ATL: ISAIAS - Post-Tropical - Discussion

[northjaxpro]

I am still not buying north of Hispaniola. The vorticity is concentrating on the southern end, and as time is passing it would have to make a more prominent turn in the NW direction to do that and I see no mechanism to force that. I believe the models have been initializing this too far north and thus are not correct.
There is a hot tower going off right over where I think the center is forming. There is also some low level flow bending toward it.

I am with you about this, which I have alluded to a few times already.

[ScottNAtlanta]

So we have Team West
NorthJaxPro
Aric
and Myself

[SFLcane]

If the system indeed takes the persistent track that the Euro has been forecasting run after run, north of Cuba, whoever thinks is going to have SW shear to deal with is lying to themselves. With the trough axis all the way west over the MS river valley it should have fairly good UL conditions.
Remember how bad they were with the intensity of Hanna 2-3 days before making landfall.

Great post!

[TheStormExpert]

If the system indeed takes the persistent track that the Euro has been forecasting run after run, north of Cuba, whoever thinks is going to have SW shear to deal with is lying to themselves. With the trough axis all the way west over the MS river valley it should have fairly good UL conditions.
Remember how bad they were with the intensity of Hanna 2-3 days before making landfall.

Any idea or guess on where PTC-9 may end up or go with that trough?

[GCANE]

Anti-cyclone is breaking down to the unsustained convection.

[jconsor]

 https://twitter.com/yconsor/status/1288565024059985925

[jconsor]

 https://twitter.com/webberweather/status/1288561209910992897

[northjaxpro]

If the system indeed takes the persistent track that the Euro has been forecasting run after run, north of Cuba, whoever thinks is going to have SW shear to deal with is lying to themselves. With the trough axis all the way west over the MS river valley it should have fairly good UL conditions.
Remember how bad they were with the intensity of Hanna 2-3 days before making landfall.

Great post!

EURO I feel has had the best handle on this system from the beginning since last weekend, mainly imo because it was able to detect the ridging pattern , which is corresponding to the forecasted + NAO to be in effect by August 1.

[Blown Away]

This thing is huge, convection really building to the N of PR. Starting to see the possibility this system can move along the N coast of DR instead of through it.

[SFLcane]

Curious about the accuracy of this ship observation near #PTC9. If verified, would indicate that the system is probably very close to being a TC with a closed circulation. We'll see if we get some other obs.

https://twitter.com/andyhazelton/status ... 27817?s=21

[hurrtracker79]

 https://twitter.com/Jackson_Dill/status/1288566613474672643

[Aric Dunn]

LLC is down on the right edge of that southern curved band.. as the cirrus clouds fade it has become visible.

[HurricaneFrances04]

 https://twitter.com/TropicalTidbits/status/1288567324967149568

[MGC]

Follow the convection. Looks like formation near 15N......MGC

[ScottNAtlanta]

Curious about the accuracy of this ship observation near #PTC9. If verified, would indicate that the system is probably very close to being a TC with a closed circulation. We'll see if we get some other obs.

https://twitter.com/andyhazelton/status ... 27817?s=21

Levi posted a reply saying it wasn't correct because sat showed it couldn't be true (I'm paraphrasing of course)

[Hammy]

Curious about the accuracy of this ship observation near #PTC9. If verified, would indicate that the system is probably very close to being a TC with a closed circulation. We'll see if we get some other obs.

https://twitter.com/andyhazelton/status ... 27817?s=21

Have they upgraded based on ship observations? I know they've done so with intensity but I can't remember if they have regarding open vs closed circulation.

[NDG]

I am still not buying north of Hispaniola. The vorticity is concentrating on the southern end, and as time is passing it would have to make a more prominent turn in the NW direction to do that and I see no mechanism to force that. I believe the models have been initializing this too far north and thus are not correct.
There is a hot tower going off right over where I think the center is forming. There is also some low level flow bending toward it.

I am with you about this, which I have alluded to a few times already.

All you have to look at are the surface pressures which are lowest near the Virgin Islands, SW of it the pressures are higher.
Satellite is starting to hint that the northern end is very close to closing a circulation.

[wxman57]

Note that the 12Z Euro initialized the "center" way too far east, by Guadeloupe Island. Same with those 51 ensemble members. That's about 200 miles too far east. I don't trust it for that reason, primarily. As for that ship ob, ships are notoriously bad at reporting winds. I've been plotting ships since the late 1970s, and you learn to take their obs with a grain of salt sometimes. Agree with Levi, it's suspect. One thing the models are in good agreement on is if this can track well east of Florida, then it may find a more hospitable environment. I don't think it will track east of Florida, however.

[ScottNAtlanta]

Curious about the accuracy of this ship observation near #PTC9. If verified, would indicate that the system is probably very close to being a TC with a closed circulation. We'll see if we get some other obs.

https://twitter.com/andyhazelton/status ... 27817?s=21

Have they upgraded based on ship observations? I know they've done so with intensity but I can't remember if they have regarding open vs closed circulation.

I know they have with buoy readings...dont know about ships

[cycloneye]

Recent ASCAT has no dice.