cieldumort
(Moderator)
Tue Sep 29 2026 08:19 PM
Isaias Lounge

A roughly eight day window for development in the Gulf is starting to get a lot more hits from extended range quality models and their ensembles. It is not immediately clear if this will be from a Central American Gyre, wave, or combination of both, but the general region of projected best genesis potential seems to favor either or both. The signal has been consistent, with the stellar Google DeepMind FNv3 now implying 40% odds of development from the western Caribbean into the Gulf during this window. Given the very consistent signal, we are starting a Lounge on this projected system, Invest TBD, at this time.

It is worth noting that 2026 has not seen a hurricane form yet in the Atlantic basin and the current El Niño has been much stronger than forecasts prior to the start of the season. In fact, this El Niño is setting all-time records going back at least decades and likely centuries. Given that we do not have much historical precedent to work off of as far as how this could influence modeling this far out, some consideration should be given that they could be overcooking things. Nonetheless, here are some examples:


Image credit: James Pettus @PettusWX pettusplots.com


The most recent DeepMind generation, WNv3, is not as impressed, at 22% development odds. Timeline is about the same, with median genesis 228 hours from 12z today (0z Oct 9)

Credit: TC-ATLAS





This feature has just been Invest tagged, 92L, and the title has been updated accordingly 10/5/26 1PM CDT
Ciel

Advisories have begun on TD NINE (from 92L) and the title has been updated accordingly. 10/6/26 4PM CDT
Ciel

NINE has become a Tropical Storm, Isaias, and the title has been updated accordingly. 10/07/26 3AM CDT
Ciel


cieldumort
(Moderator)
Wed Sep 30 2026 09:12 AM
Re: W Carib-Gulf Window Oct 6-14 Invest TBD

In general, this window favors development from all the usual suspects in and around the Gulf. However, anything that might want to form from a front in the northern Gulf could just trend more subtropical or at the very least sheared/struggling, while anything that might want to form in the Bay of Campeche (Central American Gyre-born/EPac crossover/tropical wave) looks to have much better odds of being purely tropical with potentially a higher intensity ceiling. Upper level winds/lift forecast to become quite favorable over the BoC during the middle of this window, as can be seen below.



cieldumort
(Moderator)
Fri Oct 02 2026 03:04 AM
Re: W Carib-Gulf Window Oct 6-14 Invest TBD

Out to 168 from 0z today, most Globals now advertise at least weak cyclonic surface flow in the Gulf, predominately around the Bay of Campeche-Yucatan Peninsula, save the ICON.




However, shear at this time could be prohibitive


cieldumort
(Moderator)
Fri Oct 02 2026 11:37 PM
Re: W Carib-Gulf Window Oct 6-14 Invest TBD

Globals that are at least lukewarm to the idea of some kind of development in the Gulf during this window continue favoring a CAG and/or crossover method. While there are a few runs that tease something in the northern Gulf or even the east coast of Florida, those appear to be non-tropical lows, or subtropical at best, getting mistaken for tropical.

Taking a look at today's runs that do show development potential in the western Gulf, most only support a weaker and quicker storm, which makes sense with forecasts of ongoing high levels of shear. One caveat to the shear forecast, is that a good deal of the shear models see during this otherwise so-so window is a result of and possibly contingent on the development of yet another far east Pac tropical cyclone (as seen below shown to be an 80% region to the southeast of Hurricane Rachel in the NHC TWO)


Should the Area of Interest presently southeast of Rachel not track close to mainland Mexico as forecast, shear across the Gulf could be less. Another wild card would be for this AOI to cross over into the BOC. A few models and/or ensembles suggest either as possible.

Some quick glances at a few of today's Globals

CANADIAN out to 156 hours advertising development on both sides of Central America (the previously noted AOI in the east Pac as well as a new disturbance in the BoC)


GFS takes the east Pac AOI itself across the Isthmus of Tehuantepec and creates a trof in the western Gulf, but without much development there. Rain-maker for east TX.


The AI GFS makes like the Canadian and spawns two systems on either side of Central America, but the Gulf feature is kept weak, short-lived and runs into Mexico.


The window is still open, but this is a window with a lot of doubts, and if anything does form, unlike a lot of the hype seen in social media, odds are really that it would be weak and/or short-lived, with only an outlier chance of a strong cyclone (maybe at best 10-15% of something below 995mb IMHO)


cieldumort
(Moderator)
Sat Oct 03 2026 03:49 AM
Re: W Carib-Gulf Window Oct 6-14 Invest TBD

This is an incredibly tricky season for both models and forecasters alike where the Atlantic basin is concerned. The one safe bet all season would have been, has been, should have been, "Nothing becomes a hurricane." Fay and possibly Edouard got close, but no cigar*. With this backdrop, the rational thing to do is ignore any model runs that ramp up this yet-to-form system in the Gulf beyond 60 MPH unless and until something is getting obvious.

The most recent suite of 0z Globals during this window.

Quick Globals rundown:

EURO - Sloppy Trof; borderline TD at times by 10/11/06z in northern Gulf
EURO AI - Weak Tropical Low by 10/11/0z in northwestern Gulf
GFS - TD or Low-end Trop Storm by 10/12/06z in northwestern Gulf
GFS AI - TD by 10/11/0z in the southwestern Gulf. Quickly makes landfall in western BoC mainland MX.
ICON - Borderline TD by 10/10/06z in the northern Gulf.
UKMET - Apparent TD or weak Trop Storm in the southwestern Gulf by 10/07/21z. Making landfall around Cape San Blas, Gulf County, 10/10/0z 989mb.

As for the Google DeepMind FNv3 ensembles, after a dip with their 18z run, the most recent 0z came back in implying a 30% chance of this becoming a Tropical Storm


Credits: TC-ATLAS and Google



*Both Fay and Edouard were likely stronger than operational advisories had them and one or both could easily be upgraded during reanalysis. Only referring to real-time NHC Advisories.


cieldumort
(Moderator)
Sat Oct 03 2026 02:20 PM
Re: W Carib-Gulf Window Oct 6-14 Invest TBD

Here are the results of some 12z Globals out today. Showing just TC genesis as "YES" or "NO" going out to 240 hours (10 days from today) and the date of apparent TC formation

EURO: NO
EURO AI: NO
GFS: YES Oct 8
GFS AI: YES Oct 10
CANADIAN: YES Oct 10
ICON: YES Oct 8
UKMET: YES Oct 8


cieldumort
(Moderator)
Sun Oct 04 2026 03:23 AM
Re: W Carib-Gulf Window Oct 6-14 Invest TBD

Models, including the high quality DeepMind versions and their ensembles, continue gradually, if unevenly, warming up to development potential in the Gulf within this window. In addition, an increasing number of ensemble members ramp things up a bit intensity-wise. While this season has mostly produced weak storms so far, the Gulf this time of year can see upside surprises that are also immediately landlocked and likely to make landfall somewhere.

Big jump in the DeepMind FNv3 50 suite compared to yesterday, now implying 42% odds of at least a tropical storm, with a median genesis of early morning Oct 8th

Credit: TC-ATLAS


MikeCAdministrator
(Admin)
Sun Oct 04 2026 09:58 AM
Re: W Carib-Gulf Window Oct 6-14 Invest TBD

This is a 30% area now, which seems reasonable. Most likely outcome is just a very wet messy area though, shear will likely keep it from developing, however if it lines up correctly it could change. Need to watch it either way.

cieldumort
(Moderator)
Sun Oct 04 2026 01:19 PM
Re: W Gulf Area of Interest

Marginally CAG-favorable MJO state as of today and forecast to become more supportive during this window

Image credit: Celsius.earth


cieldumort
(Moderator)
Sun Oct 04 2026 04:37 PM
Re: W Gulf Area of Interest

ASCAT displaying surface spin already evident today in two locations either side of the Isthmus of Tehuantepec

  • Far western Gulf well south of Brownsville, TX and
  • Just south of Guatemala



Base satellite/ascat map credit: Weathernerds.org



Credits: NHC


cieldumort
(Moderator)
Mon Oct 05 2026 01:59 AM
Re: W Gulf Area of Interest

Model support for development of this potential future system is effectively now approaching 100% overall, and there are also some very plausible runs making this a hurricane. Without an Invest*, it is far too early to speculate as to actual intensity and track. Lots of known unknowns that can influence its intensity that won't become clear unless and until a bona fide disturbance has taken shape. Track-wise, there are also a number of known unknowns which can shuffle things around for a while. It is even possible that the future system, assuming it develops, meanders in the western to central Gulf before taking a more decisive track inland.

For now, any one model or ensemble run remains completely uncertain and speculative, but the table is definitely set for development and potentially for substantial development.

10/05/0z Globals YES/NO and apparent earliest development date if YES:
EURO: YES Oct 8th
EURO AI: YES Oct 7th
GFS: YES Oct 7th
GFS AI: YES Oct 8th
CANADIAN: YES Oct 10th
ICON: YES Oct 6th
UKMET: YES Oct 7th


10/04/18z DeepMind Ensembles
FNv3: 77% of 1,000 members develop into a Tropical Storm (implication being even higher of at least a Tropical Depression)
WN3: 88% of 64 members develop into a Tropical Storm (same TD or better implication as above)


*Invest tag could be coming as soon as later today, in which case, hurricane models would start running and recon would most likely be flown. There is a tentative mission now already on the books for Wednesday, which would likely get moved up with the introduction of an Invest number.


MikeCAdministrator
(Admin)
Mon Oct 05 2026 06:48 AM
Re: W Carib-Gulf Window Oct 6-14 Invest TBD

Most likely it'll be a rainy weekend along the northern Gulf, hybrid or potential tropical storm. Hurricane is extremely unlikely but not impossible. I wouldn't expect much from this though. The overall Atlantic effect this year is still suppressed by El Nino, so weak once again is by far the most likely scenario. General message is, keep watch, but unlikely to be much.

cieldumort
(Moderator)
Mon Oct 05 2026 11:59 AM
Re: W Gulf Area of Interest



cieldumort
(Moderator)
Mon Oct 05 2026 12:09 PM
Re: W Gulf Area of Interest

As noted by Dr. Levi Cowen (TropicalTidbits) above, the models are basically split into two camps, with several of the classic models less bullish vs. the AIs favoring the positioning of the disturbance (then TC) in the most favorable region possible. Essentially a few stars aligned vs. almost all, if not all, stars aligned.

The implications of which scenario is most correct are stark. With the less ideal solutions, our disturbance struggles with shear and dry air, possibly never even becoming a Tropical Storm at all. On the other side, what looks to myself and others to be about an equally valid possibility, the then-Tropical Cyclone finds itself benefiting mightily from strong upper-level divergence and much lower shear while tracking over very, very warm waters.

The intensity ceiling scenario of situation #1, the weaker scenario, is probably limited to a strong tropical storm at best, unless the system stays locked in the Gulf long enough for conditions for further development to improve, which is possible.

The intensity ceiling of situation #2, the forecast increasingly preferred by AI models, is very high, with plausible Major Hurricane outcomes, albeit as of now, low odds. But as models would have it, right now they imply about a 50-50 shot of this becoming a hurricane.


cieldumort
(Moderator)
Mon Oct 05 2026 12:52 PM
Re: W Gulf Area of Interest

Results of today's 06z FNv3 1000 member ensembles are in and they are continuing the trend of greater confidence + higher potential intensities

Image credit: James Pettus @PettusWX pettusplots.com


CFHCAdministrator
()
Mon Oct 05 2026 02:01 PM
Re: W Carib-Gulf Window Oct 6-14 Invest TBD

Throwback model link https://flhurricane.com/throwbackspaghet...9&zoom=5.12






Still think it's a messy tropical storm at best, east side is where most of the weather will be. East Pacific's 92E (if it gets going quickly) likely would starve off anything in the Atlantic also. Overall concern level is low.


cieldumort
(Moderator)
Mon Oct 05 2026 02:47 PM
Re: 92L Lounge



MikeCAdministrator
(Admin)
Mon Oct 05 2026 09:33 PM
Re: 92L Lounge

The 18z euro has flipped too. We'll see if it gets going early tomorrow night or not (Recon will be out there late) Still don't think this winds up a hurricane at landfall with the shear, we'll see.

1


cieldumort
(Moderator)
Tue Oct 06 2026 02:33 AM
Re: 92L Lounge

We really need those recon missions into 92L

Several 0z hurricane models blow the Invest up while in the Gulf, but then dry air and shear takes their toll on the cyclone by the time it is nearing the coast, and unlike Edouard which was intensifying into landfall, 92L - then Isaias - weakens dramatically into landfall. Side rant ~ If this were to actually happen, we could in theory have a Major in the Gulf, watches and warnings put up along the northern Gulf coast and official forecasts from NHC calling for weakening by landfall, but with people frantically checking the latest clickbait worst-case runs on social media and freaking out. Then blame the NHC of course should Isaias roll onshore more like a wet lamb after social media posts roared like a fierce lion.

Other models, including the operationally retired HWRF, maintain a vigorous Major all the way into landfall.

Recon ASAP is going to be critical in nailing this forecast with enough time.

Here are some heading-into-landfall forecasts from the hurricane models








Screenshots credits: TropicalTidbits

Reassuring that the HWRF is now often thought of as more of a C-tier model, replaced and bested by the HAFS. Still, a model run that deserves consideration until proven otherwise.


IsoFlame
(Weather Analyst)
Tue Oct 06 2026 10:45 AM
Re: 92L Lounge

Quote:

We really need those recon missions into 92L. Several 0z hurricane models blow the Invest up while in the Gulf, but then dry air and shear takes their toll on the cyclone by the time it is nearing the coast, and unlike Edouard which was into landfall, 92L - then Isaias weakens dramatically into landfall. Side rant ~ If this were to actually happen, we could in theory have a Major in the Gulf, watches and warnings put up along the northern Gulf coast and official forecasts from NHC calling for weakening by landfall, but with people frantically checking the latest clickbait worst-case runs on social media and freaking out. Then blame the NHC of course should Isaias roll onshore more like a wet lamb after social media posts roared like a fierce lion. Other models, including the operationally retired HWRF, maintain a vigorous Major all the way into landfall. Often thought of as more of a C-tier model, replaced and bested by the HAFS. Still, a model run that deserves consideration until proven otherwise.



Impressive/explosive deep convection underway this morning: GOES-19 - Sector view: Gulf of America - GeoColor - NOAA / NESDIS / STAR


cieldumort
(Moderator)
Tue Oct 06 2026 12:04 PM
Re: 92L Lounge

This morning's DeepMind FNv3 1000-member ensemble mean coming in as a 56 KT Tropical Storm at landfall late Friday overnight/predawn Saturday


cieldumort
(Moderator)
Tue Oct 06 2026 02:41 PM
Re: 92L Lounge

Even though it missed a lot, this ASCAT is compelling


cieldumort
(Moderator)
Tue Oct 06 2026 04:06 PM
Re: 92L Lounge

Advisories likely coming at any moment.

Even without a recon mission, I'll share some initial best guesses as to future-Isaias's peak intensity. This is not necessarily intensity at landfall.

Invest-only (Currently): 0%
30-35 MPH TD: 1%
40-50 MPH Tropical Storm: 3%
60-70 MPH Tropical Storm: 11%
Cat 1 Hurricane: 13%
Cat 2 Hurricane: 20%
Cat 3 Hurricane: 23%
Cat 4 Hurricane: 22%
Cat 5 Hurricane: 7%


MikeCAdministrator
(Admin)
Tue Oct 06 2026 06:15 PM
Re: 92L Lounge

HIgh end Tropical Storm at landfall (although it will likely become a hurricane before that) , however, I could be wrong, follow the official advisories. If it makes it to the forecast windspeed it would take a Milton like fall apart (weakening) to drop down. Increases tornado risk for well east of Landfall if that occurs though. I'd guess the other option is a jet hit and it'll stay larger longer.

MikeCAdministrator
(Admin)
Tue Oct 06 2026 10:55 PM
Re: 92L Lounge

0z Models should have some of the high altitude recon jet to help figure out what's going on. Right now the satellite is fairly impressive, so wouldn't be shocked to see it get named tonight or early tomorrow. It'll probably rapidly strengthen before hitting the shear in the northern Gulf.



0z icon coming in stronger than earlier runs. Now that a system is there I'll probably be paying more attention to it tomorrow and thursday. (Been away most of the sleepy season)


cieldumort
(Moderator)
Tue Oct 06 2026 11:48 PM
Re: NINE Lounge

Back on Oct 2nd I opined, "The window is still open, but this is a window with a lot of doubts, and if anything does form, unlike a lot of the hype seen in social media, odds are really that it would be weak and/or short-lived, with only an outlier chance of a strong cyclone (maybe at best 10-15% of something below 995mb IMHO)." ( Thread continues next reply )

cieldumort
(Moderator)
Tue Oct 06 2026 11:54 PM
Re: NINE Lounge



Incredible what just 4 days can do to change things. Turns out, then-92L ended up with everything going right for it. To this point, all the stars have aligned. This did not appear at all to be its baseline just a few days ago, and to be candid, I think a number of us, myself included, have been burned one too many times this season by the would-bes that ended up wrecked by high shear (record El Niño), so were also quick to buy in to the more tepid model solutions (of which the vast majority were up until the past 48 hours or so). 

Tonight, the stars continue aligning for now NINE (possibly already a tropical storm but we have no recon or recent scatterometer pass inside to confirm). Initially, it looked to models as if the disturbance on the eastern Pacific side of the Isthmus of Tehuantepec would develop first or at least early and strongly. The opposite has occurred. Consequently, higher shear that could have been battering 92L/NINE in its formative stages has been delayed enough so that the now tropical cyclone NINE might find itself with a developing inner core, about to travel across record warm Gulf waters and have divergent outflow to both its north-northeast and southeast, and perhaps even a bona fide outflow channel stretching off to its north-northeast as the entrance region of a developing and approaching subtropical jet streak passes by to NINE's north-northeast. 

Models now largely buy into the continued all-stars-aligning scenario and thus many more ramp NINE up into a very significant hurricane. 

There are still ways for the upper-bound intensity limits seen in an increasing number of model and ensemble runs to stop from verifying, but the number of ways is decreasing and so increasing the odds of a higher-end cyclone in the Gulf heading towards US land. 

Shear is very likely to increase to moderate or even high levels prior to NINE making landfall on the Gulf Coast, but it is increasingly uncertain if shear will be high enough and early enough to induce significant enough degradation and weakening from what could be a beast of a tropical cyclone by Friday, heading towards US land. 

As Mike noted, the high altitude survey data taken today will hopefully greatly improve forecasts that come out over the next few cycles and NHC will have a better handle on all of this. Regular missions begin in earnest Wednesday morning. 



cieldumort
(Moderator)
Wed Oct 07 2026 12:11 AM
Re: NINE Lounge

07 0z Globals+Hurricane Models Tracks


07 0z Intensity guidance


cieldumort
(Moderator)
Wed Oct 07 2026 12:31 AM
Re: NINE Lounge

The forecast location of future-Isaias is coming into the purview of high-resolution regional and convective-allowing models

Here's a first look at the 0z RRFS for Saturday morning just prior to landfall


cieldumort
(Moderator)
Wed Oct 07 2026 02:13 AM
Re: NINE Lounge

Hurricane models 72 hours out from 07/0z (for Friday evening) after ingesting Tuesday's upper-air recon data








All four 0z hurricane models make NINE a Major (Cat 3/4) on approach to landfall.


cieldumort
(Moderator)
Wed Oct 07 2026 10:04 PM
Re: Isaias Lounge



cieldumort
(Moderator)
Thu Oct 08 2026 12:39 AM
Re: Isaias Lounge


Latest 0z (full) run of the high resolution RRFS possibly painting a reasonable upper-bound for the potential max wind gusts heading into landfall, provided stars continue staying aligned for now Hurricane Isaias
Note: This run does weaken slowly starting F050 (10/10/02z) as Isaias heads into landfall. Probably not the best boat day.


cieldumort
(Moderator)
Thu Oct 08 2026 01:55 AM
Re: Isaias Lounge

The latest 0z hurricane model runs are rolling in. They have now assimilated loads of recon data.

Here are some 10m wind screenshots. Credits: TropicalTidbits

The first image is going to be 48 hours out from run initialization. The second image, if there is one, is of a given model's forecast for as close to landfall time as can be possibly shown here.

HAFS-A
Cat 4 at 10/0z



Rapidly weakening heading into landfall. Possibly upper-end Tropical Storm *at* landfall per this model run.




HAFS-B
Cat 3 at 10/0z


Weakening trend. Maybe Cat 2 heading into landfall.


HMON
Landfall actually occurring roughly around 48 hours out (10/0z). Possibly higher-end Cat 2 into landfall.


HWRF
Also with a landfall right around 48 hours out from initialization (10/0z). Also possibly Cat 2 into landfall.



All in all, there is actually a lot of consensus with these four models.


OrlandoDan
(Weather Master)
Thu Oct 08 2026 08:17 AM
Re: Isaias Lounge

It will be interesting to see the impacts to the broader Florida peninsula given all of the synoptic weather patterns that will influence Isaias. Will we see some squalls and tornados in central Florida?

JMII
(Weather Master)
Thu Oct 08 2026 08:47 AM
Re: Isaias Lounge

Given the cold front to the north and the jetstream pattern Levi mentioned in his videos this storm has the potential to produce tornadoes. If the forecasted weaken occurs tornadoes in AL, GA and FL might be the biggest threat here aside from the usual strong surge along the gulf shores.

cieldumort
(Moderator)
Thu Oct 08 2026 12:19 PM
Re: Isaias Lounge



cieldumort
(Moderator)
Thu Oct 08 2026 04:58 PM
Re: Isaias Lounge


Credit: Google DeepMind/Weathermodels.com/Ryan Maue @RyanWeather


MikeCAdministrator
(Admin)
Thu Oct 08 2026 09:27 PM
Re: NINE Lounge

It looks like Isaias may try to make major overnight, about 6 hours before landfall the shear wall will hit and it will rapidly weaken, probably spawning tornadoes to the northeast. Surge will have momentum so it may still be high (it it makes major surge estimates may go up). If you are in an evacuation zone ordered to be please leave.

JMII
(Weather Master)
Fri Oct 09 2026 11:03 AM
Re: NINE Lounge

Hit Cat 3 as of the 11AM advisory. Its moving quickly and TS force winds will reach the shore by 2PM this afternoon.

IsoFlame
(Weather Analyst)
Fri Oct 09 2026 11:37 AM
Re: NINE Lounge

Depending on wobbles, looks like Destin will be ground zero for landfall, with the most significant impacts extending well east to Carabelle/Apalachicola. The comma shaped feeder band well east of the center may be quite impactful in the St. Marks area given the orientation of the coast.

OrlandoDan
(Weather Master)
Fri Oct 09 2026 03:31 PM
Re: NINE Lounge

I'm impressed by the IR Cloud Top satellite pic at this time. Notice the prominent definition to the west.


JMII
(Weather Master)
Fri Oct 09 2026 04:19 PM
Re: NINE Lounge

Despite being all the way down in Cape Coral the tide is running 1 foot above normal.
Here is a link of the storm's path and various tide stations to monitor surge:
https://tidesandcurrents.noaa.gov/inundationdb/cidstorm.html?stormname=Isaias


OrlandoDan
(Weather Master)
Sat Oct 10 2026 06:46 PM
Re: NINE Lounge

We are getting that typical long feeder band of the long comma shaped tail in east central Florida. I got 1.39 inches so far and it's still raining. I got a rain rate of 3.9//hr about 3 hours ago. I would say this is typical for a post tropical system landing where it did compared to east central Florida. I expected this.