December 2019 Med/Long Range Disco

[Bob Chill]

Hard not to stare at this... 

[WxUSAF]

Just now, yoda said:

GEFS mean and its members should be fun to see then

I think there’s going to be some bizarre divergence this winter between the gfs and GEFS because of the dynamical core differences. We’ve already seen that a bit and we’re continuing to see it in the strat. I’m really not sure how to interpret any differences either. 

[Bob Chill]

I circled the most important change on the GFS. There's defined separation with the trough north of the closed ULL. The cuts off the destructive mid level return flow that will easily wreck the column overhead and north of us. Since the features are separated it allows the dynamics of the ULL to stay consolidated and draw in colder air and not allow a big warm mid-level push. 

 

Is it believable? I suppose it's possible or the model wouldn't show it. Give me like 5 runs in a row with separation like this and my inner weenie will do things. 

 

ETA: I didn't explain things properly above... The separation is what allows the track to be further south (no tug poleward) as the closed low crosses the region. Keeping the dynamic core of the ULL intact allows good things to happen this far south. I hope that makes more sense. I'm having problems with thoughts and words... lol

[WinterWxLuvr]

I see this as possibly some light frozen in the beginning, mostly rain, ull thumps the mountains to our west, coastal gives the eastern areas a shot at some wrap around snow, but most of the northern va area is left with next to nothing. Don’t see this as a cad setup either. 
 

Not at all trying to be negative but my “reality” check tells me this is a no chance scenario for at least my local area. Eastern MD possibly but not for most of us.

[showmethesnow]

Whether some things or just noise or the real deal we are seeing improvements where we need to see them. We are seeing both the initial blocking over Canada a touch farther south and  the ridging in front of the system is show better ridging in the upper portion where we need to see it. These are slight changes and could very well be noise but whatever they are they have slightly adjusted the upper low track when it gets handed off to the 50/50s influence. That is when we are seeing the biggest difference made. We are now seeing much more interaction between the NS energy (the energy that was screwing up the Canadian heights in prior runs) and the 50/50 (Saw this in yesterdays 12Z as well). If you compare this run to the previous you can see how this is impacting the flow in the N-Atlantic and it is a difference maker on the placement of the upper low off the coast.

[pasnownut]

11 minutes ago, showmethesnow said:

Whether some things or just noise or the real deal we are seeing improvements where we need to see them. We are seeing both the initial blocking over Canada a touch farther south and  the ridging in front of the system is show better ridging in the upper portion where we need to see it. These are slight changes and could very well be noise but whatever they are they have slightly adjusted the upper low track when it gets handed off to the 50/50s influence. That is when we are seeing the biggest difference made. We are now seeing much more interaction between the NS energy (the energy that was screwing up the Canadian heights in prior runs) and the 50/50 (Saw this in yesterdays 12Z as well). If you compare this run to the previous you can see how this is impacting the flow in the N-Atlantic and it is a difference maker on the placement of the upper low off the coast.

50/50 is the way to do this IMO.  get that to back in a little more and force this whole deal a bit further south and that would be a way to score.  We need the ridging out front to get squashed/forced south.  50/50 would do that for us...or a good HP placement.  I'd take either.  I'm not picky.  . 

[Bob Chill]

2 minutes ago, pasnownut said:

  50/50 would do that for us...or a good HP placement.  I'd take either.  I'm not picky.  . 

They pretty much work in unison right? HP can only move where the 50/50 lets it. 

The handoff is uber complicated and we're going to get teased bigly every 6 hours. The front running WAA piece isn't nearly as complicated and also (stating obvious) the most likely way we'll get snow in the DC area. You are in a much better place for the big show. I've seen this show too many times and even when models are straight locked and loaded with 1-2 day leads the script is re-written in real time and my yard is kicked off the stage. 

[WinterWxLuvr]

I hope nobody takes my posts the wrong way. Anyone who is used to my posts knows that I’m a very optimistic person when it comes to our chances, sometimes stupidly so. But seriously, have you ever seen us get s winter storm from a wrapped up low in Nebraska?

I won’t even be here this weekend but I still hope for snow. I want everyone to get some fun. So can anybody give me some hope and a rationale that could support it for this event?

[WxUSAF]

Ggem says no, but closer than 0z. Loses mid level temps before the WAA precip arrives. Gfs a smidge colder, so it’s frozen precip. Ggem then takes the ULL through PA so we get some backside flurries/rain showers. 

[CAPE]

3 minutes ago, WinterWxLuvr said:

I hope nobody takes my posts the wrong way. Anyone who is used to my posts knows that I’m a very optimistic person when it comes to our chances, sometimes stupidly so. But seriously, have you ever seen us get s winter storm from a wrapped up low in Nebraska?

I won’t even be here this weekend but I still hope for snow. I want everyone to get some fun. So can anybody give me some hope and a rationale that could support it for this event?

I would feel pretty good if I lived in NE PA, NNJ, into SNE right now. The GFS scenario is obv not impossible, but seems pretty unlikely to me. CMC  looks more realistic.

[NorthArlington101]

Mean is definitely distorted by the couple of SECS but... too good not to share.

[showmethesnow]

Just now, pasnownut said:

50/50 is the way to do this IMO.  get that to back in a little more and force this whole deal a bit further south and that would be a way to score.  We need the ridging out front to get squashed/forced south.  50/50 would do that for us...or a good HP placement.  I'd take either.  I'm not picky.  . 

The ridging (between the 50/50 and the incoming upper low) is a tricky deal. Might seem counter intuitive but we need that ridging initially to be strong in the upper portions of the ridge to help block the upper lows movement northeast. As long as the greater height builds are seen in the northern portion and the southern portion stays weak or even weakens we will be fine as currently depicted as it will not effect the flow through our region. Just follow the height lines from the Midwest into the east and you can get an idea what I am referring to. Now one other thing I haven't mentioned as of yet is that we are seeing the response that we see from the upper low (dropping southward through our region) because we are seeing this strong ridging. Take that out (weaken/squash/force south the ridge ) the incentive for the upper low to drop goes away. So the ridge is a necessary evil in this setup. 

[osfan24]

4 minutes ago, NorthArlington101 said:

Mean is definitely distorted by the couple of SECS but... too good not to share.

SECS? At least 2 of those are HECS, especially for early December. Definitely getting more interesting. Let's see what the King has to say.

[NorthArlington101]

This might help people see how the GEFS gets where it does. 

[showmethesnow]

GFS throws out the tease again for a couple days after the Dec 2'nd storm. Starting to get some somewhat promising looks on the models now for that period of time. Big player at that time is what we see the Dec 2nd storm do. If we can see a legit 50/50 from that system then it could possibly be game on.

[Eskimo Joe]

^nearly all the accumulation south of Mason-Dixon comes from the ULL.  Historically, we lose 9.9/10 times this way south of Mason-Dixon.

[HighStakes]

Certainly not an impossible solution. Maybe some similarities to December 82 storm. If memory serves I think the first part of the storm was a cold rain with a little mix then the coastal took over and most of the forum got thumped. 

[Eskimo Joe]

Traditionally, the center of the ULL going west to east along the I-64 corridor works for DCA and points north.  The evolution depicted above is okay for jackpotville and the hills, but not for the majority of us, too far north.

[showmethesnow]

2 minutes ago, losetoa6 said:

Gefs mean...

Hr 135 , 138

 

Seeing a pretty significant drop of the 500's compared to previous runs. I like.

[aldie 22]

2 minutes ago, Eskimo Joe said:

Traditionally, the center of the ULL going west to east along the I-64 corridor works for DCA and points north.  The evolution depicted above is okay for jackpotville and the hills, but not for the majority of us, too far north.

Yeah but where was the center two days ago...or yesterday? Its not like the potential is hitting tonight 

[midatlanticweather]

The FV3 is still the Oprah of snowstorms.. we have to see. The 500MB track shifting south on the GEFS is much more exciting to see. Can this be like 13/14 when storms looked north and came south? I know they did for so many other reasons that year, I just want snow!

 

[Wonderdog]

Be nice to see the lp pass over sw VA . Plenty of time for that. Would like to see some snow falling on Sunday while I watch my beloved IGGLES bask in the Miami sunshine.

[wxdude64]

I do like the southern trending, gives us something to look/prod/poke at!

[WxUSAF]

Give me the GEFS hr132-138 at peak climo and I would be FULLY...um...ready for snow? 990mb off OC? Drool. 

[Bob Chill]

8 minutes ago, WxUSAF said:

Give me the GEFS hr132-138 at peak climo and I would be FULLY...um...ready for snow? 990mb off OC? Drool. 

Hoco/Moco death band is evident on this panel. 

[dallen7908]

I guess this is a good time to remind myself that 21/21 of GEFS members showing >1" of snow for College Park does not equate with a 100% chance of >1". 

 

Fractions below depend on end point 

>12" 4/21

> 6" 6/21

>3" 12/21

"1" 21/22

[WxUSAF]

Stop trying to excite me @Bob Chill! I’m trying to calm down by thinking very un-snowy thoughts like the euro showing the transfer over Portland ME. 

[psuhoffman]

12 minutes ago, WxUSAF said:

Give me the GEFS hr132-138 at peak climo and I would be FULLY...um...ready for snow? 990mb off OC? Drool. 

If we can just get a pattern repeat of basically the last few weeks and the next week sometime between Dec 15 and Feb 15th I think most of us will be happy.  

[pasnownut]

45 minutes ago, leesburg 04 said:

Yeah but where was the center two days ago...or yesterday? Its not like the potential is hitting tonight 

agreed.  this one is worth watching

#1 cause its the first of the year for many of us (i had my surprise first 1'' on Sunday)

#2 cause many of us are off and will not have much else to do, other than walk off Turkey/stuffing.

[NorthArlington101]

EURO looks like it gonna start people off with a period of light snow. Snowing at DCA at 105.

Still going at 108 -- temps aren't conducive to much more than white rain though