islands should monitor 95L closely as it organizes and prepare to put plans into action if need be, while those farther west and north should continue to check in every day or two for an update.
  • Invest 94L and a Central American gyre circulation will provide heavy rain for Mexico and Central America over the next week.

Invest 95L will be giving us headaches over the next 7 to 10 days

We’ll get to Invest 94L in a moment, but first and foremost, if you utilize social media or are weather savvy, you’ve more than likely seen some of the model solutions from deterministic models for Invest 95L, which was minted yesterday from the tropical wave in the central Atlantic. Here it is this afternoon:

Invest 95L has a nice little core of thunderstorms and a broad swirl to it already, but it is dealing with dry air in the vicinity. (Weathernerds.org)

It’s respectable. This, to me, looks more like what you’d see in the central Atlantic in August, not late June. So this feels rather bizarre. As we noted yesterday, storms in June are not unprecedented this far east, but they’re still fairly rare. So Invest 95L is humming, and it will be a good idea to monitor this.

One thing we strongly advise against this time of year is monitoring deterministic models too closely: the operational GFS, the operational ECMWF (Euro), etc. These are one-solution, one-forecast outcomes. They have inherent biases in certain situations. For example, the GFS tends to be overeager with Atlantic wave development in systems like 95L. So it wasn’t exactly a surprise to see it barreling a hurricane into the Gulf or toward Florida on a couple recent runs. The Euro has its own struggles, and it too can be prone to errors in track or intensity. But these models swing around a lot from run to run. For example, the last five runs of the GFS have shown multiple possibilities.

12z Wednesday: Southern Caribbean to Hispaniola
18z Wednesday: Yucatan to Mainland Mexico
00z Thursday: Jamaica to Yucatan to northern Mexico
06z Thursday: Haiti to Cuba to Houston
12z Thursday: South of Hispaniola, between Jamaica and Cuba, to Cancun to the Rio Grande

Intensities have fluctuated all over on each of these runs as well. So, we’re not telling you not to look at deterministic modeling. We don’t want to be condescending! But do not use them as planning tools or even as a barometer of what is most likely. Often, the deterministic modeling ends up on one extreme of the ensemble envelope, meaning it’s arguably the least likely outcome! This is why we use ensemble modeling. It gives us a breadth of outcomes and risks. And we can dig into it to pull some signal from the noise.

In this case, the European ensemble actually does a very good job of offering up just that. I don’t like sharing spaghetti plots, because they are often too difficult to understand, but in some cases, they’re extremely useful. I believe this is one of those cases. Here’s the 00z Euro ensemble spaghetti plot for 95L.

The Euro ensemble plot of 51 members shows outcomes ranging from off the East Coast to Central America, with intensities ranging from strong hurricanes to depressions or weaker. But some signal can be pulled from this. (Weathernerds.org)

What can we take from this? First, there is a very bimodal distribution of the members. In other words, there is one cluster that favors a westward or slightly north of west track all the way into Central America or Mexico. A second camp exists pulling 95L more to the north, even as far east as near Bermuda! This makes intuitive sense, and it gives us a guidepost to consider when thinking about 95L’s future. In addition to steering currents and such, one factor that will determine 95L’s future will be its own intensity. A storm that strengthens quickly will be more apt to gain latitude faster, meaning a track in the right half of the ensemble envelope. A storm that struggles to organize longer will stay at a relatively far south latitude longer, perhaps even grazing the coast of South America.

Click to enlarge this comparison showing the operational European model (left) less wound up and farther south, while the GFS (right) is more wound up and farther north.

Here’s a good way to actually use deterministic modeling to your benefit. If we look at the comparison of where 95L will be on Tuesday, you can see the GFS is farther north than the Euro. This should not come as a surprise, as it is much faster to develop and wind up 95L than the Euro.

From a practical point of view, this means that what happens over the next 3 to 5 days with Invest 95L will be fairly important. If it forms quickly, it could come farther north ultimately. If it is sluggish to organize, it will probably take a track in the southern half of the ensemble forecast envelope. This isn’t the only thing that will influence where 95L goes, but at the current time, it’s pretty important. As I noted, the GFS operational has a bias to wind these things up too quickly in this part of the world. So in many ways, this probably argues that the Euro idea (favoring the southern half of the ensemble envelope) is more likely. That being said, this is a very atypical year, with record warm water temperatures and such. With that in mind, it bears watching, especially for the Caribbean islands that will be first in line to receive whatever this is as it organizes. Those of you in the states or Central America should continue watching 95L’s progress in the days ahead.

The next name on the list is Beryl.

Invest 94L aids in heavy rain for Central America

Meanwhile, Invest 94L is heading very close to Central America today, which should really reduce its chances of development.

Invest 94L has an awful lot of thunderstorm activity, but it is tracking very close to land in Central America, likely limiting its development chances. (Tropical Tidbits)

It sure looks interesting on satellite until you realize that the center is just offshore of Honduras. This should keep any development in check over the next day or two. If it can sneak into the Bay of Campeche later this weekend, it has a slight chance to do something before going ashore in Mexico. Regardless, heavy rain is likely in Central America and Mexico with flooding possible. Anywhere from 100 to 200 mm of rain (4 to 8 inches) is likely in many spots, with higher amounts (300 mm or a foot or more) possible in some spots.

The next week of rainfall for the western Caribbean and Central America and Mexico. Yellows as seen from Belize into the eastern Yucatan and elsewhere indicate 100 mm or more. (Pivotal Weather)

Aside from 94L, a general gyre circulation will continue to provide heavy rainfall from Panama up into Mexico as well.

The deep Atlantic is waking up earlier than usual this year, while 94L in the Caribbean tries to find a pathway to develop

Headlines

  • Invest 94L in the Caribbean is unlikely to develop, but if it tracks a bit to the north, it has a puncher’s chance in the Bay of Campeche.
  • A robust signal in modeling exists for the tropical wave around 30°W in the Atlantic to organize as it tracks toward the islands next week.
  • The wave behind that is worth watching as well.

Invest 94L’s Caribbean cruise looks mostly uneventful

Yesterday, I noted that June would end on a quiet note. Well, “quiet” is a relative term. We have two systems to watch right now, and Invest 94L is the closest to land at the moment. If you look at it on satellite around midday Wednesday, you probably are not terribly impressed.

Invest 94L at midday on Tuesday was mostly just a blob of thunderstorms. (Tropical Tidbits)

The system is sort of split right now between high shear to its north and more hospitable shear to its south. This basically means that it has a chance to organize over the next few days, but it would be fairly unlikely and certainly with limited upside to intensity. This situation isn’t going to change much before it runs into Central America or the Yucatan this weekend.

I think Invest 94L’s best chance to organize may come if it crosses into the Bay of Campeche, something the Euro suggests will occur. The GFS model keeps the system really disorganized and basically over Central America and southern Mexico through the weekend. If the Euro is correct, 94L will emerge in the Bay of Campeche later on Saturday and progress into Mexico, a la the last couple of systems in this area.

European model look at mid-level “spin” in the atmosphere on Saturday evening shows 94L in the Bay of Campeche. The GFS is notably farther south and over land. The Euro scenario offers a narrow opportunity for development. (Tropical Tidbits)

It would have a narrow window to organize before coming ashore if the Euro is correct as shown above. I would probably split the difference between the two at this point, keeping a very slim chance it can get organized before heading inland. Either way, additional rain is possible in the Yucatan and Mexico from Invest 94L as it comes west.

The Atlantic is priming itself to run ahead of schedule

More attention will probably be focused on the deep Atlantic heading into next week however. A tropical wave was located around 30°W longitude today, tracking west.

A tropical wave southwest of the Cabo Verde Islands will be one to watch over the next 7 to 10 days. (Weathernerds.org)

The National Hurricane Center assigned 30 percent odds of development to this wave over the next week, which seems like a good opening volley. Modeling has been fairly aggressive with this, as both a number of GFS and European model ensemble members try to spin this one up into a depression or storm by the time it gets to the Caribbean islands. It would be rare but not totally unheard of to see a system form out here this early in the season. Per Kieran Bhatia, a leading hurricane expert in the insurance industry, only two systems have formed east of 51°W longitude in June since 1960, most recently Elsa in 2021. Whether this forms in June or the first days of July, if at all is still up for debate, of course. But it is worth watching.

Currently, this wave is located in an area with a lot of dry air to the north as Saharan dust expands across the Atlantic. In about 3 days, that situation does not really change. The Euro and GFS are generally similar about 3 days from now, showing this wave trying to organize east of the islands and very, very far south in the basin.

Saturday morning’s forecast shows the wave around 10°N latitude, trying to organize but with a lot of dry air to its north. (Tropical Tidbits)

The wave is cruising along around or just south of 10 degrees latitude, a region in which only a handful of June and July storms have generally developed.

The black line is roughly 10°N latitude, with all June and July storms since the 1800s plotted in the general vicinity of where this wave is expected to be on Saturday. Only a handful have formed this far south and east. (NOAA)

These storms ended up with mixed outcomes, including a couple hurricanes, a couple dissipating in the Caribbean, and a couple making it toward the Gulf. No strong signal exists either way. Whatever the case, the story with this wave’s southern track is that it may benefit its long-term ability to organize. If it can consolidate as a smaller system farther south, it would be more likely to incubate itself from the dry air and dust to its north, giving it an opportunity to slowly intensify as it works toward the Caribbean. If it fails to do this, it will likely struggle with dry air or wind shear, also expected to be present.

Main development region (MDR) sea-surface temperatures are currently at or above records for the end of June. (University of Arizona)

One reason to watch this one is that our sea-surface temperatures in the region are running at or above records set last year and near levels that are normal for late August. So if it finds the right environment, it has a chance to grow. I don’t want to speculate on where it goes just yet, but suffice to say, while wind shear could ultimately threaten its ability to grow significantly, it’s a little concerning to see the potential of this happening early in the season and so far east, with decent upside risk. Folks in the Caribbean should monitor this disturbance’s progress and check back for updates.

Also, the wave behind this one has shown up at times on modeling with a development opportunity. I wouldn’t worry much about it at this point, but its worth watching as well. The Atlantic seems to think its later July.

June should end on a relatively quiet note in the Atlantic tropics

Thanks for bearing with us over the last couple days as your primary author took a few days up in Chicago for only marginally cooler weather than Houston and nearly found himself in an EF-0 tornado. We are back and rolling now.

Headlines

  • A disturbance in the Caribbean has a 20 percent chance of development over the next week as it tracks toward Central America or the Yucatan.
  • Another potential wave behind it is worth watching into next week, but Saharan dust may play a role in this one.
  • Today’s post also gives you some other recommended reading during hurricane season.

Disturbances and dust

We are one named storm and a couple disturbances into what was expected to be a very, very active Atlantic hurricane season. So is it trending to a bust, as I’ve seen some rumblings of lately? It’s important to remember that June’s outcomes do not have any real significant bearing on what the rest of hurricane season will bring. By total accumulated cyclone energy (ACE), we are only 1.6 percent of the way through the season climatologically. So over 98 percent of the season awaits in terms of that metric. It’s a marathon.

We have one disturbance coming across the Caribbean with about a 20 percent chance of development over the next week or so.

The disturbance being monitored for development is just entering the Caribbean above South America. (Weathernerds.org)

Despite the look on satellite, weather modeling is not overeager about this disturbance’s future. It’s expected to basically maintain this track west-northwest toward Central America or the Yucatan, following in the general footsteps of Alberto and Invest 93L this past weekend. We’ll continue to monitor this one, but at this point it’s not expected to become a serious problem.

Elsewhere, we don’t currently expect development over the next week or so. Modeling is beginning to hint at an Atlantic disturbance sometime next week, but it’s far too early to speculate on potential development or down-the-road impacts.

Saharan dust is pretty widespread over the Atlantic now, so that may be a limiting factor in future tropical development next week. (University of Wisconsin CIMSS)

Meanwhile, we have a healthy blast of Saharan dust, not atypical for June spreading across the Atlantic. That may very well be a player in any potential development next week. Stay tuned.

Shopping around for other weather experts

One question I am often asked is “Who else do you recommend I follow?” We obviously want folks to follow us, but I strongly encourage people to have multiple sources to use for weather information. Find a few that fit your consumption habits best and lean on them.

In general, it’s a tough question. There are so many voices in the field of meteorology, particularly on social media that deserve to be elevated, and I try to do this where possible and include some of their work here when it’s topical. But today I just want to shout out a few who provide daily or relatively frequent tropical updates through the season that I feel are worth your time to read or subscribe to.

You may remember Michael Lowry from his time on The Weather Channel, but he currently works as the hurricane and storm surge expert for WPLG in South Florida. He also publishes a daily tropical update on Substack that you should subscribe to. He and I see eye to eye (pun intended) on a lot of weather communication topics, and he’s one of the best in the field at cutting through the noise and focusing on impacts, a critical need today.

Dr. Jeff Masters developed a beloved hurricane blog and audience at Weather Underground through much of the 2000s. He and Bob Henson have found their way over to Yale Climate Connections “Eye on the Storm” blog. For most hardcore weather enthusiasts, you know exactly what you’ll get from those two. For those new to them, just take my advice and follow them both. Two of the best to ever do it.

Another source you should consider following: Weather Tiger, also known as Dr. Ryan Truchelut. He earned his stripes at Florida State University and has been writing about tropical weather for a number of years, frequently cited in USA Today. He has a free and paid option on Substack, and you’ll find his work engaging, enlightening, and entertaining.

I recommend these three sources specifically because they’re easily accessible, good character people, they do phenomenal work, and they all have a lengthy history of publishing high quality, trustworthy content on weather, climate, and specifically the tropics.

I want to also be clear that I have obviously left some sources out and also that not every excellent communicative meteorologist or tropical expert is a prolific writer. In a future post, I want to also highlight some social media follows and those with websites that have data, posts, or imagery that may be of interest as well from the same caliber individuals as above. Look for that soon.

Alberto ashore as attention shifts to the next Gulf system and the little one off Florida

Headlines

  • Alberto made landfall in Mexico this morning, with heavy rains continuing for some areas.
  • The system behind Alberto will likely track similarly but the northern extent of impacts will be much less this time around.
  • Invest 92L off Florida has about 24 hours to get together before coming ashore in Florida or Georgia.

Alberto makes landfall in Mexico

Tropical Storm Alberto came ashore this morning in Mexico near Tampico as it continues to deliver pockets of heavy rain, gusty winds, and tidal flooding.

Alberto is over Mexico now, dumping very heavy rain in parts of the country. (Tropical Tidbits)

The heaviest rain by far is in northeast Mexico, which has the potential to see up to another foot of rainfall. Serious flooding will be possible in spots, even if a lot of this rain is generally beneficial. It’s almost never all good news with these things.

Alberto’s rainfall is expected to continue in norther Mexico today, with up to a foot (300 mm) additional rain possible. (NOAA WPC)

Tides and winds will continue to slowly subside today on the Texas coast. Waves will probably stay up into tomorrow as broad east or east-southeast flow across the length of the Gulf helps to aid in that.

Rain totals have generally been manageable in Texas, with some flash flooding in spots. Almost seven and a half inches of rain fell between Corpus Christi and Refugio just near Copano Bay.

Multi-sensor rain total estimates show a widespread 2 to 6 inches on the Texas Coastal Bend, with the highest amounts on either side of Corpus Christi, particularly over Copano and Aransas Bays. (NOAA NSSL)

Most parts of South Texas received about 1 to 4 inches of rain from Alberto. In reality, it would have been nice to see more rain in this region, as reservoirs remain in bad shape due to long-term drought. Some additional rain will be possible over the next 24 hours or so before a break and then only a glancing blow from the next system. Perhaps we can eek out another inch or two in spots, which would help reservoirs a bit further.

Another inch or two of rain is possible in South Texas over the next week or so, but the bulk of the rain is likely to occur in Mexico with the next system. (Pivotal Weather)

Speaking of…

Alberto’s tagalong

We continue to watch the chances of an Alberto II type system move into the Bay of Campeche this weekend. The National Hurricane Center has given it an odds boost today, up to a 50 percent chance of development now. If sports betting were a thing in weather, you’d probably be placing money on a same month parlay in the Bay of Campeche. This system will probably emerge out of Central America tomorrow or Saturday and quickly track on Alberto’s heels into Mexico.

The forecast map early Sunday morning shows the system already approaching Mexico, while much drier air than was in place for Alberto sits over much of Texas and the northern Gulf. (Tropical Tidbits)

This system, while sitting with a 50 percent chance of development may have some more hurdles to overcome than Alberto did. The key one may be drier air than was in place this week with Alberto. By early Sunday morning, model guidance has this system moving toward or into Mexico, but it has a large area of dry air to the north, something that was not in place this week. High pressure in the upper atmosphere will sink south this weekend from the Mid-Atlantic into the Plains and Mid-South, which will put the squeeze on this disturbance and limit intensity and how far north it can come. For Texas, this system may be a non-issue, aside from some (welcome) rain as noted earlier. For Mexico, this will have the potential to again produce heavy rain and flooding concerns in the mountains. We’ll continue to watch.

Invest 92L off Florida

Our last stop today takes us off Florida, where Invest 92L has formed from the disturbance tracking westward toward the Bahamas. Odds of development are up to 40 percent with this one, and it will quickly come ashore in Florida or Georgia tomorrow. Could it become a tropical depression? It’s certainly possible. Whether or not it does, we’ll see.

A swirl off the coast of Florida indicates Invest 92L, which has about a 40 percent chance of becoming a depression over the next 24 hours or so. (College of DuPage)

Invest 92L is in a bit of a tough environment. While the exposed center is a neat looking feature on satellite, it indicates generally hostile surroundings for development. Still, it’s got a chance to put something together before landfall tomorrow. A little bit of extra rain or a breeze will be possible north of about Cape Canaveral from this one, into coastal Georgia. But land impacts should not go much farther than that. Anyone vacationing in Florida or Georgia should be mindful of very high rip current risks the next couple days though.

That’s all for today. I’m taking a few days off, but Eric will be around to jump in as needed through the weekend!