January 2026 Short/Medium Range Thread

[Carvers Gap]

1 minute ago, Holston_River_Rambler said:

I particularly liked the 995mb low over the GA blue ridge with no snow anywhere in the eastern US.

The great thing is the 18z GFS seems to have figured out that the trough has to kick out if under an EPO ridge like that.  Just wait till 0z, we will have something new!  Haha.

[Holston_River_Rambler]

Wait a minute, I was wrong. I found some snow on the COD algorithm 

[Weatheriscool]

7 minutes ago, Carvers Gap said:

The EPO ridge hasn't been delayed as of yet.  We lost a couple of cold fronts on the 4th and 8th.  This has been moving pretty steadily in time.  But we all obviously know the rules.  Most of the folks here are pretty solid veterans when it comes to flip flops.  

Well, the wetness has continued 

[Holston_River_Rambler]

1 minute ago, Holston_River_Rambler said:

Wait a minute, I was wrong. I found some snow on the COD algorithm 

AAannnnddddd weatherbell:

[Carvers Gap]

7 minutes ago, Weatheriscool said:

Well, the wetness has continued 

We will see.  The GFS is relying on the ridge being over the East and return flow from the Gulf.  The trends right now are bit time towards a trough over the East on that model.  That model is incrementally caving IMHO.  If so, the trend would be much more dry.

[Golf757075]

19 minutes ago, Carvers Gap said:

The EPO ridge hasn't been delayed as of yet.  We lost a couple of cold fronts on the 4th and 8th.  This has been moving pretty steadily in time.  But we all obviously know the rules.  Most of the folks here are pretty solid veterans when it comes to flip flops.  

This is the true current pdo if anyone is interested. 

[Carvers Gap]

The deterministic GFS over the last four runs has shifted the 500 pattern about 500-1100 miles eastward depending on the feature.  

[Golf757075]

21 minutes ago, Golf757075 said:

This is the true current pdo if anyone is interested. 

Also, this Niña is now east based with the colder anomalies off of south america/Peru region. Typically when that occurs, we will see colder later than earlier in winter. 21-22 is a small example. Doesn't guarantee that, but have seen it before

[Carvers Gap]

The 18z AIFS Euro ensemble is pretty much awesome.  Big ridge out West, and big trough over the East.  Makes sense.

[Carvers Gap]

[Carvers Gap]

The actual EPO is to supposed to build Jan 8-9th.  So, that transition is well within ten days.  Right now, that ridge building starts at about 180.  The transition to that ridge is arueably occurring now.

[Golf757075]

20 minutes ago, Carvers Gap said:

Carver, ultimately we will see if the aifs ensembles are really that good compared to everything else. I still believe too many models to content with lol

[Carvers Gap]

10 minutes ago, Golf757075 said:

Carver, ultimately we will see if the aifs ensembles are really that good compared to everything else. I still believe too many models to content with lol

The 12z EPS and GEPS have this as well.  AI models can be sketchy for sure - completely unknown.  I am not sure they are actually "learning.".  I like the EURO AIFS better than the AIGFS(seems not overly rigorous) FWIW.  The 18z GEFS continues to trend the rest of the other ensembles w/ the eastern trough.  The good thing is the EPO ridge moving into position is almost 7 days out.  I will feel a lot more confident once it sets up shop.  The NAO has verified as pretty strong...so good sign modeling is handling blocking well.

We have definitely tracked patterns which fizzle.  Let's hope this isn't one of them.  We have also tracked many patterns which eventually verify.  Good info on the ENSO and PDO regions - thank you!

[Carvers Gap]

GEFS trends from 0z to 18z.  Pretty big moves.

[*Flash*]

BAM doing [what appears to be] some backpedaling this morning. Could this be the beginning of #wintercancel2026? Facetiousness aside, I get why transparency is important when discussing risk/what could go wrong, though if the 0z Euro Det is on to something, then yeah, extended PV placement will be a concern and thus, the alignment of historically favorable teles would simply result in seasonably cool as opposed to substantial cold. We're still in the land of monitoring trends so hopefully people don't overreact today. If I was a betting man (thank God, I am not), I would be tempted to take plus money on the bulk of my 2025-26 wintry precip coming via overrunning. Knowing our mean luck, by the time all things MJO, AAM, etc. sort out, we'll have the SE ridge flexing its muscle again. 

BAM Weather on X: "Here is a PERFECT example of how a very ideal blocking pattern can yield nothing in return for cold. EPS and AI on the top 10-15 day GEFS and AI on the bottom 10-15 day Aside from the EPS AI the other 3 datasets see no true cold air and the reason for the DESPITE the -EPO/+PNA https://t.co/mAcdc7fS8R" / X

[Carvers Gap]

The good thing about mid January is that AN Canadian air masses often verify as BN or seasonal here.    Watch as the air moves south…it often flips to BN.  Of note, I didn’t think the surface maps looked terrible at all at this range.  

The real risk is if the EPO ridge at 500 continues to retrograde and the upcoming trough retrogrades after the 20th…leaving us with only a 7-10 day window.  The GEPS ensemble at 0z shows that risk at 300.  We need that retrograding pattern to pause or slow once in the right spot.  Nina winters really want to put the trough in the Mountain West after January.

I am gonna give things a few runs to shake out in terms of whether cold fills the trough or not.   If the trough forms and the EPO holds, then cold is less of a concern for me.  

So with the “what could go wrong” out of the way first.  Here are some things to consider.  

The EPS and Euro at range have struggled to see cold this winter…but generally have been good at 500 - but not infallible.   That last comment is generally true for most models not named the Canadian.  

I have simply stopped using the GFS…It flip flops every run (or every other run) and has too many biases to account for.  I like the GEM, but must account for its cold bias.  The GFS is going to have to show some skill before I use it past day5.  I will discuss its solutions, but it has been bad.

As for AI, the jury is still out.  The AIFS Euro and ensemble have had some rigor.  They look good for the upcoming pattern reshuffle, but they aren’t remarkable in their scoring in my book.  The AI GEFS ensemble - I don’t trust it but it looks good.

So overall, let’s get this potential pattern inside of day 5.  The EPO ridge setting up shop has sped up just a hair overnight.  I think the EPO ridge forming is about 48 hours from locking-in as “real” on modeling.  It is about 5-6 days out.   Once inside of d5, I will “buy” that feature, and that goes for the rest of the features in the map.

Until it sets up, I don’t think we are going to really know if the trough fills with cold, if the NAO bridges over, or if the EPO ridge holds long enough to be a force.  That is a lot to juggle.   I would guess (and could be wrong) that once the EPO forms that cold will fill the eastern trough IF the EPO ridge holds and doesn’t continue retrograding to Asia.
 

 

[Carvers Gap]

Looking at the CFSv2 LR model this morning, it does indeed keep retrograding the 500 ridge into Asia.  It retrogrades the eastern trough into the Mountain West....and then it retrogrades yet another ridge into the West and holds it.  If that happens, Larry Cosgrove is going to score the coup, and kudos to him for a great seasonal forecast if it does.  He has adamantly held that the end of January and early February will hold the worst of winter, and cautioned patience.  I think the ridge getting knocked down out west, reforming....wash, rinse, repeat...is the likely pattern beginning on the 12th.  One could make a pretty good case that began on Dec 29th.  I think at least one of those cycles will have very cold air in the pattern.  A lot of decent winters featured that pattern.  Let's see if that is how it unfolds.  Either way, this winter has been one of wild swings...I fully expect that to continue.

[Carvers Gap]

Just sifting through teleconnections this morning, the 6z GFS deterministic run is the only model(that I can find) which goes positive with the EPO on the 12th.   All other modeling turns the EPO negative - ensembles, AI, determinstics.  Could the GFS be right?  Certainly.  But I have some serious doubts.  The real question in my mind which has to be answered(and really cannot be yet) is whether that EPO ridge continues to retrograde into Asia, and whether another subsequent EPO ridge then takes its place.  I tend to think it continues to retrograde, but then another EPO ridge reforms as the pattern continues to retrograde even more.  That second EPO ridge, in my mind, delivers the worst of the cold per winter toward the end of Jan and beginning of Feb.  That does not mean I don't think we see chances w/ the first EPO ridge...I just don't think those details are not worked out in modeling w/ so much being juggled and with us still being about ten days out.  It is still entirely possible(probable) that the first EPO ridge sticks, modeling adjusts, and locks in that ridge for 3-4 weeks.  I just think a back and forth pattern is more likely as that has been the pattern all winter.

[Met1985]

1 hour ago, Carvers Gap said:

The good thing about mid January is that AN Canadian air masses often verify as BN or seasonal here.    Watch as the air moves south…it often flips to BN.  Of note, I didn’t think the surface maps looked terrible at all at this range.  

The real risk is if the EPO ridge at 500 continues to retrograde and the upcoming trough retrogrades after the 20th…leaving us with only a 7-10 day window.  The GEPS ensemble at 0z shows that risk at 300.  We need that retrograding pattern to pause or slow once in the right spot.  Nina winters really want to put the trough in the Mountain West after January.

I am gonna give things a few runs to shake out in terms of whether cold fills the trough or not.   If the trough forms and the EPO holds, then cold is less of a concern for me.  

So with the “what could go wrong” out of the way first.  Here are some things to consider.  

The EPS and Euro at range have struggled to see cold this winter…but generally have been good at 500 - but not infallible.   That last comment is generally true for most models not named the Canadian.  

I have simply stopped using the GFS…It flip flops every run (or every other run) and has too many biases to account for.  I like the GEM, but must account for its cold bias.  The GFS is going to have to show some skill before I use it past day5.  I will discuss its solutions, but it has been bad.

As for AI, the jury is still out.  The AIFS Euro and ensemble have had some rigor.  They look good for the upcoming pattern reshuffle, but they aren’t remarkable in their scoring in my book.  The AI GEFS ensemble - I don’t trust it but it looks good.

So overall, let’s get this potential pattern inside of day 5.  The EPO ridge setting up shop has sped up just a hair overnight.  I think the EPO ridge forming is about 48 hours from locking-in as “real” on modeling.  It is about 5-6 days out.   Once inside of d5, I will “buy” that feature, and that goes for the rest of the features in the map.

Until it sets up, I don’t think we are going to really know if the trough fills with cold, if the NAO bridges over, or if the EPO ridge holds long enough to be a force.  That is a lot to juggle.   I would guess (and could be wrong) that once the EPO forms that cold will fill the eastern trough IF the EPO ridge holds and doesn’t continue retrograding to Asia.
 

 

This is on point. 

[Carvers Gap]

The 12z GFS and GEM....now, that is a much better way to start a suite.  Very, very close to being something good.  I would think models are getting a handle on that EPO ridge now.  Plenty to digest with those two.

[Holston_River_Rambler]

GFS had an ideal fantasy situation. Caribbean tropical wave about to try and phase with a bunch of other shortwaves. 

[Weatheriscool]

The 12Z GFS seems disjointed, maybe it is just my untrained eye 

[Holston_River_Rambler]

12z Euro wasn't too bad either 

[Holston_River_Rambler]

I've seen worse:

 

And at least it managed a bit of snow on the NW side of that system. 

[Carvers Gap]

I don’t have a ton of time, but good trends at 12z across modeling.  The 12z GEPS has a much stronger eastern trough before dumping it west in the last few frames of fantasy land.  If we take the idea that modeling trends west with storms….not a bad place to be right now.

[jaxjagman]

Typical +TNH,while we get into wk2 of Jan,+PNA,Trough AXIS in the middle of the country,subtropical ridge builds over Florida and the JET is well north of the Tn Valley,i actually thought we'd have a chance last week to maybe have somewhat a better pattern,but even tho it looks good in East Asia,other teleconnections still play a part in NA,so this time seemingly might not work out well for us