December 2025 Short/Medium Range Forecast Thread

[Carvers Gap]

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.

[Carvers Gap]

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

[Carvers Gap]

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.

[Carvers Gap]

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.

[Golf757075]

16 minutes ago, Carvers Gap said:

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.

The key for any winter weather and cold of any significance moving forward is to dislodge the aleutian ridge. Imo, that's the main thing to watch. We shall see

[Carvers Gap]

14 minutes ago, Golf757075 said:

The key for any winter weather and cold of any significance moving forward is to dislodge the aleutian ridge. Imo, that's the main thing to watch. We shall see

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. 

[Carvers Gap]

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.

 

[Carvers Gap]

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).  

 

[Carvers Gap]

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 ->

Spoiler

December 1984

[Carvers Gap]

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.

[KakashiHatake2000]

https://m.facebook.com/story.php?story_fbid=1434077554743564&id=100044239995530&http_ref=eyJ0cyI6MTc2NjI1OTY4NTAwMCwiciI6IiJ9&hpir=1
post on facebook from mitch west weather and also ross elliot

[Matthew70]

2 minutes ago, KakashiHatake2000 said:

https://m.facebook.com/story.php?story_fbid=1434077554743564&id=100044239995530&http_ref=eyJ0cyI6MTc2NjI1OTY4NTAwMCwiciI6IiJ9&hpir=1

Uh oh.  Gonna upset those winter canceled peeps.lol!

[jaxjagman]

Yeah but comparing 2000 to 2025 is nonsense

[KakashiHatake2000]

lol haha alright i guess we will have to pack it up then nah im jk also at the bottom of the text he says that not 2000-2001 but rather 2008 and 2010 december im no expert but i feel like december 2008 seems like the closest match and gotcha jaxjagman