December 2022 Medium/Long Range Pattern Discussion Thread

[Carvers Gap]

We will soon find out if the high latitude blocking signatures pay dividends for our area.  May need a boat and may also need snow shovels.  We'll try separating this into threads by month.  If that doesn't work, I will simply switch this to Part I of winter.  Have fun and good luck!

[Carvers Gap]

High latitude blocking galore.  Please see comments in the Fall thread.

 

[Carvers Gap]

As noted in the Fall thread, take with a grain of salt as this is in the 10-15 day range.  EPS is a hair slower.  Overall, Atlantic blocking likes to hang around once established.  Winters of late have tended to buck some of the analog packages.  

 

[PowellVolz]

Bring it


.

[nrgjeff]

I figure that SER, really more of a south-central US ridge, will try to hold on through early next week. Eventually the dam breaks in December*. Just too much blocking.

*That's a generalization. Not a forecast. I have a long infamous history of jinxing weather patterns; so, just idle chatter.

[Holston_River_Rambler]

GFS and Euro wanting to show a bit of a split of the SPV. Looks like there is probably some relationship with the -NAO ridge developing. 

Euro:

GFS:

 

Here is the 3D model from the 0z GFS run last night:

 

 

 

 

[Carvers Gap]

-NAO anyone?

 

[Carvers Gap]

I was reading the MA forum earlier.  They were talking about '10-11 as a possible analog.  I looked at 83-83, 89-90, 95-96, 20-21...no match.  JB and/or others have mentioned those.  But take a look at this.

 

 

[Daniel Boone]

Those 500 charts look almost identical to the progged lr pattern. Dec. Jan. 2010-11 were cold with solid snowcover much of the time. 

[Carvers Gap]

22 minutes ago, Daniel Boone said:

Those 500 charts look almost identical to the progged lr pattern. Dec. Jan. 2010-11 were cold with solid snowcover much of the time. 

Yeah, I was looking back at some of MRX's climatology.   I have my doubts if it doubles down colder after December, but 10-11 was definitely front loaded Dec/Jan.  It is a great fit for the currently ascending QBO.

[Carvers Gap]

The 12z GFS is still advertising a significant period of cold.  The block is impressive.  We will see how source regions set-up in terms of the severity of cold.  

[Carvers Gap]

The 12z GEFS supports the operational.  Looks like it is going to be cold.  Main concern is that we are currently experiencing drought conditions.  That means timing of systems(re: snow storms) will be exceptionally important.

[John1122]

2 hours ago, Carvers Gap said:

The 12z GEFS supports the operational.  Looks like it is going to be cold.  Main concern is that we are currently experiencing drought conditions.  That means timing of systems(re: snow storms) will be exceptionally important.

 

That was an issue in 1989. It was constantly cold enough for snow but it was a dry cold for the most part.

[Holston_River_Rambler]

What in the world is that at the end of the 18z GFS:

The ultimate -NAO storm?

[Carvers Gap]

41 minutes ago, Holston_River_Rambler said:

What in the world is that at the end of the 18z GFS:

The ultimate -NAO storm?

LOL.  Glad I wasn't the only one.  That might be the most screwed up GFS run I have ever seen!  I had to loop it backwards to make it look right.  I am sure it will verify as it is messed-up(like on drugs).  

[Carvers Gap]

43 minutes ago, Holston_River_Rambler said:

What in the world is that at the end of the 18z GFS:

The ultimate -NAO storm?

The Apps blizzard of '22 came from Nova Scotia. 

[Carvers Gap]

2 hours ago, John1122 said:

 

That was an issue in 1989. It was constantly cold enough for snow but it was a dry cold for the most part.

This has some elements of '89 in the pattern.  As the NAO breaks down, we need the Pacific to jump right in like 10-11...

[Met1985]

Im sure we are going to see some crazy solutions regarding the significance of this block in the NAO region.  I read in the Mid Atlantic forum that some models are spitting out the highest pressure ever recorded in Greenland.  With a block to this magnitude who knows what we see from the models....

[Carvers Gap]

I think w/ potential record AN heights in the area of Greenland....good luck to all models and may the odds be ever in their favor.  It's Hunger Games time for modeling.  

[Met1985]

1 minute ago, Carvers Gap said:

I think w/ potential record AN heights in the area of Greenland....good luck to all models and may the odds be ever in their favor.  It's Hunger Games time for modeling.  

Yeah the interesting thing was that last year didn't we see a record PNA for the season when it was so negative?

[Daniel Boone]

4 hours ago, John1122 said:

 

That was an issue in 1989. It was constantly cold enough for snow but it was a dry cold for the most part.

Yep.  only 10 inches for that cold month. One 5 incher and the rest light events. 

[Carvers Gap]

2 hours ago, Holston_River_Rambler said:

What in the world is that at the end of the 18z GFS:

The ultimate -NAO storm?

 

Reminds me of this set-up from 2004.   

[PowellVolz]

What in the world is that at the end of the 18z GFS:

The ultimate -NAO storm?

I’ve never seen anything like that before. Almost like the gif is in reverse


.

[Carvers Gap]

@Holston_River_Rambler, had this the other day.  The 6zGFS continues to advertise a family significant "split" of the SPV 50mb and above.  I noticed this, because the EPS Control briefly hooked the NAO into an eastern ridge.  In the past, when I have seen this...that is a precursor to a split or at least significant jostling of the higher latitude pattern.  With an early season block and SPV split underway(at the very least warming in the strat), modeling is going to struggle as evidenced by the wild model outcome of the 18z GFS yesterday.  For now, the pattern looks relatively dry.  That said, model mayhem is likely well underway.  As a note of caution, recent SSWs/SPV splits have wrecked what looked like a good pattern on modeling in the long range.  Now, in reality nothing was wrecked at all as that was what was going to happen regardless.   I will say the SPV split/SSW looks to invoke a nearly immediate response at our latitude(sometimes we have to wait 2-3 weeks).  That said, the worst of the cold may not arrive unit mid-month or just after.  The actual pattern change which initiates an east based NAO begins in about 96 hours.  That block will then retrograde in the 7-10 days which follow.  So, the actual HL shuffle is within the 5 day window.  It is the dominoes which fall due to this reshuffle which have to be ironed out.

[Holston_River_Rambler]

One of the interesting things about the strat PV disruption is that I think it is 100% related to this NAO block (not sure which is the chicken and which is the egg in this case though). However, long range strat PV is showing another sort of SPV evolution that might result in a warming and not just a split:

GFS

 

Euro:

 

I think what we are looking at in the medium/ shorter range is more like what happened in 2018 when we had the nice blocking in March after the strat split or warming (can't remember which)  in late Feb. the gifs above would be like more recent SSWs but they're pretty far out in 300+ hr  "magical retrograding snowstorm on the 18z GFS" land, so who knows. 

 

It's such and awesome block, I hope someone one in the eastern half of the US gets hammered at some point. With such a big NAO, you might think we would be looking at an Archambault event as the block eventually breaks down.

 

 

That is a summary of the nature of the events from the page below and was written in regards to a different event. 

http://easternmassweather.blogspot.com/2019/03/pacific-archambault-signal-for-equinox.html

 

I think these are the publications if anyone is interested. I may dig into one later when I have more time:

 

 

 

[Holston_River_Rambler]

The 6z GFS shows what could be a downright magical pattern evolution. Not saying this going to happen, but I guess it is at least on the table. Imagine what would happen if the NAO block trapped a vort under it in a massive rex block on a continental scale:

And then it retrograded west enough to keep us on the NW edge of a upper level SW flow, while maintaining cold air:

 

[Carvers Gap]

Not saying that is going to happen, but that is a complete reversal by the 12z GFS at the mid latitudes - complete.  I don't think that verifies as the GFS is simply producing flavor-of-the-month runs every run.  BUT, we have seen more than one strat split/SSW cause chaos in modeling.

[Carvers Gap]

OTH, if the 6z CFSv2 is correct, we will all be crying uncle about mid January.  That run flips from a massive -NAO to a massive EPO/PNA ridge.  If I could draw-up a winter pattern, that would be it.

[nrgjeff]

Relaod. Rutgers (not shown) has AN snow on the southern periphery of Asia snowcover. We patiently (or not so patiently) await the North America response. Even if SER (or more likely south-central ridge) early, the cold should eventually win out.

[Daniel Boone]

3 hours ago, Carvers Gap said:

Not saying that is going to happen, but that is a complete reversal by the 12z GFS at the mid latitudes - complete.  I don't think that verifies as the GFS is simply producing flavor-of-the-month runs every run.  BUT, we have seen more than one strat split/SSW cause chaos in modeling.

The Libs tampered with the Model. Climate agenda.