December 2025 Short/Medium Range Forecast Thread

[Carvers Gap]

I don’t buy the 12z EPS right now.  It has no support from its deterministic model and has been wrong for several weeks in trying to slide a permanent ridge into the east.  I think a ridge is coming but more likely around the 20th.  I can’t tell if it just rolls through or is a pattern change.   I could be wrong, but I think we are good through the 18th with possibly one more trough after that before we get a break. 

[John1122]

11 minutes ago, Carvers Gap said:

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.  

Griteater was talking about the MJO, saying that while it's in Phase 8 per RMM, a KW/convection area flares in the Indo/Pacific and causes it to act like it's in Phase 6 through around December 12th-20th, before clearing and returning to a phase 8 look. That's likely the culprit behind the big warm up being modeled.

[Carvers Gap]

2 hours ago, John1122 said:

Griteater was talking about the MJO, saying that while it's in Phase 8 per RMM, a KW/convection area flares in the Indo/Pacific and causes it to act like it's in Phase 6 through around December 12th-20th, before clearing and returning to a phase 8 look. That's likely the culprit behind the big warm up being modeled.

I just don’t see the evidence of it being in 6.  There is no ridge in the east at the moment.   Only the EPS is modeling a big warm up.  It could happen.   There were some overnight runs which support that.  But the EPS has struggled mightily.  All of these warmups have yet to verify.  I think after the 20th seems right.

[Carvers Gap]

I do think there will be a ridge which rolls through between the cold shot on the 14th and the next one on the 18th.  That has been strongly modeled,  Bastardi has noted the WPO has been erroneously modeled by the Euro/EPS suite for weeks.  He thinks there is a problem with its algorithm.  He noted the WPO appears to be driving the pattern.  When it weakens, other drivers take over. 

[Carvers Gap]

I think the bigger warmup comes between Dec 22 and mid Jan…that could be wrong, but that is what it appears to me.  Lots of precip in the MC at that time.

[Carvers Gap]

Currently snow is falling in west Kingsport. A little band has been set up.  Just barely missed today.  

[Holston_River_Rambler]

21 minutes ago, Carvers Gap said:

Currently snow is falling in west Kingsport. A little band has been set up.  Just barely missed today.  

I was thinking if this system was just 150 or so miles south this would be an eerily similar start to winter to Dec 1995. 

[Daniel Boone]

18 minutes ago, Holston_River_Rambler said:

I was thinking if this system was just 150 or so miles south this would be an eerily similar start to winter to Dec 1995. 

South or Southwest. SE Virginia is getting hammered now. Been watching Live Cam from Colonial Heights, near Petersburg. 4 inches and pouring big Flakes. Truly rare for there this early. 

[Carvers Gap]

The 18z GFS has the anafront again.  Gonna be wild if it hits from d16.  Seems like it hit that Christmas Eve anafront(from a few years back) at the same range.

[Carvers Gap]

Really, the pattern right now is cold, reload, and more cold.  That might end later in December.  

[Carvers Gap]

The 18z GFS has two "mood flake" systems, and one boomer.  Plenty to track for December.

[Carvers Gap]

That is a blizzard.  Wow.  It will assuredly change, but the 18z has a full fledged blizzard after 300.  

[Carvers Gap]

It would make a lot of sense if the pattern was about to break for warm...for that blizzard to show in exactly that spot.  The GFS has held to that since yesterday.  I would encourage everyone to not get their hopes up.  I actually don't like tracking Christmas systems since so many get their hopes up.  But I really want to see the GFS hit this from day 16.  Also, do remember that systems are often lost between d5-7.  Let's get that out of the way now.  LOL.

[Carvers Gap]

Lets try that again, and this time NOT in centimeters.  In my haste I clicked centimeters.  Up to 30" of 10:1 snow.  Most assuredly, if that wasn't Digital snow, that would be much more due to higher rates due to colder air.  40" Kuchera in W VA.

[Carvers Gap]

Real temps behind that fall to -10F in some places and -20F for WCs.  Fun run.  Unlikely we see that every run, but fun!

[Carvers Gap]

In TRI, that would be 0.5" of ice preceding 10-12" of snow.  Give me the snow...I don't want any ice.  Slow-ish moving wave.  If it was closer, I would post maps.  

[Matthew70]

The thing I don’t like about the anafront is hopefully it’s nothing like a couple years ago.  The landscape was wet and it froze so quickly that it killed most of the landscaping around this area. I would hate to see that again.

[BNAwx]

54 minutes ago, Carvers Gap said:

The 18z GFS has the anafront again.  Gonna be wild if it hits from d16.  Seems like it hit that Christmas Eve anafront(from a few years back) at the same range.

Remember it all too well.  Our refrigerator went out on December 23rd.  It was cold enough outside that we just put most of our perishables outside in a cooler.  That night (technically early Christmas Eve morning) our daughter just happened to go downstairs to get something and came running back up the stairs saying water was coming out of our chandelier.  Luckily I was able to break the ice and turn off the water to the house.  It all worked out but I can’t imagine what we’d have woken up to the next morning if she hadn’t gone back downstairs.

[Carvers Gap]

1 hour ago, Matthew70 said:

The thing I don’t like about the anafront is hopefully it’s nothing like a couple years ago.  The landscape was wet and it froze so quickly that it killed most of the landscaping around this area. I would hate to see that again.

 I have shrubs that finally recovered this season!!!  They got absolutely scorched.  

[Carvers Gap]

1 hour ago, BNAwx said:

Remember it all too well.  Our refrigerator went out on December 23rd.  It was cold enough outside that we just put most of our perishables outside in a cooler.  That night (technically early Christmas Eve morning) our daughter just happened to go downstairs to get something and came running back up the stairs saying water was coming out of our chandelier.  Luckily I was able to break the ice and turn off the water to the house.  It all worked out but I can’t imagine what we’d have woken up to the next morning if she hadn’t gone back downstairs.

Fortunate indeed!   I remember walking through the neighborhood and just listening to the wind how as very fine snow was falling.  Fun evening.

[housemtnTN]

3 hours ago, Carvers Gap said:

That is a blizzard.  Wow.  It will assuredly change, but the 18z has a full fledged blizzard after 300.  

Wow no kidding! Nearly a foot for the valley lol.

[John1122]

Rough looks on modeling again overnight and this morning. Between that and what I'm seeing about January, we may be in for a lot of misery this winter. 

[brewman22001]

Rough looks on modeling again overnight and this morning. Between that and what I'm seeing about January, we may be in for a lot of misery this winter. 

Just one big snow and I’ll be happy. Everyone needs to start doing the big snow dance!!


.

[John1122]

1 minute ago, brewman22001 said:

Just one big snow and I’ll be happy. Everyone needs to start doing the big snow dance!!


.

The way it looks now, we may be dodging severe weather instead of snow. It'll be wild if we are -5 to -10 for half of December but my snowiest day of the season is November 10th, but that looks to be the case barring a miracle.

[Kentucky]

We desperately need the ridge and blocking to link up. And while I haven't totally given up on winter, I'm becoming less optimistic each day.

[John1122]

7 minutes ago, Kentucky said:

We desperately need the ridge and blocking to link up. And while I haven't totally given up on winter, I'm becoming less optimistic each day.

The Pacific hates us. It seems to always find a way to screw up everything for us. 

[Matthew70]

I don’t see severe happening either.  I see it staying near average temp wise & rain to chilly rains at times.  Which I will gladly take over severe wx any day. They can have the tornadoes out over the open plains where people don’t lose their homes or lives.  

[AMZ8990]

  December is always a tough month for snow and below average temps, so I tend not to worry about the forecast too much at this point despite how disheartening it may be.  Peak climatology is still ahead of us, so we have that in our favor.  

[Matthew70]

December is still below normal temps wise & looks to average close to normal for the rest of December.  Much better than 70’s at Christmas. 

[Carvers Gap]

Cancel winter at your own peril on Dec 9th.  It's a Mid Atlantic forum tradition which I don't partake in.

Also, remember when I "canceled" the cold to start December? How well did that work out?  I do think we see some warmth after the 20th.  Is it a pattern change?  It could be, but a 2-3 week pattern relaxation seems about right.

The 12z Euro actually looks decent.  Cold to the end of the run.

The MJO is all over the place.  I think there is convection in a lot of areas which is producing conflicting signals.  John noted that yesterday.  The plots at CPC are to the left of center, but chose your own adventure. The MJO has managed to loop back barely to 7 in the COD.  I would guess it comes back around to 8.  It normally goes counter clockwise.  Why?  Because the weather moves from west to east.  Unless that changes, it doesn't really make long term transits in reverse.

And my broken record advice...climatology does not support much snow at this time of year in the valleys.  Enjoy being in the game in early December - that is a bonus for all bu the 1960s and a handle of winters since then.  FTR, I have sat through many early December Christmas parade in short sleeves!