December 9, 2017 - Storm Discussion (Breaking the seal on the season for many)

[Ginx snewx]

1 minute ago, dryslot said:

He posted in the model thread yesterday i believe.

Cool

[ineedsnow]

GEFS came west a tad at 6z.. At this point just want an inch or two and I'll be happy

[USCAPEWEATHERAF]

So did the 6z GFS

[JC-CT]

Hey bud, I'm here. Just watching, not overly excited about this one. It's a nice look setting up in the mid range though.

[Damage In Tolland]

Nice bumps west again overnight. More confidence in 2-4” for much of SNE Sat Am

[Go Kart Mozart]

Still whiffing like Judge for me.

[USCAPEWEATHERAF]

Just now, Go Kart Mozart said:

Still whiffing like Judge for me.

Sorry, you just aren't in a good location for this system, maybe the mid week system

[Go Kart Mozart]

1 minute ago, USCAPEWEATHERAF said:

Sorry, you just aren't in a good location for this system, maybe the mid week system

Mid-week looks like a super-fast late developer.  Good for you maybe, but bad for me.

[USCAPEWEATHERAF]

16 minutes ago, Go Kart Mozart said:

Mid-week looks like a super-fast late developer.  Good for you maybe, but bad for me.

maybe

[Damage In Tolland]

Ukie was a nice hit and came west too

[CoastalWx]

The euro has a little more concentrated vort. So that may help. The problem is the s/w right behind it. That won't allow the first s/w to really curl up and buckle the flow like it could have. So, I'm not really sure how much more west it could go. Although...since the QPF shield is so abrupt...even 30 miles could mean flurries or 1-2". 

[STILL N OF PIKE]

2 minutes ago, CoastalWx said:

The euro has a little more concentrated vort. So that may help. The problem is the s/w right behind it. That won't allow the first s/w to really curl up and buckle the flow like it could have. So, I'm not really sure how much more west it could go. Although...since the QPF shield is so abrupt...even 30 miles could mean flurries or 1-2". 

Great

The kicker

[USCAPEWEATHERAF]

I think models might have a mis handle on that second shortwave (kicker disturbance)

[weathafella]

6 minutes ago, USCAPEWEATHERAF said:

I think models might have a mis handle on that second shortwave (kicker disturbance)

Why?

[USCAPEWEATHERAF]

Because most models unlike the GFS don't handle the progressive flow that well, an example the EURO, while it is better with southern stream interactions, it is not good with northern stream interactions with the arctic jet.  The GFS has a progressive bias, but that does not happen within a fast la nina induced northern stream.  So I think the models could actually lean towards a more neutral solution with the kicker disturbance either kicking it faster through the flow, or actually phase partially with the northern stream and arctic streams.  We are less than 84 hours away from the first flakes or drops

[CoastalWx]

11 minutes ago, STILL N OF PIKE said:

Great

The kicker

Well that is the one that could have made Sunday a little more interesting. At this stage, I think we hope to have the lead s/w sharper and help curl the moisture field back west a bit. I'm always a little more cautious when you have GOM moisture with a sharp s/w. That's a recipe for west if the flow allows for it.  

[USCAPEWEATHERAF]

Just now, CoastalWx said:

Well that is the one that could have made Sunday a little more interesting. At this stage, I think we hope to have the lead s/w sharper and help curl the moisture field back west a bit. I'm always a little more cautious when you have GOM moisture with a sharp s/w. That's a recipe for west if the flow allows for it.  

Could the models be mishandling the second shortwave and that actually be allowed to phase with the Pacific disturbance?

[CoastalWx]

5 minutes ago, USCAPEWEATHERAF said:

Could the models be mishandling the second shortwave and that actually be allowed to phase with the Pacific disturbance?

I assume you mean the s/w that sort of rides through the southwest and then traverses the GOM?

[USCAPEWEATHERAF]

Yes

[RUNNAWAYICEBERG]

Sometimes, models are correct. 

Modelology > Weenieology

[weathafella]

18 minutes ago, USCAPEWEATHERAF said:

Because most models unlike the GFS don't handle the progressive flow that well, an example the EURO, while it is better with southern stream interactions, it is not good with northern stream interactions with the arctic jet.  The GFS has a progressive bias, but that does not happen within a fast la nina induced northern stream.  So I think the models could actually lean towards a more neutral solution with the kicker disturbance either kicking it faster through the flow, or actually phase partially with the northern stream and arctic streams.  We are less than 84 hours away from the first flakes or drops

My understanding was a progressive flow is the GFS best pattern.  It tends to fail in big east coast storm patterns.

[CoastalWx]

17 minutes ago, USCAPEWEATHERAF said:

Yes

It's possible the energy may be buried too far southwest. That can happen, and will cause that lead s/w to be stretched a bit and not buckle the flow. But, you can't always look at a model and try to force yourself to find a reason why it's wrong. That's what weenies do. You look at trends, biases..ensembles etc and make a call. 

[USCAPEWEATHERAF]

Right that is what I was trying to figure out, what needs to change for a big storm, not that I'm saying it's not possible just what needs to correct

[STILL N OF PIKE]

29 minutes ago, USCAPEWEATHERAF said:

Right that is what I was trng to figure out, what needs to change.  for a big storm, not that I'm saying it's not possible just what needs to correct

Just dont mention A greenland block Could help, Thus u be strikith  down and asked If  u dont u recall transient blocking Lol   

[Baroclinic Zone]

38 minutes ago, weathafella said:

My understanding was a progressive flow is the GFS best pattern.  It tends to fail in big east coast storm patterns.

It performs better but I'm still not sold on any solution with such a large PNA ridge and data sparse areas of canada not sampling as good.  The kicker behind this lead system will mean the difference between nothing and upside of modest snows.

[STILL N OF PIKE]

6 minutes ago, Baroclinic Zone said:

It performs better but I'm still nocould on any solution with such a large PNA ridge and data sparse areas of canada not sampling as good.  The kicker behind this lead system will mean the difference between nothing and upside of modest snows.

Besides hoping the kicker slows down in this fast flow , i mean how Is this achieved.

If  The sampling is poor?

[Baroclinic Zone]

49 minutes ago, STILL N OF PIKE said:

Besides hoping the kicker slows down in this fast flow , i mean how Is this achieved.

If  The sampling is poor?

If the upstream ridge is pumped up higher it may allow the downstream kicker to slow.  Also if the ridging is sharper it may allow the kicker to be further w than currently modeled.  If you loop the N American 500mb images on TT you can see you the ridge out west gets beat down and it also shifts E as  we get closer to the weekend.

https://www.tropicaltidbits.com/analysis/models/?model=gfs&region=namer&pkg=z500_vort&runtime=2017120606&fh=0

[SnowHole413]

9z SREF came west of 3z. Let the West trend begin

[Ginx snewx]

big Jet differences in the NAM, it will be closer, WAR looks in a good position

[ORH_wxman]

12z NAM might be fun...of course it's the NAM, and even worse, the NAM between 72-84 hours.