March 13 - 15 Major Winter Storm Potential

[NYCGreg]

1 minute ago, Rjay said:

And the plumes have gone up...

Then I'm wrong and I accept all the criticism thrown my way.  I can accept that.

[White Gorilla]

Just now, swamplover56 said:

Depends on how far inland a 50 mile correction is just that a correction for Albany or readding pa sure for our metro area. No

Yeah, barring huge changes, we are all on track for a big kahuna. 

[winterwarlock]

if you are going to laugh then why do we have the GFS at all, shouldnt look at it

[Rjay]

2 hours ago, KeithB said:

Rjay....may I ask why are ensembles much more important 48+ hours, but inside of 48 hours much less meaningful?

Bc they're good to use for trends, possible future solutions from it's OP l,  to see the spread of solutions possible and to see if the OP was on crack.  Ensemble means generally are less prone to wild swings like OP runs are.   Obviously the further out you are from a possible event the more wild the swing, even on ensembles.  Once we're inside 48 hours they become less useful as the members become tightly clustered together.

[Rjay]

3 minutes ago, NYCGreg said:

Then I'm wrong and I accept all the criticism thrown my way.  I can accept that.

Why would I criticize you for a mistake?  Only aholes do that. 

[eduggs]

I don't think the GFS should be completely discounted.  I also don't think any innate bias or lack of resolution is affecting the model.  It just depicts an ever so slightly different height field evolution and SLP track than most other guidance.  The lead wave is clearly slightly less sharp and the low center tracks slightly east of most other guidance.  These are small differences, but at this juncture, the impacts are noticeable.  The differences are real, the question is whether it will be closer or further from reality in the end.

It's comforting to see a multi-model consensus building for a high QPF even and coastal hugging track.  That definitely lends confidence.  But I do note that most guidance tracks the SLP NE and then ENE after passing the Delmarva.  That's a climatologically favored track.  It's not hooking into NY harbor.  Any changes in timing or development and we could easily see a GFS type track and precip field.  For example, if the storm slows down and doesn't make enough northward progress, it could easily be shunted east before the really heavy precip. makes it into the area.

All that said, the GFS is still a major snowstorm for most of the area.  And it has been slowly trending better the past few runs.  The multi-model consensus right now, including the GFS, is about as good as it ever gets.

[KeithB]

1 minute ago, Rjay said:

Bc they're good to use for trends, possible future solutions from it's OP l,  to see the spread of solutions possible and to see if the OP was on crack.  Ensemble means generally are less prone to wild swings like OP runs are.   Obviously the further out you are from a possible event the more wild the swing, even on ensembles.  Once we're inside 48 hours they become less useful as the members become tightly clustered together.

gotcha...thanks!

[SnowGoose69]

The current track by the RGEM and Euro IMO are too close for the NYC metro to see jackpot amounts, but they'd still do well.  Those tracks would almost definitely semi dry slot the area for a point and put max totals in similar spots to say the 96 blizzard.   With 48 hours to go though that track could shift of course 

[Rjay]

4 minutes ago, winterwarlock said:

if you are going to laugh then why do we have the GFS at all, shouldnt look at it

We have such a strong model concensus that it's easy to toss the GFS at this point.  Also knowing a model's bias helps when deciding how much to weigh that particular model into your forecast.  Not everyone will agree on whether to toss the GFS or not but that's why we have places like this to discuss and put forth our reasoning. 

[winterwarlock]

well the NAM doesnt agree either, having its own solution as well. do we toss that too

[PB GFI]

Just now, winterwarlock said:

if you are going to laugh then why do we have the GFS at all, shouldnt look at it

 

You know better .

 

It continues to lag behind the guidance .

once again during predicted east coast cyclogenesis its east 48 hours prior .

When the breath of the guidance is close to 2 inches L/E 

PARA/UKMET/EURO/EPS/GEM/RGEM and the same model shows the same SE bias why would not recognize that its continuing to correct.

 

Unless you want to ignore the explosive guidance and key on the 1 poor model on the E/C for the sake of trolling.

[Paragon]

2 minutes ago, SnowGoose69 said:

The current track by the RGEM and Euro IMO are too close for the NYC metro to see jackpot amounts, but they'd still do well.  Those tracks would almost definitely semi dry slot the area for a point and put max totals in similar spots to say the 96 blizzard.   With 48 hours to go though that track could shift of course 

Yes that's what our media sources are saying, no mixing unless you'e way out on the eastern half of the Island but lower ratios and a risk of dry slotting.  Temps will remain 32 or below throughout.

 

[PB GFI]

1 minute ago, winterwarlock said:

well the NAM doesnt agree either, having its own solution as well. do we toss that too

 

PARA does and its replacing the NAM 

[Rjay]

1 minute ago, winterwarlock said:

well the NAM doesnt agree either, having its own solution as well. do we toss that too

I always toss the NAM but that's just me lol.  

The Ukie, RGEM (inside 36 hours) and the Euro/EPS are a deadly combo.   I'd never bet against that consensus.   

[PB GFI]

3 minutes ago, Rjay said:

We have such a strong model concensus that it's easy to toss the GFS at this point.  Also knowing a model's bias helps when deciding how much to weigh that particular model into your forecast.  

 

I apologize if that was dck ish , it wasnt directed at him but the same lag in the guidance that seems to continue. 

[Rjay]

Just now, PB GFI said:

 

I apologize if that was dck ish , it wasnt directed at him but the same lag in the guidance that seems to continue. 

It's was fine.  I'm pretty pumped for this event.  

[USCG RS]

 

 

You know better .

 

 

 

It continues to lag behind the guidance .

 

once again during predicted east coast cyclogenesis its east 48 hours prior .

 

When the breath of the guidance is close to 2 inches L/E 

 

PARA/UKMET/EURO/EPS/GEM/RGEM and the same model shows the same SE bias why would not recognize that its continuing to correct.

 

 

 

Unless you want to ignore the explosive guidance and key on the 1 poor model on the E/C for the sake of trolling.

 

And this is why you're my favorite poster

 

EDIT: one of them anyway lol

[Paragon]

8 minutes ago, Rjay said:

Bc they're good to use for trends, possible future solutions from it's OP l,  to see the spread of solutions possible and to see if the OP was on crack.  Ensemble means generally are less prone to wild swings like OP runs are.   Obviously the further out you are from a possible event the more wild the swing, even on ensembles.  Once we're inside 48 hours they become less useful as the members become tightly clustered together.

Closer in to an event the the reasons for why ensembles exist- to compensate for data or equations that are slightly off- become less necessary because these only manifest themselves out as large scale errors at longer lead times.

 

[swamplover56]

Just now, winterwarlock said:

well the NAM doesnt agree either, having its own solution as well. do we toss that too

We don't toss anything as eduggs just so eloquently posted we weigh models differently. The nam is a meso scale model that really should be only used within 24 hours. The models with the best verification scores at this lead time are the euro by far, then the ukie. The rgem is also a mesoscale model that is best used within 24 hours. All models have tendencies and biases just need to understand that. What the gfs depicted could happen as eduggs explained or the nam etc we just have to wait them correctly. Ok now I'm really taking a break see you guys at oz 

[psv88]

Ride the Euro

[SnowGoose69]

1 minute ago, Paragon said:

Yes that's what our media sources are saying, no mixing unless you'e way out on the eastern half of the Island but lower ratios and a risk of dry slotting.  Temps will remain 32 or below throughout.

 

The winds will hurt the ratios for sure.  The temps on the GFS soundings which are the only ones I have access to at home right now would suggest 12-15 to 1, but with those winds I doubt it.  BTW, even the GFS soundings actually have shown the classic thundersnow signatures on some runs.  I've rarely seen that, usually its more evident on the higher resolution models

[Rjay]

1 minute ago, Paragon said:

Closer into an event the the reasons for why ensembles exist- to compensate for data or equations that are slightly off- become less necessary because these only manifest themselves out as large scale differences at longer lead times.

 

Yes but they generally aren't as useful as we get close in.  The spread is just too small. 

[PB GFI]

2 minutes ago, Rjay said:

It's was fine.  I'm pretty pumped for this event.  

 

After the last 6 weeks , a 6 to 12 would have been epic , but this oofa.

 

 

[Paragon]

1 minute ago, Rjay said:

Yes but they generally aren't as useful as we get close in.  The spread is just too small. 

Yep, plus once inside 24 hrs globals probably shouldn't be used at all.

[eduggs]

2 minutes ago, Rjay said:

I always toss the NAM but that's just me lol.  

The Ukie, RGEM (inside 36 hours) and the Euro/EPS are a deadly combo.   I'd never bet against that consensus.   

The UK is a good model in almost every respect except QPF.  Of course QPF is the least accurate model parameter for any model, but the UK in particular has very coarse QPF output.

[Paragon]

3 minutes ago, SnowGoose69 said:

The winds will hurt the ratios for sure.  The temps on the GFS soundings which are the only ones I have access to at home right now would suggest 12-15 to 1, but with those winds I doubt it.  BTW, even the GFS soundings actually have shown the classic thundersnow signatures on some runs.  I've rarely seen that, usually its more evident on the higher resolution models

Yes 50-60 mph winds could cap this to around 18 inches, like we had on the western half of the Island for the Boxing Day blizzard.  Winds would be similar to that.  I could see the city getting to 20.

[PB GFI]

7 minutes ago, USCG RS said:

And this is why you're my favorite poster

 

EDIT: one of them anyway lol

 

Thank you  .

 

At 48 hours out , absolutes are a sin and there are no locks here but this has a chance to be a top 10 NESIS storm from DC to N/E .

I cant rule out a mix at the height but there could b 2 to 2.5 inches of liquid that  fall s / mix for 3 hours and 20 inches still fall .

 

People do not realize the genre this type of storm is falling into , its not your run of the mill 6 to 12 for most .

[jm1220]

6 minutes ago, Paragon said:

Yes that's what our media sources are saying, no mixing unless you'e way out on the eastern half of the Island but lower ratios and a risk of dry slotting.  Temps will remain 32 or below throughout.

 

I'm paying attention to the 700mb low tracks on the models-if it goes overhead or west of you, typically the dryslot stays east of you. If it goes west of you, then mixing and the dryslot are likely. So far at least for the western half of the island, the 700mb low tracks where we want. But we can't afford anymore west shifts where we are-if so, then we definitely have issues with it and also mixing. I'm thinking this ends up slightly east of the consensus now (minus the GFS, I'm not even considering it). The progressiveness of the system overall might help this track more NNE off the Carolina coast, not almost due north.

[Paragon]

1 minute ago, jm1220 said:

I'm paying attention to the 700mb low tracks on the models-if it goes overhead or west of you, typically the dryslot stays east of you. If it goes west of you, then mixing and the dryslot are likely. So far at least for the western half of the island, the 700mb low tracks where we want. But we can't afford anymore west shifts where we are-if so, then we definitely have issues with it and also mixing. I'm thinking this ends up slightly east of the consensus now (minus the GFS, I'm not even considering it). The progressiveness of the system overall might help this track more NNE off the Carolina coast, not almost due north.

JM isn't this storm going to become vertically stacked so the lows are aligned with each other?

 

[Rjay]

7 minutes ago, eduggs said:

The UK is a good model in almost every respect except QPF.  Of course QPF is the least accurate model parameter for any model, but the UK in particular has very coarse QPF output.

The Ukie is my favorite model nowadays.  It's been so good the last couple of years with EC threats.  It hasn't been great with this storm so far.   It's been jumping around much like the other models but nothing too extreme.     Even the gfs hasn't been that bad overall.  It hasn't lost the storm once.