December 2022 Medium/Long Range Pattern Discussion Thread

[Holston_River_Rambler]

That 18z GFS was the ultimate La Niña run! 

[Daniel Boone]

1 hour ago, Carvers Gap said:

If the GFS(all runs today) is correct, the trough will set up shop in the West and just roll periodic cold fronts through the East.  I am definitely dialing back expectations now.  

yeah, if its correct i'm right with you. depressing.

[Carvers Gap]

1 hour ago, Daniel Boone said:

yeah, if its correct i'm right with you. depressing.

The EPS still give us plenty of hope, but the GEFS seems to be leading the way right now.  That said, in the fifteen years we have lived in this house, this is the first time I have seen the leaves off the trees this early.  Completely stripped bare are most of them.  I would guess Mother Nature knows something.

[Daniel Boone]

1 hour ago, Carvers Gap said:

The EPS still give us plenty of hope, but the GEFS seems to be leading the way right now.  That said, in the fifteen years we have lived in this house, this is the first time I have seen the leaves off the trees this early.  Completely stripped bare are most of them.  I would guess Mother Nature knows something.

This was the earliest leaf fall here in many years. The earliest I remember was 1976. Trees were bare by the first week of November.  Maples began changing color by the 3rd week in August!

[Holston_River_Rambler]

Well, since y'all have brought up the Nature signs...

Birds and squirrels have been behaving like the winter of all winters is coming to us on the plateau. I actually thought about trying to get a picture of them around my house, but never got around to it. 

[Holston_River_Rambler]

I wonder if the suprema la nina look on the long range GFS is partially caused by the big convective flare up in perhaps one of the worst places for us to see it.

This is a gif of the sat. imagery over the SW Pac over the past 5 days:

 

I wish I could make it go a little slower, but not sure how to adjust speed on giphy. Notice at the beginning there was very little south of Vietnam and Laos, but some pretty good flare ups recently. I think the flare up over N. Australia that drifts east towards the areas E and SE of New Guinea is associated with the MJO movement into the west Pac, but as seems typical of La Nina, it all get shunted SE. That convection created a big rise and now a big drop (but not to negative numbers yet) in the SOI. In the past 7 days it has gone from approx. -4, up to 30, and now back to 15. Interestingly, the overall 30 average of the SOI has been lowering:

 

I guess that's a lot of huffing and puffing just to talk myself into waiting to see what happens once the block gets established and give the tropical convection some time to keep working itself out. I think the long range OP model runs can, for the continental US pattern, be really dependent on how the tropical Pacific looks for any given run's initialization. 

Even if it does just turn into our typical la Nina, think of the poor flooding rains we missed out on last year! We could get started on those early this year to help with drought striken areas!

Even the WPC gives a 5-7" total over the next 168 hours near MBY:

[Carvers Gap]

The global ensembles continue to advertise a fairly significant pattern change between the 11-12th of this month.  We are gonna be fighting a terrible Pacific set-up which is going to influence the pattern.  If it is going to take a record -NAO to provide balance, we have a good idea of what is coming when the NAO breaks down.  Unless the Pacific flips to the -EPO after the NA0 degrades, a very hostile Pacific will run the pattern.  As many have noted, there is some '89-90 in this pattern.   With the warm start to projected for the month, '89 looks less of a match with each passing day.   2010-2011 looks like a decent match for December.

Back to the pattern change.  It remains to be seen just how cold this pattern will get.  For now, seasonably below normal once the pattern changes seems about right.  The opportunity to go much below normal is there.  Right now, it looks like the cold goes west and then slides east, which oddly, is very similar to what we have seen after nearly every strat warm of the past few winters....

[Carvers Gap]

Fairly significant changes to the 6z GEFS right after 240.  It has lost the ridge over the East when compared to 0z.  A trough is now in place.  We will see how the rest of the run looks here in a minute.  Good sign.

[Carvers Gap]

The 0z EPS and 12z EPS are singing the same song so to speak.  Now, we need to reel the pattern inside of d10.  Good looks on the ensembles, and now we need to see the operationals get on board by Sunday or Monday.

[Carvers Gap]

The 12z GEFS operational at 500 looks(for now!) like what one would imagine a -NAO block would look.

[John1122]

Models almost universally see pattern changes too quickly. Either breaking them down or beginning them.  While it can snow here and has many times in the first half of December, I never really start looking for serious winter threats until after December 15th-20th. 

[Carvers Gap]

I feel like we are just about able to nail down the onset of seasonably cold air by mid-December's standards anyway.  Looks to me like it will be here around December 12th, give our take 24 hours.  Most operationals(not the CMC), and all major global ensembles seem to have this as at the start date.  I was reading @WxUSAF's comments in the MA forum about how the high latitude bridge will potentially fail to capture a portion of the TPV.  IMHO, that will cause our source region to be continental Canadian air masses.  That's not too shabby(to quote Sandler), but it ain't TPV vodka cold.   

As noted earlier, the Pacifica (PNA, EPO) is so hostile that it will take a near record -NAO just to balance the sheet slightly BN in terms of temps.  What happens after the NAO decays will be the topic of much debate.  Does the EPO reform?  I think it might, but there are also analogs where the cold goes west and doesn't come back for months.  

For the time being, I think we get BN temps beginning around the 13th and hold that for a couple of weeks at least.  Honestly, as John noted, winter is really just showing up on time.  

[fountainguy97]

18Z GEFS member 8.  1993 anyone?

 

[Holston_River_Rambler]

27 minutes ago, fountainguy97 said:

18Z GEFS member 8.  1993 anyone?

 

Hopefully one of these years! 

[Itryatgolf70]

Hey guys. It's been a while. I moved to jackson tn this past April. I tried posting the animation of 12zeps, but size was too large. If we can get height rises over Alaska, it will get cold east of the rockies. Towards the end of the run, it is hinting at that possibility 

[Holston_River_Rambler]

Op GFS at 6z was another ideal La Nina run. I think I could draw up a pattern like that if you just told me La Nina. 

You can even make a really fast gif of the run and it doesn't matter for our area. Not much changes:

0z Euro was a bit different. It ends at 240 with a nice trough:

I know ensembles are better at long range, but it just struck me this morning how badly the pattern could potentially work out if the GFS is right. 

 

As we've been saying, the GEFS and EPS still like the better pattern day 10+. So at least we still have that. 

GEFS:

 

EPS:

 

Western Pac looking a little better (even if still not great) with some convection north of New Guinea:

 

Strat split seems to have worked out and is within 90 hours now:

Both the Euro and GFS show it reconsolidating after this. Not sure how healthy it will be though. 

 

 

 

 

[Carvers Gap]

I think we are looking at a pretty big bust regarding east coast temps.  Where modeling was originally looking at the 12-13th for cold...it is now pushed way back.  The only cold  is way out there if it is there at all (6s GFS is void of cold in our half of the nation).  It is possible we will still see some cold after the 15th,  for now the cold was just a mirage. Could it be delayed?  Sure, But we need the Pacific to throw us a bone, or the cold is headed there.  The tough part about this is Dec is often the colder month of La Nina’s(not always but often).  The NAO may well just be too early.  An NAO during late spring and summer can cause very warm temps.  

[Carvers Gap]

What essentially is occurring is a standing wave(SE ridge on steroids ad nauseam).  The ensembles do have us cooling back to normal by the 15th, but I am not sure how believable the LR is after this likely bust.   Could it flip back? Sure.  At this point I think we have seen another strat warm which was handled poorly by modeling.  During future strat warms...we will look for a similar bias(cold in LR which doesn’t verify).  For now, much above normal temps for the first half of Dec look likely. 

[Itryatgolf70]

1 hour ago, Carvers Gap said:

What essentially is occurring is a standing wave(SE ridge on steroids ad nauseam).  The ensembles do have us cooling back to normal by the 15th, but I am not sure how believable the LR is after this likely bust.   Could it flip back? Sure.  At this point I think we have seen another strat warm which was handled poorly by modeling.  During future strat warms...we will look for a similar bias(cold in LR which doesn’t verify).  For now, much above normal temps for the first half of Dec look likely. 

That would be interesting if we had similar pattern to last winter, where December was warm and then we had a decent winter after that. I doubt it happens, but similar patterns have repeated theirself. Hopefully we can eventually take advantage of a -nao that bring us consistent cold.

[Daniel Boone]

1 hour ago, Carvers Gap said:

What essentially is occurring is a standing wave(SE ridge on steroids ad nauseam).  The ensembles do have us cooling back to normal by the 15th, but I am not sure how believable the LR is after this likely bust.   Could it flip back? Sure.  At this point I think we have seen another strat warm which was handled poorly by modeling.  During future strat warms...we will look for a similar bias(cold in LR which doesn’t verify).  For now, much above normal temps for the first half of Dec look likely. 

SER and -NAO too strong for one ; allowing for easy coupling. Too bad the SER isn't further east out by the Sargasso Sea. That would allow cold to come further East even if they were connected/coupled.

        Hopefully, at the very least one will be weaker than modeleled and allow for a disconnected conduit. 

[Itryatgolf70]

10 minutes ago, Daniel Boone said:

SER and -NAO too strong for one ; allowing for easy coupling. Too bad the SER isn't further east out by the Sargasso Sea. That would allow cold to come further East even if they were connected/coupled.

        Hopefully, at the very least one will be weaker than modeleled and allow for a disconnected conduit. 

The 0zeps is trying to develop more Alaskan ridging in the day 14-15 time frame. Still way out there but I feel that will be our best opportunity there for good cold

[Daniel Boone]

36 minutes ago, Itryatgolf70 said:

The 0zeps is trying to develop more Alaskan ridging in the day 14-15 time frame. Still way out there but I feel that will be our best opportunity there for good cold

Yeah. That would definitely help and may very well be what happens as that has been the case this fall.

     Model's always have problems when blocking sets up. It's possible they revert back to sustained troughiness in the East like earlier depictions.

 Back in my day, over 90% of the time a -NAO led to cold in the East even while the West was cold. Recently, the SER/-NAO hook-up has been more prevalent. I may research and see if the occurrence is mainly during Nina's. I suspect it is. Makes sense. 

[Carvers Gap]

1. We definitely need help from the Pacific.  There have been runs which show the EPO/PNA ridge building.   For you all in middle and west TN, the western ridge is money.  In E TN, the NAO or HB block (especially in conjunction w/ a falling QBO and weak Nino) is a better result.  The EPO/PNA ridge during Ninas is often too far west(for E TN) which leaves E TN in the warm sector.  So, kind of depends on where one lives.  But for now, we definitely need help from the Pacific.  We "should" catch some brief cycles into phases 7-8 and let that ridge out West build.  A -PNA is not good for any of us east of the MS.  

2. Again, watching the 12z GFS flip-flop yet again.....I am not sure modeling is handling the NAO block well.  The 12z GFS has again flipped to a much colder run.  

3. As for E TN winters, NE TN has not had great winters during the past several years, especially once December is over.  Nina winters favor E TN during December and middle/western areas are favored as winter progresses into Jan/Feb.   Middle and west TN have scored big due to the Nina pattern, even Knoxville.  The eastern mountains and NE TN have drawn the short straw.  That is cool though, the pendulum will swing back.  This Nina cycle has been greatly needed in order to reset the gradient so that El Nino's actually have a normal effect.  

[Carvers Gap]

Whoa.  Mercy me, what a flip from the 12z GFS.  Now, that is understandable at this range...but that is a nearly complete reversal from d8-16.  If we get cold, send me a Christmas card for the from earlier this morning.  LOL.

[Carvers Gap]

Pretty interesting.  So a standing wave (monster SER) has been a characteristic of recent GFS runs(not this one).  The 12z has a system slide across the MidWest on the 12th, and it (and the subsequent system) just destroys the SER.  Good call by @Daniel Booneabove.  That is the golden ticket.  If the SER establishes, we are pretty much screwed.  The 12z GFS really shows the NAO block flex.  I am not buying that run quite yet, but FINALLY the actual operational matches the previous ensembles.

[Carvers Gap]

12z Euro follows suite (operationals finally showing what ensembles have shown).  If the 12z EPS holds, this train may have somehow gotten back on the tracks.

[Carvers Gap]

12z EPS holds.  I won't say, "Game on," but if I can see 3-4 more operational runs/ensembles....After some shaky overnight runs, much improved 12z suite.  Will it hold?

[Itryatgolf70]

46 minutes ago, Carvers Gap said:

12z EPS holds.  I won't say, "Game on," but if I can see 3-4 more operational runs/ensembles....After some shaky overnight runs, much improved 12z suite.  Will it hold?

I know they have mentioned about convection in Indian Ocean. Could be throwing models off right now. 

[Carvers Gap]

47 minutes ago, Itryatgolf70 said:

I know they have mentioned about convection in Indian Ocean. Could be throwing models off right now. 

I’d think the near record -NAO in combination with a terrible MJO(IO influence) is not something most modern models have ever had to contend with during a third year Niña.  There might be 2-3 analogs at best.

[Itryatgolf70]

4 hours ago, Carvers Gap said:

I’d think the near record -NAO in combination with a terrible MJO(IO influence) is not something most modern models have ever had to contend with during a third year Niña.  There might be 2-3 analogs at best.

Where do you think the mjo is currently? In the IO or in Western hemisphere? I believe that's extremely important moving forward. I know Eric webb, who has a good knowledge of patterns said the IO convection that has bubbled up is all part of the mainstream pattern mechanism that leads to perhaps a colder outcome later on, but not sure yet if I agree with that sentiment