ATL: GRACE - Remnants - Discussion

[Ubuntwo]

Recon finds the center further south than estimated. Below 15.9N. Pressure <1013 but does not appear to be as deep as the NHC's 1005mb.

The background state is 1021mb That is pretty high, and they have not found the center yet

Yes it is still a substantial pressure drop vs. the environment.

[ouragans]

https://imagizer.imageshack.com/img922/2414/FDClgK.gif

Looks like Guadeloupe, Montserrat, St.Kitts & Nevis, Antigua & Barbuda are in for some serious rain with Grace

Guadeloupe is Thunderstorm/Heavy rain orange warning since 12PM, bot nothing else

[Blinhart]

I'm afraid Grace is not going to be destroyed by Bahamas shear. Hurricane north-central Gulf next Saturday.

Any educated guesses as possibility of strength for North-central Gulf area? I know it is a week away so a lot can change from now to then.

[Shell Mound]

Recon finds the center further south than estimated. Below 15.9N. Pressure <1013 but does not appear to be as deep as the NHC's 1005mb.

 https://twitter.com/AndyHazelton/status/1426596719203131393



 https://twitter.com/webberweather/status/1426599311152873478



 https://twitter.com/AndyHazelton/status/1426599687625248776



 https://twitter.com/JackSillin/status/1426598779931615245

[Blown Away]

Not impossible, but somewhat rare for a named system to move from central Atlantic N of PR, Hispaniola, and Cuba and make it to the Central GOM. If Grace moves S or through the islands it is much more likely.

[PTrackerLA]

Amazing how fast the tables can turn once you reach mid-August. Hoping for the best for Haiti but Florida and Gulf residents need to start paying close attention.

[Shell Mound]

High-resolution visible imagery indicates outflow boundaries in the eastern semicircle, so Grace is almost certainly less organised than it appears to be.

What?

If Grace is indeed organising fairly rapidly, do you know why the latest HWRF has trended toward a much weaker system in the short term vs. the previous run?

[Category5Kaiju]

Not impossible, but somewhat rare for a named system to move from central Atlantic N of PR, Hispaniola, and Cuba and make it to the Central GOM. If Grace moves S or through the islands it is much more likely.

Hurricane 8 in 1933 did manage to do that

[aspen]

What is it with all of these really high pressure named storms? First Elsa, then Fred, now Grace.

[kevin]

The Gulf is an explosive region atm waiting for a storm to reach it. If Grace reaches the Gulf the water at least won't be a problem. Theoretical limits show sub 900 mbar pressures. Of course it won't become nearly that strong (hopefully I didn't jinx it) but it is an indicator that the Gulf region is highly favorable in terms of hurricane potential.

[AnnularCane]

What is it with all of these really high pressure named storms? First Elsa, then Fred, now Grace.

I was just wondering that too. Seems like something weird is going on out there.

[Woofde]

What is it with all of these really high pressure named storms? First Elsa, then Fred, now Grace.

All of them seem to want to run into Hispaniola too! I'm hoping for Haiti's sake it does not run into them. They already got loads of rain from Fred and a Earthquake. The last thing they need is another storm. That would be like Eta and Iota landing in the same spot level of unlucky.

[Shell Mound]

Not impossible, but somewhat rare for a named system to move from central Atlantic N of PR, Hispaniola, and Cuba and make it to the Central GOM. If Grace moves S or through the islands it is much more likely.

Of the twenty-eight systems of TS or greater status that passed within 60 n mi of 16.2°N 57.9°W during the month of August, five eventually reached the Gulf of Mexico. Of those five, each made landfall on the U.S. Gulf Coast as a hurricane, three of which were majors at landfall. The remainder either curved OTS after affecting the Leeward Islands or continued through the Bahamas to strike either the east coast of peninsular Florida or the Outer Banks of North Carolina. Notably, eight of the twenty-eight cyclones affected Hispaniola.

[Hypercane_Kyle]

Very underwhelming recon so far. Can't say I'm surprised, Grace has the look of a storm that's a lot of bluster on satellite but not a lot of action under the hood. Waiting to see the center though.

[skyline385]

Doubt Grace is RI'ing, its still lacking a well defined centre...

[IsabelaWeather]

Recon finds the center further south than estimated. Below 15.9N. Pressure <1013 but does not appear to be as deep as the NHC's 1005mb.

The background state is 1021mb That is pretty high, and they have not found the center yet

That's interesting, I'm only reading 1013.8 right now, is there a massive ridge east of PR?

[Shell Mound]

The mid-level easterly shear is likely to continue to displace the MLC to the west of the LLC and also prevent the LLC from assuming a WNW component.

Perhaps, however if Grace manages to continue to strengthen over the next 24-36 hours there is a better chance that it does in fact take a more WNW path... wait and see.

Personally, I don’t think that Grace is actually intensifying much, if at all. Structurally it is stagnant, and structure is more important than convection, at least in this case. Currently Grace has very little outflow, and the convection is clearly to the west of the LLC, as is the MLC. As Grace interacts with Puerto Rico and the eastern Dominican Republic, orographic lift associated with mountainous terrain will combine with easterly shear to prevent the LLC from assuming a WNW component. Instead, the MLC and the convection will remain to the west and south of the LLC and instead “drag” the LLC farther west and even south of due west, similarly to Fred. Unfortunately, I think the very high PWATs may work to offset Grace’s fast motion and still result in locally prolific rainfall over Puerto Rico and Hispaniola. This would also affect areas recently impacted by the latest earthquake.

 https://twitter.com/cyclonicwx/status/1426603694062190600

[Blown Away]

Not impossible, but somewhat rare for a named system to move from central Atlantic N of PR, Hispaniola, and Cuba and make it to the Central GOM. If Grace moves S or through the islands it is much more likely.

https://i.ibb.co/W3vsH2d/Ska-rmavbild-2021-08-14-kl-19-49-05.png

Of the twenty-eight systems of TS or greater status that passed within 60 n mi of 16.2°N 57.9°W during the month of August, five eventually reached the Gulf of Mexico. Of those five, each made landfall on the U.S. Gulf Coast as a hurricane, three of which were majors at landfall. The remainder either curved OTS after affecting the Leeward Islands or continued through the Bahamas to strike either the east coast of peninsular Florida or the Outer Banks of North Carolina. Notably, eight of the twenty-eight cyclones affected Hispaniola.

None of those moved N of the GA islands and made it to the GOM, so it’s a decent benchmark to watch over next 48 hours.

[Hypercane_Kyle]

I'm pretty confident Grace has a closed LLC based on recon. I think they might have missed the actual center, but we've got an entire page of winds from the SSW. It must be a very small LLC. Remember Elsa and how difficult it was to get a VDM with such a small, fast moving LLC.

[aspen]

Is it possible Grace is undergoing a center reformation and recon has found the old LLC, with a new one forming under the main convective blob to the NNW?