December Medium/Long Range Discussion

[Solution Man]

11 hours ago, bncho said:

Congrats, Richmond!

Short Pump, not Richmond 

[Ji]

its close. That high pressure is too dominant though

[NorthArlington101]

1 minute ago, Ji said:

its close. That high pressure is too dominant though

im a stable guy but if we happen to miss two storms in a row to OBX before a torch (even brief) I might stand near the ledge

[stormtracker]

6 minutes ago, Ji said:

what the hell are you tracking again?

Are you ok?

[Solution Man]

1 minute ago, NorthArlington101 said:

im a stable guy but if we happen to miss two storms in a row to OBX before a torch (even brief) I might stand near the ledge

I like where we are, get away from the ledge

[ravensrule]

13 minutes ago, stormtracker said:

Are you ok?

Has he ever been?. 

[psuhoffman]

25 minutes ago, stormtracker said:

Doesn't seem like this is gonna be it.  Monday might have been a mirage.

I don't think it's a mirage...the setup has the potential for an actual snowstorm.  We need the timing of a northern stream wave to change.  If it does...and asking for that kind of change at this range is not crazy...the setup is there.  That doesn't mean, of course, we will get the changes we need...but I don't think the threat is dead yet.  

12z GFS 

The problem is there is a wave coming across right on top of the potential system as it's entering the TN Valley...suppressing it right at the critical moment for our purposes.  If that wave to our north is 12 hours further along...there might be room...if it is 12 hours further behind...it opens the door to a phase in a helpful way instead of a suppressive impact.  There are options here that very reasonable changes to this depiction could very easy result in snow for our area.  Most of the ingredients we need for a snowstorm are right there...with just one thing we need to get out of the way.  I wouldn't give up on it yet.  

[Jersey Andrew]

Just now, psuhoffman said:

I don't think it's a mirage...the setup has the potential for an actual snowstorm.  We need the timing of a northern stream wave to change.  If it does...and asking for that kind of change at this range is not crazy...the setup is there.  That doesn't mean, of course, we will get the changes we need...but I don't think the threat is dead yet.  

12z GFS 

The problem is there is a wave coming across right on top of the potential system as it's entering the TN Valley...suppressing it right at the critical moment for our purposes.  If that wave to our north is 12 hours further along...there might be room...if it is 12 hours further behind...it opens the door to a phase in a helpful way instead of a suppressive impact.  There are options here that very reasonable changes to this depiction could very easy result in snow for our area.  Most of the ingredients we need for a snowstorm are right there...with just one thing we need to get out of the way.  I wouldn't give up on it yet.  

Is this more a Mid-Atlantic threat in your opinion or Northeast too?

[psuhoffman]

Just now, Jersey Andrew said:

Is this more a Mid-Atlantic threat in your opinion or Northeast too?

It's far enough out that making that kind of determination is risky.  I will say this...if the northern stream is very close to what is being depicted right now...its a threat for the southern mid atlantic.  If the northern stream were to relax some or that wave were to get ahead more and out of the way...it becomes a threat for our area perhaps...but would still have a cap to how far north it could make it...and my biggest fear would still be a fringe, if the northern stream wave were to be further behind...and possibly phase...that would open the door to a coastal climbing system that could threaten further north.  I have no read on this, I've not had time to really dig in more than some superficial analysis... so I am not going to pretend to have any insight into which way it's more likely to go.  

[Ephesians2]

The CMC looks a lot closer for the Monday potential, as in it is not completely out to sea anymore

[SnowenOutThere]

9 minutes ago, psuhoffman said:

I don't think it's a mirage...the setup has the potential for an actual snowstorm.  We need the timing of a northern stream wave to change.  If it does...and asking for that kind of change at this range is not crazy...the setup is there.  That doesn't mean, of course, we will get the changes we need...but I don't think the threat is dead yet.  

12z GFS 

The problem is there is a wave coming across right on top of the potential system as it's entering the TN Valley...suppressing it right at the critical moment for our purposes.  If that wave to our north is 12 hours further along...there might be room...if it is 12 hours further behind...it opens the door to a phase in a helpful way instead of a suppressive impact.  There are options here that very reasonable changes to this depiction could very easy result in snow for our area.  Most of the ingredients we need for a snowstorm are right there...with just one thing we need to get out of the way.  I wouldn't give up on it yet.  

Something I've been trying to watch with this storm is the initial energy phasing between the NS and the low off Mexico and how that impacts the ability for downstream cyclogenesis. Though being honest that analysis starts to stretch the limit of my understanding. Generally I've assumed we want the low off Mexico to be further North and East (and more energetic) in order to feed energy and get fully captured by the NS shortwave though I'd like to know your read on it as I could also see a possibility where that Mexican low destructively interferes by not getting cleanly absorbed eastward.

[psuhoffman]

2 minutes ago, SnowenOutThere said:

Something I've been trying to watch with this storm is the initial energy phasing between the NS and the low off Mexico and how that impacts the ability for downstream cyclogenesis. Though being honest that analysis starts to stretch the limit of my understanding. Generally I've assumed we want the low off Mexico to be further North and East (and more energetic) in order to feed energy and get fully captured by the NS shortwave though I'd like to know your read on it as I could also see a possibility where that Mexican low destructively interferes by not getting cleanly absorbed eastward.

There are so many variables and permutations...they all matter to some degree.  I was not even really focusing on that feature, which does NOT mean it's not important, just means it wasn't where my attention was...the Mexican energy mostly washes out and the wave that ends up in the TN valley is from the energy that comes into the PAC NW and ejects from the Rockies around 100 hours.  IMO the wave is healthy enough, the biggest problem is the timing and strength of that NS wave in front of it and the orientation of the NS.  If we can just get one change...that is the one I would look for.  But there are a ton of variables...we could root for a ton of other little factors that could lead to a better result...better phasing between that Mexican energy and the PAC wave leading to an even stronger TN valley system...changes in the timing of that system, if it were to slow down by 12-24 hours...but then does that introduce temp issues...UGH see it gets complicated and I am trying to keep it simple lol 

[Cobalt]

16 minutes ago, Ephesians2 said:

The CMC looks a lot closer for the Monday potential, as in it is not completely out to sea anymore

Past two runs have had increasing separation between the southern and northern waves. That looks like an ample route to a success scenario.

[SnowenOutThere]

BTW: CMC has a really nice mid-20s snowstorm the 12z that brings 6 inches from the MD/PA border to south of Richmond

[psuhoffman]

1 minute ago, Cobalt said:

Past two runs have had increasing separation between the southern and northern waves. That looks like an ample route to a success scenario.

This is what I meant in my last comment about so many permutations...the CMC actually made the changes we need with the NS, but it has a weaker more disjointed southern system and has this little kicker behind it that wasn't there before or on other guidance...so it ends up with the same result.  If you had that NS look from the CMC with the GFS/Euro TN valley look...it would be a snowstorm for us.  But I'm not good enough to figure out all these little variables from this range and I am not going to project false confidence and pretend I am.  

[psuhoffman]

What I will say is that I decided to let my "slightly above average snowfall" seasonal forecast ride.  And nothing I've seen so far makes me regret that.  

[SnowenOutThere]

7 minutes ago, psuhoffman said:

There are so many variables and permutations...they all matter to some degree.  I was not even really focusing on that feature, which does NOT mean it's not important, just means it wasn't where my attention was...the Mexican energy mostly washes out and the wave that ends up in the TN valley is from the energy that comes into the PAC NW and ejects from the Rockies around 100 hours.  IMO the wave is healthy enough, the biggest problem is the timing and strength of that NS wave in front of it and the orientation of the NS.  If we can just get one change...that is the one I would look for.  But there are a ton of variables...we could root for a ton of other little factors that could lead to a better result...better phasing between that Mexican energy and the PAC wave leading to an even stronger TN valley system...changes in the timing of that system, if it were to slow down by 12-24 hours...but then does that introduce temp issues...UGH see it gets complicated and I am trying to keep it simple lol 

I haven't looked at the upper level progression yet today so I was going off of yesterday (which may have had that low more important who knows). I was treating the situation as if we can get more energy together earlier we have a better shot at running the gamut of confluence to our North (I am also 100 miles south so I care a little less about the confluence). That said, I definitely see overall how changing the NS wave would help us out more concretely than anything else as it is the direct inhibitor to strengthening. 

[yoda]

3 minutes ago, SnowenOutThere said:

BTW: CMC has a really nice mid-20s snowstorm the 12z that brings 6 inches from the MD/PA border to south of Richmond

11th-12th time period... I believe a few people on here have mentioned that time period as a potential threat

[psuhoffman]

1 minute ago, yoda said:

11th-12th time period... I believe a few people on here have mentioned that time period as a potential threat

If you take a step back and just look at the larger pattern progression it might be the period that makes the most sense...but it's also the furthest out of all the concrete threats.  

[SnowenOutThere]

4 minutes ago, psuhoffman said:

This is what I meant in my last comment about so many permutations...the CMC actually made the changes we need with the NS, but it has a weaker more disjointed southern system and has this little kicker behind it that wasn't there before or on other guidance...so it ends up with the same result.  If you had that NS look from the CMC with the GFS/Euro TN valley look...it would be a snowstorm for us.  But I'm not good enough to figure out all these little variables from this range and I am not going to project false confidence and pretend I am.  

FWIW the 12z CMC seems to have more interaction with the low I was talking about earlier and its to the shortwaves seeming determent as its unable to turn more neutral to negative as both runs fail to ingest the vorticity but 12z gets more interaction without phasing. Maybe there's a minimum in potential between either no interaction outwest and relying on just the NS diving and the other potential of a relatively complete and clean phase (which would have a higher upside)

12z

last 12z