Hurricane Isaias

[MANDA]

2 minutes ago, cardinalland said:

It appears the eye is starting to clear

Looking good with some nice ventilation going on even in the SW quadrent. Has about 24 hours to maximize itself before shear starts to really impinge.

[yoda]

BULLETIN
Hurricane Isaias Intermediate Advisory Number 8A
NWS National Hurricane Center Miami FL       AL092026
100 PM CDT Thu Oct 08 2026
 
...ISAIAS EXPECTED TO STRENGTHEN FURTHER...
...PREPARATIONS TO PROTECT LIFE AND PROPERTY FROM STORM SURGE AND
DAMAGING WINDS IN THE WARNING AREA SHOULD BE RUSHED TO COMPLETION
TODAY...
 
 
SUMMARY OF 100 PM CDT...1800 UTC...INFORMATION
----------------------------------------------
LOCATION...24.0N 89.8W
ABOUT 185 MI...300 KM N OF PROGRESO MEXICO
ABOUT 355 MI...570 KM S OF THE MOUTH OF THE MISSISSIPPI RIVER
MAXIMUM SUSTAINED WINDS...85 MPH...140 KM/H
PRESENT MOVEMENT...ENE OR 60 DEGREES AT 10 MPH...17 KM/H
MINIMUM CENTRAL PRESSURE...975 MB...28.80 INCHES

[beanskip]

Last recon pass is up 2 mb to 978mb. Never seen a strengthening storm that doesn't lose any pressure for 5 hours ...

[Boston Bulldog]

I don’t think that’s a legit eye, IR suggests that the inner core convection still isn’t organized enough yet to pop one. Pause in strengthening for now, let’s see if Isaias can get going again soon.

[cptcatz]

Looks like it's struggling. What else do you expect from #2026?

[Interstate]

1 minute ago, cptcatz said:

Looks like it's struggling. What else do you expect from #2026?

Yep I was going to say the same thing... It just cannot keep the convection going.... every time it gets a burst, it fizzles out.

[cardinalland]

It’s passing over some slightly cooler SSTs right now

[ROOSTA]

I don't see an "EYE". Just hallucinations with convection sheared well to the NE. 

I named this sat capture as GONZO 

[eyewall]

Cloud tops warmed pretty quick. This system is definitely struggling right now. 

[NorthHillsWx]

Been on the same pattern since yesterday of convection really dying off during diurnal minimum but coming back with a vengeance overnight 

[GaWx]

1 hour ago, cptcatz said:

Looks like it's struggling. What else do you expect from #2026?

That’s good news if it holds for those threatened. Hopefully shear will do its thing and keep it struggling. But it looks like it will probably still be a hurricane when it comes in and thus be no picnic for them.

[jm1220]

30 minutes ago, NorthHillsWx said:

Been on the same pattern since yesterday of convection really dying off during diurnal minimum but coming back with a vengeance overnight 

I would think tonight’s its last chance to ramp up. It’s clearly struggling already with dry air and shear. Looks elongated already. 

[NorthHillsWx]

1 hour ago, Boston Bulldog said:

I don’t think that’s a legit eye, IR suggests that the inner core convection still isn’t organized enough yet to pop one. Pause in strengthening for now, let’s see if Isaias can get going again soon.

Looks like a legit eye to me but it’s only cleared out bc the convection waned and isn’t overshooting it from the SW I believe. Looks legit now 

[NorthHillsWx]

Recon seems supportive of 80 kts, closing in on cat 2 at a much more modest rate today 

[olafminesaw]

14 minutes ago, NorthHillsWx said:

Recon seems supportive of 80 kts, closing in on cat 2 at a much more modest rate today 

I would expect one more significant ramp up tonight before it hits the shredder Tommorow 

[cptcatz]

Looks like it's trying to wrap some deep convection around the west side of the eye. If it can hold on and build an eyewall out of this, that's it's shot.

[NorthHillsWx]

20 minutes ago, olafminesaw said:

I would expect one more significant ramp up tonight before it hits the shredder Tommorow 

 

16 minutes ago, cptcatz said:

Looks like it's trying to wrap some deep convection around the west side of the eye. If it can hold on and build an eyewall out of this, that's it's shot.

Yep. Core is there and it will be moving over slightly warmer waters too. Diurnal max will be the max for this system. Imo 95-105 kts is attainable 

[vortex95]

On 10/6/2026 at 4:50 PM, NorthHillsWx said:

This system has escalated quite a bit from what the original thinking was. Definitely some potential for a strong hurricane especially in the middle of the gulf 

Probably b/c of it small size.  Global models had trouble picking it up.

[nycwinter]

we ll know from past history these gulf storms intensify last day right up to landfall even in cases of strong wind shear..

[hawkeye_wx]

Models have been predicting a good drop in pressure tonight as the center passes over the warm loop current eddy.

[vortex95]

Isaias is a atypical TC situation esp. for a landfall. In a way it reminds me of Sandy in Oct 2012, but some differences.  However, it has similar implications.

 

The models, both global and hurricane, all along have showed very rapid weakening of Isaias the last 9-12 hr to landfall.

 

12z HAFS-A   09/18z 951 mb /110 kt

                    10/03z 984 mb / 63 kt

12z HAFS-B   09/18z 964 mb / 99 kt

                    10/03z 985 mb / 57 kt

 

So there is a serious question if it will be a hurricane at landfall.

 

In addition, looking at the storm structure forecast, it is difficult to imagine it will still be classifiable as a tropical cyclone at landfall.

 

The SHIPS shear value is 35 kt 09/12z increasing to 49 kt 10/00z.  It is fully embedded in a 250 jet streak near landfall and all the convection sheared off N of the center at the time.  Very dry air (<20% 700-300 RH) is completely wrapped around and over the center (HAFS A/B forecast attached) and clear, defined frontal features apparent on the moisture fields.

 

Since Isaias is rather small and not that strong, it is unlikely to be able to ward off wind shear and dry air intrusion, like Ian did in Sep 2022.

 

Despite all of the above, I do not see any real emphasis currently in the mainstream on this very real possibility.  I've seen this before from NHC.  They avoid much emphasis on rapid weakening close to landfall b/c they think ppl will not take the warnings are seriously, but I find this disingenuous.  They are not being objective and transparent.  This was apparent w/ Milton, which is the most rapid weakening for a HU in a short period leading up to a U.S. landfall.

 

Our forecast skill/modeling have come a long way for TCs, so confidence in outlier or atypical scenarios is higher these days and we should take full advantage of this operationally.

 

I know of no Gulf hurricane situation quite like this one where such rapid weakening and quick PT/ET transition occurs near landfall (Milton comes close).  And I see no reason why the HAFS weakening forecast would be wrong given the synoptic pattern currently and this model handled the very rapid weakening of Milton.  That was a strong baroclinic interaction with high shear impacting the hurricane.

 

So this presents a problem/challenge as to how Isaias could be handled.  The concern is that in deference to messaging, it may not be called PT/ET at landfall or below hurricane strength even if it clearly is since within 12 hr of landfall it may be much stronger.

 

From an objective meteorological standpoint?  It should not matter where a TC is (close to a landfall or far at sea), how strong it is, or what type of watches/warnings are in effect, it should be treated "as is" operationally.  So if goes ET/PT just before landfall, call it for what is it.  The atmosphere does not care about our subjective policies/rules, it does what it does. There is nothing that says a TC can not go ET/PT just before landfall, and it has been done before (Sandy).  And after Sandy, things were adjusted so tropical watches/warnings remain in place even if a TC goes ET/PT, so things are covered here from a messaging standpoint.
 

This kind of objectivity is important to the meteorological science.  A hurricane at landfall or not is significant from a climo standpoint.  And in some cases depending on the state, county, or city/town, what something is called/labeled makes a difference from an insurance and legal standpoint.

 

Some may say all what I say above is being pedantic or picayune, but I beg differ.  There were significant discussions and controversy in the meteorological and other fields as to what Sandy was called at landfall.  I am just proactively pointing out beforehand a similar TC situation currently.