December 2025 Short/Medium Range Forecast Thread

[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.

[*Flash*]

Happy Winter Solstice, everyone?

[Carvers Gap]

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.  

[Carvers Gap]

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.  

[Carvers Gap]

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.

[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.

[Kentucky]

I really respect Eric and if he's going to be wrong he'll be backtracking on Twitter soon. 

[*Flash*]

25 minutes ago, Kentucky said:

I really respect Eric and if he's going to be wrong he'll be backtracking on Twitter soon. 

I respect the knowledge base for sure. Just not always the way its conveyed or responded to when counters are presented. Either way, I believe it's wise we maintain a diverse portfolio of follows this time of year. Lot of credible voices out there, not all are doom and gloom on this first day of winter.

[Matthew70]

4 hours ago, *Flash* said:

Happy Winter Solstice, everyone?

Webb is knowledgeable but changes his mind all the time.  He’s more negative than he is positive.  Seems many on other forums cancel winter before it’s even begun.