Thursday Thumper or Thirst-Quencher

[CT Rain]

I've been out of the loop and just starting to catch up on things.

As Will said the GFS is definitely the outlier but I wouldn't totally toss it. The Euro seems the get overly amped with these things so I think a 75% Euro/25% GFS blend is a good starting point right now. Definitely a nod to the Euro/EPS. There aren't really any crazy SREF members here - and some really good clustering <6" for BDL. Also the EPS keep the 6" mean snowfall north of CT/MA line and the probability of 6"+ for BDL is pretty low off the EPS - maybe like 20 percent or so. 

I do think that latitude helps quite a bit with this - particularly here in CT. With the upper level low cutting off mainly north of us it may hurt areas south of the Pike. 

My forecast would be really close to what BOX just put out - I think that looks good right now here in CT. 

 

[CTWeatherFreak]

Why are we under a Winter Storm watch in Hartford area, when the watch verbiage reads 3-6".  Isnt 6+" the minimum criteria for a WSW?

[CT Rain]

Just now, CTWeatherFreak said:

Why are we under a Winter Storm watch in Hartford area, when the watch verbiage reads 3-6".  Isnt 6+" the minimum criteria for a WSW?

Yeah it's pretty odd. Who knows. 

[moneypitmike]

44 minutes ago, dendrite said:

I'm glad they added a 50-100" range on the "at least" map.

LMAO.  What a hoot!

5 minutes ago, CT Rain said:

Yeah it's pretty odd. Who knows. 

Welcome back, Ryan--you've been missed.

[moneypitmike]

7 minutes ago, CTWeatherFreak said:

Why are we under a Winter Storm watch in Hartford area, when the watch verbiage reads 3-6".  Isnt 6+" the minimum criteria for a WSW?

I figure with the watch they can either advance to a warning or backtrack to advisory.  I suppose they could have worded it with "the potential of 6" or more" and leave it at that then throw in a range that was really sub-warning levels.

[ORH_wxman]

The explosive potential of these systems that add uncertainty to the forecast is part of what makes tracking them a lot of fun. Who knows if it works out to the more explosive/earlier development this time around, but the possibility exists which creates much larger error bars on a forecast than usual for less than 48 hours out. This isn't like a SWFE where perhaps we're talking about how 3-4" could become 6" if things break right...that's uncertainty, and it's fun...but this is on another level. There's some areas where like 1" of slush is forecast that could realistically get 10" if things broke right...and we're not talking a hail mary chance either. Prob something like 1 in 4 or similar.

[CT Rain]

2 minutes ago, moneypitmike said:

LMAO.  What a hoot!

Welcome back, Ryan--you've been missed.

Thanks! I've missed all of you guys as well. Have just been really busy and the weather has been horribly boring. Twitter and Facebook take up a lot of my time these days - a lot of it I have to do for work.

Anyways back to this storm... I'm not really excited about my backyard but I think Kevin's area up through ORH and the Rt 2 corridor in Mass up your way should be in good shape. 

[Ginx snewx]

6 minutes ago, ORH_wxman said:

The explosive potential of these systems that add uncertainty to the forecast is part of what makes tracking them a lot of fun. Who knows if it works out to the more explosive/earlier development this time around, but the possibility exists which creates much larger error bars on a forecast than usual for less than 48 hours out. This isn't like a SWFE where perhaps we're talking about how 3-4" could become 6" if things break right...that's uncertainty, and it's fun...but this is on another level. There's some areas where like 1" of slush is forecast that could realistically get 10" if things broke right...and we're not talking a hail mary chance either. Prob something like 1 in 4 or similar.

3k NAM shows potential GFS shows other potential. Flow seems a tad too far North today. Classic Whites, Western Maine crusher

[CT Rain]

6 minutes ago, Ginx snewx said:

3k NAM shows potential GFS shows other potential. Flow seems a tad too far North today. Classic Whites, Western Maine crusher

I agree with that, Steve. Not sure how much time we have south of the Pike to get in on the goods. 

[Allsnow]

Talk about a short term model war! Euro has a foot for Orh and the gfs a inch 

[Damage In Tolland]

19 minutes ago, CT Rain said:

Thanks! I've missed all of you guys as well. Have just been really busy and the weather has been horribly boring. Twitter and Facebook take up a lot of my time these days - a lot of it I have to do for work.

Anyways back to this storm... I'm not really excited about my backyard but I think Kevin's area up through ORH and the Rt 2 corridor in Mass up your way should be in good shape. 

Hopefully can extend that down to Ginx 

[ORH_wxman]

5 minutes ago, Allsnow said:

Talk about a short term model war! Euro has a foot for Orh and the gfs a inch 

GFS is prob too warm in the boundary layer...even if the rest of the solution is correct.

[TauntonBlizzard2013]

3 minutes ago, Allsnow said:

Talk about a short term model war! Euro has a foot for Orh and the gfs a inch 

Yeah... this thing is moving along at a good clip... not much margin for error for places like ORH Berkshires and NW CT... if the development takes a bit longer than what the euro shows.... those areas won't get much.. despite more favorable temp profiles.

id probably blend euro 60% GFS 40%.... I think the GFS is to slow developing and I think the euro is probably too quick.

i wouldn't be shocked if it backed off a bit. I think in the end, the bulk of the heavy action will be in central New Hampshire over to Maine 

[powderfreak]

23 minutes ago, ORH_wxman said:

The explosive potential of these systems that add uncertainty to the forecast is part of what makes tracking them a lot of fun. Who knows if it works out to the more explosive/earlier development this time around, but the possibility exists which creates much larger error bars on a forecast than usual for less than 48 hours out. This isn't like a SWFE where perhaps we're talking about how 3-4" could become 6" if things break right...that's uncertainty, and it's fun...but this is on another level. There's some areas where like 1" of slush is forecast that could realistically get 10" if things broke right...and we're not talking a hail mary chance either. Prob something like 1 in 4 or similar.

And you've got places that are forecast to get 10" that could realistically get 1-3" if things break wrong.  Large scale bust potential in a very large area on both ends of the spectrum.

[TauntonBlizzard2013]

Just now, powderfreak said:

And you've got places that are forecast to get 10" that could realistically get 1-3" if things break wrong.

Right. It goes both ways...there is incredible bust potential on both the positive and negative side 

[RUNNAWAYICEBERG]

welcome to gradient living folks. 

[Allsnow]

4 minutes ago, ORH_wxman said:

GFS is prob too warm in the boundary layer...even if the rest of the solution is correct.

That would narrow the gap a bit. As you said the upside could be very big 

[Typhoon Tip]

Here's what I'm thinking...

First, I'm not sure why folks think the cold air in this thing is dynamic-reliant (for lack of better phrase). There will certainly be some of that effect.  But, there's plenty of cold air lain down antecedent to this things arrival.  Pick a model, you can see CAA leading... Pick a window, stick your head out...it's getting chilly again. 

Second, if more important to the quicker (plausibility) of explosive development is that the 850 mb temperature contours are very compressed down along the Del Marva up through NJ. That means that the frontal interface in that region (collocated with the zygote 850 mb low) is exceptionally upright angled.  That is important, because as that massively powerful jet max rides over top and instantiates restoring inflow ...that flow will be deflect almost vertically, which maximizing several feed-back process.  For one upglide convection gets rather hard for hydrostatic model types because well...they kinda don't know it's there.

It seems this 18z NAM version broke a better multi-cycle continuity it had established relative to its own history of this thing. It would seem prudence requires waiting to see if that has more consistency before sans the previous dynamics.  Also, we'll have to monitor/now-cast the incoming cold and see how it lays down the slab from the midriff m/a on up.  I suspect this recent NAM solution decided to thin it out some and therefore, is not processing for the same sort of thermal compression it was seeing among the previous depictions.  I'm just not sure it's handling things on this run.  Others and my self noted earlier that the 06 and 18z runs of the NAM have been alternating away; I'm still wondering if that's somehow assimilation - but I'm far from certain there. 

Every time I've seen that type of thermal wall set up from fresh CAA, then... watched a negatively tilted jet maxes run right over top the result has been more intense than originally anticipated.    

 

[Damage In Tolland]

It's crazy anyone gives credence to the GFS. It's been moving towards other models for 2 days and still correcting. It's well known it handles east coast bombogenisis terribly . Could the Euro be overamped? Yup.. it probably is.. but you don't for a second give all this weight to the GFS. It had a mild frontal passage 2 days ago 

[powderfreak]

3 minutes ago, Damage In Tolland said:

It's crazy anyone gives credence to the GFS. It's been moving towards other models for 2 days and still correcting. It's well known it handles east coast bombogenisis terribly . Could the Euro be overamped? Yup.. it probably is.. but you don't for a second give all this weight to the GFS. It had a mild frontal passage 2 days ago 

It seems most all posts here have been arguing for a blend between the two, weighted heavier towards the EURO?  Haven't seen many tossing the EURO in favor of the GFS.  So chill the EURO down and amp the GFS up a bit...everyone knows where they'd fall if its a blend of the two to some extent.

[klw]

So it looks like 4 to 16 inches is the call for my new backyard.

[moneypitmike]

2 minutes ago, klw said:

So it looks like 4 to 16 inches is the call for my new backyard.

You're range is larger than mine.  I'm going for 4-12" here at the Pit.

[ORH_wxman]

5 minutes ago, powderfreak said:

It seems most all posts here have been arguing for a blend between the two, weighted heavier towards the EURO?  Haven't seen many tossing the EURO in favor of the GFS.  So chill the EURO down and amp the GFS up a bit...everyone knows where they'd fall if its a blend of the two to some extent.

 

Yeah I'd prob go 70/30 blend or so...that is typically what I do anyway.

 

I'm waiting one more cycle to see if we should really lean on the non-hydrostatics. If we get the earlier development like the Euro shows, then I may start leaning on the RGEM/NAM a lot more than usual. But it is conditioned on early enough development that the obscene convective processes take over. Tip has made many references to the physics of this and how hydrostatic models "won't know it's there". But we have some time still...no need to throw in the ginxy-gone-wild DVD yet...we can see if the 00z cycle warrants it...and even 12z tomorrow.

[dryslot]

12z Euro and 18z GFS both print out roughly 1.5" qpf here, Euro is 14" of snow, And GFS is 3".......................

[CoastalWx]

21 minutes ago, Typhoon Tip said:

Here's what I'm thinking...

First, I'm not sure why folks think the cold air in this thing is dynamic-reliant (for lack of better phrase). There will certainly be some of that effect.  But, there's plenty of cold air lain down antecedent to this things arrival.  Pick a model, you can see CAA leading... Pick a window, stick your head out...it's getting chilly again. 

Second, if more important to the quicker (plausibility) of explosive development is that the 850 mb temperature contours are very compressed down along the Del Marva up through NJ. That means that the frontal interface in that region (collocated with the zygote 850 mb low) is exceptionally upright angled.  That is important, because as that massively powerful jet max rides over top and instantiates restoring inflow ...that flow will be deflect almost vertically, which maximizing several feed-back process.  For one upglide convection gets rather hard for hydrostatic model types because well...they kinda don't know it's there.

It seems this 18z NAM version broke a better multi-cycle continuity it had established relative to its own history of this thing. It would seem prudence requires waiting to see if that has more consistency before sans the previous dynamics.  Also, we'll have to monitor/now-cast the incoming cold and see how it lays down the slab from the midriff m/a on up.  I suspect this recent NAM solution decided to thin it out some and therefore, is not processing for the same sort of thermal compression it was seeing among the previous depictions.  I'm just not sure it's handling things on this run.  Others and my self noted earlier that the 06 and 18z runs of the NAM have been alternating away; I'm still wondering if that's somehow assimilation - but I'm far from certain there. 

Every time I've seen that type of thermal wall set up from fresh CAA, then... watched a negatively tilted jet maxes run right over top the result has been more intense than originally anticipated.    

 

The antecedent airmass is not cold. When it warms to 1-2C at 925...I'd say that's not the best airmass. But, it's serviceable as ageostrophic flow takes over and draws lower Tw air south.

[Damage In Tolland]

18 minutes ago, powderfreak said:

It seems most all posts here have been arguing for a blend between the two, weighted heavier towards the EURO?  Haven't seen many tossing the EURO in favor of the GFS.  So chill the EURO down and amp the GFS up a bit...everyone knows where they'd fall if its a blend of the two to some extent.

I think you have some folks simply using snow maps. So someone sees an inch at ORH on 1 model and 12 on the other. That's the problem. If those said folks used known model biases and looked at temps from top down in a bombing system you'd find the amounts are much closer than 11 inches. You might come to the conclusion 7-10" is most likely at ORH. But if one is using a snow map only, they'd think that ORH was getting An inch or 2 

[HIPPYVALLEY]

There really isn't much more to say until the 0z runs start rolling.

Also if the 0z GFS doesn't budge I would certainly not completely discount it yet.  

I honestly won't be confident about outcomes in SNE/CNE until after tomorrow's 12z runs. 

[Typhoon Tip]

37 minutes ago, CoastalWx said:

The antecedent airmass is not cold. When it warms to 1-2C at 925...I'd say that's not the best airmass. But, it's serviceable as ageostrophic flow takes over and draws lower Tw air south.

The antecedent airmass is cold.  When the 540 advects actively south of the region, and 850 is down below -2 C, it's cold enough ...particularly, where it matters, off the deck where the mechanics are at work.

[powderfreak]

47 minutes ago, ORH_wxman said:

 

Yeah I'd prob go 70/30 blend or so...that is typically what I do anyway.

 

I'm waiting one more cycle to see if we should really lean on the non-hydrostatics. If we get the earlier development like the Euro shows, then I may start leaning on the RGEM/NAM a lot more than usual. But it is conditioned on early enough development that the obscene convective processes take over. Tip has made many references to the physics of this and how hydrostatic models "won't know it's there". But we have some time still...no need to throw in the ginxy-gone-wild DVD yet...we can see if the 00z cycle warrants it...and even 12z tomorrow.

Yeah I'm at the point where if the EURO and Ensemble mean stays the course tonight at 00z, I think you have to lean the forecast that way.  It's just been so rock steady. Remember the EURO was showing 12-18" for Dendrite and adjacent areas like 3 days ago when the other models had nothing but 1-3" of upper level trough snows.  That model holds and I think you have to go that way.

[nzucker]

1 hour ago, Ginx snewx said:

3k NAM shows potential GFS shows other potential. Flow seems a tad too far North today. Classic Whites, Western Maine crusher

Yea it's been trending in the wrong direction for those of us further west. Definitely later deepening and a slower CCB, which makes it harder. 

Catskills went from 6-10 on yesterday's Euro to 3-5 now.