Winter 2021/22 December Thread

[Mr. Kevin]

1 hour ago, Carvers Gap said:

Models looks really good at 12z.  GEPS ensemble looks perfect.  -NAO is showing up.  Models are sensing that feature now.  Always seems like it takes a few days to reflect effects at the mid latitudes once the NAO shows up on modeling.

Webberweather made a few good tweets earlier today on Twitter. 

[Carvers Gap]

27 minutes ago, Mr. Kevin said:

Webberweather made a few good tweets earlier today on Twitter. 

Feel free to share.  Would enjoy reading them.

[Mr. Kevin]

1 hour ago, Carvers Gap said:

Feel free to share.  Would enjoy reading them.

[Daniel Boone]

41 minutes ago, Mr. Kevin said:

Was looking at that earlier. Looking interesting in the near future.

[Carvers Gap]

Love the posts @Mr. Kevin.  Some of that makes my head spin, but good stuff!!!

18z GEFS is a great pattern evolution with the -NAO placed perfectly.  Would be seasonal cold with a suppressed storm track.  That would work.

[Carvers Gap]

The 6z GEFS is a classic -NAO look.  Will be interesting to see how that plays.  I have seen some talk that NAOs are not a lock for cold.  Noted and agree.  However, what will happen is likely a suppressed storm track.  I still think modeling is just now settling back down after the MJO snafu.  Again, I also thing modeling takes a while to adjust to blocking.  The trend on the GEFS this morning might be evidence that modeling is now starting to work through those things.  The GEPS is nearly perfect.  Let's see if the GEFS trends that way.  

[Carvers Gap]

Just looking at both the 6z GEFS and 0z GEPS, I think it is reasonable to begin to start looking at a cold shot beginning somewhere during the first two weeks of January which given climatology is not surprising.  Those are normally cold weeks.  It would appear that Dec20-30th will be a transition time.  IMHO, we are looking at roughly a 1-2 weeks of seasonal cold to potentially BN in early January.  If we see BN temps showing up in early January, that is cold indeed as that is climatologically one of our coldest weeks of the year.  The flip of that is that we don't want to see AN temps in early to mid August, because those temps are really warm.  Again, once we see the MJO settle back down and the NAO establish itself, I suspect we see modeling trend colder.  

An aside, I consider a good thing to see the NAO for a second year straight during winter.  -NAOs tend to cluster in groups of winters.  Maybe we are at the beginning of a cycle where the NAO becomes a dominant feature during winter after a prolonged absence.  

[Carvers Gap]

These were published yesterday.  Seasonal temps with normal precip in January....we take.

 

 

[Carvers Gap]

Courtesy of WxBell.  The Australian MJO plot....that is a good look.

[Daniel Boone]

1 hour ago, Carvers Gap said:

These were published yesterday.  Seasonal temps with normal precip in January....we take.

 

 

To add some enlightment to that. For NOAA/CPC to put EC over us is a great sign. Hard for them to do that even without La nina. If the block is formidable during January and we get the MJO go slowly thru cold phases, that ec will be bn and possibly encompass areas further east as well. 

   As we all know, even if Canada were to go milder than avg. that air funneled down here would still be cold for us. Even the sour winter of 2001-02 featured the right setup in early Jan and Canada was very mild. We still received a significant snowfall during that in much of the area.

    Just thought I'd throw that out there to strengthen the positive about the likely looking 500 mb pattern. Not saying Canada goes mild but that has been known to happen . Doesn't look likely this time though.

     I agree with Carvers totally in that IF that Pattern continues to be advertised, Models will adjust colder.

[Carvers Gap]

Boone right on time with those comments as both the 12z GEFS and GEPS both show what would be a sharply colder pattern just edging into view of LR models.  Get some split flow into that pattern and that has potential.

[Mr. Kevin]

I notice the ecmwf has the ao going pretty negative and I'm assuming the eps does also but not to the extent as ecmwf op run. 

[Carvers Gap]

Fantastic post.  Click the header.

That much of an anomalous west-based -NAO on a 10-15 day mean is just insane. We should start to see some chances around Christmas into the New Year with shortwaves rolling underneath the block (like the 12z GFS). It might warm up for a bit as the SE ridge pumps for a day or two in that timeframe, but that will be transient if it happens. Models often take a while to see the full effect of the block on the longwave pattern, and the EPS has generally done a horrible job from the start determining the strength of the block to begin with, so I'm not so sure I trust its depiction of the pattern over the CONUS as much as the other ensembles.

 

[Mr. Kevin]

15 minutes ago, Carvers Gap said:

Fantastic post.  Click the header.

That much of an anomalous west-based -NAO on a 10-15 day mean is just insane. We should start to see some chances around Christmas into the New Year with shortwaves rolling underneath the block (like the 12z GFS). It might warm up for a bit as the SE ridge pumps for a day or two in that timeframe, but that will be transient if it happens. Models often take a while to see the full effect of the block on the longwave pattern, and the EPS has generally done a horrible job from the start determining the strength of the block to begin with, so I'm not so sure I trust its depiction of the pattern over the CONUS as much as the other ensembles.

 

That alutian ridge is incredibly intense currently. I'm not a big fan of it, but if it can shift somehow, we then may be looking better and I guess the mjo progression if it can happen. 

[Carvers Gap]

12 minutes ago, Mr. Kevin said:

That alutian ridge is incredibly intense currently. I'm not a big fan of it, but if it can shift somehow, we then may be looking better and I guess the mjo progression if it can happen. 

Reminds me A LOT of last winter....w/ the blocks in almost identical positions.  Aleutian Ridge looks like it is going to be there for some time.  As Jax noted a few pages ago, sometimes that ridge slides into the GOA...and that is optimal.  Thing is that second year Nina's (off the top of my head) tend to center cold a bit more eastward.  I noticed feedback in modeling in early December. I took 10-14 days for the feedback to eventually show something that didn't look like a "copy and paste" pattern.  Pretty good look out there right now.  Again, I think when modeling shows the "copy and paste" look in the LR, it is likely wrong.  We don't need wall-to-wall cold for snow in January.    Very interesting to see the CPC go w/ equal chances for pretty much the entire forum areas.  Brave forecast in the face of a week of big warmth.  They wouldn't put that out there if they didn't have pretty good reasoning.  So, some good signs.  Important to note that the Atlantic can drive our weather pattern here, doesn't always have to be the Pacific.  Been a long time since we have seen back-to-back winters with strong -NAOs to work with.  Though, I do think Pacific driven patterns are generally easier for computer wx models to work with.  

[Carvers Gap]

The 0z GFS looks great.  It will surely change by the next run, but that is a perfectly placed -NAO and the model reflects that.

[Carvers Gap]

That is the first time in a while that we have seen the GFS break in continuity for that time frame.  Really can't draw-up a better LR pattern than the 0z GFS.  We have rarely had that look during the past 25 years.  Both a -EPO and -NAO.  Kind of doubt that verifies, but the NAO is doing its work there.  Big change.  Let's see if the model can hold onto that at least somewhat consistently for the next few days.  

[Carvers Gap]

And the 0z. ICON looks similar, but is probably too quick with the transition....but that is a whopper of a NA trough at 500.  0z is less enthused, but if extrapolated....likely would have gotten there.

[jaxjagman]

Think i'd be careful with this Nina,its stronger than what you might think it is.

Unlike last year where the SOI bounced all around it's not that way  right now.The Equatorial subsurface is cooling once again and where we saw those impressive anomalies down in the subsurface earlier a few  weeks ago, its getting cold the same area again.

Be nice if that map was right but is it?Not sure NINA works like that,but if its like that think ,it would be a active jet for sure in Jan

 

[John1122]

As I expected a week ago, the GFS was trying to bring the pattern change too quickly and the Euro, with basically no pattern change at all on the Weeklies was delaying too much. As of now, the extended ensembles on all modeling has a potent, well placed NAO, a good Pacific set up, and very cold air on tap for our side of the world. Lots of BN heights across the lower 48 with reds where we want them. As Carvers mentioned, we don't often have that many things going correctly. Some of the times we had a cooperative Atlantic, and Pacific in a La Nina was 1995-96, and 1984-1985. We are definitely having a torchy December ala 1984.

[Holston_River_Rambler]

20 hours ago, Carvers Gap said:

Courtesy of WxBell.  The Australian MJO plot....that is a good look.

Looks even better this AM:

Our little typhoon friend has restrengthened though:

 

But it only has about 72 hours left to live. 

 

I think after Monday, we start to get some nice 240+ hour storms on the GFS and Euro control. 

Here are the overnight gifs of teh ensembles for all you gif fiends out there (EPS, GEFS, and GEPS):

 

 

 

Euro control and OP GFS were both showing the storm track pushing south at the end of their runs, so that seems to agree with these means. 

 

 

[Icy Hot]

Remember everyone, Winter does not begin for 3 more days. DECEMBER 21. :)

[Carvers Gap]

As Holston mentions, the 500 pattern after d10 has the NAO retrograde west and slightly south.  Trend overnight(and yesterday) is for some modeling to connect that NAO to the Pac ridge.   What we are seeing, and it is out here so huge grains, is a pattern which could potentially go BN right during the coldest weeks of winter.  It is not impossible that a piece of the PV could get dislodged under that type of block and get sent into the Lower 48.  

[Carvers Gap]

Another nice set of ensembles at 12z. 

[Holston_River_Rambler]

13 minutes ago, Carvers Gap said:

Another nice set of ensembles at 12z. 

They all looked so good (albeit at 10+) that I almost can't believe it. Only subtle differences between the major 3. 

The OP GFS even shows a wild scenario where the NAO ridge and the EPO ridge merge to form an AO ridge displaced over the Beaufort Sea:

 

Even the Euro Control was still pushing the storm track south and had some energy that looked like it would be forced from the 4 corners area to the Gulf. Not saying that will happen, but there is some pattern support for storms eventually taking the low road from the CO Plateau to the SE Coast in these ensembles. 

 

 

[Daniel Boone]

2 hours ago, Holston_River_Rambler said:

They all looked so good (albeit at 10+) that I almost can't believe it. Only subtle differences between the major 3. 

The OP GFS even shows a wild scenario where the NAO ridge and the EPO ridge merge to form an AO ridge displaced over the Beaufort Sea:

 

Even the Euro Control was still pushing the storm track south and had some energy that looked like it would be forced from the 4 corners area to the Gulf. Not saying that will happen, but there is some pattern support for storms eventually taking the low road from the CO Plateau to the SE Coast in these ensembles. 

 

 

  Good stuff! 95-96 featured those se moving storms that were miller A/B hybrids. 

    Man, those can really hammer us !

[Carvers Gap]

5 hours ago, Holston_River_Rambler said:

They all looked so good (albeit at 10+) that I almost can't believe it. Only subtle differences between the major 3. 

The OP GFS even shows a wild scenario where the NAO ridge and the EPO ridge merge to form an AO ridge displaced over the Beaufort Sea:

 

Even the Euro Control was still pushing the storm track south and had some energy that looked like it would be forced from the 4 corners area to the Gulf. Not saying that will happen, but there is some pattern support for storms eventually taking the low road from the CO Plateau to the SE Coast in these ensembles. 

 

 

JB mentioned this evening that some of the air being modeled is so cold that it is giving models fits.  Remember last year how the models had the EC at record cold temps for a while, but it switched to the nation's mid-section.  Models will be all over the place with very cold air.  Key right now are the delivery systems are in place for Arctic air.  Looks like cold will setup shop out West and push East.  Classic, classic La Nina look.  But everyone should have a health distrust of modeling at this range.  Huge grains, right!!!

[Bigbald]

Merry Torchmas.  I don't see how Wolf Ridge and some of these smaller ski resorts stay in business. It's hard for to see sustained snow making opportunities before January by the looks of the last few runs of the GFS and Canadian, its really balmy the week after xmas.  I am trying to remember if Wolf has been closed the entire month of December before (?). 

 

[Holston_River_Rambler]

On the bright side they could turn the slopes into extreme whitewater rafting experiences if the 6z GFS is right:

 

Fortunately the EPS doesn't see it (except notably, to an extent, in the control)

But I'm always nervous about the trough dropping over the 4 corners and aiming the jet at the OH Valley, so we get stuck in the right entrance region of jet streak after jet streak and get soaked. The creeks up here in Morgan county are already very happy after the past couple of days:

 

I'd say they are about half again higher today (that pic was taken Friday AM). 

 

 

Our little typhoon friend that has been messing with the RMM plots is finally starting to weaken after bottoming out at 915mb yesterday. 

BOM looks good this AM, once again:

 

The Euro just spins in in 7:

 

GEFS is more hopeful:

 

We finally have some actual convection over the Western Pac again, associated with the MJO wave:

Hopefully it doesn't turn into another typhoon, lol. 

Strat still looks kind of stressed in the long term, but no major splits or warmings consistently modeled yet. 

[Kentucky]