ATL: MARIA - Models

[invest man]

Looks like NHC is buying the idea the trough from Jose stretching southwestward is going to split the uprights between Hatteras and Bermuda on its way OTS!!! The model trends to the west must be discounted by NHC.

[stormreader]

That midwest trough in the 12z Euro at 216 hrs shreds whats left of Maria. It also could mark the beginning of the end to this hellish atlantic basin season. Would likely drive a strong cold front all the way through Florida.

a cold front all the way through the peninsula in september would be very rare.

But welcome.

Would probably spell the end for the Cabo Verde mid Atlantic type storms. However, that kind of trough might actually provide impetus for something to spin up in the Yucatan Channel or southern GOM. Last couple of days of Sept would be ideal for something like that.

[Aric Dunn]

NHC has Jose here in 24 hours.. FORECAST VALID 21/1800Z 39.6N 67.9W


recon just fixed the center

39.21N 68.41W

moving NE at 8 to 10 mph.. no signs of slowing down or turning yet..

IT would have to pass 67w and still show no sign of slowing down for me to really think some thing is different. the models will at that point likely start showing different solutions.

which may or may not affect maria's track..

[NJWxHurricane]

NHC has Jose here in 24 hours.. FORECAST VALID 21/1800Z 39.6N 67.9W


recon just fixed the center

39.21N 68.41W

moving NE at 8 to 10 mph.. no signs of slowing down or turning yet..

IT would have to pass 67w and still show no sign of slowing down for me to really think some thing is different. the models will at that point likely start showing different solutions.

which may or may not affect maria's track..

it isn't suppose to turn till earliest tomorrow afternoon

[BYG Jacob]

^ My only point being is that Jose will maintain a circulation (that slowly weakens) for a number of days. This won't just be gone by tomorrow.

It might be a naked low level swirl, but convection will be completely gone, it almost is gone right now.

[RL3AO]

^ My only point being is that Jose will maintain a circulation (that slowly weakens) for a number of days. This won't just be gone by tomorrow.

It might be a naked low level swirl, but convection will be completely gone, it almost is gone right now.

But the vorticity field and decreased heights will persist for days which determines the large scale flow and leaves the weakness in place.

[Aric Dunn]

NHC has Jose here in 24 hours.. FORECAST VALID 21/1800Z 39.6N 67.9W


recon just fixed the center

39.21N 68.41W

moving NE at 8 to 10 mph.. no signs of slowing down or turning yet..

IT would have to pass 67w and still show no sign of slowing down for me to really think some thing is different. the models will at that point likely start showing different solutions.

which may or may not affect maria's track..

it isn't suppose to turn till earliest tomorrow afternoon

exactly my point.. at which time with current forward speed would make it way east of all guidance unless it slows down... and it has not yet..

[invest man]

NHC has Jose here in 24 hours.. FORECAST VALID 21/1800Z 39.6N 67.9W


recon just fixed the center

39.21N 68.41W

moving NE at 8 to 10 mph.. no signs of slowing down or turning yet..

IT would have to pass 67w and still show no sign of slowing down for me to really think some thing is different. the models will at that point likely start showing different solutions.

which may or may not affect maria's track..

What do you think models will show if it crosses 67w? Just your best hypothesis!

[BYG Jacob]

^ My only point being is that Jose will maintain a circulation (that slowly weakens) for a number of days. This won't just be gone by tomorrow.

It might be a naked low level swirl, but convection will be completely gone, it almost is gone right now.

But the vorticity field and decreased heights will persist for days which determines the large scale flow and leaves the weakness in place.

I'm not seeing it, but you're the pro met, so I'll just defer to your judgement.

[Aric Dunn]

NHC has Jose here in 24 hours.. FORECAST VALID 21/1800Z 39.6N 67.9W


recon just fixed the center

39.21N 68.41W

moving NE at 8 to 10 mph.. no signs of slowing down or turning yet..

IT would have to pass 67w and still show no sign of slowing down for me to really think some thing is different. the models will at that point likely start showing different solutions.

which may or may not affect maria's track..

What do you think models will show if it crosses 67w? Just your best hypothesis!

common sense would say that if it does not slow and turn around and becomes farther east then the ridge that builds off the east coast could build farther east turning maria more towards the South/north carolinas coast to New england.

just have to watch and see. very complex situation.

[RL3AO]

It might be a naked low level swirl, but convection will be completely gone, it almost is gone right now.

But the vorticity field and decreased heights will persist for days which determines the large scale flow and leaves the weakness in place.

I'm not seeing it, but you're the pro met, so I'll just defer to your judgement.

It's the conservation of vorticity. A storm is completely happy to maintain its relative vorticity unless something forces it to lose it. It could be advected away by the background flow, it could be moved poleward (Coriolis increases and therefore relative vorticity decreases to maintain a constant total vorticity), or you could increase the stability of the atmosphere. Since it will barely be moving, the first two won't impact it much. There might be a small increase in stability, but otherwise, it won't change a whole lot.

That means the low will just slowly spin down as the weak background flow, friction, and small changes in stability slowly decrease the storms relative vorticity over a period of 3 to 5 days.

[invest man]

NHC has Jose here in 24 hours.. FORECAST VALID 21/1800Z 39.6N 67.9W


recon just fixed the center

39.21N 68.41W

moving NE at 8 to 10 mph.. no signs of slowing down or turning yet..

IT would have to pass 67w and still show no sign of slowing down for me to really think some thing is different. the models will at that point likely start showing different solutions.

which may or may not affect maria's track..

What do you think models will show if it crosses 67w? Just your best hypothesis!

common sense would say that if it does not slow and turn around and becomes farther east then the ridge that builds off the east coast could build farther east turning maria more towards the South/north carolinas coast to New england.

just have to watch and see. very complex situation.

Kinda of thought that it what you'd say thanks! However, NHC sees a trough stretching back to the Gulf from Jose. Would it really matter how far it got east if the trough stretched that far or would HP build in and cut the trough off allowing a NW movement instead of N movement?

[Voltron]

for instance on this eueo run if jose stays north and does not drop back south the ridging that develops behind it likely wont break and maria likely to stay on a more wnw course. but the 00z has jose drop back to the south weakening the ridging again and thus maria goes through it.

Yeah... not sure why posters are so convinced of an OTS scenario for Maria given all the confounding factors with Jose. cranky gives a great synopsis of this in his tweet:

 https://twitter.com/crankywxguy/status/910166896095498242




Seems like the only way Maria will go OTS is if Jose loops back around, but cranky also point out that factors are converging to kick Jose OTS for good.

This was a great modeling scenarios that seems like a great time to bring up again

[Aric Dunn]

What do you think models will show if it crosses 67w? Just your best hypothesis!

common sense would say that if it does not slow and turn around and becomes farther east then the ridge that builds off the east coast could build farther east turning maria more towards the South/north carolinas coast to New england.

just have to watch and see. very complex situation.

Kinda of thought that it what you'd say thanks! However, NHC sees a trough stretching back to the Gulf from Jose. Would it really matter how far it got east if the trough stretched that far or would HP build in and cut the trough off allowing a NW movement instead of N movement?

HArd to say..

[gatorcane]

As long as the GFS and ECMWF are safely out to sea, I wouldn't get too concerned. The pattern is too complex for models like the NAVGEM and CMC. I do agree there is some uncertainty as far as whether Maria could ultimately landfall in the continental US because we are just too far out right now to know for sure. But at least the GFS and ECMWF models have not brought her to shore in any of the recent runs (subject to change of course)..

Closest approach to mainland US on 12Z ECMWF:

[Alyono]

strong ridging at 500mb, but Maria is able to plot NNE. Must be due to the trough (hope not the GFS again being GFS taking systems through a ridge)

[BYG Jacob]

But the vorticity field and decreased heights will persist for days which determines the large scale flow and leaves the weakness in place.

I'm not seeing it, but you're the pro met, so I'll just defer to your judgement.

It's the conservation of vorticity. A storm is completely happy to maintain its relative vorticity unless something forces it to lose it. It could be advected away by the background flow, it could be moved poleward (Coriolis increases and therefore relative vorticity decreases to maintain a constant total vorticity), or you could increase the stability of the atmosphere. Since it will barely be moving, the first two won't impact it much. There might be a small increase in stability, but otherwise, it won't change a whole lot.

That means the low will just slowly spin down as the weak background flow, friction, and small changes in stability slowly decrease the storms relative vorticity over a period of 3 to 5 days.

So, that's enough to pull Maria North? That.. doesn't seem right.

[Alyono]

ridge not as defined at 12Z

Becoming cautiously optimistic that we will be giving thanks to annoying Jose

[NJWxHurricane]

jose is more east and weaker
maria is also east of the 12z run on the 18z run of the GFS.
trough is about to come in and kick this ots

[hurricaneCW]

I'd be more comfortable if the models did show her make landfall day 6-8 than not. I don't like the look of this setup and the NAO is rapidly shifting, which is often a precursor to a big storm.

If the models don't change course over the next two days then I think we can breath easy.