Tracking Jan 7 coastal storm. Lingering compression/flow velocity has not lent to consensus, but it seems at 30 hours out.. finally?

[Typhoon Tip]

10 minutes ago, eduggs said:

If you overlay the 500mb vorticity chart of the NAM at 84hrs with the GFS at 80hrs, they look pretty similar considering the lead time. The NAM is maybe a touch sharper and there's more ridging both up- and downstream. But still very similar. So the GFS should be a reasonable estimation of what the NAM run might have led to. In this case, a deep and powerful storm in the Maritimes. 

Mmm. GFS and NAM models employ different physical parameterization for things like cloud physics … convective processes; this is why the Nam blew. all the other models away on that 2005 December 10 event.

… plus with a Nam running a negatively tilting Vmax with 120 mph wind core up over the gulf stream that models going to absolutely MESO-beta scale bomb that at historic RI rates - if that were a metric kept track of.  

[TalcottWx]

Mid levels and ensembles. The key to winter forecasting. Lol

[40/70 Benchmark]

Just now, WinterWolf said:

 

 

Absolutely. Speed of movement is the most overrated aspect of snowfall forecasts. It's all about rates...how often do you get 24 hours of heavy snow? Even slow movers ultimately become a red headed, occulded step child.

[40/70 Benchmark]

2 minutes ago, Typhoon Tip said:

Mmm. GFS and NAM models employ different physical parameterization for things like cloud physics … convective processes; this is why the Nam blew. all the other models away on that 2005 December 10 event.

… plus with a Nam running a negatively tilting Vmax with 120 mid mph wind core up over the gulf stream that things going to absolutely MESO-beta scale bomb that at historic RI rates - if that were a metric kept track of.  

You gotta understand, living in NJ, he's protecting his concern for a late bloomer. Lol

[WinterWolf]

3 minutes ago, 40/70 Benchmark said:

If you can't get heavy totals from a 12 hours event, then the storm either sucked, and/or didn't take a favorable track. 

That’s kind of my thinking as well. But that’s a moot point at the moment…we have to see how this thing comes together still.  

[dryslot]

1 minute ago, 40/70 Benchmark said:

If you can't get heavy totals from a 12 hours event, then the storm either sucked, and/or didn't take a favorable track. 

And neither one of these are set yet.......... lol, We should know more at 0z tomorrow night or 12z Weds.

[40/70 Benchmark]

Just now, dryslot said:

And neither one of these are set yet.......... lol, We should know more at 0z tomorrow night or 12z Weds.

I agree on that...just saying. This could still fizzle, though I do nor hedge that way. Very possible 

[HIPPYVALLEY]

1 minute ago, 40/70 Benchmark said:

Absolutely. Speed of movement is the most overrated aspect of snowfall forecasts. It's all about rates...how often do you get 24 hours of heavy snow? Even slow movers ultimately become a red headed, occulded step child.

Yeah, I guess if you are under the ccb death bands or western deformation bands then 2-4 hours of SN/SN+ can make a storm memorable no matter how fast it's hauling out. 

[Typhoon Tip]

10 minutes ago, PhineasC said:

Big west move.

Perfect climate spot on that particular frame … really 

[dryslot]

Just now, 40/70 Benchmark said:

I agree on that...just saying. This could still fizzle, though I do nor hedge that way. Very possible 

I doubt it will as well, Just looked at the Ukie and it traded places with the GFS ha ha.

[MJO812]

Ukie flat 

[ineedsnow]

GEFS mean. 

[eduggs]

6 minutes ago, Typhoon Tip said:

Mmm. GFS and NAM models employ different physical parameterization for things like cloud physics … convective processes; this is why the Nam blew. all the other models away on that 2005 December 10 event.

… plus with a Nam running a negatively tilting Vmax with 120 mph wind core up over the gulf stream that models going to absolutely MESO-beta scale bomb that at historic RI rates - if that were a metric kept track of.  

All I'm saying is the GFS has almost the same negative tilt, same vmax placement, same jet core and positioning etc... which is why it develops a very intense SLP - low 960s or something - in the Canadian Maritimes. The NAM and GFS are not typically so similar 84 hours out. Maybe the NAM would go even wilder, but they don't seem so far off to my eye. 

[WinterWolf]

Just now, ineedsnow said:

GEFS mean. 

That’s a thing of beauty! 

[SnoSki14]

2 minutes ago, MJO812 said:

Ukie flat 

Flow is fast. We're going to see dramatic model shifts next couple days. 

I'm leaning towards a whiff right now.

[PhineasC]

GFS and NAM big west moves. CMC drifted SE. UKMET doing what it does and heading to Portugal.

Still a lot of uncertainty. If Euro holds serve or moves west a little I think we can start to feel decent.

[WinterWolf]

Just now, SnoSki14 said:

Flow is fast. We're going to see dramatic model shifts next couple days. 

I'm leaning towards a whiff right now.

A whiff? Really? 
 

hmm ok. 

[MJO812]

3 minutes ago, SnoSki14 said:

Flow is fast. We're going to see dramatic model shifts next couple days. 

I'm leaning towards a whiff right now.

LOL no

[MJO812]

The flow isn't that fast.

Pna is improving 

[ineedsnow]

alot of those GEFS members go over eastern MA and the cape

[Typhoon Tip]

11 minutes ago, eduggs said:

All I'm saying is the GFS has almost the same negative tilt, same vmax placement, same jet core and positioning etc... which is why it develops a very intense SLP - low 960s or something - in the Canadian Maritimes. The NAM and GFS are not typically so similar 84 hours out. Maybe the NAM would go even wilder, but they don't seem so far off to my eye. 

That’s not entirely true tho; the 84 hour position on those models vary by almost 300 nautical miles with the Nam further back Southwest. 

Plus the NAMs total curvature field is broader with the same velocity imbedded as GFS was, when it was in that NAM position. The NAM is propagating more mechanical power. Additional to those other params the NAM’s ability to exceed the deepening rate of that GFS solution is that it also has more time to do it. 

[eduggs]

It's true we shouldn't be paying much attention to QPF at this stage. But this 36hr QPF image tells the tale of where a late developing coastal storm blows it load. Most would sign on for this type of outcome. Ensembles also give some indication of a higher ceiling. But let's not go crazy building up unrealistic potential based on the currently modeled features.

[eduggs]

6 minutes ago, Typhoon Tip said:

That’s not entirely true tho; the 84 hour position on those models vary by almost 300 nautical miles with the Nam further back Southwest. 

Plus the NAMs total curvature field is broader with the same velocity imbedded as GFS was, when it was in that NAM position. The NAM is propagating more mechanical power. Additional to those other params the NAM’s ability to exceed the deepening rate of that GFS solution is that it also has more time to do it. 

As I clearly said, if you overlay the 80 hr GFS with the 84 hr NAM they are very close in most key features - unusually so. If you cannot concede that, you are being unreasonable IMO. The NAM does not have any more time to deepen. On NCEP, the GFS is 2mb deeper, 4 hours earlier, in nearly the same location. None of the rest of what you said makes any sense. It doesn't matter anyway, since we're 3.5 days out and it will change every 6 hours. I just think your original comment exaggerated a little bit. 

[dendrite]

GFS started closing off the midlevels just in time for ENE…got a little easterly inflow at H7 for a last hurrah over E MA/ME.

[weathafella]

Uncle still sleeping off the holiday bender it seems....

[wxsniss]

Even just through hr 66 can see shortwave is digging less over Missouri... this run will not hug

[weathafella]

5 minutes ago, wxsniss said:

Even just through hr 66 can see shortwave is digging less over Missouri... this run will not hug

It's CMCesque in the end.  However the 87 hour 850 inflow suggests to me that qpf is underdone.

 

 

[wxsniss]

0z Euro and GFS stepped toward each other, maybe even a little do si do

Like GFS, would not take QPF verbatim especially in eSNE

[weathafella]

1 minute ago, wxsniss said:

0z Euro and GFS stepped toward each other, maybe even a little do si do

Like GFS, would not take QPF verbatim especially in eSNE

I still think this will make us flirt with taint by the time the track is settled.  At least we'll have snow cover for a few days (hopefully)

[Henry's Weather]

Operational models switched places at hour 84 in a progressive flow? Color me shocked. Ensembles, ensembles, ensembles until Wednesday afternoon.