December 2025 Short/Medium Range Forecast Thread

[Daniel Boone]

Another thing to note about '95-96 is there was a warmup after the aforementioned Snowstorm in December. It ended right before Christmas and Rain changed to Snow here in the early morning hours of Christmas and we had an inch of Snow at 7 A.M. 

One other thing about that Winter; it did have an extreme Arctic Outbreak. February 3rd and 4th Heavy Snow fell dropping 10-24 inches in the mid and upper great Valley. the front passed and the Temp fell to -21 feb 5 with the high of -4 in Pennington gap.

[jaxjagman]

It dont look very cold cold to me in the long range,this is in part due to the Walker Circulation ,when you see these strong EWB'S this strenghtens the Walker circulation and pushes the Jet Steam the jet more Northward in winter time during LaNina,in summer time we can see droughts in our parts,which is what we seen this summer,this is what you seem to be seeing right now with the ensembles long range

[Carvers Gap]

35 minutes ago, Daniel Boone said:

I remember it having systems travel from the Pac NW down through the Plains into the Tn Valley along the Jet. Some would drop to the mid South and form a Miller A from a Miller B( transfer). Those were the Ones that would cut up the Coast from NC on up(Noreaster). Several low riding B and Clipper Systems as well. I was thinking awhile ago after reading Johns post and pondered that really all we need is this Pattern with the Trough dipped further South a 25-100 Miles. Then we'd be in the area getting the Snow that Area's that distance up are getting. So close. A stronger block would do it. Taller western Ridge would. 

The Euro Weeklies this evening strongly hint at a 95-96 type of progression.  Warmup around Christmas.  Cold returns mid-Jan or just after.  That also fits the pattern of recent winters.  The good thing about all of this...eastern portions of the forum have missed w/ the second cold shot during recent Nina winters.   I doubt that happens this winter.  I think the cold in later January pushes to the coast.  Just a hunch.

[Carvers Gap]

31 minutes ago, Daniel Boone said:

Another thing to note about '95-96 is there was a warmup after the aforementioned Snowstorm in December. It ended right before Christmas and Rain changed to Snow here in the early morning hours of Christmas and we had an inch of Snow at 7 A.M. 

One other thing about that Winter; it did have an extreme Arctic Outbreak. February 3rd and 4th Heavy Snow fell dropping 10-24 inches in the mid and upper great Valley. the front passed and the Temp fell to -21 feb 5 with the high of -4 in Pennington gap.

Basically, the December 1995 pattern would repeat later that winter, but with better climatology in place for cold air to make it to this latitude and hold. IMBY(not the folks at elevation), we are fighting climatology every step of the way right now.  It eases up after Dec 10th or so, and becomes more favorable with each day.  When I first started tracking, I rarely tracked during the first 20 days of December.  But if this pattern were to repeat during the second half of winter, I think the cold presses more.  Now, the STJ is inactive...so northern stream systems are gonna have to do the trick.  I still think we have a shot to score before this breaks just short of Christmas.  

One caveat, this may not break down before Christmas.  Some MJO plots are stalled through the end of the month and into early January on the left side of the MJO.  Also, modeling tends to break down patterns a bit too early.  That said, a New Year's thaw seems realistic.  If it is twenty below w/ five feet of snow...you can look back on this comment and thank me for it!

[jaxjagman]

28 minutes ago, jaxjagman said:

It dont look very cold cold to me in the long range,this is in part due to the Walker Circulation ,when you see these strong EWB'S this strenghtens the Walker circulation and pushes the Jet Steam the jet more Northward in winter time during LaNina,in summer time we can see droughts in our parts,which is what we seen this summer,this is what you seem to be seeing right now with the ensembles long range

I mean basically this is what we are seeing if you look towards Eastern Aussie land,not saying we will torch but its not gonna get that cold,cold air is gonna be trapped in Canada,Upper Plains

 

[jaxjagman]

 

[Daniel Boone]

'95-96 was weak La Nina. 2010-11 was a moderate to strong La Nina. Both featured alot of cold and Snow. I've not looked into how the Walker or Hadley Cells were those Winters.  don't know if you can get Archived Data irt that. Maybe you can see what you can find Jax. 

I will say, if they were active in the way the upcoming is predicted, I wonder if the strong Blocking those Winters countered that. ?. Law of physics would say strong upstream Blocking would alter the effects of the Cells  thereby keeping the Jet from being forced North . Of course, there would be a battle between the two as they'd war against each other. So, depending on how strong the EWB'S are and how persistent I suppose on whether they would force the Block out or not. Of course , as of now strong Blocking doesn't exist on ensembles. They actually look as if what blocking there is is eroding but, that could be them seeing the Cells forcing doing that.   

     The Other fly in the Ointment is what Carvers mentioned about the MJO. How will that affect the Cells typical response.?.

[John1122]

Looks like the cold for next weekend is basically up in smoke now. The 00z GFS is now 20 degrees warmer than it was for next weekend than it was last night at 00z. 

What looked promising somewhat is  a dumpster fire for winter chances here into Christmas, if the models are correct. 

Deep Gulf of Alaska low flooding Pacific air across the lower 48, hostile Pacific, hostile Atlantic. It doesn't get much worse than that run.  

[Carvers Gap]

The 6z GFS has returned to a much colder look.  The 0z Euro is definitely warmer after mid-month.  Its ensemble is not as much.  Both the 0z GEPS and 0z GEFS are not warm.  I think the warm-up looks to be set just after mid month.  But there is this on the LR GFS, and take with a huge grain of salt...a major league anafront.  This would be a nightmare or travel.  You don't have to guess what the weather looks like under that.   Lots of uncertainty after the 20th, so we'll see.

[Carvers Gap]

The 0z EPS has a much different solution than any other global ensemble including the AIFS.  The GEFS, GEPS, and AIF still have the cold shot next weekend.  The 6z GFS has a the Christmas Eve cold shot(which really could go either way).  I think the widely diverse solutions are due to the various MJO solutions.  The EURO at range has struggled so far during late fall and winter.  It certainly is good enough to score a coup, but it erroneously called for the beginning of December to be warm(after the weeklies had it cold).  I would suspect there is a severe cold shot headed into the Lower 48.  Things get scrambled when that happens.

[Carvers Gap]

For ONLY kicks and giggles, let's see if the 6z GFS can hit the half court shot on Christmas Eve.

[Carvers Gap]

This if for roughly the same time frame.  The 6z GFS, 0z EPS, and 0z CMC.  Let's see if the Euro deterministic is leading a change.  For now, the ensembles are not there.  The 6z Euro looked like it would have been cold.  Time will tell.  I certainly am no fortune teller!

 

[Carvers Gap]

RadarScope is changing over to mix over the northern TRI.  It mostly rain, but I can see mix on the windshield.   This is early for that.

[housemtnTN]

2 hours ago, Carvers Gap said:

For ONLY kicks and giggles, let's see if the 6z GFS can hit the half court shot on Christmas Eve.

I was just looking at this on the GFS model, looks absolutely wild.

[fountainguy97]

I'm not surprised at all but this event has been a complete and total failure by the models. It's a toasty 38 here and I've racked up .30 of rain.  Hrrr and nam and RRFS had only a couple hrs of rain before a changeover around 6am.  
 

I don't think even the NW stuff will be snow this afternoon. I hope my friends and family over in Eastern NC don't have the same fate! 

[GBOVolz]

RadarScope is changing over to mix over the northern TRI.  It mostly rain, but I can see mix on the windshield.   This is early for that.

Got some sleet right at the end of the precipitation in N Knox.


.

[Carvers Gap]

I think a lot of this is just fighting climatology.  Again, and I sound like a broken record...it is really rare to track snow prior to mid-December at lower elevations.  The higher elevations above 2500'...that is a different story.  For most of us, we just recently exited meteorological fall.  Our best climatology is mid-Jan to early-Feb.  So, we are about 5-6 weeks away from best climatology IMBY.  

That said, the RGEM, NAM, and GFS all show light snow this weekend.  In some cases there are two chances.  Nothing big, but mood stuff.  Higher elevations could score 1-3" of snow.

[Carvers Gap]

It appears the 12z GFS will have the anafront on Christmas Eve.  Only 60 more runs to go.  What could go wrong?!

[Daniel Boone]

Snowing lt to moderate here and 35 degree's.

[Carvers Gap]

7 minutes ago, Daniel Boone said:

Snowing lt to moderate here and 35 degree's.

Cold rain here, but....the GFS did nail the deformation band over NE TN.  Unfortunately, the thermals not so much!

[Carvers Gap]

The 12z Euro is much colder than its 0z version.  Was 0z the hiccup or is 12z the hiccup?  I would tend to think that 12z follows continuity.  So, we stick w/ it, but with one eye over our shoulder.

[Daniel Boone]

Didn't last long and ended as a mix. It was pretty heavy for a few minutes. 0.05" from it melted in gauge in about 20 minutes.

[Carvers Gap]

Not without precedent, but these are some BIG swings d10-15.  Good trends at 12z.  Newer runs are on the left.  12z GFS vs 6z GFS 5d 500 anomaly map.  12z Euro vs 0z Euro.  The Euro moved from an eastern trough to a western trough.  Now, this is just deterministic stuff.  So far, ensembles look pretty steady.

 

 

[Carvers Gap]

The 12z GEFS moved the core of d10-15 cold from the Yukon to Quebec when compared to 0z.

[Carvers Gap]

And this one day map is mildly creepy.  

[Carvers Gap]

Basically on 12z modeling, I am seeing a continuation of the current pattern w/ a chance of strong amplification around or just after mid-month.  Which side of that amplification we end up?  That is certainly up for debate, but I "think" the MJO probably places us in the trough.  There is a rapid progression of short waves along the northern branch.  For now, most of them are just a bit too far north.  That could easily change.  Each one will have to be watched.  There are a lot of them.  Definitely northern stream driven w/ some minor interaction w/ the Gulf.  

[BuCoVaWx]

Had rain here all morning. Changed over to a mix around 11. It's changed to all snow and pretty good sized flakes for the past 30 minutes. 

[John1122]

It snowed here for about 30 minutes around 10 to 10:30 this morning. 

MJO is active with KW in 6, so the weather is reflecting that on modeling.  

Not sure what pattern reshuffle we will get, but unless we can get the EPO to move East, and get that death vortex out of the GOA we are going to be watching systems fly by to the north of us. Good news for the NE Kentucky, Va and north. On runs where the ridge in the west sharpens and Western Canada goes from -PNA to +PNA the cold gets unleashed. 

[Daniel Boone]

59 minutes ago, John1122 said:

It snowed here for about 30 minutes around 10 to 10:30 this morning. 

MJO is active with KW in 6, so the weather is reflecting that on modeling.  

Not sure what pattern reshuffle we will get, but unless we can get the EPO to move East, and get that death vortex out of the GOA we are going to be watching systems fly by to the north of us. Good news for the NE Kentucky, Va and north. On runs where the ridge in the west sharpens and Western Canada goes from -PNA to +PNA the cold gets unleashed. 

Yeah. I had noticed that vort in the GOA last Week and thought that typically hurts us but, was weak at the time and looked like was going to be shunted eastward and then maybe travel down the Jet SEward. Some Model's are indicating a gradual +TNH developing as the Aleutians Alaskan Ridge moves over Alaska and expands over the Arctic Domain. Sooner the better for us if you want the real Cold and much higher Snow Probability.

[Carvers Gap]

Interestingly, the Euro Weeklies control and ensemble are exactly opposite again.  Last time, the control won that battle.   The control is  30 day strong trough.

As for the MJO, there is some activity in 7-8-1-2.  This morning it began the anticipated loop/stall in 8.  I have little doubt the convection forecast for 1-2 will eventually propagate into 6.  It looks to me like that will happen sometime in the third or fourth week of December.  It could be earlier.   Currently the MJO plot is in 8 and the atmosphere reflects that with an eastern trough in place and eastern troughs forecast through roughly Dec 20.
 

Again, it is early December.  This is not snow climo for valley locations.