18z Model Thread 12/22

[tornadojay]

at 78, low pressure is in north central GOM, just south of the AL, MS state border.

[jcwxguy]

hr 72

High pressure formed east of flordia right near a low

[rickrd]

If we can get the surface low to actually go over the GOMEX for a bit, that should really juice the system up.

HR 72 NAM 18 Z - LP stopping by for a drink of GOM?

[thunderman]

1016 closed off at the surface over the northern GOM at 72hrs. H5 still closed off as well over the central LA coast.

[joey]

this looks promising

http://www.nco.ncep....00_s_loop.shtml

if it captures 6 hours earlier we would be in great shape.

[Gibbsfreeenergy]

so lets add another another model with positive trends toward the euro solution (even if its perhaps a bit overdone). But again, this is the 18z nam, lol

[tornadojay]

at 84, low pressure is in northeastern GOM, south of the FL panhandle.

[Ji]

NAM looks great...heavy snow in W SC is a good sign for the mid Atlantic

[pojrzsho]

NAM looks great...heavy snow in W SC is a good sign for the mid Atlantic

and at 78 is so much more amplified, and healthier, than 84 12 Z

[baroclinic_instability]

NAM doesn't look great. It is the 18Z NAM, so I don't care, but it is way too positively tilted and has too much of an easterly component to the trough digging through the plains. This solution would still be way OTS. Positive trend from 12Z? Perhaps, but it still would suck in the end. Personally I don't think it matters, NAM will come around sooner or later.

[Eskimo Joe]

NAM doesn't look great. It is the 18Z NAM, so I don't care, but it is way too positively tilted and has too much of an easterly component to the trough digging through the plains. This solution would still be way OTS. Positive trend from 12Z? Perhaps, but it still would suck in the end. Personally doesn't matter, NAM will come around sooner or later.

I was just about to say the same thing. The entire trough from the surface to 200mb has yet to show any sign of going neutral or negative.

[WhiteoutWX]

First 72 hours looked great, not sure what happend after that as this would still be a miss on the NAM. Doesnt matter though it trended way towards the Euro.

[ohleary]

NAM looks poised to strike to me at h84, but its hard to extrapolate much. 5h with the energy driving down the back side of the trough, similarly the 3h jet also driving due south on the back side of the trough. Of course we can't see this thing phase and that's the piece we need to see...unless we imagine it, and when I do, it looks great.

[PhineasC]

NAM doesn't look great. It is the 18Z NAM, so I don't care, but it is way too positively tilted and has too much of an easterly component to the trough digging through the plains. This solution would still be way OTS. Positive trend from 12Z? Perhaps, but it still would suck in the end. Personally I don't think it matters, NAM will come around sooner or later.

Sort of weird to read all of these "NAM looks great" comments and then see this one.

[kurtstack]

First 72 hours looked great, not sure what happend after that as this would still be a miss on the NAM. Doesnt matter though it trended way towards the Euro.

It kinda dissolved the southern stream vort ala the GFS before it came on board with Euro. I don't think NAM is handling the southern stream well toward the end of it's run.

[baroclinic_instability]

I was just about to say the same thing. The entire trough from the surface to 200mb has yet to show any sign of going neutral or negative.

Yeah agreed, not favorable at all. Needs to dig the trough/cold air advection farther S into the GOM for this to be a viable solution. Without the low level diabatic effects the GOM provides, this solution would not be able to alter the height fields aloft and go negative tilt through positive feedback cyclogenesis and it would be OTS. But it is the NAM. Only reason I mention a positive trend is it is a tad farther S with the southern PV.

[tornadojay]

I was just about to say the same thing. The entire trough from the surface to 200mb has yet to show any sign of going neutral or negative.

I agree with both of your assessments. If anything, at least it's very slowly trending in a direction like the others, but still has a bit ways to go.

[tornadojay]

Yeah agreed, not favorable at all. Needs to dig the trough/cold air advection farther S into the GOM for this to be a viable solution. Without the low level diabatic effects the GOM provides, this solution would not be able to alter the height fields aloft and go negative tilt through positive feedback cyclogenesis and it would be OTS. But it is the NAM. Only reason I mention a positive trend is it is a tad farther S with the southern PV.

exactly. I am definitely in agreement with your summary as well. At least all of these model runs are trying to really dig down deeper than before.

[baroclinic_instability]

Sort of weird to read all of these "NAM looks great" comments and then see this one.

I gave a much better analysis in the philly/ny region overnight. Start at 681, goes to 693. With pictures makes it more understandable. http://www.americanw...2/page__st__680

[tornadojay]

Sort of weird to read all of these "NAM looks great" comments and then see this one.

The "NAM looks great" comment could be a "relatively speaking" comment compared to what it looked like it might have been extrapolating to in the last few days. Compared to how it looks now and how it was looking before, I would say it looks great, but if you compare it to the Euro or the last run of the GFS, it still lags behind a bit in what we all percieve would be the best looking solution to get a major nor'easter up the coast.

[baroclinic_instability]

The "NAM looks great" comment could be a "realtively speaking" comment compared to what it looked like it might have been extrapolating to in the last few days. Compared to how it looks now and how it was looking before, I would say it looks great, but if you compare it to the Euro or the last run of the GFS, it still lags behind a bit in what we all percieve would be the best looking solution to get a major nor'easter up the coast.

Exactly. I concur with this statement.

[CTWeatherFreak]

I was just about to say the same thing. The entire trough from the surface to 200mb has yet to show any sign of going neutral or negative.

I dont know.. look at the H5 plot for the 12z gfs at 90 hrs, and its the same tilt as this NAM run at 84, and we all know the gfs excited alot of people today.

[vinylfreak89]

I gave a much better analysis in the philly/ny region overnight. Start at 681, goes to 693. With pictures makes it more understandable. http://www.americanw...2/page__st__680

excelent analysis... you're getting a bit beyond my knowledge base with the equations but very insightful nontheless.

[Don Cherry's Jacket]

I gave a much better analysis in the philly/ny region overnight. Start at 681, goes to 693. With pictures makes it more understandable. http://www.americanw...2/page__st__680

Thanks for posting this in the general forum and not just the regional thread. Should be required pre-reading by non-Mets (like me).

[PhineasC]

The "NAM looks great" comment could be a "realtively speaking" comment compared to what it looked like it might have been extrapolating to in the last few days. Compared to how it looks now and how it was looking before, I would say it looks great, but if you compare it to the Euro or the last run of the GFS, it still lags behind a bit in what we all percieve would be the best looking solution to get a major nor'easter up the coast.

Exactly. I concur with this statement.

I agree too guys. I was just noting that folks were probably getting a little too excited over late NAM panels. Still some work to do, but no reason to think it won't get there. The storm is still out of the NAM's range and far from its best time range.

[DJ Amenzo]

To those of you saying "NAM is too positively tilted and 300mb doesnt show any signs of going negative" I show you this map. See that 110+kts jet streak coming shooting down the front side of the ridge and being forced into the belly of the trough complex?? THAT is why the NAM is monstrous and about to show a Euro-like solution when extrapolated.

[baroclinic_instability]

To those of you saying "NAM is too positively tilted and 300mb doesnt show any signs of going negative" I show you this map. See that 110+kts jet streak coming shooting down the front side of the ridge and being forced into the belly of the trough complex?? THAT is why the NAM is monstrous and about to show a Euro-like solution when extrapolated.

Here is my quick and simple counterpoint. The 0Z GFS.

That digging trough you point out is TOO late. As the leading wave ejects over the EC, that jet you mention does this (circled red):

Au Revoir and way OTS (blue line).

[ohleary]

The trend continued and for that we are thankful. Saying that you do or don't like the 84 hour solution is fine but meaningless as it probably doesn't represent what is actually going to occur at that time. 3-5 days out is trends time folks, and they are going in the right direction for a Euro-like solution. Even with the much maligned 18Z NAM.

[Clinch Leatherwood]

To those of you saying "NAM is too positively tilted and 300mb doesnt show any signs of going negative" I show you this map. See that 110+kts jet streak coming shooting down the front side of the ridge and being forced into the belly of the trough complex?? THAT is why the NAM is monstrous and about to show a Euro-like solution when extrapolated.

Personally I think the NAM looks fine considering the range. It's going to have a monster low somewhere off the SE coast. That's all you're going to get out of these models at this time range in this pattern.

[baroclinic_instability]

The trend continued and for that we are thankful. Saying that you do or don't like the 84 hour solution is fine but meaningless as it probably doesn't represent what is actually going to occur at that time. 3-5 days out is trends time folks, and they are going in the right direction for a Euro-like solution. Even with the much maligned 18Z NAM.

Indeed, that is why I mentioned I don't care since it is the 18Z and it is still lagging about 2-3 iterations from the GFS, 4+ iterations of the ECM.