Carvers Gap

The 0z Euro, 0z CMC, and 6z GFS all move a trough into the East which looks to possibly have some staying power. The CMC is much quicker and the GFS is the slowest. But they all get tend get to a similar point. Starting to be concerned the Music City Bowl is going to be cold.

@John1122atmospheric river alerts are posted for Mammoth later in the week. The webcams should be hopping.

The 18z GEFSAI and EuroAI are the first ensembles for flip. Let’s see if they stay that way - much cooler since yesterday I think.

The Euro Weeklies control had an EPO ridge, NAO, and trough east of Hawaii.

The control run of the Weeklies looked like this…the best run of the season for the control,

FWIW, the Euro control Weeklies looked just fine…even bullish on cold.

The good thing is the Weeklies have been pretty awful this winter so far. I don’t think ensembles will handle this pattern well quite yet. Reference my post above.

FTR, I don't think we go 1985. That is its own benchmark kind of like March 1993. We perch that year on the mantel and just take it down to look at when we get bored or want to reminisce. I have had that in the back pocket for several, several days. It is why I simply refuse to let the likely brief chinook bother me. A raging NAO took over that pattern above just after the New Year, and brought the hammer for two weeks. It was the one time in my life that I was ready for spring at the end of January. I think what is coming has yet to be defined by d10+ modeling. If the NAO takes over, we are good. If it is one-hit-wonder, the rotten Pac could take back over. But the NAO is so difficult for models to handle. It is interesting tracking with it on the table. To me, I kind of think a back-and-forth pattern witch some strong cold shots looks likely.

And if I showed you all this December analog, you might not be enthused. I can only imagine the number of folks who would have canceled winter had the internet been around. It looks almost identical to the last 10 days models for this December. That is ->

Jan and Feb 1996....I don't mind ridging into the Aleutians. Recently, that hasn't been a good thing. Historically, it isn't bad. January 2015 had it. But look at January of 1996. We kind of want hp to not be centered on top of the Aleutians. But AN heights in the Aleutians can be really good as long as it is centered to one side. The ticket is getting a trough to slide in over Hawaii or just to the east of it. A lot of great patterns flirted with disaster at times(torch).

Here is the difference between the mean and actually what the individual members depict. As is, that not a slam dunk warm pattern. Many of those are BN for temps or headed that way within the next slide or two. When you look at the mean, it is easy to assume that we are headed for a warm pattern. It is why the deterministic models have to be given a bit more weight than normal.

IDK. There are definitely some colder winters with it there. I was surprised when I went and looked last year. There has to be Atlantic help to overcome it. It is the rex block which it creates which is the problem, and that (to the best of my knowledge) doesn't form every time. There are some crazy good winters with teleconnections which are out of whack.

If you created a median(and not mean) of temps after d10, it would look MUCH different than the mean on the GEFS. Roughly 5/30 crazy warm members are skewing the temps warm. That means ensembles are stuck in catchup mode.

I really like the BOMM MJO which is shown on the CPC today. It rotates the MJO rapidly through the warm phases. It is sitting in phase 3/4 around NY and that isn't always a bad spot for snow. I don't see any model camping out in 6...maybe 48-72 house at the most. There is a bit of trend in modeling to dry out the MC if I heard JB correctly. The signal will still likely be weak. That means other drivers could take over the pattern. That also means the Aleutian Ridge is probably on the clock now.

The 12z AI-GFS has snow storm on NYE. The CMC is very close as well.

The 12z AIGFS is much different than the 12z GFS - night and day. I don't think we can completely rule out a path to continue warmer temps after the 29th...but with each run cold seems to be more likely.

Take GaWx's analogs and run with them. Great information. 95-96(lite) sure looks reasonable to me. The 12z deterministic suite had great trends with the exception of the GFS. Ensembles are getting hugely skewed by just a few warm members - I bet...haven't looked for 12z, but they were overnight for sure. The NAO looks like a player. I kind of play by a couple of rules with the NAO. Sometimes modeling overdoes the NAO. Modeling will often try to break it down too quickly once it breaks down. With that ridge in the Aleutians....we take the NAO regardless of whether we don't get as cold as Europe. It could hook into the SE ridge for a time, but that is not a stable pattern with subtropical air being pumped into Greenland. A mature NAO pattern often yields big storms. Without the Pac, I wouldn't call that a big storm pattern, but we could back our way into some snow w/ that look. I think this is QBO and SSW(in concert) driven. This will be chaotic for a few more days - maybe very chaotic from run to run within the same model. Lots of cold air running around. We need one, good cutter.

Some good runs overnight. The ensemble means are washed out at range which is understandable, but their individual members have it. There are 4-5 warm scenarios per suite which are skewing the greater number of cold members. We saw the same things happened with recent cold fronts....ensembles couldn't see them in the mean. The deterministic runs of the Euro, GFS(6z and 12z), and CMC have strong NAO solutions - some extreme which I doubt verify. That said...any model without the NAO right now can't be discounted, but the ones with it....are more likely to have correct solutions.

That control @Holston_River_Rambler. Delta from high to low...9! The good thing is the mean is negative. I actually favor the control run - wild swings likely. AO looks pretty much the same. This has gotta be that SSW moving things around. This also fits QBO climatology which favors HL blocking. Probably all of that is connected in some way.

I think models are in a huge state of flux right now. They were wrong about the Baja lows. They are wrong about over-doing too many NW Pac lows. They could be overdoing the Aleutian and/or NAO and/or AO HL blocking. We have seen modeling miss on HL blocking at exactly this time of year, but we have seen it score. Just too early to tell.

I am mainly confident, because recent Nina climatology suggests there will be 10-14 days of very cold temps sometime between week 2-4 of January. Plus, this seems to be one of those years where warm-ups get shortened as they draw closer. We are in the "warm-up" which was originally modeled to be anomalous. This morning, I was running in 30+mph winds with wind chills in the 20s. If the more aggressive models are correct, the warm-up may be confined to Dec 24-28th. Might be the most talked about warm-up ever to only amount to about 120 hours of AN temps. LOL. I hope that is what happens!!! I am pulling for the NAO to occur, because I am tired of talking about the MJO (no offense meant to those who like it...it is effective). So far, this has fit Nina climatology like a glove....

The Euro Weeklies are full bore winter in January. They have increasingly BN temps. That LR ext ensemble and the GEPS have broken towards cold today. We were waiting for ensembles to track....some good trends. In the case of the Euro Weeklies...great trends. 95-96(lite) and some 84-85 vibes as you all noted earlier in the thread.

The real fun with that is the NAO and Aleutian's highs bridge across the top. They trap a lobe of the TPV in NA. I think the biggest take away from 12z is that HL blocking is showing up across modeling, and the signal is stronger at 12z than yesterday at this time. Good trends.

Models have "likely" made two big errors this year. One was the Baja low situation for early December. The next one(appears as of now) was the repetitive lows sliding out of British Columbia to off the Coast of California. The Rex block might produce one or two storms on the West Coast...but not the sequence which was causing the endless chinooks. Even though modeling is still working things out....the exiting of feedback helps. Some chinook makes sense...but it was way overdone it appears. Now, is the NAO feedback? IDK. I have definitely witnessed years when models over-did how strong it was and missed the duration (sometimes too little duration...sometimes too much). The same could be said for the Aleutians high - but it has actual precedence for being there and at that intensity. I think we end up w/ a full latitude trough w/ cold dropping into Montana, modifying just a bit, and then heading eastward. I think the difference this year(compared to recent Nina winters), the source is much colder and this cold finds its way all the way to the Atlantic coast. I do suspect models could be too quick with the move back to cold, but again, sometimes they aren't quick enough if the NAO is going to be a player. The storm track could be more favorable as we enter January. As your friend notes, mid-Jan makes a bit more sense or even just the second week of January.

12z is definitely a choose your own adventure. Definitely NOT an easy pattern to model, but LIKELY to produce some interesting solutions on deterministic runs. Normally, I would say check the ensembles, but I think they are at least 24-36 hours behind the curve.