Carvers Gap

I guess the overall trend I am seeing at 12z is the tendency to amplify a trough over the eastern half of the United States. Some models are doing this on the 29th(Euro). Others are doing it with the next system just after New Year's(GFS and CMC). I can see the path to a warmer pattern, but it sure looks like the cold is going to be pay-me-now or pay-me-later...ie the cold is coming with the NAO block in place and it is a matter of time.

The normally warmi-sh Euro at 12z rolled this for the Music City Bowl...I truly hope that is wrong, but it looks like a cold front will possible slide in the evening of the 28th. I am still waiting on my warm-up - I need a short warm-up! This morning is the first morning I haven't run with gloves in a long time...so that is a start.

One other thing LC noted last night was that the MJO has no real clear signal - at least that is how I read it. He has cautioned multiple times about using it recently. He noted it was almost impossible to decipher the phase it was in. He did add that there is room for cold and snow further south after January 20th. I think he has likely nailed this. When I read his original forecast back in the fall, I was like, "Wow. That is really sound reasoning, but it conflicts with so many of the other social media seasonal forecasts." Heck, it conflicted with mine which came out during June of last summer. Veteran forecasters are savvy. And the great thing about the human brain....it doesn't tend to get caught in feedback loops. I think we have some circles of thought where opposing ideas are not allowed to be cultivated. That leads to group think. Back in the fall, Cosgrove produced a forecast where he cautioned that those waiting on winter would have to be patient. It is hard not to look at the deterministic runs at noon, and think they are not gonna be in a good place by the second week in January.

All three deterministic 12z runs bring the trough eastward w/ a mega strong -NAO in place. Larry Cosgrove mentioned that cold could be coming back east by the New Year, but also noted the forecast is incredible difficult during that time frame. We have seen this exemplified as models are swinging wildly from one solution to the other. He notes the NE would take the brunt of this. I do think we are seeing December 28-29th as a step off point towards another cold front of the seasonal variety. That could have a decent amount of amplification with it, so it will need to be watched. It is what happens immediately after that which I think will determine the first weeks of January. 12z has a good look. I think the NAO is making its presence felt on modeling now. I normally defer to ensembles, but maybe not this time. I think ensembles are way behind the curve on this pattern right now. It is unusual for that to happen, but it does occur w/ complex setups. The Euro control and its ensembles(for the Weeklies) were night and day yesterday. I think this is one of these patterns which would be easy to over analyze. For now, I just admire the wild solutions that are out there. Kind of fun! I personally think the end game of this is very cold air getting dumped into the Lower 48. The mechanism is in place to unload a majorly cold airmass southward. We may not have a long lead for when this occurs. Things to watch as we go forward....strength and duration of the NAO. It is the counterbalance to the Aleutian low.

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.