Tropical Wave over the far Eastern Atlantic (10/60)

[StormWeather]

This is more reminiscent of Irma than Erin ever was. Don’t get me wrong, this may not even form at all, or if it does form its track could be significantly more different than when the models are showing.

This has come off of Africa further south than Erin (could definitely work in its favor)

What’s the high pressure situation?

I’m also going to throw the disclaimer out there that I’m not suggesting every single system is like Irma. I never intend for it to sound like that.

I’m just looking at the model runs here and now vs what was going on when the models were working out what would become Irma.

Ive been trying to look at similarities in the pattern recently that could compare to the pattern that lead to Irma.

I understand. Will be interesting to watch how the pattern evolves over the coming days

Indeed. Definitely seemed like a nothing burger at first. Let’s just see what happens down the road and go from there.

[Kazmit]

Vastly different model solutions today. Of course the GFS is bearish now that the ICON is on board.

[StormWeather]

Vastly different model solutions today. Of course the GFS is bearish now that the ICON is on board.

Typical model wars.

“Begun, the model wars have.”

[TomballEd]

GFS almost killing it, turning it N, then strengthening it as it recurves well E of Bermuda, semi-Fernand-ish except this does become a sub 980 hurricane in the sub-tropics.

[cycloneye]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 PM EDT Mon Sep 1 2025

For the North Atlantic...Caribbean Sea and the Gulf of America:

Eastern Tropical Atlantic:
A tropical wave located over the far eastern tropical Atlantic
south-southeast of the Cabo Verde islands is producing disorganized
showers and thunderstorms. Environmental conditions appear
conducive for gradual development of this system, and a tropical
depression could form by the middle or later part of this week.
This system is expected to move westward to west-northwestward at
around 15 mph across the eastern and central tropical Atlantic
throughout the week.
* Formation chance through 48 hours...low...10 percent.
* Formation chance through 7 days...medium...50 percent.

$$
Forecaster Beven

[Woofde]

Vastly different model solutions today. Of course the GFS is bearish now that the ICON is on board.

It's more inline with it's ensemble package now, 6z was an outlier. That said I don't buy the overly quick development and subsequent jump north near CV, the GFS has a bias for that. Gradual development as it moves west as the ICON depicts seems more plausible.

[wzrgirl1]

That development cone has more of a bend to the left or west than it did before usually in the five day timeframe you could start seeing the development cone with the West Northwest curve to it. I don’t see it at least yet anyway. I wonder if this means it will be more of a slow development system.

[cycloneye]

What a few weeks, lower model support and a persistent recurve pattern will do. At this point in Erin's pre-Invest AOI thread, it was pushing 10 pages.
But then again, the models were VERY bullish on that one.

It's simple. Models are consistent about a non threat to CONUS and the activity in the site and thread goes down.

[MEANINGLESS_NUMBERS]

What a few weeks, lower model support and a persistent recurve pattern will do. At this point in Erin's pre-Invest AOI thread, it was pushing 10 pages.
But then again, the models were VERY bullish on that one.

It's simple. Models are consistent about a non threat to CONUS and the activity in the site and thread goes down.

We are all guilty of caring about where we live. I know every Bermuda storm draws me in. The Gulf of Mexico storms are less interesting to me.

[Stratton23]

12z EPS says slow you’re horses on a clean recurve out to sea

[cycloneye]

What a few weeks, lower model support and a persistent recurve pattern will do. At this point in Erin's pre-Invest AOI thread, it was pushing 10 pages.
But then again, the models were VERY bullish on that one.

It's simple. Models are consistent about a non threat to CONUS and the activity in the site and thread goes down.

I include also a threat to the Lesser Antlles / Northern Leewards, BVI/ USVI, Puerto Rico and Dominican Republic and Haiti that cause a spike on posts as we have many members that live in the islands myself included.

[LarryWx]

Fwiw, here are 12Z op. models not yet mentioned:
-Euro: H recurves 250 miles SE of Bermuda

-CMC easily strongest run yet with 992 mb at ~17N, 47W moving WNW but then weakening back to 1005 mb and likely about to recurve E of Bermuda per H5/climo

-UKMET like last few runs no TC but still has organized LLC moving WNW to 22N,60W at 192; per H5 and climo, this is likely about to recurve probably meaning a miss of the US but even if so, could threaten Bermuda had this run gone out further

-JMA not as threatening as yesterday’s run when it had a TD moving WSW at 14N, 45W at 192; today’s is further N and moving WNW at ~17N, 45W at 192 as a TD; per H5 and climo likely not US threat from there with Bermuda needing to watch it more

[emeraldislenc]

I really don't understand why people are saying that based on climo, it's not a US threat. I think in the past we have had Cape Verde storms in Sept that have been a US threat and even hit the US. Am I missing something or has climo
changed? Or what do people mean by climo? Just trying to understand not being rude but want to learn.

[crownweather]

I really don't understand why people are saying that based on climo, it's not a US threat. I think in the past we have had Cape Verde storms in Sept that have been a US threat and even hit the US. Am I missing something or has climo changed? Or what do people mean by climo? Just trying to understand not being rude but want to learn.

Yep, I can think of a few Cape Verde hurricanes in September that were CONUS landfalls.

1938 New England and Long Island hurricane.
Hurricane Gloria of 1985 also impacted New England.
Hurricane Hugo of 1989 impacted the Virgin Islands, PR and South Carolina.


Sent from my iPhone using Tapatalk

[Category5Kaiju]

I really don't understand why people are saying that based on climo, it's not a US threat. I think in the past we have had Cape Verde storms in Sept that have been a US threat and even hit the US. Am I missing something or has climo changed? Or what do people mean by climo? Just trying to understand not being rude but want to learn.

Generally speaking, Cape Verde hurricanes, or at least those that turn into a depression/storm anywhere within 500 miles of the Cape Verde islands, have a hard time making it all the way across the Atlantic to hit land, particularly the CONUS. Climo dictates that at some point while traveling west, a given Cape Verde hurricane would have a high chance of getting picked up by a trough and flung out to sea. For every one historic Cape Verde hurricane that impacts land, I can give you 5 others that didn't. Big storms that impact the CONUS typically form closer to North America/the Caribbean as opposed to next to Africa.

Storms like Georges, Hugo, Ivan, Irma, and Florence are, in the grand scheme of things, very rare and not the norm. However....just because they're rare doesn't mean they can't happen, and every once in a while we do get a big Cape Verde system that impacts the CONUS. When will something like this happen again? It remains to be seen, although there is one thing that many of these impactful Cape Verde hurricanes share in common: they happen during the month of September.

[LarryWx]

I really don't understand why people are saying that based on climo, it's not a US threat. I think in the past we have had Cape Verde storms in Sept that have been a US threat and even hit the US. Am I missing something or has climo changed? Or what do people mean by climo? Just trying to understand not being rude but want to learn.

I assume you’re referring to my post just above yours. I’ll explain.

I said: -CMC….at ~17N, 47W moving WNW….and likely about to recurve E of Bermuda per H5/climo

-UKMET….moving WNW to 22N,60W at 192; per H5 and climo, this is likely about to recurve probably meaning a miss of the US

-JMA….today’s is further N and moving WNW at ~17N, 45W at 192 as a TD; per H5 and climo likely not US threat from there

Climo, which is based on the history of numerous actual tracks over last 150+ years, doesn’t mean certainty. Rather, it’s a tool that if used correctly gives one an idea of the most likely outcomes.

I was mainly looking at the lat/long, direction of movement, and the H5 progression at the end of the 3 12Z runs above. Based on that info alone, I feel that a safe recurve from the Conus is the most likely scenario for each run had it gone out further. In addition when I look at climo, it gives its own support for that likelihood.

Notice I said likelihood, not certainty. But regardless, keep in mind that a large majority of TCs at 22N, 60W moving WNW (~80% have missed CONUS per a chart* I just saw) as well as TCs moving WNW near 17N, 46W (~85% have missed CONUS per that chart*) have missed the Conus.

* Link to that climo based chart: I strongly encourage folks to look at and use this as a tool to help forecast the most likely outcomes. Note that only storms closer to the US than that white line have a 50%+ chance of hitting:
http://moe.met.fsu.edu/tcprob/usa.png

[IcyTundra]

I really don't understand why people are saying that based on climo, it's not a US threat. I think in the past we have had Cape Verde storms in Sept that have been a US threat and even hit the US. Am I missing something or has climo changed? Or what do people mean by climo? Just trying to understand not being rude but want to learn.

Climo is that most CV hurricanes will turn north OTS before reaching the CONUS but that is true for all months and is not just a September phenomenon. It is true though that the later it is in September the lower the odds of a CV hurricane making it all the way west to the CONUS.

Here are some September CV hurricanes that have impacted the CONUS, the dates each system formed, and what part of the CONUS was impacted.

9/25/1893 Great Charleston Hurricane (South Carolina)
9/6/1928 Lake Okeechobee Hurricane (South Florida)
9/9/1938 New England Hurricane (Long Island and New England)
9/4/1947 Fort Lauderdale Hurricane (South Florida)
9/10/1955 Hurricane Ione (North Carolina)
9/21/1966 Hurricane Inez (Florida Keys)
9/16/1985 Hurricane Gloria (Outer Banks, Long Island, and New England)
9/10/1989 Hurricane Hugo (South Carolina)
9/15/1998 Hurricane Georges (Eastern Gulf)
9/7/1999 Hurricane Floyd (North Carolina)
9/6/2003 Hurricane Isabel (North Carolina and Virginia)
9/2/2004 Hurricane Ivan (Eastern Gulf)
9/1/2008 Hurricane Ike (Upper Texas Coast)

[AJC3]

I really don't understand why people are saying that based on climo, it's not a US threat. I think in the past we have had Cape Verde storms in Sept that have been a US threat and even hit the US. Am I missing something or has climo changed? Or what do people mean by climo? Just trying to understand not being rude but want to learn.

I assume you’re referring to my post just above yours. I’ll explain.

I said: -CMC….at ~17N, 47W moving WNW….and likely about to recurve E of Bermuda per H5/climo

-UKMET….moving WNW to 22N,60W at 192; per H5 and climo, this is likely about to recurve probably meaning a miss of the US

-JMA….today’s is further N and moving WNW at ~17N, 45W at 192 as a TD; per H5 and climo likely not US threat from there

Climo, which is based on the history of numerous actual tracks over last 150+ years, doesn’t mean certainty. Rather, it’s a tool that if used correctly gives one an idea of the most likely outcomes.

I was mainly looking at the lat/long, direction of movement, and the H5 progression at the end of the 3 12Z runs above. Based on that info alone, I feel that a safe recurve from the Conus is the most likely scenario for each run had it gone out further. In addition when I look at climo, it gives its own support for that likelihood.

Notice I said likelihood, not certainty. But regardless, keep in mind that a large majority of TCs at 22N, 60W moving WNW (~80% have missed CONUS per a chart* I just saw) as well as TCs moving WNW near 17N, 46W (~85% have missed CONUS per that chart*) have missed the Conus.

* Link to that climo based chart: I strongly encourage folks to look at and use this as a tool for forecasting the most likely outcomes. Note that only storms closer to the US than that white line have a 50%+ chance of hitting:
http://moe.met.fsu.edu/tcprob/usa.png

From a CONUS standpoint, it's incredibly fortuitous that the higher probabilities for a FL through east coast landfall coincide with passage over the most mountainous terrain of the GA (Hispaniola, eastern Cuba). I suspect passage over Jamaica may be more associated with FL west coast/Gulf landfalls.

[LarryWx]

I really don't understand why people are saying that based on climo, it's not a US threat. I think in the past we have had Cape Verde storms in Sept that have been a US threat and even hit the US. Am I missing something or has climo changed? Or what do people mean by climo? Just trying to understand not being rude but want to learn.

I assume you’re referring to my post just above yours. I’ll explain.

I said: -CMC….at ~17N, 47W moving WNW….and likely about to recurve E of Bermuda per H5/climo

-UKMET….moving WNW to 22N,60W at 192; per H5 and climo, this is likely about to recurve probably meaning a miss of the US

-JMA….today’s is further N and moving WNW at ~17N, 45W at 192 as a TD; per H5 and climo likely not US threat from there

Climo, which is based on the history of numerous actual tracks over last 150+ years, doesn’t mean certainty. Rather, it’s a tool that if used correctly gives one an idea of the most likely outcomes.

I was mainly looking at the lat/long, direction of movement, and the H5 progression at the end of the 3 12Z runs above. Based on that info alone, I feel that a safe recurve from the Conus is the most likely scenario for each run had it gone out further. In addition when I look at climo, it gives its own support for that likelihood.

Notice I said likelihood, not certainty. But regardless, keep in mind that a large majority of TCs at 22N, 60W moving WNW (~80% have missed CONUS per a chart* I just saw) as well as TCs moving WNW near 17N, 46W (~85% have missed CONUS per that chart*) have missed the Conus.

* Link to that climo based chart: I strongly encourage folks to look at and use this as a tool for forecasting the most likely outcomes. Note that only storms closer to the US than that white line have a 50%+ chance of hitting:
http://moe.met.fsu.edu/tcprob/usa.png

From a CONUS standpoint, it's incredibly fortuitous that the higher probabilities for a FL through east coast landfall coincide with passage over the most mountainous terrain of the GA (Hispaniola, eastern Cuba). I suspect passage over Jamaica may be more associated with FL west coast/Gulf landfalls.

Indeed! If not, I bet there wouldn’t be nearly as many people living on the E coast.

Also, I find it interesting that just 50-75 miles off the E coast of FL/GA is that yellow area indicating only about a 2/3 chance of hitting the US. I say “only” because a 2/3 chance from that short of distance may seem counterintuitive until one realizes the high # of TCs there that are already recurving N to NE and away from much of the SE US. Also, I’m assuming that a good portion of those have already had a FL/GA impact from the Gulf and that the shown % chance hit for those is actually for a SECOND impact further up the US E coast.

I LOVE this FSU chart. I discovered it only last month!

Edit: Now regarding the minority of TCs 50-75 miles E of FL that are moving between WSW and WNW, the chance of a U.S. hit would easily be 90%+ rather than just 2/3.

Edit #2: If we were looking strictly at Sept. 20 and beyond, the chance of a later U.S. landfall for TCs in that same area 50-75 miles offshore GA/FL would almost certainly be lower than that 2/3 and quite possibly be under 50%. Alternatively, if we were looking only at August, that chance would almost certainly be higher than that that 2/3...possibly ~4/5.

[cycloneye]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 PM EDT Mon Sep 1 2025

For the North Atlantic...Caribbean Sea and the Gulf of America:

1. Eastern Tropical Atlantic:
A tropical wave located over the far eastern tropical Atlantic
south of the Cabo Verde islands is producing disorganized showers
and thunderstorms. Environmental conditions appear conducive for
gradual development of this system, and a tropical depression could
form by the middle or latter part of this week. This system is
expected to move westward to west-northwestward at around 15 mph
across the eastern and central tropical Atlantic throughout the
week.
* Formation chance through 48 hours...low...10 percent.
* Formation chance through 7 days...medium...60 percent.



Forecaster Pasch