Major Hurricane Isaias

[vortex95]

Given the fcst 850-200 mb wind shear over the northern Gulf is fcst in excess of 50 kt and how the global models depict the storm structure, I have a tough time thinking this can sustain a tropical status once farther N.  Sfc winds E of the center will likely get quite strong, but due to baroclinic deepening.

If this were a well-established strong TC already, I would not be as concerned about the shear here.

Here are two storms in early Oct 1992 and 1994 that fit this scenario. The 1992 event deepened to 996 mb and and 1994 to 1000  mb from baroclinic processes.

[GaWx]

0Z UKMET: landfall ~175 miles W of 12Z run with it near far SE LA and then MS. Strongest run yet with high end TS/990 mb:

NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 54 HOURS
FORECAST POSITION AT T+ 54 : 22.2N 92.1W

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
1200UTC 08.10.2026 60 22.7N 91.7W 1003 30
0000UTC 09.10.2026 72 22.9N 89.9W 1001 30
1200UTC 09.10.2026 84 25.4N 88.6W 999 39
0000UTC 10.10.2026 96 26.4N 88.5W 997 48
1200UTC 10.10.2026 108 29.2N 88.7W 990 58
0000UTC 11.10.2026 120 32.1N 89.5W 992 29
1200UTC 11.10.2026 132 33.8N 88.8W 1002 25
0000UTC 12.10.2026 144 38.4N 83.2W 1003 12
1200UTC 12.10.2026 156 CEASED TRACKING

[Windspeed]

00z GFS was much more realistic with the progression of this system and the synoptic setup. Though it does still bring the TC to hurricane status in the southern and central GOM, significant weakening occurs by landfall due to all the aforementioned issues discussed previously.

[vortex95]

2 hours ago, Windspeed said:

00z GFS was much more realistic with the progression of this system and the synoptic setup. Though it does still bring the TC to hurricane status in the southern and central GOM, significant weakening occurs by landfall due to all the aforementioned issues discussed previously.

The 00z ECMWF still has a stark 700-300 mb RH gradient early on that just intensifies as it heads N.  The pattern/structure at 108 hr for this parameter looks more like a baroclinic leaf than anything.

It dependents it to 998 mb, 9 nm weaker than the 00z, which is in line w/ the 1992 and 1994 early Oct events as to am ET low development in the Gulf making landfall.

The HAFS-B is much deeper, but also look at its 700-300 mb RH fcst (attached).  That configuration strongly suggests a frontal structure and baroclinic leaf.  I would find it hard to believe it could drop into the 970s from largely baroclinic forcing.  The deepest ET low in the Gulf ion record s 980 mb from the Bliz of 1993 and that had unreal baroclinic support!

The GFS does the opposite of the HAFS-B, it makes it strong as a TC early, and  *then* weakens is as it heads N.  That coulld happen.
 

[yoda]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 AM EDT Tue Oct 6 2026

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

Southwestern Gulf of America (AL92):
Showers and thunderstorms are showing signs of organization in 
association with a broad area of low pressure located over the 
southwestern Gulf of America. Continued development of this system 
is expected, and a tropical depression is anticipated to form over 
the next day or so while it drifts eastward. The low pressure area 
could bring gusty winds and areas of heavy rain to the western 
portions of the Yucatan Peninsula of Mexico in a couple of days. 

The disturbance is expected to turn to the north or northeast toward 
the northern Gulf Coast by the end of the week. It is still too 
early to determine specific impacts to the northern Gulf Coast, but 
interests from the Florida Panhandle to Louisiana should closely 
monitor the progress of this system. The NOAA Gulfstream is 
scheduled to sample the environment over the Gulf later today and an 
Air Force reconnaissance aircraft is scheduled to investigate the 
system tomorrow.
* Formation chance through 48 hours...high...90 percent.
* Formation chance through 7 days...high...90 percent.

$$
Forecaster Cangialosi

[NorthHillsWx]

Guidance is pretty stacked towards this becoming a hurricane at some point. Also starting to look like this becomes the dominant system between it and the EPAC storm, which will have some lessening of shear than we were thinking yesterday. 

[NorthHillsWx]

92L is very clearly organizing this morning with a robust and cohesive flare up of thunderstorms overnight. Organizational trends today will be critical as to whether this system manages to take advantage of the more favorable conditions present before shear increases later in the week. A lot of the weak models keep this thing disorganized for 48 hours whereas the stronger ones really start ramping up by tonight/tomorrow morning 

[jm1220]

Looks like a wall of shear before anything hits the Gulf coast. The SE is pretty dry so a good rainer would help. If we’re really dealing with 40kt shear on the Gulf coast, hard for me to see how anything beyond a moderate/strong TS can make it. 

[olafminesaw]

35 minutes ago, jm1220 said:

Looks like a wall of shear before anything hits the Gulf coast. The SE is pretty dry so a good rainer would help. If we’re really dealing with 40kt shear on the Gulf coast, hard for me to see how anything beyond a moderate/strong TS can make it. 

Depending on the track, shear could be a net neutral, even allowing for strengthening through landfall as the shear vector is aligned with the storms track if it tracks more to the East/faster. 

[SnowGoose69]

Obviously early RI would probably make this stronger at landfall too as if it becomes a Cat 3 extremely rapidly over the next 60 hours that would allow it to do the whole "making its whole environment around it" thing

[NorthHillsWx]

Right now, I’d say a strong TS or Cat 1 hurricane impact on the northern gulf coast is looking most likely. Does it peak as higher end intensity in middle of the gulf (most hurricane models)? Does it stay mostly weak (Euro, GFS)? Think the next 24 hours answer those questions but if I was on the northern gulf coast from lake Charles to Panama City I’d probably start planning for strong TS or Low end hurricane impacts being most probable with impacts likely starting late Friday 

[GaWx]

 I wonder if the GA/AL game in Tuscaloosa on Sat night (7:30PM EDT start) will be heavily impacted by the Gulf tropical cyclone forecasted to form soon. Any guesses?

[Winter Wizard]

The new GFS has future Isaias positioned just above the Yucatan Saturday at 6z whereas yesterday's 12z run had a hurricane landfall over Louisiana. The slower progression mean that it makes landfall as barely a tropical storm.

Very much in line with what Andy Hazleton said: this is a rare case where you actually want this to spend more time over the warm waters of the Gulf to minimize impacts, as shear will tear it apart. Whereas a faster, or more NE tracking storm would limit time in a hostile environment and therefore is more likely to peak as a hurricane. 

 

[GaWx]

12Z UKMET is strongest run yet with a H (65 knots/983 mb) hitting Biloxi followed by a move N into MS:

NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 24 HOURS
FORECAST POSITION AT T+ 24 : 21.6N 93.7W

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
1200UTC 07.10.2026 24 21.6N 93.7W 1005 29
0000UTC 08.10.2026 36 22.0N 93.2W 1003 28
1200UTC 08.10.2026 48 22.6N 92.4W 1000 35
0000UTC 09.10.2026 60 22.7N 90.9W 999 31
1200UTC 09.10.2026 72 24.6N 89.6W 995 41
0000UTC 10.10.2026 84 26.4N 89.2W 992 45
1200UTC 10.10.2026 96 29.2N 88.7W 983 65
0000UTC 11.10.2026 108 32.3N 90.0W 994 26
1200UTC 11.10.2026 120 33.4N 90.4W 1003 27
0000UTC 12.10.2026 132 CEASED TRACKING

[NavarreDon]

New video by Dr. Cowan

.

[olafminesaw]

[NavarreDon]

ZCZC MIATWOAT ALL
TTAA00 KNHC DDHHMM

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 PM EDT Tue Oct 6 2026

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

1. Southwestern Gulf of America (AL92):
Satellite images and surface observations indicate that showers and
thunderstorms are becoming better organized while surface pressures
are gradually falling. If these trends continue, advisories will
likely be issued on this system later today or tonight while it
moves slowly eastward. The low pressure area could bring gusty winds
and areas of heavy rain to the western portions of the Yucatan
Peninsula of Mexico in a couple of days.

The disturbance is expected to turn to the north or northeast toward
the northern Gulf Coast by the end of the week. It is still too
early to determine specific impacts to the northern Gulf Coast, but
interests from the Florida Panhandle to Louisiana should closely
monitor the progress of this system. The NOAA Gulfstream jet is en
route to sample the environment over the Gulf this afternoon and Air
Force and NOAA reconnaissance aircraft are scheduled to investigate
the system tomorrow.
* Formation chance through 48 hours...high...near 100 percent.
* Formation chance through 7 days...high...near 100 percent.



Forecaster Cangialosi


.

[wncsnow]

Euro AI looks similar to the UK and Google

[olafminesaw]

5 minutes ago, wncsnow said:

Euro AI looks similar to the UK and Google

The GFS is so bad it has quite literally been replaced by AI

[MANDA]

14 minutes ago, olafminesaw said:

The GFS is so bad it has quite literally been replaced by AI

GFS is a useless model.  Not sure why anyone uses it for anything more than 36-48 hours in advance.  It flips and flops like a fish out of water from one run to the next.

The big snow event in the Northeast last February was one of the very few times the blind squirrel found the nut.

 

[wncsnow]

Euro has a much deeper storm this run compared to last. 

[SnowGoose69]

AI's seem too fast with track

[WxWatcher007]

Very sensitive solutions still based on track. What’s becoming increasingly likely however is that the rain associated with this extends well into the south, mid-Atlantic, and maybe further north. 

[Scott747]

1 hour ago, MANDA said:

GFS is a useless model.  Not sure why anyone uses it for anything more than 36-48 hours in advance.  It flips and flops like a fish out of water from one run to the next.

The big snow event in the Northeast last February was one of the very few times the blind squirrel found the nut.

 

I get the hate for the last few years for the GFS and you can go with the ol 'broken clock twice a day' angle.

But the GFS has been sniffing this out since a week ago. And pretty damn good if it hits on the corresponding storm in the EPAC that far out.

[hawkeye_wx]

12z Google... pretty locked into the FL panhandle.  It's pretty bullish on the strength before weakening at landfall.

[Nomz]

Advisories for TD Nine forthcoming at the top of the hour per the NHC website

[Nomz]

Google 12z is really quite aggressive. Worth noting the other AI models tend to agree while the classic models are less bullish.

[NorthHillsWx]

NHC brings this to cat 2 at landfall

[yoda]

1 minute ago, NorthHillsWx said:

NHC brings this to cat 2 at landfall

Tropical Depression Nine Discussion Number   1
NWS National Hurricane Center Miami FL       AL092026
400 PM CDT Tue Oct 06 2026
 
Satellite imagery indicates that the area of low pressure located
over the southwestern Gulf of America has recently developed a
closed circulation, though it might still be elongated. Associated
showers and thunderstorms have also become better organized, and
this system now meets the criteria to be a tropical depression, the
ninth one of the season. The initial intensity is set at 30 kt based
on a Dvorak classification from TAFB.
 
The depression has barely moved over the past 6 to 12 hours, with 
the initial motion estimated to be 120/1 kt. The cyclone is expected 
to track slowly eastward or east-northeastward during the next 
couple of days while it moves in the flow near the base of a broad 
deep-layer trough, and could bring gusty winds and heavy rains to 
the western portions of the Yucatan Peninsula on Thursday. By 
Friday, a sharp turn to the northeast is expected when a shortwave 
trough forms over Texas and a ridge strengthens over the western 
Atlantic. This pattern change should cause the system to accelerate 
toward the northern Gulf Coast on Friday and into early Saturday. 
The NHC track forecast lies near the fast side of the guidance, in 
best agreement with the GDMI and ECAI aids. It should be noted that 
there is significant uncertainty in where the system makes the 
northeast turn and how fast it moves toward the coast. It appears 
that the stronger the system gets, the faster it will move toward 
the coast given the strength of the deep-layer flow. The NOAA G-IV 
jet is currently sampling the environment and special upper-air 
soundings are being deployed over the south-central U.S. The 
assimilation of these data into the dynamical models should improve 
their representation of the current environmental conditions, 
ideally yielding more reliable track and intensity guidance.
 
The environmental conditions appear generally conducive for
strengthening over the next few days, and given that the storm
appears compact, it will likely steadily strengthen during that
time. The NHC intensity forecast shows the system becoming a
tropical storm by early Wednesday and a hurricane on Thursday. Based
on the environmental conditions and the model guidance, the cyclone
will likely peak in strength before reaching the coast. Although not
seen in the forecast, some weakening seems likely when the storm
nears the Gulf Coast due to an increase in vertical wind shear, but
it is still expected to be a dangerous hurricane when it makes
landfall. This forecast is in fair agreement with the consensus
aids, but it should be noted that there are skillful models that are
higher than the current forecast.
 
Although the storm is expected to be compact for the next few days,
it will likely grow significantly in size, particularly on the
eastern side, when it reaches the northern Gulf Coast. Therefore,
based on the forecast uncertainty and expected larger size, users
are urged not to focus on the forecast points and stay tuned to
updates.
 
Key Messages:
 
1. There is an increasing risk of dangerous wind and storm surge 
impacts along portions of the northern Gulf Coast, and watches could 
be required on Wednesday. Residents from Louisiana to the Florida 
Panhandle should closely monitor the latest forecast updates and 
ensure they have their hurricane plan in place.
 
2. The system will bring areas of heavy rainfall to the central 
U.S. Gulf coast Friday into the weekend.  Flash and urban flooding, 
along with isolated river flooding, will be possible.
 
3. Yucatan Peninsula of Mexico: The depression is expected to
strengthen and could bring gusty winds and areas of heavy rain to
the western portion of the Yucatan Peninsula in a couple of days.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  06/2100Z 22.1N  95.6W   30 KT  35 MPH
 12H  07/0600Z 22.1N  95.0W   35 KT  40 MPH
 24H  07/1800Z 22.6N  93.4W   45 KT  50 MPH
 36H  08/0600Z 23.1N  91.8W   55 KT  65 MPH
 48H  08/1800Z 24.2N  90.1W   70 KT  80 MPH
 60H  09/0600Z 25.9N  88.8W   80 KT  90 MPH
 72H  09/1800Z 28.5N  88.3W   85 KT 100 MPH
 96H  10/1800Z 34.0N  88.7W   30 KT  35 MPH...INLAND
120H  11/1800Z 38.9N  86.5W   20 KT  25 MPH...POST-TROP/INLAND
 
$$
Forecaster Cangialosi

[yoda]