December Medium/Long Range Discussion

[psuhoffman]

@Ji That isnt a crazy scenario... the 10 or so 12z EPS members that managed to give our area pretty much no snow next week did it that exact way.  A suppressed monday wave that was just too warm to snow anywhere...then a crazy far north wednesday system where the snow started north of the mason dixon line.  That is how this all falls apart.  I would argue that its not JUST the monday wave though...the monday wave is acting in conjunction with the more significant wave on top of it...and that is what becomes the 50/50...so a weaker monday system is indicative of a weaker wave that turns into the 50/50.  The pattern is good...but its still only mid December, with an only ok antecedent airmass, and a block that is a little north of ideal, and a pacific that is only mediocre...if you remove the ideal 50/50...this is probably an interior northeast storm.  

[psuhoffman]

2 minutes ago, JakkelWx said:

We have something potential showing up on the LR GEFS ensembles

That's just our christmas blizzard.  

[Buddy1987]

Just now, psuhoffman said:

My gut tells me it is way too soon to be making detailed predictions for a storm 5 days away.  I don't like to pretend I am confident or know something when the truth is I don't know.  I am comfortable admitting when I don't know.  But...this is a pretty good setup in terms of the longwave pattern.  I would like that block to be centered a little south of where it is...like CAPE has said.  But we have snowed with a similar H5 look often.  I would like a slightly colder thermal profile in front of it but its December...is what it is.  But there is a reason big all snow events are VERY rare in DC this early in the year.  I do think this ends up pretty amplified when its all said and done...and that in a way reduces the chances of an all snow south track some.  My "gut" says this is probably going to be DC's first accumulating snow of the season and break the snow drought...but the really big totals are going to be further north/west.  Even up here...if you asked me what I am more worried about...a north trend and rain is a way bigger concern for me att then missing heavy snow to the south.  Now watch 0z come in suppressed lol.  

Hahahaha appreciate the honesty. Just for the fact first storm creates a 50/50 and we have a good cold source of high pressure (1034-1036) for the Wednesday system, screams to me at the minimum a mixed bag. I naturally tend to view my area more so than DC because I don’t have marine influence or I’m not associated as closely to the low track as you all could possibly be. I could definitely see it going either way with good potential frontogenesis and lift up that way to where if it’s borderline it could be a wet heavy snow or to where unfortunately above 850 gets cooked by southerly flow and flips to a mess. Jury is still out so I guess you are right although when I see thermals on Canadian it gives me cause to be reasonably positive for a majority of us. 

[psuhoffman]

with it being only a few days away why don't we just move the Monday stuff to the obs thread unless it becomes worthy of its own thread in the near future.  Discussion of how that wave effects Wed can stay here.  

[WinterWxLuvr]

1 minute ago, psuhoffman said:

with it being only a few days away why don't we just move the Monday stuff to the obs thread unless it becomes worthy of its own thread in the near future.  Discussion of how that wave effects Wed can stay here.  

You’re behind. There’s already a thread 

[psuhoffman]

nevermind i see the other thread...I am ok with that too...I am not the superstitious type. 

[psuhoffman]

1 minute ago, WinterWxLuvr said:

You’re behind. There’s already a thread 

somehow several posts didn't load when I updated the thread...

[WinterWxLuvr]

I just looked. The least amped gfs run for Monday in the past 5 runs was yesterday at 18z. It also produced its least amped solution for Wed in that run also.

Ill roll the dice. I want snow for both. And I think we can get it.

[psuhoffman]

16 minutes ago, losetoa6 said:

@psuhoffman

I believe your analysis as far as comparing "A to B " but not sure I believe it's that cut and dry though . Probably other variables come into play .Ensembles also are lower resolution. Maybe your right but Monday lies ahead 1st and actually I think it ends up a bit more amped in the end Monday .

You are 100% right.  There are other variables that could make snow on snow a possibility here. 

One would be if the Monday starts south but still amplifies...but that one is kinda difficult since its washing out and being absorbed into the developing vortex to our north.  If it starts de-amplified it probably ends up even more so.  

Another option would be a more amplified NS system that bombs out regardless of a less amplified monday wave.  So far those 2 features seem to be acting in conjunction but that does not mean they will continue to do so.  Or the 50/50 could be less amplified but move out slower.

Most likely way to mitigate would be like I discussed on the 18z plot at 90 hours.  There are some things out west that could offset a less ideal 50/50.  One would be a more positively tilted system that goes neutral later.  A flatter flow on top.  Even with an obviously less ideal 50/50 its not apparent from that 90 hour 18z euro that the storm would end up north.  Those other 2 factors could end up making it further south...who knows.  

So it's not a 1;1 correlation.  But I do think its fair to say...a colder monday solution PROBABLY increases the chances that we have a less amplified 50/50 low and that is a net negative if we think the bigger risk Wednesday is a warm/north trend.  

[psuhoffman]

3 minutes ago, WinterWxLuvr said:

I just looked. The least amped gfs run for Monday in the past 5 runs was yesterday at 18z. It also produced its least amped solution for Wed in that run also.

Ill roll the dice. I want snow for both. And I think we can get it.

The other day when I looked at the GEFS I did NOT notice the same correlation.  But the GFS in general is much less amplified on EVERYTHING next week...and imo its wrong on that.  So if I think its mishandling the longwave pattern I would not put much stock into its handling of the details of how the two waves are playing off each other.  But that is just my opinion.  Just affirming your observation regarding the GFS is correct but explaining why I didn't put much weight into it.  

[Eskimo Joe]

31 minutes ago, losetoa6 said:

Posted them(ARWs) in the Banter thread for Mondays storm 

ARW...Always Really Wet

NMM...Not Much Moisture

[Eskimo Joe]

18 minutes ago, nj2va said:

Eskimo Joe would approve.

[BristowWx]

12 minutes ago, WinterWxLuvr said:

I just looked. The least amped gfs run for Monday in the past 5 runs was yesterday at 18z. It also produced its least amped solution for Wed in that run also.

Ill roll the dice. I want snow for both. And I think we can get it.

You can get both I think. I can see a scenario where some of us get neither.  Maybe just CAPE.. but still some will be snow starved on Friday next.  

[Amped]

2 hours ago, Maestrobjwa said:

Wait, was that the snowy Ravens-Vikings game with the epic finish?

No it was two days after. Close, it was a couple days after that event.

[HighStakes]

17 minutes ago, Amped said:

No it was two days after. Close, it was a couple days after that event.

Right. 5 inches here on tuesday morning.

[jaydreb]

I’m kind of dreading the 0z runs to be honest.  Nowhere to go but down.  

[Snowchaser]

Icon looking like snow to freezing rain or plain rain for most on Wednesday.

[Amped]

2 minutes ago, losetoa6 said:

Icon seems to go bonkers on thermals out in time but once in range it corrects. 

Icon shows the storm you'd expect given the H5 track. 

[psuhoffman]

4 minutes ago, Amped said:

Icon shows the storm you'd expect given the H5 track. 

Icon h5 isn’t that significantly different from other guidance. But it never cleanly transfers energy so the h5 keeps lifting with the primary v turning east to consolidate with the coastal.  But up until that last part the h5 track looks similar imo. 

[nj2va]

Just now, psuhoffman said:

Icon h5 isn’t that significantly different from other guidance. But it never cleanly transfers energy so the h5 keeps lifting with the primary v turning east to consolidate with the coastal.  But up until that last part the h5 track looks similar imo. 

Better confluence would have negated that (verbatim)?

[psuhoffman]

@Amped honestly the whole h5 track of the initial system is not ideal even on runs that show a big hit. We need that monster 50/50 to offset that. Or we need the system to trend south with the track of the initial system. 

[psuhoffman]

@PhineasC icon says you should stay Monday then head back to NH 

[psuhoffman]

3 minutes ago, nj2va said:

Better confluence would have negated that (verbatim)?

Yea icon is way weaker and further north with the confluence. Less 50/50 

[Amped]

Just now, psuhoffman said:

@Amped honestly the whole h5 track of the initial system is not ideal even on runs that show a big hit. We need that monster 50/50 to offset that. Or we need the system to trend south with the track of the initial system. 

Yep I think the lack of a strong primary is also a factor on the runs showing a quick coastal transfer.   I'd rather not rely on that though.

[Buddy1987]

Confluence looks slightly better at 72 on gfs but I don’t have the knowledge to know if that will have a direct influence in the later frames. 

[yoda]

Confluence looks a lil better at 78 as the s/w is a tad further west comparing to 18z 84 (00z GFS)

[Maestrobjwa]

11 minutes ago, psuhoffman said:

@Amped honestly the whole h5 track of the initial system is not ideal even on runs that show a big hit. We need that monster 50/50 to offset that. Or we need the system to trend south with the track of the initial system. 

Uh...would you mind translating that a bit? Need what system to trend south of what now? Lol

[Buddy1987]

[psuhoffman]

3 minutes ago, Buddy1987 said:

Confluence looks slightly better at 72 on gfs but I don’t have the knowledge to know if that will have a direct influence in the later frames. 

It is but also a slightly slower more amplified system out west so other variables could offset. We will see. Minor changes have significant impacts when your worried about a 50 mile shift at 5 days. 

[yoda]

Just now, psuhoffman said:

It is but also a slightly slower more amplified system out west so other variables could offset. We will see. Minor changes have significant impacts when your worried about a 50 mile shift at 5 days. 

Slightly slower at 96... but i see slightly higher h5 heights ahead of it