ATL: LAURA - Post-Tropical - Discussion

[Aric Dunn]

they are not looking for the center there.. they are decending to 1500 GPM before then enter the convection

[eastcoastFL]

Normally discussions would include something along the lines of “...it is still uncertain how strong TD13 will be by the time it reaches the Bahamas” or “...it is unclear how favorable the environment will be for TD13”

Yes I am looking for something like this which I just wrote up:

The intensity guidance is highly uncertain. Some dry air as well as mid-level shear may hinder development over the next day or two as the depression moves through an area of dry air from the Saharan Air Layer to the SW of an upper-level trough. By days 3 and 4, an upper-level anticyclone over the Bahamas and stretching north of the Greater Antilles should provide a favorable upper-level environment for strengthening as shown by the HWRF and HMON models as well as the CMC, NAVGEM, and UKMET models. In fact the HWRF and HMON bring the depression to major hurricane status by days 4 and 5. On the other hand, the GFS, and ECMWF models, despite a favorable upper environment, keep the system as a broad low through days 5 possibly because of the aformentioned mid-level shear weakening the structure to allow some dry air in the vicinity of the Bahamas to prevent any significant strengthening. For the now the intensity is a continuation from the previous advisory and not adjusted upward out of respect for the GFS and ECMWF.

I see we didn’t get some more details on the models from the NHC still. Bold is what I wrote earlier which I am looking for

They’re obviously not giving the euro any weight right now

[ColdMiser123]

Like with Isaias, there will be a northern jet present due to the SAL surge, so expect to see some decently high FL wind values there since recon is flying in the lower atmosphere.

[Aric Dunn]

pk they are heading in for a pass..
down to 780 gpm operational altitude.

[Hammy]

Like with Isaias, there will be a northern jet present due to the SAL surge, so expect to see some decently high FL wind values there since recon is flying at ~850 hPa.

Would that aide in spinning up or more work to squash the circulation?

[ColdMiser123]

Like with Isaias, there will be a northern jet present due to the SAL surge, so expect to see some decently high FL wind values there since recon is flying at ~850 hPa.

Would that aide in spinning up or more work to squash the circulation?

If you picture a branch floating along a stream, perpendicular to the flow of the water, an area of faster water will cause that part of the branch get pushed ahead, which turns the branch and rotates it.

The atmosphere is no different since it is also a fluid. That theoretically should increase the amount of spin in the atmosphere because of that difference in wind over a small distance, generating shear vorticity.

[AutoPenalti]

NHC still keeping it at a conservative intensity out of respect of the Euro and GFS



LMFAO...


If that doesn’t tell you how bad it’s been doing...

[Frank2]

There's also a lobe (of the large ULL well to the north) that is just west of 13, in addition to the SAL - ULL's are always a wild card.

[Kazmit]

NHC still keeping it at a conservative intensity out of respect of the Euro and GFS



LMFAO...


If that doesn’t tell you how bad it’s been doing...

I don’t think they would raise it too much anyway right now unless it showed substantial organization/strengthening faster than forecast.

[DestinHurricane]

Slightly off topic, but i'd like to share some posts from last year's Dorian thread to remind people that this can easily strengthen.
There are some striking similarities. The GFS/Euro didn't like Dorian early on either, the HWRF/HMON did.
Not saying this is going to be a cat 5. All I am saying is think big picture before you call this off.

No offense meant to these posters at all.
Here are some posts from the Dorian threads:

"Dry sinking airmass will probably prevent this system from developing the euro just poofs it as it nears the islands."
- SFLcane, August 23, 2019.

"The euro happens to have completely screwed this one up so far. Not sure we should be trusting it for this particular system."
- NikhilTri, August 23, 2019.

"Good news this morning if this even develops it will more then likely be decapitated as it nears the islands. Conditions just are not favorable overall"
- SFLcane, August 24, 2019.

"I do have some doubts about that NHC forecast verifying. I don't think the intensity models are really taking into account its size and how much dry air/wind shear TD5 will be facing."
- Hurricane_Kyle, August 24, 2019.

"I would forecast it to be dissipating in the NE Caribbean, not a hurricane. Using HWRF for intensity guidance????"
- wxman57, August 24, 2019.

"I'm betting the NHC thinks the global models have a poor handle on the system, which makes sense considering the ECMWF hardly even showed a vortex, let alone a TC, until like yesterday for Dorian."
- Hurricane_Kyle, August 24, 2019.

"I do wonder if the GFS is too struggling now with the size of Dorian. If conditions are favorable until the islands then why doesn’t it strengthen it much?"
- TheStormExpert, August 24, 2019.

"GFS/Euro basically do nothing with Dorian, hard to go against those models..."
-Blown Away, August 25, 2019.

[MarioProtVI]

Multiple spots of deep convection starting to fire near the center. Looks like it might be getting it’s act together.

[AutoPenalti]

Multiple spots of deep convection starting to fire near the center. Looks like it might be getting it’s act together.

It could be popcorn convection.

[OuterBanker]

Slightly off topic, but i'd like to share some posts from last year's Dorian thread to remind people that this can easily strengthen.
There are some striking similarities. The GFS/Euro didn't like Dorian early on either, the HWRF/HMON did.
Not saying this is going to be a cat 5. All I am saying is think big picture before you call this off.

No offense meant to these posters at all.
Here are some posts from the Dorian threads:

"Dry sinking airmass will probably prevent this system from developing the euro just poofs it as it nears the islands."
- SFLcane, August 23, 2019.

"The euro happens to have completely screwed this one up so far. Not sure we should be trusting it for this particular system."
- NikhilTri, August 23, 2019.

"Good news this morning if this even develops it will more then likely be decapitated as it nears the islands. Conditions just are not favorable overall"
- SFLcane, August 24, 2019.

"I do have some doubts about that NHC forecast verifying. I don't think the intensity models are really taking into account its size and how much dry air/wind shear TD5 will be facing."
- Hurricane_Kyle, August 24, 2019.

"I would forecast it to be dissipating in the NE Caribbean, not a hurricane. Using HWRF for intensity guidance????"
- wxman57, August 24, 2019.

"I'm betting the NHC thinks the global models have a poor handle on the system, which makes sense considering the ECMWF hardly even showed a vortex, let alone a TC, until like yesterday for Dorian."
- Hurricane_Kyle, August 24, 2019.

"I do wonder if the GFS is too struggling now with the size of Dorian. If conditions are favorable until the islands then why doesn’t it strengthen it much?"
- TheStormExpert, August 24, 2019.

Lol, great post.

[SouthFLTropics]

Slightly off topic, but i'd like to share some posts from last year's Dorian thread to remind people that this can easily strengthen.
There are some striking similarities. The GFS/Euro didn't like Dorian early on either, the HWRF/HMON did.
Not saying this is going to be a cat 5. All I am saying is think big picture before you call this off.

No offense meant to these posters at all.
Here are some posts from the Dorian threads:

"Dry sinking airmass will probably prevent this system from developing the euro just poofs it as it nears the islands."
- SFLcane, August 23, 2019.

"The euro happens to have completely screwed this one up so far. Not sure we should be trusting it for this particular system."
- NikhilTri, August 23, 2019.

"Good news this morning if this even develops it will more then likely be decapitated as it nears the islands. Conditions just are not favorable overall"
- SFLcane, August 24, 2019.

"I do have some doubts about that NHC forecast verifying. I don't think the intensity models are really taking into account its size and how much dry air/wind shear TD5 will be facing."
- Hurricane_Kyle, August 24, 2019.

"I would forecast it to be dissipating in the NE Caribbean, not a hurricane. Using HWRF for intensity guidance????"
- wxman57, August 24, 2019.

"I'm betting the NHC thinks the global models have a poor handle on the system, which makes sense considering the ECMWF hardly even showed a vortex, let alone a TC, until like yesterday for Dorian."
- Hurricane_Kyle, August 24, 2019.

"I do wonder if the GFS is too struggling now with the size of Dorian. If conditions are favorable until the islands then why doesn’t it strengthen it much?"
- TheStormExpert, August 24, 2019.

Lol, great post.

LMAO... Don't you just love the digital age. Nothing ever goes away!!! Just a reminder to be careful what you say...It may come back to haunt you.

[St0rmTh0r]

Slightly off topic, but i'd like to share some posts from last year's Dorian thread to remind people that this can easily strengthen.
There are some striking similarities. The GFS/Euro didn't like Dorian early on either, the HWRF/HMON did.
Not saying this is going to be a cat 5. All I am saying is think big picture before you call this off.

No offense meant to these posters at all.
Here are some posts from the Dorian threads:

"Dry sinking airmass will probably prevent this system from developing the euro just poofs it as it nears the islands."
- SFLcane, August 23, 2019.

"The euro happens to have completely screwed this one up so far. Not sure we should be trusting it for this particular system."
- NikhilTri, August 23, 2019.

"Good news this morning if this even develops it will more then likely be decapitated as it nears the islands. Conditions just are not favorable overall"
- SFLcane, August 24, 2019.

"I do have some doubts about that NHC forecast verifying. I don't think the intensity models are really taking into account its size and how much dry air/wind shear TD5 will be facing."
- Hurricane_Kyle, August 24, 2019.

"I would forecast it to be dissipating in the NE Caribbean, not a hurricane. Using HWRF for intensity guidance????"
- wxman57, August 24, 2019.

"I'm betting the NHC thinks the global models have a poor handle on the system, which makes sense considering the ECMWF hardly even showed a vortex, let alone a TC, until like yesterday for Dorian."
- Hurricane_Kyle, August 24, 2019.

"I do wonder if the GFS is too struggling now with the size of Dorian. If conditions are favorable until the islands then why doesn’t it strengthen it much?"
- TheStormExpert, August 24, 2019.

Lol, great post.

LMAO at people still believing GFS!

[AdamFirst]

Destin bringing the RECEIPTS out here, I love it

[Evil Jeremy]

Playing the "this person said that last year" game is a unnecessary, slippery slope. Destin, I could point out the numerous hyperbolic flip-flopping statements you said in the week leading up to Isaias passing by Florida, but that wouldn't really contribute anything to the current situation. I think that's a game better left unplayed. No one is perfect. 95% of us here are amateurs. It would help if everyone tones down the hyperbole, the model wars, and the "gotcha" mentality.

[tolakram]

TD 13 please, let's stop fighting one another. People can give their opinion.

[SouthFLTropics]

Looking at the last visible image before the sun sets and it appears that there are two distinct rotations. One to the NW, which I assume is the LLC, and one to the SE which I would guess might be the MLC. I think the biggest issue right now is the LLC is running away from the MLC and they aren't stacked. They are severely tilted from NW to SE. The low level flow is just screaming from East to West. The MLC can't keep up.

[Hammy]

All the "But Dorian" posts here are going to look foolish in a few days when we have an open wave going through the Bahamas. Recon confirms there's no circulation as all the winds are out of the southeast and the favorable conditions down the road aren't going to matter if all you have is an open wave scraping the north end of the islands, something that is a distinct possibility--NHC even points out their forecast is highly uncertain.

This is not Dorian, which was never in this bad of shape and most of the posts refer to down the road conditions, not the current state of things. Dorian was always expected to weaken based on the models (most of which poorly initialized it due to it's small size, similarly with Danny in 2015), which was what never happened.

I can easily point to Karen last year when people were insistent it would reorganize just like Dorian because of those favorable conditions, and that of course played out differently.