December 2022 Medium/Long Range Pattern Discussion Thread

[John1122]

Another late run major winter storm with rain to ice for snow for the areas Carvers mentioned earlier but it eventually spreads all the way to the mountains. Bitter cold air behind it. Lows in the single digits and low teens, even colder in deeper snowpack areas in Kentucky. Obviously not set in stone but just shows the potential we have over the Dec 16th and beyond period. 

[BuCoVaWx]

Once again the GFS marches right back into Weenieville USA this past run 

[Holston_River_Rambler]

The big storm that was going to be a big front next week has almost turned into a Miller B on the 6z GFS. 

The GFS depicts the low transfer from Dubuque, Iowa to Cape Fear

[AMZ8990]

On 12/8/2022 at 6:02 AM, Carvers Gap said:

The 0z Euro control is insanely cold over the Plains and Front Range.  That is a fantastic set-up for those who live in western areas of the forum.  The EPS supports that look(core of the cold in the western Plains) w/ the furtherest extent of the cold reaching the Atlantic.  Remember the strat split a while back?  Yep, that is where it normally dumps cold first in NA(if it goes to NA), and right on time 2-3 weeks after the event.  Would be interesting if the background driver was a combination of SSW and Pac forcing(not the good kind).    Anyway, the set-up depicted is very similar to the over-running event for Memphis a few years back.

 Let’s Lock it in!! lol 

[Daniel Boone]

4 hours ago, Holston_River_Rambler said:

The big storm that was going to be a big front next week has almost turned into a Miller B on the 6z GFS. 

The GFS depicts the low transfer from Dubuque, Iowa to Cape Fear

That is actually a probable solution with strong blocking. Even a further South track is possible but, most likely not this go around. It would be nice to finally get into a 95-95 type pattern. Several Miller B transfers of which tracked far to the South. 

[John1122]

The GFS and Canadian are getting into agreement with a few bouts of wintry precip for 40 and north as the holidays approach. The pattern definitely supports a frozen precip outcome for our area. It would be an early event for most of the area, as non-elevated areas usually see their first snowfall between December 28th and January 6th on average across the region. Last year the GFS was really good at sniffing out storms in the longer range. It was rarely great at their strength, often overamping everything like the NAM. This time frame will be the first true winter threat test for the new core they've updated.

[PowellVolz]

That is actually a probable solution with strong blocking. Even a further South track is possible but, most likely not this go around. It would be nice to finally get into a 95-95 type pattern. Several Miller B transfers of which tracked far to the South. 

While that season was epic for ETn, it was extremely frustrating for Knoxville. We where probably 15 miles SW of the “all snow” line. That being said… it was one of the most active winters of my life time. I’m 48 so I’ve seen some really good events but not many very good winters. My dad use to talk about the 50’s and 60’s where we would have snows on the ground for a week at a time. Two weeks later it would snow again.


.

[Daniel Boone]

1 minute ago, PowellVolz said:

While that season was epic for ETn, it was extremely frustrating for Knoxville. We where probably 15 miles SW of the “all snow” line. That being said… it was one of the most active winters of my life time. I’m 48 so I’ve seen some really good events but not many very good winters. My dad use to talk about the 50’s and 60’s where we would have snows on the ground for a week at a time. Two weeks later it would snow again.


.

Yeah, I remember that being the case. We were fortunate up this way. Wise in Wise County broke the State Seasonal Record that year; 123.4 inches ! I recorded 52" in Pennington gap here in Lee County ( not a record here ) .

       The 60's was a snowy decade for the area. Nina, Nino, -PDO, -PNA, it didn't matter, lol

[John1122]

It may not produce but it's hard to ask for a better looking pattern than what we have on tap beginning about a week from today. Christmas won't be spent at the grill, flipping burgers and wearing shorts to say the least according to the EPS.

[Daniel Boone]

12 minutes ago, John1122 said:

It may not produce but it's hard to ask for a better looking pattern than what we have on tap beginning about a week from today. Christmas won't be spent at the grill, flipping burgers and wearing shorts to say the least according to the EPS.

You got that right Buddy. Looks promising for much of the area having a white Christmas actually. 

[Holston_River_Rambler]

Someone in the MA forum linked to this today. Some good insights into how the CPC folks see the pattern evolving:

https://www.cpc.ncep.noaa.gov/products/predictions/WK34/

For me, it was striking how much came down to La Nina probabilities. Not saying they are wrong to do that, but the whole write up was fascinating in terms of trying to see how the pros reason through medium to long range forecasting. 

 

Some good MJO disco in there too. 

[Daniel Boone]

17 minutes ago, Holston_River_Rambler said:

Someone in the MA forum linked to this today. Some good insights into how the CPC folks see the pattern evolving:

https://www.cpc.ncep.noaa.gov/products/predictions/WK34/

For me, it was striking how much came down to La Nina probabilities. Not saying they are wrong to do that, but the whole write up was fascinating in terms of trying to see how the pros reason through medium to long range forecasting. 

 

Some good MJO disco in there too. 

Yeah, enso is heavily weighted by them.

[1234snow]

Someone in the MA forum linked to this today. Some good insights into how the CPC folks see the pattern evolving:
https://www.cpc.ncep.noaa.gov/products/predictions/WK34/
For me, it was striking how much came down to La Nina probabilities. Not saying they are wrong to do that, but the whole write up was fascinating in terms of trying to see how the pros reason through medium to long range forecasting. 
 
Some good MJO disco in there too. 

This was well worth the read everyone. I’m going to start reading these discussions as they come out. Talks about how Atlantic wave breaking can keep the -NAO going longer, how the -PNA will break down and then come back later in the period, and how MJO may not influence the Asian jet where the convection is located.

[Carvers Gap]

Afternoon ensembles were pretty much a beaut, Clark.  

[Carvers Gap]

Been super busy for the past couple of days.  If you haven't looked at today's ensembles, you should.  No idea if right...but. The ensembles are close to the coldest that I have seen them in the d10-15.  Pretty rare to see ten degrees below the average at that range on the EPS.  The actual EPS at 12z was throwing at a big dog pattern.  Looks like the first cold front is still moving forward in time around the 16th.  

[EastTNWeatherAdmirer]

The GEFS and latest GFS runs want to keep next week’s trough hanging back in the western United States. Really quite remarkable; as Carvers likes to say the word, a “coup” is forming between the models. The Canadian, European, and both of their ensembles want to keep the “bowling ball” rolling across the lower 48 by Wednesday of next week which would ultimately allow an ULL to drop deeply into the southeast and mid atlantic, drawing down very cold air, mountain & maybe plateau snow by late next week into the weekend. This ULL, with enough assumed forcing and moisture inflow from the Atlantic, could create a pretty gnarly wrapped up snowstorm for New England and the Northeast Atlantic Corridor by next weekend. That’s one resolution, and the Canadian and European are betting on that right now.

However, I beg to differ. If we recall, there have been a few systems noted by global models to be big snow makers that never came to fruition at all because of how the primary trough hasn’t been in its prime location(eg, -PNA trough & 50/50 low only mean one thing for sure…and that’s plenty of cold to folks living far out in the western US and a reduced risk for any impactful Midwestern, Ohio Valley, Mid - Atlantic, or Southeastern Snowstorms). We thought the arrival of major cold would be Dec 9/10 several days ago. Instead, we have seen a weak but very persistent southern ridge allow mild air to surge north, with the western US states being very cold and the far northeastern United States remaining quite chilly, because of the concrete 50/50 low hanging out up there. Like I’ve said, the Euro and Canadian show next week’s upcoming system effectively undercutting the blocking and negative NAO with a really impressive ULL stationed over the Ohio Valley along with East TN valley flurry and mountain snow activity. Instead of the system becoming a fully autonomous upper level cyclone like that, latest GFS and GEFS trends want most of the ULL itself to stay in the Northern Great Plains, Pacific Northwest and Western US as a whole, with only a weak exchange of lower height anomalies being *transferred* across the central US and Mid-Atlantic, with less deep cold here and no New Eng or App Storm. The front would still come through with rain nevertheless, but much of the cold and upper level low pressure activity and lower thickness levels would remain across the western United States with a very suppressed storm that spins its way to death out to sea in the Atlantic, just as the latest 18z Dec 9 & 00z Dec 10 GFS show.

Despite the fact that the GFS changes with almost every run in a mind boggling and fundamental way and as a result many don’t put their trust in the GFS, I have come to find that it and its ensemble suite lead the way and are the first to sniff out trends in the modeling. I like to think of the GFS as a bipolar leader of a group of people. It seems to have no idea where it’s going and changes its mind a lot but is still ultimately the real leader of the group (all of the modeling), picking up on the realistic and true changes before every other model follows behind. Even though the Euro and CMC and their ensembles want the bowling ball to effectively spin deep and by itself across our part of the US by late next week, I think the GFS is onto something with the -PNA persisting and the ULL not undercutting the block very much but only simply transferring weak lower height anomalies and pretty wimpy cold(although a pretty big change to what we’re seeing now) to the East which is very much unlike recent Canadian and European runs. Over the next few days I expect the Euro, Canadian, their ensembles, and all other models to gradually wake up to where their bipolar leader is leading them and will look pretty similar to what the Dec 10th 00z GFS and Dec 10th 00z GEFS looks like through hour 192(December 18th.)

[John1122]

11 minutes ago, EastTNWeatherAdmirer said:

The GEFS and latest GFS runs want to keep next week’s trough hanging back in the western United States. Really quite remarkable; as Carvers likes to say the word, a “coup” is forming between the models. The Canadian, European, and both of their ensembles want to keep the “bowling ball” rolling across the lower 48 by Wednesday of next week which would ultimately allow an ULL to drop deeply into the southeast and mid atlantic, drawing down very cold air, mountain & maybe plateau snow by late next week into the weekend. This ULL, with enough assumed forcing and moisture inflow from the Atlantic, could create a pretty gnarly wrapped up snowstorm for New England and the Northeast Atlantic Corridor by next weekend. That’s one resolution, and the Canadian and European are betting on that right now.

However, I beg to differ. If we recall, there have been a few systems noted by global models to be big snow makers that never came to fruition at all because of how the primary trough hasn’t been in its prime location(eg, -PNA trough & 50/50 low only mean one thing for sure…and that’s plenty of cold to folks living far out in the western US and a reduced risk for any impactful Midwestern, Ohio Valley, Mid - Atlantic, or Southeastern Snowstorms). We thought the arrival of major cold would be Dec 9/10 several days ago. Instead, we have seen a weak but very persistent southern ridge allow mild air to surge north, with the western US states being very cold and the far northeastern United States remaining quite chilly, because of the concrete 50/50 low hanging out up there. Like I’ve said, the Euro and Canadian show next week’s upcoming system effectively undercutting the blocking and negative NAO with a really impressive ULL stationed over the Ohio Valley along with East TN valley flurry and mountain snow activity. Instead of the system becoming a fully autonomous upper level cyclone like that, latest GFS and GEFS trends want most of the ULL itself to stay in the Northern Great Plains, Pacific Northwest and Western US as a whole, with only a weak exchange of lower height anomalies being *transferred* across the central US and Mid-Atlantic, with less deep cold here and no New Eng or App Storm. The front would still come through with rain nevertheless, but much of the cold and upper level low pressure activity and lower thickness levels would remain across the western United States with a very suppressed storm that spins its way to death out to sea in the Atlantic, just as the latest 18z Dec 9 & 00z Dec 10 GFS show.

Despite the fact that the GFS changes with almost every run in a mind boggling and fundamental way and as a result many don’t put their trust in the GFS, I have come to find that it and its ensemble suite lead the way and are the first to sniff out trends in the modeling. I like to think of the GFS as a bipolar leader of a group of people. It seems to have no idea where it’s going and changes its mind a lot but is still ultimately the real leader of the group (all of the modeling), picking up on the realistic and true changes before every other model follows behind. Even though the Euro and CMC and their ensembles want the bowling ball to effectively spin deep and by itself across our part of the US by late next week, I think the GFS is onto something with the -PNA persisting and the ULL not undercutting the block very much but only simply transferring weak lower height anomalies and pretty wimpy cold(although a pretty big change to what we’re seeing now) to the East which is very much unlike recent Canadian and European runs. Over the next few days I expect the Euro, Canadian, their ensembles, and all other models to gradually wake up to where their bipolar leader is leading them and will look pretty similar to what the Dec 10th 00z GFS and Dec 10th 00z GEFS looks like through hour 192(December 18th.)

 

Honestly, the GFS shows almost every possible solution over a given 24-48 hour period these days, to the extent that at least one of it's solutions will probably be correct. As noted by the CPC, it's been plowing storms northward into -NAO blocking. That causes every domino after that to fall askew for the model. 

[Matthew70]

33 minutes ago, EastTNWeatherAdmirer said:

The GEFS and latest GFS runs want to keep next week’s trough hanging back in the western United States. Really quite remarkable; as Carvers likes to say the word, a “coup” is forming between the models. The Canadian, European, and both of their ensembles want to keep the “bowling ball” rolling across the lower 48 by Wednesday of next week which would ultimately allow an ULL to drop deeply into the southeast and mid atlantic, drawing down very cold air, mountain & maybe plateau snow by late next week into the weekend. This ULL, with enough assumed forcing and moisture inflow from the Atlantic, could create a pretty gnarly wrapped up snowstorm for New England and the Northeast Atlantic Corridor by next weekend. That’s one resolution, and the Canadian and European are betting on that right now.

However, I beg to differ. If we recall, there have been a few systems noted by global models to be big snow makers that never came to fruition at all because of how the primary trough hasn’t been in its prime location(eg, -PNA trough & 50/50 low only mean one thing for sure…and that’s plenty of cold to folks living far out in the western US and a reduced risk for any impactful Midwestern, Ohio Valley, Mid - Atlantic, or Southeastern Snowstorms). We thought the arrival of major cold would be Dec 9/10 several days ago. Instead, we have seen a weak but very persistent southern ridge allow mild air to surge north, with the western US states being very cold and the far northeastern United States remaining quite chilly, because of the concrete 50/50 low hanging out up there. Like I’ve said, the Euro and Canadian show next week’s upcoming system effectively undercutting the blocking and negative NAO with a really impressive ULL stationed over the Ohio Valley along with East TN valley flurry and mountain snow activity. Instead of the system becoming a fully autonomous upper level cyclone like that, latest GFS and GEFS trends want most of the ULL itself to stay in the Northern Great Plains, Pacific Northwest and Western US as a whole, with only a weak exchange of lower height anomalies being *transferred* across the central US and Mid-Atlantic, with less deep cold here and no New Eng or App Storm. The front would still come through with rain nevertheless, but much of the cold and upper level low pressure activity and lower thickness levels would remain across the western United States with a very suppressed storm that spins its way to death out to sea in the Atlantic, just as the latest 18z Dec 9 & 00z Dec 10 GFS show.

Despite the fact that the GFS changes with almost every run in a mind boggling and fundamental way and as a result many don’t put their trust in the GFS, I have come to find that it and its ensemble suite lead the way and are the first to sniff out trends in the modeling. I like to think of the GFS as a bipolar leader of a group of people. It seems to have no idea where it’s going and changes its mind a lot but is still ultimately the real leader of the group (all of the modeling), picking up on the realistic and true changes before every other model follows behind. Even though the Euro and CMC and their ensembles want the bowling ball to effectively spin deep and by itself across our part of the US by late next week, I think the GFS is onto something with the -PNA persisting and the ULL not undercutting the block very much but only simply transferring weak lower height anomalies and pretty wimpy cold(although a pretty big change to what we’re seeing now) to the East which is very much unlike recent Canadian and European runs. Over the next few days I expect the Euro, Canadian, their ensembles, and all other models to gradually wake up to where their bipolar leader is leading them and will look pretty similar to what the Dec 10th 00z GFS and Dec 10th 00z GEFS looks like through hour 192(December 18th.)

In my opinion the GFS is not bi polar   its schizophrenic. I have seen data showing that the GFS verification scores were not as good as the other models. That was before this latest update.  Maybe I read them wrong but one run the GFS is like the other models then the next run it’s not.  Yet the other models with their support have been steady for several runs now.  Maybe you are right but word on street is the GFS is a disaster right now. Of course believing any model past 5 days is risky to say the least. 

[Holston_River_Rambler]

Overnight ensembles:

EPS

 

GEFS

 

GEPS

 

GEFS is definitely in ints own world with regards to the SE ridge and troughs in the western trough.

But I'm kind of in what can go wrong, may go wrong mode right now... hopefully that's just a personal problem lol

[Holston_River_Rambler]

I'll add that the EPS is pretty enthused about at least snow showers and flurries next week on the plateau and mts:

Plateau:

 

 

Mts:

 

But, is the GFS the new Dr. No? Even if it is ultimately wrong, can it effectively show how things could go south? 

 

[Carvers Gap]

If the cold arrives this weekend, the GFS is already in “bust mode” as it, at one point, had several runs over the forum area never went below normal and was under a standing wave.  The model is likely behind right now, and won’t catch up until the pattern changes.  But I still cast a wary eye.
 

Thus question is worth asking so that we ourselves don’t follow bad modeling off a cliff.....What exactly is the GFS handling poorly?  Is it a bias?  Is it right on some level when biases are accounted for?  Or is it off-the-wall bad right now?  
 

One set of models is in for a fairly significant bust.  

[Holston_River_Rambler]

Ehh 6z GEFS seems to be a bit more optimistic than earlier runs about the upslope next week:

[Holston_River_Rambler]

1 minute ago, Carvers Gap said:

Thus question is worth asking so that we ourselves don’t follow bad modeling off a cliff.....What exactly is the GFS handling poorly?  Is it a bias?  Is it right on some level when biases are accounted for?  Or is it off-the-wall bad right now?  

You put that a lot better than I did. But that was what I was trying to get at. 

[Carvers Gap]

Normally rolling with whichever model is warmest is not a bad idea.  Right now, I am not so certain that modeling is cold enough.

[Holston_River_Rambler]

 6z GFS jumped in a big way toward how the Euro and CMC were handling the system next week. Hopefully that is a sign that it is handling things poorly right now because its long range looked warm. 

[fountainguy97]

Models starting to come to some semi-agreement in a NW event with this first system. 
 

that being said there is a LOT to iron out even with this first system.  The chances behind it are even better. Have to like where we are right now. If we can even score with our first system that's gravy on top.

[John1122]

2 hours ago, Carvers Gap said:

If the cold arrives this weekend, the GFS is already in “bust mode” as it, at one point, had several runs over the forum area never went below normal and was under a standing wave.  The model is likely behind right now, and won’t catch up until the pattern changes.  But I still cast a wary eye.
 

Thus question is worth asking so that we ourselves don’t follow bad modeling off a cliff.....What exactly is the GFS handling poorly?  Is it a bias?  Is it right on some level when biases are accounted for?  Or is it off-the-wall bad right now?  
 

One set of models is in for a fairly significant bust.  

The long range discussion linked yesterday summed it up nicely. The GFS isn't letting cyclones feel the effect of blocking properly and when it doesn't, it throws off the entire run. 

[Carvers Gap]

1 hour ago, John1122 said:

The long range discussion linked yesterday summed it up nicely. The GFS isn't letting cyclones feel the effect of blocking properly and when it doesn't, it throws off the entire run. 

That was good discussion by you all.  I haven't read that article yet.  Normally, the GFS has had some predictable tendencies...too cold in the long range, too progressive with storms along the coast inside day 7,  too quick to break down HL blocks.  Once one factored all of that in, it was usable.  What it is doing right now just doesn't seem usable - not predictable and erratic.  I was almost wondering if it was handling the MJO regions poorly or just not getting SSTs correctly modeled(edit).  I thought I someone note that the jet was being handled differently by it as well.   It did get right the push back of the pattern change, so I hate to discount it completely.  It is almost like it is overdoing the heat at the mid latitudes, and giving the jet too much strength as a result.  

[Daniel Boone]

6 minutes ago, Carvers Gap said:

That was good discussion by you all.  I haven't read that article yet.  Normally, the GFS has had some predictable tendencies...too cold in the long range, too progressive with storms along the coast inside day 7,  too quick to break down HL blocks.  Once one factored all of that in, it was usable.  What it is doing right now just doesn't seem usable - not predictable and erratic.  I was almost wondering if it was handling the MJO regions poorly or just not getting SSTs correctly.  I thought I someone note that the jet was being handled differently by it as well.   It did get right the push back of the pattern change, so I hate to discount it completely.  It is almost like it is overdoing the heat at the mid latitudes, and giving the jet too much strength as a result.  

Yeah, the latest "upgrade" appears to really fouled some things up.

     For one, they over compensated for it's " cold bias". Apparently didn't do anything irt how it doesn't work well with blocking. Other things they've tampered with appear to be evident as well. 

[Carvers Gap]

ICON and GFS at 12z have some fairly interesting solutions - meaning passes by low pressure to our south.