December 2025 Short/Medium Range Forecast Thread

[GBOVolz]

Is it me or is the clipper precip shield much further South than I was anticipating.


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[Golf757075]

Hello guys. Somewhat new to the forum. Live in west tennessee. Its going to pretty cold Sunday. Interesting pattern so far. I'm somewhat intrigued in the pdo, which has risen somewhat the last few weeks

[GBOVolz]

Hello guys. Somewhat new to the forum. Live in west tennessee. Its going to pretty cold Sunday. Interesting pattern so far. I'm somewhat intrigued in the pdo, which has risen somewhat the last few weeks

Welcome to the board fellow golfer


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[Golf757075]

2 minutes ago, GBOVolz said:

Welcome to the board fellow golfer


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Lol. I try man! Tough game for me lol

[GBOVolz]

Lol. I try man! Tough game for me lol

For all of us. lol


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[Daniel Boone]

6 minutes ago, Golf757075 said:

Hello guys. Somewhat new to the forum. Live in west tennessee. Its going to pretty cold Sunday. Interesting pattern so far. I'm somewhat intrigued in the pdo, which has risen somewhat the last few weeks

Welcome to the Board !

[Matthew70]

15 minutes ago, Golf757075 said:

Hello guys. Somewhat new to the forum. Live in west tennessee. Its going to pretty cold Sunday. Interesting pattern so far. I'm somewhat intrigued in the pdo, which has risen somewhat the last few weeks

Welcome.  Good to have you!

[Golf757075]

20 minutes ago, Matthew70 said:

Welcome.  Good to have you!

I see you post alot on tennessee weather forum. Bruce is a trip lol. Ive known him for a while. 

[TellicoWx]

1 hour ago, GBOVolz said:

Is it me or is the clipper precip shield much further South than I was anticipating.


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Thought same thing but sometimes modeling will show nothing if the precipitation is virga

[Holston_River_Rambler]

Went ahead and created an obs. thread for anyone who sees something from the clipper. 

[brewman22001]

Hello guys. Somewhat new to the forum. Live in west tennessee. Its going to pretty cold Sunday. Interesting pattern so far. I'm somewhat intrigued in the pdo, which has risen somewhat the last few weeks

Welcome! I’ve been here for a few years and everyone on here is kind and I have learned so much from them. Definitely my go to and I think you like it here!! Now we all need to do a snow dance for the Knoxville Tennessee area lol.


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[tnweathernut]

3 hours ago, Golf757075 said:

Hello guys. Somewhat new to the forum. Live in west tennessee. Its going to pretty cold Sunday. Interesting pattern so far. I'm somewhat intrigued in the pdo, which has risen somewhat the last few weeks

Welcome.  Glad you found us….  Stay warm this weekend!  No golf for me until it warms up.  

[Carvers Gap]

3 hours ago, Golf757075 said:

Hello guys. Somewhat new to the forum. Live in west tennessee. Its going to pretty cold Sunday. Interesting pattern so far. I'm somewhat intrigued in the pdo, which has risen somewhat the last few weeks

Welcome to the board.  Tell us more about the PDO going up.  I haven't even looked at it lately!  

[Golf757075]

50 minutes ago, Carvers Gap said:

Welcome to the board.  Tell us more about the PDO going up.  I haven't even looked at it lately!  

The WCS does a daily PDO number compared to CPC, which only does a monthly reading. Its been extremely negative, but has risen pretty good

[Carvers Gap]

Interestingly, several overnight runs found another cold front(strong on Euro) right around the 20th.  It sure looks like another front is gonna roll through on the 26th.  So, maybe this won't be a full on torch?  IDK.  Modeling today and tomorrow should either erode the warmth or lock it in after the 20th.

Last night is a good example of what cold fronts can do during winter, and how modeling can indeed miss.  Congratulations to @Holston_River_Ramblerfor going with the thread!!!

Sunday looks like the next chance for a sneaky system.  I gotta be honest...I wouldn't mind a few warm morning to run.  I am gonna need moderation after Sunday/Monday.

[Holston_River_Rambler]

Someone may have already mentioned this, but it looks like we get a GFS suite of AI models starting Dec 17. 

[Golf757075]

1 hour ago, Carvers Gap said:

 

Interestingly, several overnight runs found another cold front(strong on Euro) right around the 20th.  It sure looks like another front is gonna roll through on the 26th.  So, maybe this won't be a full on torch?  IDK.  Modeling today and tomorrow should either erode the warmth or lock it in after the 20th.

Last night is a good example of what cold fronts can do during winter, and how modeling can indeed miss.  Congratulations to @Holston_River_Ramblerfor going with the thread!!!

Sunday looks like the next chance for a sneaky system.  I gotta be honest...I wouldn't mind a few warm morning to run.  I am gonna need moderation after Sunday/Monday.

The RMM charts are misleading sometimes. The mjo may have been in phase 8 for a little while. I hope it don't stay there for too long in warmer phases and we get what we need to see to get a better pattern after the warm up. 

[Daniel Boone]

1 hour ago, Carvers Gap said:

 

Interestingly, several overnight runs found another cold front(strong on Euro) right around the 20th.  It sure looks like another front is gonna roll through on the 26th.  So, maybe this won't be a full on torch?  IDK.  Modeling today and tomorrow should either erode the warmth or lock it in after the 20th.

Last night is a good example of what cold fronts can do during winter, and how modeling can indeed miss.  Congratulations to @Holston_River_Ramblerfor going with the thread!!!

Sunday looks like the next chance for a sneaky system.  I gotta be honest...I wouldn't mind a few warm morning to run.  I am gonna need moderation after Sunday/Monday.

I think the strength and staying power(duration) you mentioned Yesterday may be a strong Indicator irt whether we have a great Winter or not as you mentioned Yesterday. Historical backing.

Even '95-96 had a mild stretch mid December before going cold by Christmas. 89-90 had extreme cold the entire Month rhat flipped the last Day to a long mild period and stayed mild overall. The great '70's Winter's as example here, featured a couple mild periods of between 1-3 Days , and those weren't very mild at that ! I remember January of '78 the only one in Pennington that Month and it was one Day. 38 for the High !

[Golf757075]

9 minutes ago, Daniel Boone said:

I think the strength and staying power(duration) you mentioned Yesterday may be a strong Indicator irt whether we have a great Winter or not as you mentioned Yesterday. Historical backing.

Even '95-96 had a mild stretch mid December before going cold by Christmas. 89-90 had extreme cold the entire Month rhat flipped the last Day to a long mild period and stayed mild overall. The great '70's Winter's as example here, featured a couple mild periods of between 1-3 Days , and those weren't very mild at that ! I remember January of '78 the only one in Pennington that Month and it was one Day. 38 for the High !

We definitely need a reshuffle of the current pattern and hope we get one that better supports cold and snow. Once in January, time goes by really fast lol

[Carvers Gap]

17 minutes ago, Golf757075 said:

We definitely need a reshuffle of the current pattern and hope we get one that better supports cold and snow. Once in January, time goes by really fast lol

Traditionally, you all "should" do better if/when the cold returns.  Here in NE TN, we normally have to hit early with regards to La Nina winters.  Middle and west TN should get some chances as the SER should help your storm track.  We are fighting climatology IMBY regarding snow this early, but December is usually better for E TN folks during Nina winters w/ some notable exceptions.  

I picked up about and inch or two of snow this morning which is a bonus.   Anything before Christmas here is bonus.  I have kind of resigned myself(due to recent winters) to January thaws.  That said, La Nina winters tend to deliver extreme cold at some point.  Sunday and Monday should be cold w/ wind chills in the single digits for some and light snow showers.  I don't think that will be the worst of winter.  I would guess we see 1-2 weeks of cold by late Jan or early Feb.

As for where this heads in the medium range...really tough to know.  Models had early December cold.  Then, they flipped warm.  Then, they flipped back cold again.  Model feedback was a problem over the Baja then, and I think the Pac NW now. I kind of suspect we may see something similar(feedback issues), but that voice in the back of my head also notes it could be a pattern shift.  The chinook looks like a lock.  

I normally roll with 4-6 weeks per pattern during winter.  By the 20th, we will be right at four weeks since we shifted to an eastern trough.  During recent winters, we have had pretty stable 6 week pattern cycles.  We are likely looking at four weeks cycles right now, and the Weeklies sort of show that.  Both the GEFS ext and Euro Weeklies have temps back to normal by mid Jan.  Larry Cosgrove has been adamant that winter would be at its worse from late January through March.  He was saying this while the weeklies were cold and warning of a December warm-up along w/ muted cold.  He may be about to score a coveted seasonal forecast coup.

Great to have you posting.  

[Daniel Boone]

10 minutes ago, Golf757075 said:

We definitely need a reshuffle of the current pattern and hope we get one that better supports cold and snow. Once in January, time goes by really fast lol

A Modification of the current one would work actually. Pop that HP on east into Alaska and get rid of any semblance of a GOA Low and strengthen Blocking upstream. That way the Clipper's and Miller B's would travel further South. 

   The worry of a complete reshuffle is we never get back to a base Eastern Trough.

What's really needed is a tall Western Ridge connecting with, in conjunction with or connecting with the Alaskan HP. A -AO as well.

Another, although not neccesary but helps, is formidable blocking in the NAO Domain, preferably with a 50-50 or thereabouts Low. That would work for us. An active STJ in the Mix would raise the odds for heavy Snowfalls.

    It has been weak or lacking in those Area's during this cold Stretch.

[Carvers Gap]

39 minutes ago, Daniel Boone said:

I think the strength and staying power(duration) you mentioned Yesterday may be a strong Indicator irt whether we have a great Winter or not as you mentioned Yesterday. Historical backing.

Even '95-96 had a mild stretch mid December before going cold by Christmas. 89-90 had extreme cold the entire Month rhat flipped the last Day to a long mild period and stayed mild overall. The great '70's Winter's as example here, featured a couple mild periods of between 1-3 Days , and those weren't very mild at that ! I remember January of '78 the only one in Pennington that Month and it was one Day. 38 for the High !

89-90 is definitely a concern during any winter where we start fast like this one - lots of cold and snow.  That said, this winter just seems like it might have some more fight in it.  I always remember 95-96 not being overly cold, but I was in Knoxville.  We just hit jackpot with every cold wave.  The storm track was nearly perfect by January.  

I kind of divide my winters up like this.  Pre 1990 and post 1990. Post 1990, I really enjoyed 92-93, 93-94, 09-10, and 14-15.  Whichever recent year we had that howler of a cold front hit on Christmas Eve..that was fun.  Prior to 1990, I just remember the 70s as generally having several consistent winters, and of course 84-85 which is my favorite winter of all.  Lots of negative QBO winters in there, and that might be our saving grace this winter as well.

[Daniel Boone]

3 minutes ago, Carvers Gap said:

Traditionally, you all "should" do better if/when the cold returns.  Here in NE TN, we normally have to hit early with regards to La Nina winters.  Middle and west TN should get some chances as the SER should help your storm track.  We are fighting climatology IMBY regarding snow this early, but December is usually better for E TN folks during Nina winters w/ some notable exceptions.  

I picked up about and inch or two of snow this morning which is a bonus.   Anything before Christmas here is bonus.  I have kind of resigned myself(due to recent winters) to January thaws.  That said, La Nina winters tend to deliver extreme cold at some point.  Sunday and Monday should be cold w/ wind chills in the single digits for some and light snow showers.  I don't think that will be the worst of winter.  I would guess we see 1-2 weeks of cold by late Jan or early Feb.

As for where this heads in the medium range...really tough to know.  Models had early December cold.  Then, they flipped warm.  Then, they flipped back cold again.  Model feedback was a problem over the Baja then, and I think the Pac NW now. I kind of suspect we may see something similar(feedback issues), but that voice in the back of my head also notes it could be a pattern shift.  The chinook looks like a lock.  

I normally roll with 4-6 weeks per pattern during winter.  By the 20th, we will be right at four weeks since we shifted to an eastern trough.  During recent winters, we have had pretty stable 6 week pattern cycles.  We are likely looking at four weeks cycles right now, and the Weeklies sort of show that.  Both the GEFS ext and Euro Weeklies have temps back to normal by mid Jan.  Larry Cosgrove has been adamant that winter would be at its worse from late January through March.  He was saying this while the weeklies were cold and warning of a December warm-up along w/ muted cold.  He may be about to score a coveted seasonal forecast coup.

Great to have you posting.  

Coz has always been a good long Ranger. Could be right about last half. If so, even with the mild period, it would turn out overall a cold Winter, especially going by this Era's Standards.  Glad you had a decent Score over there with this one buddy ! You were under the same bands that moved over here.

[Carvers Gap]

4 minutes ago, Daniel Boone said:

A Modification of the current one would work actually. Pop that HP on east into Alaska and get rid of any semblance of a GOA Low and strengthen Blocking upstream. That way the Clipper's and Miller B's would travel further South. 

   The worry of a complete reshuffle is we never get back to a base Eastern Trough.

What's really needed is a tall Western Ridge connecting with, in conjunction with or connecting with the Alaskan HP. A -AO as well.

Another, although not neccesary but helps, is formidable blocking in the NAO Domain, preferably with a 50-50 or thereabouts Low. That would work for us. An active STJ in the Mix would raise the odds for heavy Snowfalls.

    It has been weak or lacking in those Area's during this cold Stretch.

I just think we are fighting climatology at this time of year.  The deeper TRI gets into December(as evidenced by the sneaky system overnight), the better chance we have at lower elevations.   I would suspect the NAO will fire at some point.  I "suspect" the worst of winter probably sets up shop in the northern Plains which is not always a bad setup for us.  International Falls was a number I watched as a kid.  If it was cold there, I knew cold was coming here!  That didn't always work out, but that was my "teleconnection."  During the 70s, we must have gotten a lot of sliders.  I always watched Memphis as well.  If it was snowing there, it made its way to Knoxville where I grew up.  My general rule of thumb was trying to get one snow before New Year...if that happened, then winter was on track.

[Carvers Gap]

4 minutes ago, Daniel Boone said:

Coz has always been a good long Ranger. Could be right about last half. If so, even with the mild period, it would turn out overall a cold Winter, especially going by this Era's Standards.  Glad you had a decent Score over there with this one buddy ! You were under the same bands that moved over here.

Yeah, it was a good pop for sure.  LC has been adamant(and right for the most part) so far this winter.  Looking forward to his updated Saturday night.

[Daniel Boone]

4 minutes ago, Carvers Gap said:

89-90 is definitely a concern during any winter where we start fast like this one - lots of cold and snow.  That said, this winter just seems like it might have some more fight in it.  I always remember 95-96 not being overly cold, but I was in Knoxville.  We just hit jackpot with every cold wave.  The storm track was nearly perfect by January.  

I kind of divide my winters up like this.  Pre 1990 and post 1990. Post 1990, I really enjoyed 92-93, 93-94, 09-10, and 14-15.  Whichever recent year we had that howler of a cold front hit on Christmas Eve..that was fun.  Prior to 1990, I just remember the 70s as generally having several consistent winters, and of course 84-85 which is my favorite winter of all.  Lots of negative QBO winters in there, and that might be our saving grace this winter as well.

'76-77 and 77-78 were just unreal for this Area. Theyveere great Northern like Winters. River's, Creeks and Ponds were frozen completely over and thick. You could walk on them ! Constant Cold. I'm thinking the MJO hung out in cold Phases. Blocking was strong in 76-77 but oddly the NAO was neutral to slightly positive. Strong -AO Both. Strong +PNA as well. Not surprising, '77-78 was my Snowiest Winter with 72" recorded just west of Pennington gap. 

[Daniel Boone]

13 minutes ago, Carvers Gap said:

I just think we are fighting climatology at this time of year.  The deeper TRI gets into December(as evidenced by the sneaky system overnight), the better chance we have at lower elevations.   I would suspect the NAO will fire at some point.  I "suspect" the worst of winter probably sets up shop in the northern Plains which is not always a bad setup for us.  International Falls was a number I watched as a kid.  If it was cold there, I knew cold was coming here!  That didn't always work out, but that was my "teleconnection."  During the 70s, we must have gotten a lot of sliders.  I always watched Memphis as well.  If it was snowing there, it made its way to Knoxville where I grew up.  My general rule of thumb was trying to get one snow before New Year...if that happened, then winter was on track.

Yeah, had the same Pattern came later that we've been in it's possible if not probable we'd gotten Snow from the cold rain and mix one's we got.

I remember doing same as you. When the cold dropped down from North Dakota and Minnesota. Fun times watching Margie Isom . Use to Snow would hit Memphis then Chatt and spread up the Valley. The whole Valley would get in on many of the Snow storm's. Miller A's were more prevalent.

[Carvers Gap]

1 hour ago, Golf757075 said:

The RMM charts are misleading sometimes. The mjo may have been in phase 8 for a little while. I hope it don't stay there for too long in warmer phases and we get what we need to see to get a better pattern after the warm up. 

What is wild, I normally don't look to the MJO as much of a driver in December.  The PDO is really what we need to help us.  If that can come up for some air, then the MJO takes a back seat.

[Golf757075]

47 minutes ago, Carvers Gap said:

What is wild, I normally don't look to the MJO as much of a driver in December.  The PDO is really what we need to help us.  If that can come up for some air, then the MJO takes a back seat.

It has definitely risen some, which is good, but we will see if it translates to colder later. I hope it does. We haven't seen any snow or ice here yet

[Carvers Gap]

The 12z RGEM "almost" has what looks like a gradient type anafront which comes in early Sunday morning.  By Monday morning, temps at TRI are below zero.  I am posting the precip map for Sunday AM and real feel for Monday AM.