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.
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.
A satellite image of the Atlantic this morning shows nothing of concern to develop right now. But an area of thunderstorms (indicated by brighter colors in the satellite imagery) showing up over western Africa may be the next disturbance with some chance to develop by next week in the middle of the Atlantic (College of DuPage)
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.
Historical origin points of tropical systems in the final third of June through 2015. (NOAA)
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.
Since 2015, we’ve added Bret in 2017, Else in 2021, and Bonnie in 2022 to the only previously known Atlantic storm in June, Ana in 1979. (NOAA)
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.
The European model (and similarly, the GFS) show a signal for potential development just east of the Lesser Antilles by early to midweek next week. (Tropical Tidbits)
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.
It is likely that even if this system does begin to develop, at some point it will feel the impact of dry air nearby (not shown) and wind shear (shown here), which would limit development. (Tropical Tidbits)
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.
At The Eyewall, our focus will be extreme weather of all types. But initially, we will stick with what we know best, which is tropical weather. As the 2023 Atlantic Hurricane Season gets underway, it is obvious that residents along the coast of the Gulf of Mexico are on heightened alert. When Hurricane Harvey devastated the Coastal Bend of Texas and flooded Houston and the Golden Triangle in 2017, it marked the beginning of a trend that has become uncomfortably common in the years since: Gulf storms have been finding ways to rapidly intensify, often up to the moment of landfall, striking the coast at or near their absolute worst.
After Harvey, Hurricane Michael devastated parts of the Florida Panhandle in 2018 as only the fourth landfalling category 5 hurricane on record in the Mainland United States. Hurricane Laura came into southwest Louisiana as a high-end category 4 storm in 2020, strengthening up to landfall. Hurricane Sally later that year also managed to intensify up to landfall in Alabama. Hurricane Zeta hit the New Orleans area late in that season, rapidly intensifying up to landfall. In 2021, Hurricane Ida crashed into southeast Louisiana as a strong category 4 storm. And of course, last year Hurricane Ian hit southwest Florida just past its category 5 peak.
Hurricane Michael just after landfall near Mexico Beach, FL in 2018. (NOAA)
All of this raises the question: Why? Is this a new normal? Is climate change “loading the dice” for this to happen more frequently? Is it bad luck? Is the Gulf Coast facing an existential crisis of sorts? A pile of research has dropped in recent years that paints an uncomfortable but murky picture for the Gulf Coast.
Editor’s Note: For those of you that want to dive into this research, we go deep into things below, with links to research papers that have been published in recent years on this topic. We spoke to several researchers in the field who provided guidance and help while we dug into this. But here at The Eyewall, we also pride ourselves on being to the point. What’s the takeaway? What matters?
One-sentence summary
While the storms of the last few years in the Gulf fit some of what research says about climate change and future hurricanes, we cannot confidently say that this is the beginning of a new trend and it is more likely that these themes represent season to season variability.
Key messages
The Gulf of Mexico is undergoing a warming trend.
Research strongly points to storms getting stronger, faster (rapid intensification) globally.
Over the next 50 to 75 years, the research strongly suggests that the Gulf will become more hospitable to higher end, faster intensifying storms due to climate change, along the lines of what we’ve seen since 2017.
Variability across basins and within basins make it difficult to say with high confidence how climate change will actually affect those future storms in specific places.
Researchers have keyed in on a trend of slowing of storms at landfall, increasing the potential for heavy rain and freshwater flooding, in addition to higher storm surge driven by increasing sea levels and coastal land subsidence.
So to answer the questions: We cannot say with any confidence that this is a new normal, and for all we know it may just be a function of bad luck and seasonal variability. But the research implies that the future will feature more seasons like those recent ones for the Gulf of Mexico. While there is much focus on intensity and wind, there is growing confidence in the theory that storms are slowing more at landfall, which is leading to rainier outcomes with more flooding.
For more details on the specific research and what it says, read on.
More storms, getting stronger, faster
Scientific questions are usually complex and multi-faceted, and this is no different. For one, the Gulf has seen storms intensifying up to landfall, coming ashore at or near their peak intensities. Tangential to this, storms are intensifying more rapidly, more often in the Atlantic Basin, which includes the Gulf of Mexico.
In 2019, a group of authors led by Kieran Bhatia of Princeton and NOAA at the time, published an article in Nature Communications which took tropical systems from 1982 through 2009 and determined that there were significant increases in intensification rates in the Atlantic Basin that were unusual when compared to model estimates of internal climate variations. In other words, according to that study the data argues that storms were getting stronger faster in the Atlantic, beyond natural variability alone. Bhatia (now with Guy Carpenter) and his co-authors published another article in Nature Communications last November that suggests the likely culprit of these observed changes comes from “anthropogenic forcing,” or climate change.
“Furthermore, thermodynamic environments around tropical cyclones have become more favorable for intensification, and climate models show anthropogenic warming has significantly increased the probability of these changes,” write the authors. Their updated study looked at storms from 1982 through 2017, and it was determined that the Atlantic basin saw a very significant increase in the proportion of cases where a storm had conditions that could have supported rapid intensification.
The location of the average August-October 28.5°C/83.3°F isotherm (line of consistent temperature) has been migrating closer to the Gulf and Southeast coasts since the 1980s, indicating that Gulf water temperatures have been warming, thus becoming more hospitable for stronger tropical systems. (Courtesy of Dr. Kim Wood, Mississippi State University)
But what about the Gulf of Mexico specifically? In 2017, Kerry Emanuel of MIT published a timely paper in the Bulletin of the American Meteorological Society (BAMS) entitled “Will Global Warming Make Hurricane Forecasting More Difficult?” His work found that the most rapidly intensifying storms in the immediate 24 hours prior to landfall do so in the Gulf. When climate change is factored in, their research suggests that there will be a significant increase in rapidly intensifying storms at landfall in the Gulf of Mexico into the second half of the 21st century. In other words, what has occurred in recent years seems to align with Emanuel’s work, albeit a bit sooner than expected. While we are actually beginning to broadly see the increasing rate of intensification in tropical cyclones that would theoretically be expected (as in Bhatia’s 2019 paper), when asked if we’ve seen the start of this idea in the Gulf, Emanuel advises caution.
“Six years is way too short to be able to detect a trend with any statistical confidence, so I do not think we can say much about the recent spate of rapidly intensifying storms in the Gulf,” Emanuel told me via email.
Others think that within the Atlantic basin as a whole, there will be variability. Dr. Stephanie Zick, an assistant professor at Virginia Tech has even found variability within the Gulf of Mexico itself. “In my research, we’ve seen that storms that make landfall in the eastern Gulf tend to be organizing (becoming more central and compact), whereas storms that make landfall in the western Gulf (particularly with a westward trajectory) tend to be losing organization (becoming less central and compact),” Zick told me via email. As time goes on, she believes we should see both the warming of sea-surface temperatures (SSTs) and the impacts on hurricanes to be uneven around a basin and globally.
Such research can be frustrating, but that’s science. Predating Bhatia’s work, Thomas Knutson of NOAA found a general decrease in overall Atlantic tropical systems with co-authors in papers from 2013 and 2015. However that did come with an increase in stronger storms, meaning fewer storms overall but stronger ones. He was also co-author on a study published in Science in 2010 that showed the same general outcome. In 2020, Knutson was also lead author on a climate assessment in BAMS that looked at the research and had each author assign confidence levels to various statements related to tropical cyclones and climate change. The authors agreed most on the idea that sea level rise will lead to higher storm inundation levels (worsening storm surge). Most had confidence that the global average of intensity would also increase. Opinions were more mixed on the total number of storms. The research continues evolving.
Damage in Louisiana from Hurricane Laura in 2020. (Defense Visual Information Distribution Service)
We can find further complexities when looking elsewhere. In a 2022 letter in AGU’s Geophysical Research Letters Karthik Balaguru of the Pacific Northwest National Laboratory and co-authors determined that the intensification rates of hurricanes near the Atlantic coast from 1979 through 2018 had increased significantly. But the same was not true of storms in the Gulf. Their work found that the potential intensity of storms in the Gulf has increased, but it was somewhat offset by other meteorological variables in the environment. In other words: It’s complicated. It is notable that their study stops in 2018. It’s possible that a study taking us through 2022 might show a different outcome in the Gulf. But as noted above from Zick, there will likely be variability across the globe.
Separate to this, a research article published in the April 7, 2023 issue of Science Advances, also led by Balaguru concludes that the frequency of Gulf hurricanes is likely to increase in the second half of this century. On top of that, the same paper explains that storms approaching the populous Gulf Coast may be more likely to slow down on approach as steering currents change. The idea of storms slowing down at landfall is not necessarily new research. Similar ideas were found by James Kossin in 2018 and Gan Zhang and others in 2020. However, the potential for an increasing frequency of storms, in addition to slower forward speed at landfall would not be a great outcome for anyone. Notably, the experts tasked in Knutson’s 2020 work could not agree on this question. Again, this is evolving research, but it is striking how often replies to my questions about hurricane intensity included the fact that worsening storm surge and heavier rainfall due to slower moving storms was a big concern going forward.
Other complications
There are other avenues of research to pursue. Lew Gramer of NOAA and others published a letter in AGU’s Geophysical Research Letters in 2022, which finds that depending on how some storms approach the coast, they can produce a downwelling situation with nearshore shelf water. Downwelling sustains the warmer shelf waters, inhibits cooler, mixed water from taking over and inadvertently creates a better, longer lasting environment for strengthening, even in the face of other external hindrances, such as wind shear. They specifically looked at intensification cases from 2020 in the Gulf of Mexico, Sally and Hanna (as well as Eta in the Caribbean).
Downwelling can occur as warm surface water is pushed toward the coast and “forced” back down as it runs into land. Sinking water is more likely to warm, allowing for a deeper nearshore warm layer. (US Army)
This idea seems to fly in the face of what was known about the Gulf of Mexico. Back in 2010, Ed Rappaport and co-authors from inside and outside NOAA determined that, in general, strong Gulf hurricanes tended to weaken as they neared landfall, while weaker hurricanes tended to intensify on approach. In other words, most Gulf hurricanes would, on average, trend toward the mean of a Category 3 level storm. As awful as they were, storms like Rita and Katrina in 2005 fit that paradigm, as have storms like Opal in 1995 and Ike in 2008. That has seemingly not been the case in recent years. Research published in March 2023 in the Journal of Climate found that there has been a substantial increase in Gulf of Mexico oceanic heat content. The surface warming trend is about double what has been seen in the global ocean since the 1970s.
Tying it together
When one examines all this research together, it does seem to say that the Gulf Coast is becoming or will eventually become increasingly vulnerable to worse and worse outcomes from hurricanes, be they stronger, wetter, or with worse surge. But there are significant nuances and multiple threads of thought that need further research.
Dr. Kim Wood is an associate professor at Mississippi State and focuses on tropical meteorology. When asked what people along the Gulf Coast should be thinking as they digest all this research, she says that the long-term situation is certainly a concern for this region, but it’s not as if a switch is going to flip. “Trends identified by research don’t mean every hurricane season will be worse than the previous one,” she told me via email. For long-term sustainability, Wood thinks that there have been strides in the Southeast U.S. to adapt to future changes in storms, but more needs to be done.
“More efforts—ideally efforts coordinated across city and state lines—are needed to ensure our communities are resilient to tropical cyclone hazards,” she said. Wood also has concerns about the research that shows storms slowing down their forward speed at landfall. While wind and storm surge are serious issues with respect to hurricanes, severe freshwater flooding, as seen in big storms like Harvey and comparatively smaller storms like 2019’s Tropical Storm Imelda or the unnamed Louisiana flood event in 2016, is critically important to monitor. Zick also echoed this concern. “We have stronger confidence that hurricanes are producing more rainfall and that these rains are falling at faster rates,” she says, noting that while wind is important, it’s fairly localized, and it is all the other hazards that impact many more people. Water is the biggest problem. This idea has also been emphasized by the new director of the National Hurricane Center, Michael Brennan.
Flooding near Baton Rouge, LA in 2016 from an unnamed tropical low pressure. (USDA)
There is a lot here to digest. But for her part, Wood says that while thinking about these things can be scary, preparing now can make it a little less scary—and easier. “Having a plan and thus knowing what you might do ahead of a hazardous weather event saves mental bandwidth for decision-making should that event occur.”
What’s next? Obviously more research will continue to be produced about these topics, and it is research that will be important for both the meteorology community and government decision-makers to understand. From a forecast perspective, we are slowly chipping away at intensity forecasting errors. Zick tells me that “hurricane forecasting models are getting better at predicting rapid intensification, and hurricane forecasters are able to forecast RI much more confidently in the last 5 years or so.”
Additionally, the fifth National Climate Assessment will be unveiled later this year, and for the Southeast, this is expected to discuss various weather and climate hazards and the compounding factors of population growth and land use change. If the research outlined above is any indicator, there will be a lot to discuss and plan for going forward on the Gulf Coast.
A special thanks to Dr. Kim Wood of Mississippi State, Dr. Stephanie Zick of Virginia Tech, Dr. Andy Hazelton of NOAA’s Hurricane Research Division, Dr. Kerry Emanuel of MIT, and Dr. Kieran Bhatia of Guy Carpenter for answering my questions and confirming my understanding of the research that exists.
As promised, let’s take a look at the dust situation in the Atlantic today.
Michael Lowry, in his excellent tropical weather blog last week noted that dust has been running very, very low so far this season in the key main development region (MDR) of the Atlantic basin. Indeed that’s the case. While low dust does not mean no dust, as seen on the Saharan air layer color-infused satellite image from the University of Wisconsin below, it certainly has been a bit lackluster thus far.
Dust is out there, but it’s been extremely weak so far this season. The signature in the Gulf is just dry air, not dust. (University of Wisconsin SSEC)
Note the presence of extremely dry air in the Gulf of Mexico. That isn’t dust; it’s just that dry as high pressure begins flexing over Texas.
Dry air extends from the Gulf into the Caribbean and well out into the Atlantic as well, which will assist in keeping things quiet in the near-term. (Tropical Tidbits)
Brown on the image above implies dry air, while green implies moist air. More brown than green in key areas we care about means that dust or not, the atmosphere is not terribly conducive for development.
Over the next 7 to 10 days, we will likely see pockets of dust begin to migrate further across the basin, tinging the skies in the Lesser Antilles, Puerto Rico, and Hispaniola with dust by later this week and again next week.
Some of the brighter colors on the loop from the NASA GEOS model above imply that dust will begin coming across the Atlantic in light to moderate bursts over the next 10 days, with perhaps noticeable dust in the Caribbean at times later this week and next week. (Weather Bell)
This also keeps much of the Atlantic basin quiet, as it should be this time of year. We’ll keep up on dust as it peaks in the coming weeks before declining in concert with the ramp up in hurricane season historically.
One sentence summary
Conditions continue to look relatively benign across the Atlantic, but a couple items pique our interest in the medium and longer range.
Happening now
All remains quiet this morning with no areas highlighted in either the Atlantic or Pacific basins by the National Hurricane Center over the next couple days.
The medium range (days 6-10): Mostly fine but not quiet
No real concerns are seen out through the weekend and into early next week. But there are a couple things to watch. First, the NHC did add an area to watch in the Pacific over the next 7 days, the first sign of change since the very beginning of the month.
The NHC has assigned a 20 percent chance for development to a portion of the Eastern Pacific, the first sign of meaningful change in the tropics since the beginning of June. (NOAA)
Meanwhile, in the Atlantic, there are some subtle model hints that low pressure may try to slowly develop just south of the main area of dust and dry air in the Atlantic just east of the Windward Islands. The map below shows the individual ensemble members of the European model on day 8 (next Tuesday), and about 20 percent of the 51 members show development, a minority to be sure but interesting nonetheless.
About 20 percent of the European ensemble members (and GFS ones too) show low-end development in the Atlantic early next week. (Weathernerds.org)
Remember, one off model runs like the GFS operational we’ve been discussing in fantasyland since last week are called deterministic models. Ensembles are when we tweak the initialization of each model run a bit and run it 30 to 50 different times. This creates wider goal posts, which is what we want as meteorologists. We need to see a realistic buffet of options when forecasting 5 to 10 days out, not a singular deterministic outcome.
We have seen a barrage of waves in the Atlantic so far this season, and although nothing has organized, they may be trying to prime the pump a bit for something. I don’t believe any system that forms next week would become a serious issue, but I would not be floored to see something out there. We’ll look closer at that tomorrow and Thursday.
Fantasyland (beyond day 10): A little noisy
We continue to see plenty of signs of some noise in the Caribbean or southwest Gulf in the fantasyland timeframe. But we also continue to see no reason to believe anything organized will come of it at this point. The GFS continues to periodically try to develop spurious storms, but we will continue to ignore it completely.
