Dec/Jan Medium/Long Range Disco

[pazzo83]

2 minutes ago, NorthArlington101 said:

I bet someone here knows more than me, but that’s my understanding. It’s trained off historical weather data and tries to use that to predict the weather going forward. Conceptually that seems like a great application of that kind of learning to me.

yeah training on re-analysis is brilliant.  in this way the model can "figure out" the math on its own.

[WesternFringe]

13 minutes ago, pazzo83 said:

again - you are missing the point.  the fact that it was a model output at any point is the concern.

If every model run’s output is a concern to you, you are ridiculous and missing the point.  Hour 192 never verifies on the GFS.  But yeah, I am missing the point!? Lol

eta:  it was model output that we were discussing that never happened at 192, and hasn’t been modeled since as even close to our area at 186 or 180 in the 2 subsequent models runs, but I am missing the point? I should have been alarmed by the one run?
 

Okay, you are right.  The fact the models showed something that never happened is evidence of….what exactly?

[CAPE]

7 minutes ago, NorthArlington101 said:

Butterfly effect ends up with a substantial winter storm for GA (by their standards) up into the Carolinas for the 3-4th. Wacky run

I like the wave timing for that window with the predecessor low in a good spot and HP just west/sw of there where we want it. It's one of those simple paths to victory with a well timed discrete shortwave tracking underneath and a favorable look in the NA. Cold enough verbatim. Just need it a little further north.

[WxUSAF]

19 minutes ago, NorthArlington101 said:

Butterfly effect ends up with a substantial winter storm for GA (by their standards) up into the Carolinas for the 3-4th. Wacky run

GFS working overtime to avoid giving us digital blue after the Christmas miracle fantasy HECS.

[jayyy]

I like the wave timing for that window with the predecessor low in a good spot and HP just west/sw of there where we want it. It's one of those simple paths to victory with a well timed discrete shortwave tracking underneath and a favorable look in the NA. Cold enough verbatim. Just need it a little further north.

There are certainly worse positions to be in. Maybe it doesn’t pan out ultimately, but I’d almost rather things be where they are now. Models showing us being fringed with a low tracking to the south with a workable airmass in place… than have models show a flush hit over a week out.

[pazzo83]

14 minutes ago, WesternFringe said:

If every model run’s output is a concern to you, you are ridiculous and missing the point.  Hour 192 never verifies on the GFS.  But yeah, I am missing the point!? Lol

eta:  it was model output that we were discussing that never happened at 192, and hasn’t been modeled since as even close to our area at 186 or 180 in the 2 subsequent models runs, but I am missing the point? I should have been alarmed by the one run?
 

Okay, you are right.  The fact the models showed something that never happened is evidence of….what exactly?

just keep your head buried in the sand I guess.

[WxUSAF]

11 minutes ago, WxUSAF said:

GFS working overtime to avoid giving us digital blue after the Christmas miracle fantasy HECS.

See…shamed it into performance!

[EastTNWeatherAdmirer]

Who knows if the JMA is even worth checking out and I wish I could see the surface precip with it, but it shows a significant storm for Jan 2nd over the mid Atlantic. Probably won’t verify of course, but this seems like the most bullish model on this storm yet. 

[BristowWx]

1 minute ago, EastTNWeatherAdmirer said:

Who knows if the JMA is even worth checking out and I wish I could see the surface precip with it, but it shows a significant storm for Jan 2nd over the mid Atlantic. Probably won’t verify of course, but this seems like the most bullish model on this storm yet. 

I’ve seen the JMA score a coup hundreds of times…thousands

[nj2va]

2 minutes ago, WxUSAF said:

See…shamed it into performance!

I was about to call for a GFS upgrade to get it back into being a weenie model.  Digital blue at HH, baby!

[SnowenOutThere]

30 minutes ago, MDScienceTeacher said:

volcanic activity, sun spots and astroid strikes are all capable of changing the earths weather patterns.

I feel like we are leaving something out … must just be my imagination!  

[WesternFringe]

14 minutes ago, pazzo83 said:

just keep your head buried in the sand I guess.

If that means discounting an op run at 192 that never happened that it’s own two subsequent runs disagreed with and said would not happen, count me an ostrich!  Lol

ETA: but keep preaching to me about events that never happened.  That will prove your point.

[pazzo83]

2 minutes ago, WesternFringe said:

If that means discounting an op run at 192 that never happened that it’s own two subsequent runs disagreed with and said would not happen, count me an ostrich!  Lol

again - you are focusing on the discrete (PSA to the board - not you WF - the word is discrete, not discreet - discreet describes acting in a way so as to avoid attention) outcome relative to others in the overall model timeseries vs the fact that the model generated such an output at all - and we've seen myriad other such outputs over the past couple of years (and real outcomes that match them).

[BristowWx]

10 minutes ago, nj2va said:

I was about to call for a GFS upgrade to get it back into being a weenie model.  Digital blue at HH, baby!

Cold air draining like ground beef grease at the end of the run over Canada.  Damn.  

[WesternFringe]

19 minutes ago, pazzo83 said:

again - you are focusing on the discrete (PSA to the board - not you WF - the word is discrete, not discreet - discreet describes acting in a way so as to avoid attention) outcome relative to others in the overall model timeseries vs the fact that the model generated such an output at all - and we've seen myriad other such outputs over the past couple of years (and real outcomes that match them).

Yeah, we were all talking about a discrete threat, so you have it right about that.

The models saw rain bc the ground layers were warm in its depiction of the future.  And then we all agreed to kinda see what actually happens in 8 days instead of focusing on one model run’s output.  But I am missing the point?  Enlighten me

eta:  And it is bs if you say it is concerning when the model says this at all.  Where were you all in saying it was concerning when the models were portraying 20-30 inches a few runs ago?  Get real and accept the good with the bad. And also realize that 192 hr depictions rarely verify.

[Kevin Reilly]

31 minutes ago, EastTNWeatherAdmirer said:

Who knows if the JMA is even worth checking out and I wish I could see the surface precip with it, but it shows a significant storm for Jan 2nd over the mid Atlantic. Probably won’t verify of course, but this seems like the most bullish model on this storm yet. 

One thing it does have that all the other models have is no high to our north.

[psuhoffman]

WRT the SSW a few things I’d need answered before formulating an opinion. 
 

what does evidence say is the difference in predicted outcomes if the warming peaks just shy of a reversal and official SSW v achieving?
 

That other study linked that it has more impact if the TPV is already negative. So how much of this is cross contamination of data?  

We’ve had this debate and when the AO was hostile rarely do I remember the SSW making a significant difference. On the other hand the times it seems to have got credit like 2010 we already had a blocking regime. Dec 2009 happened before the SSW. 

[pazzo83]

11 minutes ago, WesternFringe said:

Yeah, we were all talking about a discrete threat, so you have it right about that.

The models saw rain bc the ground layers were warm in its depiction of the future.  And then we all agreed to kinda see what actually happens in 8 days instead of focusing on one model run’s output.  But I am missing the point?  Enlighten me

eta:  And it is bs if you say it is concerning when the model says this at all.  Where were you all in saying it was concerning when the models were portraying 20-30 inches a few runs ago?

yeah i mean that's what we'd expect from a slightly cold-biased model output given low position and other factors.  i think the question is, on that particular model run (and we've seen this in quite a few others over the past couple of years), why - given the low position, antecedent air mass, etc - was the boundary layer so warm?  What is having the model generate that as the highest probability outcome?  We've seen a number of such outputs - and actual events - that should have some snow that were rain for virtually everyone.  Obviously the concern here is that the base state has warmed significantly and models are starting to output scenarios - even fleeting - that reflect that.  You disagree with that premise so you try to undermine any such concern.  That's fine - but don't trivialize the concern.

[NorthArlington101]

GEFS looks slightly improved for the 2nd and 4th, FWIW. Not worth getting excited about but should reassure folks neither threat is “dead.” Also has that same window of opportunity on the 7th/8th.

Would be really funny if we did all this handwringing and somehow went on a heater.

[WEATHER53]

8 minutes ago, psuhoffman said:

WRT the SSW a few things I’d need answered before formulating an opinion. 
 

what does evidence say is the difference in predicted outcomes if the warming peaks just shy of a reversal and official SSW v achieving?
 

That other study linked that it has more impact if the TPV is already negative. So how much of this is cross contamination of data?  

We’ve had this debate and when the AO was hostile rarely do I remember the SSW making a significant difference. On the other hand the times it seems to have got credit like 2010 we already had a blocking regime. Dec 2009 happened before the SSW. 

I believe that in our righteous efforts to better predict weather, this is another sampling that’s unproven. Hell we are having trouble with long established Enso and Ao/NAO being reliable so the new indexes that seem to pop up every 3/4 years just don’t have enough outcomes yet  to be a reliable prediction package 

[WesternFringe]

11 minutes ago, pazzo83 said:

yeah i mean that's what we'd expect from a slightly cold-biased model output given low position and other factors.  i think the question is, on that particular model run (and we've seen this in quite a few others over the past couple of years), why - given the low position, antecedent air mass, etc - was the boundary layer so warm?  What is having the model generate that as the highest probability outcome?  We've seen a number of such outputs - and actual events - that should have some snow that were rain for virtually everyone.  Obviously the concern here is that the base state has warmed significantly and models are starting to output scenarios - even fleeting - that reflect that.  You disagree with that premise so you try to undermine any such concern.  That's fine - but don't trivialize the concern.

Again, people putting words in my mouth.  I don’t disagree with any premise you mentioned.  I also am not going to pretend that a 192 hr op depiction proves anything!   That is my point.  I am not talking climate change at all.  The next 2 runs of the fricking same model showed nothing like we were talking about!!!!  So why even say this shouldn’t happen when it never fucking did!!!!  Jesus Christ, that is all I am saying!!!

[eduggs]

The 18z GFS has a parade of between 6 and 10 successive shortwaves (depending on how you distinguish them) that partially interfere with each other over the next 10 days to prevent any significant local storm development. This highlights one of the problems of using LR time-blended height anomalies to try to identify favorable or active "periods." The averaged anomalies look interesting over the next week, but as usual, everything comes down to the evolution and orientation of the height fields. The actual weather could end of being quite boring depending on the fine details of wave interaction.

I prefer Walt Drag's method of threat identification mostly keeping inside of 10 days using a mid-range multi-model super-ensemble focusing on QPF and temperature distributions. To my knowledge Walt doesn't mention climate indices or height anomalies. And he doesn't frequently trigger annoyed disappointment with a lot of LR false alarms. 

[nj2va]

Can @pazzo83 and @WesternFringe take it to banter or just create a CC thread?  FFS.

[WesternFringe]

6 minutes ago, nj2va said:

Can @pazzo83 and @WesternFringe take it to banter or just create a CC thread?  FFS.

Yeah, whatever man.  See my post.  I am not even arguing either side of cc though

my whole point is that the cavalry is late bc the model doesn’t even show what we were arguing over being impossible even happening anymore

[Jebman]

Fellow weather enthusiasts, I am so happy you are all so active on the topic, I really am. But I dont have as much time as you do. If you haven't noticed yet - Ever since I moved to Texas, my life is markedly different lol. And thats a good thing. But this topic is so active - I dont think I am gonna be able to catch up until next year lmao!

Keep up the excellent discourse! Great job!

Okay, back to Page 42.

Gotta try to catch up, gotta try to catch up, gotta try to catch up.........

[nj2va]

19 minutes ago, NorthArlington101 said:

GEFS looks slightly improved for the 2nd and 4th, FWIW. Not worth getting excited about but should reassure folks neither threat is “dead.” Also has that same window of opportunity on the 7th/8th.

Would be really funny if we did all this handwringing and somehow went on a heater.

Honestly, the GFS OP has been all over the place, even inside 120 hours, so to your point, no one should be writing things off based on OP runs.  With so many vorts, I have a feeling we’ll be having things pop up in the medium term vs long lead threats - unless we get some insane blocking thanks to our (now cancelled?) SSW.  

[Jebman]

On 12/25/2023 at 10:12 AM, Kevin Reilly said:

I will take 1996 and 2010 for $1,000 Alex!

You just won that question TWICE!

DC gets twice as much snow as they got in both those years, in one incredible winter!

[Weather Will]

In an attempt to lighten the mood, fantasy range WB GFS 18Z northern plains windchills, first time I have seen this in forever....hint of things to come?????

[Stormchaserchuck1]

28 minutes ago, Weather Will said:

In an attempt to lighten the mood, fantasy range WB GFS 18Z northern plains windchills, first time I have seen this in forever....hint of things to come?????

578dm -NAO and 554dm -EPO.. pretty good run @384. I think they are really anticipating Stratosphere warming: It has +3 correlation on NAO at +0D but +10 correlation at +20-30 day. But even so, the last 3 Stratosphere warmings have effected us when the Pacific also became unfavorable (so negatively) so it should be interesting 

[Stormchaserchuck1]

2 hours ago, EastTNWeatherAdmirer said:

Who knows if the JMA is even worth checking out and I wish I could see the surface precip with it, but it shows a significant storm for Jan 2nd over the mid Atlantic.

It has literally never gotten one right when against other models.