Tropical Discussion 2025
Looks like the Euro is starting to try to sniff out some organization near the tip of the Yucatán in a similar timeframe as the GFS still seems to be doubling down on its model-cane.
It is the start of the season. It is heating up.
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Stratton20
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looks like we get a stalled frontal boundary setting up over se texas next week, that could actually help to draw up moisture fron the EPAC into the western gulf, combine that with moisture from the caribbean and man it could be a very wet week next week, and cant rule out some development in the southern gulf as the EPS has kinda been hinting at that in the 10-11 day range
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tireman4
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The Eyewall
A quiet Atlantic persists but for how long? And more about the GFS scareicanes!
By Matt Lanza on June 5, 2025
In brief: Today we explain why the Pacific should be more active than the Atlantic through the next 7 to 10 days and when that could theoretically change. We also talk more about the GFS model's phantom storm bias.
We'll keep this fairly brief today. The Atlantic is quiet, so I don't want to go fishing for speculative information. Plenty of other sites do that. That said, we know people want to know how long the generally calm conditions will persist.
Pacific or Atlantic?
The atmosphere over the eastern Pacific and western Atlantic right now appears to be entering a phase that is indeed favorable for tropical development. If we look at what is called a "Hovmöller" plot, we can identify areas in the tropics that are favorable or unfavorable in terms of where rising air is located.
A Hovmöller diagram can indicate where rising air in the tropics is located. Currently and for the next 10 days, it will be over Central America or on either side. (ECMWF)
So over the next 10 days, we have an area of rising air, indicated by the blue/green colors above. This is actually showing what we call "divergence" in the upper atmosphere, which typically correlates to "convergence" in the lower atmosphere. For air to rise, you want converging winds. For tropical systems you want rising air. So that's firmly in place near Central America for the next 10 days.
Here's where the models have actually been somewhat useful. Recall, the GFS model has been going bonkers with a Gulf system almost every day this month and several days last month. But also notice how it's never advancing in time. It's always been on like days 10-15. More on that in a second. But if you look under the hood on the GFS and European models, you have also seen a decent signal for Pacific tropical activity.
Odds of tropical development in the Eastern Pacific are quite high over the next few days. (NOAA NHC)
When we look at European model guidance, we can clearly see this Eastern Pacific area that will move out into the Pacific. But we can also see perhaps 1 or 2 other areas by day 10 that may develop close to the Central American or Mexican coast.
The European ensemble shows a busy eastern Pacific but a mostly quiet Caribbean and Gulf. (Weathernerds.org)
Now, the focus is clearly on the Pacific here, but there are elements of interest on this model very close to the east coast of Mexico in the Bay of Campeche. In theory we could see something like that later next week, but the proximity to land would likely hinder its organization significantly.
So I think over the next 10 days, while that area of rising air is in place over Central America, the odds will heavily favor Pacific systems over Atlantic ones, though the odds of a Gulf or Caribbean system may begin to increase after the 12th or so. That said, there's no reliable model guidance showing anything of real concern in the Atlantic over the next 10 to 12 days.
The GFS phantom menace
I'm not going to belabor the point about the GFS model, but no matter how often we say it, it still seems people get spooked by this model still showing storms in the Gulf. Again, that is virtually always incorrect. And by virtually always, I cannot recall a major June storm in the Gulf in the last 10 years but I can recall dozens of instances of GFS refrigerator material every single year. In fact, as some others have shown recently, this signal of phantom storms actually stands out in verification metrics.
All my X's live in the Caribbean. (Florida State University)
On the image above, each X indicates a time where the GFS showed something developing last year and it never formed. The majority of the X's on that map are in the Caribbean (and likely in the early and late season), exactly where the GFS has been showing all the hubbub so far this season. The real tell though is when the storm is perpetually stuck in the day 10 to 15 day purgatory and never advances forward in time. It's a dead giveaway that this model is up to its old tricks again.
Some people may say the GFS model is useless then, but reality is more nuanced, of course. The model has made improvements in skill over the years, including handling some tropical systems after they've formed. But as a forecaster, it's important to recognize the model bias when you see it, and that's certainly what we're seeing right now.
A quiet Atlantic persists but for how long? And more about the GFS scareicanes!
By Matt Lanza on June 5, 2025
In brief: Today we explain why the Pacific should be more active than the Atlantic through the next 7 to 10 days and when that could theoretically change. We also talk more about the GFS model's phantom storm bias.
We'll keep this fairly brief today. The Atlantic is quiet, so I don't want to go fishing for speculative information. Plenty of other sites do that. That said, we know people want to know how long the generally calm conditions will persist.
Pacific or Atlantic?
The atmosphere over the eastern Pacific and western Atlantic right now appears to be entering a phase that is indeed favorable for tropical development. If we look at what is called a "Hovmöller" plot, we can identify areas in the tropics that are favorable or unfavorable in terms of where rising air is located.
A Hovmöller diagram can indicate where rising air in the tropics is located. Currently and for the next 10 days, it will be over Central America or on either side. (ECMWF)
So over the next 10 days, we have an area of rising air, indicated by the blue/green colors above. This is actually showing what we call "divergence" in the upper atmosphere, which typically correlates to "convergence" in the lower atmosphere. For air to rise, you want converging winds. For tropical systems you want rising air. So that's firmly in place near Central America for the next 10 days.
Here's where the models have actually been somewhat useful. Recall, the GFS model has been going bonkers with a Gulf system almost every day this month and several days last month. But also notice how it's never advancing in time. It's always been on like days 10-15. More on that in a second. But if you look under the hood on the GFS and European models, you have also seen a decent signal for Pacific tropical activity.
Odds of tropical development in the Eastern Pacific are quite high over the next few days. (NOAA NHC)
When we look at European model guidance, we can clearly see this Eastern Pacific area that will move out into the Pacific. But we can also see perhaps 1 or 2 other areas by day 10 that may develop close to the Central American or Mexican coast.
The European ensemble shows a busy eastern Pacific but a mostly quiet Caribbean and Gulf. (Weathernerds.org)
Now, the focus is clearly on the Pacific here, but there are elements of interest on this model very close to the east coast of Mexico in the Bay of Campeche. In theory we could see something like that later next week, but the proximity to land would likely hinder its organization significantly.
So I think over the next 10 days, while that area of rising air is in place over Central America, the odds will heavily favor Pacific systems over Atlantic ones, though the odds of a Gulf or Caribbean system may begin to increase after the 12th or so. That said, there's no reliable model guidance showing anything of real concern in the Atlantic over the next 10 to 12 days.
The GFS phantom menace
I'm not going to belabor the point about the GFS model, but no matter how often we say it, it still seems people get spooked by this model still showing storms in the Gulf. Again, that is virtually always incorrect. And by virtually always, I cannot recall a major June storm in the Gulf in the last 10 years but I can recall dozens of instances of GFS refrigerator material every single year. In fact, as some others have shown recently, this signal of phantom storms actually stands out in verification metrics.
All my X's live in the Caribbean. (Florida State University)
On the image above, each X indicates a time where the GFS showed something developing last year and it never formed. The majority of the X's on that map are in the Caribbean (and likely in the early and late season), exactly where the GFS has been showing all the hubbub so far this season. The real tell though is when the storm is perpetually stuck in the day 10 to 15 day purgatory and never advances forward in time. It's a dead giveaway that this model is up to its old tricks again.
Some people may say the GFS model is useless then, but reality is more nuanced, of course. The model has made improvements in skill over the years, including handling some tropical systems after they've formed. But as a forecaster, it's important to recognize the model bias when you see it, and that's certainly what we're seeing right now.
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Yep, too much wind shear.Ptarmigan wrote: ↑Mon Jun 09, 2025 8:57 pmEarly storms in June are generally weak.
The June 1899 Tropical Storm dumped heavy rain over a large area. Up to 33 inches of rain fell, including 24 inches in 24 hours at Hearne. It is likely higher rainfall amounts fell, possibly 50 inches and higher. I would not be surprised if some areas in the 1899 event got up to 4 feet of rain in 24 hours. Keep in mind, there were less people living Texas and less weather stations and rain gauge. It is likely on par with Harvey.
https://www.tshaonline.org/handbook/ent ... od-of-1899
https://www.climate.gov/news-features/e ... d-flooding
https://journals.ametsoc.org/view/journ ... 0_co_2.pdf
https://wateringholdclubhouse.blogspot. ... flood.html
https://climatexas.tamu.edu/products/se ... ather.html
https://pubs.usgs.gov/of/1966/0119/report.pdf
That’s very interesting! I bet it came from a CAG. Those can carry a tremendous amount of precipitation with them.Ptarmigan wrote: ↑Mon Jun 09, 2025 9:36 pmThe June 1899 Tropical Storm dumped heavy rain over a large area. Up to 33 inches of rain fell, including 24 inches in 24 hours at Hearne. It is likely higher rainfall amounts fell, possibly 50 inches and higher. I would not be surprised if some areas in the 1899 event got up to 4 feet of rain in 24 hours. Keep in mind, there were less people living Texas and less weather stations and rain gauge. It is likely on par with Harvey.
https://www.tshaonline.org/handbook/ent ... od-of-1899
https://www.climate.gov/news-features/e ... d-flooding
https://journals.ametsoc.org/view/journ ... 0_co_2.pdf
https://wateringholdclubhouse.blogspot. ... flood.html
https://climatexas.tamu.edu/products/se ... ather.html
https://pubs.usgs.gov/of/1966/0119/report.pdf
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Stratton20
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CMC/ GFS on bord with some mischief in the BOC in 9/10 days, though gets buried in mexico, not that it mattera in that range anyways
The 1899 Tropical Storm was a huge flood event and was deadly. If it happened today, it would be like Harvey. I would not be surprised the 1899 Tropical Storm was from a Central American Gyre (CAG). Helene was from a CAG and devastated North Carolina.Cpv17 wrote: ↑Mon Jun 09, 2025 9:53 pmThat’s very interesting! I bet it came from a CAG. Those can carry a tremendous amount of precipitation with them.Ptarmigan wrote: ↑Mon Jun 09, 2025 9:36 pmThe June 1899 Tropical Storm dumped heavy rain over a large area. Up to 33 inches of rain fell, including 24 inches in 24 hours at Hearne. It is likely higher rainfall amounts fell, possibly 50 inches and higher. I would not be surprised if some areas in the 1899 event got up to 4 feet of rain in 24 hours. Keep in mind, there were less people living Texas and less weather stations and rain gauge. It is likely on par with Harvey.
https://www.tshaonline.org/handbook/ent ... od-of-1899
https://www.climate.gov/news-features/e ... d-flooding
https://journals.ametsoc.org/view/journ ... 0_co_2.pdf
https://wateringholdclubhouse.blogspot. ... flood.html
https://climatexas.tamu.edu/products/se ... ather.html
https://pubs.usgs.gov/of/1966/0119/report.pdf
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tireman4
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The Eyewall
Status quo continues as Atlantic activity remains unlikely for a bit
By Matt Lanza on June 11, 2025
In brief: The Atlantic remains quiet, so today we look at recent pre-July activity and assess the odds of a weak disturbance forming next week in the southwest Gulf.
Quick note: Colorado State updated their seasonal hurricane outlook with no changes in expectations today. You can see the full update here.
Would anyone care to hazard a guess as to the last time we got to the end of June with no tropical storms having formed in the Atlantic? Anyone? No? Okay.
2014.
Suffice to say, the May-June storm story has been one of busy-ness the last several years, indeed the last decade. At least in terms of named storms happening.
All pre-July storms since 2014, with Hurricane Beryl sticking out like a sore thumb across the Caribbean. (NOAA)
Other than Beryl last year, most Atlantic systems this time of year are weaker. Beryl was an exceptional case that tapped into a favorable atmosphere and rocket fuel waters. In general, most of these early season outcomes are sloppier, more rain and flooding than wind and surge, and mostly infrequent. Some of the cases in recent years were borderline storms at best. Some may have been missed in the pre-satellite era. So, despite the increases in activity in recent years, it may just be that we're seeing more of the real risk than we had previously presumed.
Whatever the case, we've got about 19 days left in the month. We have weather model data that covers about 14 to 15 of those, and no reliable modeling is showing any serious threat at this time. Maybe this will be the year that breaks the 11-year streak.
One area to watch next week, I guess
There is one very, very low probability candidate for development, and that remains next week in the western half of the Bay of Campeche. The window for anything to develop looks narrow; the proximity to land is a problem. But we do see at least some hints of a disturbance there.
A disturbance pinwheeling around some Pacific activity may find itself in the SW Gulf trying to develop. But it will probably run out of time and come ashore before it's able to do so. (Tropical Tidbits)
The Pacific remains busy with another storm or two possible there over the next week. Around midweek next week, there have been fairly consistent hints in model guidance that a disturbance would sort of pinwheel out of the southwest Caribbean into the southwest Gulf of Mexico or Bay of Campeche and come ashore in Mexico around next Wednesday or Thursday. Realistically, this is almost certainly going to run out of time over water before it has a chance to develop, but the odds are slightly greater than zero.
High pressure expanding from Florida across the Gulf will probably help direct any disturbances in the southwest Gulf quickly ashore into Mexico. (Tropical Tidbits)
It does appear that high pressure building west across the Gulf (seen in the expanding reddish colors above) will push this disturbance quickly inland in Mexico and probably keep the moisture out of Texas as well.
In summary: There's almost certainly nothing to worry about here.
And aside from that, the Atlantic is quieter than the bats of the Colorado Rockies.
Status quo continues as Atlantic activity remains unlikely for a bit
By Matt Lanza on June 11, 2025
In brief: The Atlantic remains quiet, so today we look at recent pre-July activity and assess the odds of a weak disturbance forming next week in the southwest Gulf.
Quick note: Colorado State updated their seasonal hurricane outlook with no changes in expectations today. You can see the full update here.
Would anyone care to hazard a guess as to the last time we got to the end of June with no tropical storms having formed in the Atlantic? Anyone? No? Okay.
2014.
Suffice to say, the May-June storm story has been one of busy-ness the last several years, indeed the last decade. At least in terms of named storms happening.
All pre-July storms since 2014, with Hurricane Beryl sticking out like a sore thumb across the Caribbean. (NOAA)
Other than Beryl last year, most Atlantic systems this time of year are weaker. Beryl was an exceptional case that tapped into a favorable atmosphere and rocket fuel waters. In general, most of these early season outcomes are sloppier, more rain and flooding than wind and surge, and mostly infrequent. Some of the cases in recent years were borderline storms at best. Some may have been missed in the pre-satellite era. So, despite the increases in activity in recent years, it may just be that we're seeing more of the real risk than we had previously presumed.
Whatever the case, we've got about 19 days left in the month. We have weather model data that covers about 14 to 15 of those, and no reliable modeling is showing any serious threat at this time. Maybe this will be the year that breaks the 11-year streak.
One area to watch next week, I guess
There is one very, very low probability candidate for development, and that remains next week in the western half of the Bay of Campeche. The window for anything to develop looks narrow; the proximity to land is a problem. But we do see at least some hints of a disturbance there.
A disturbance pinwheeling around some Pacific activity may find itself in the SW Gulf trying to develop. But it will probably run out of time and come ashore before it's able to do so. (Tropical Tidbits)
The Pacific remains busy with another storm or two possible there over the next week. Around midweek next week, there have been fairly consistent hints in model guidance that a disturbance would sort of pinwheel out of the southwest Caribbean into the southwest Gulf of Mexico or Bay of Campeche and come ashore in Mexico around next Wednesday or Thursday. Realistically, this is almost certainly going to run out of time over water before it has a chance to develop, but the odds are slightly greater than zero.
High pressure expanding from Florida across the Gulf will probably help direct any disturbances in the southwest Gulf quickly ashore into Mexico. (Tropical Tidbits)
It does appear that high pressure building west across the Gulf (seen in the expanding reddish colors above) will push this disturbance quickly inland in Mexico and probably keep the moisture out of Texas as well.
In summary: There's almost certainly nothing to worry about here.
And aside from that, the Atlantic is quieter than the bats of the Colorado Rockies.
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Stratton20
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Id still say we should keep an eye on that potential disturbance in the BOC, GFS has a weakness in the ridge allowing something to move into south texas and kind of just meander around inland , Euro has a weak cut off low that could erode the ridge over the gulf, definitely not set in stone that whatever may try to form just gets shoved into mexico, worth watching how this evolves
If the EPAC keeps burning through developing systems, it will likely signify a much quieter Atlantic season. It is well-documented the calming effect an active EPAC has on our end of the Basin.
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Stratton20
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Keep in mind though, quieter doesnt also necessarily a good thing, some of the most damaging hurricanes on record have occured in less active seasons in the atlantic, ill also point out that the gulf is well on its way to having record breaking upper ocean heat content energy, so thats something to really watch ahould a wave find its way into the gulf later in the season
So very true.Stratton20 wrote: ↑Wed Jun 11, 2025 3:33 pm Keep in mind though, quieter doesnt also necessarily a good thing, some of the most damaging hurricanes on record have occured in less active seasons in the atlantic, ill also point out that the gulf is well on its way to having record breaking upper ocean heat content energy, so thats something to really watch ahould a wave find its way into the gulf later in the season
Yes. That’s the only way we’d die by that proverbial sword….is if any coalesced portion creeps out into the BOCStratton20 wrote: ↑Wed Jun 11, 2025 3:33 pm Keep in mind though, quieter doesnt also necessarily a good thing, some of the most damaging hurricanes on record have occured in less active seasons in the atlantic, ill also point out that the gulf is well on its way to having record breaking upper ocean heat content energy, so thats something to really watch ahould a wave find its way into the gulf later in the season
We would probably be screwed in TX if that happens