December 2025 Short/Medium Range Forecast Thread

[nrgjeff]

EPS followed the ECMWF warmer but it could be a one-off. AI version still has the back door front chances northeast Tenn. This is all for closer to the New Year. Basically we're looking for a little -NAO. Questions are mainly around whether the Pacific side will help, or just give us the Chinook finger. 

Of course Carvers I'm always down for mixing weather and basketball. Just like the Vols are back on track, perhaps the ECMWF will get colder again. The warm GEFS does not concern me.

PS that Vols game was about the only major vs major this week - a nice treat! 

[Carvers Gap]

@nrgjeff, are the new AI ensembles decent?  I notice the 12z GEPS and both AI ensembles (GFS/Euro) had a lot of cold members after 300.  

The Vols losing three straight was like looking at non-stop chinooks on modeling - same result, same set-up.  We needed that Louisville shake-up(red like an NAO! - it's a sign).

[Carvers Gap]

Cherry picking some stuff from the Euro Weeklies, though I didn't think the ensemble was half bad!

 

[Carvers Gap]

The one thing that makes the Weeklies(any brand) fallible is that they tend to perpetuate the week two pattern - true feedback. That is why it is important not to put to much stock in LR ext modeling unless IMHO they change from that two week pattern.  In other words, if the model doesn't continue in perpetuity...that is worth paying attention to.  I have seen cold patterns modeled for all six weeks...not even make it into week 3.  That also works for warm air masses.  So, that is why I like looking at the control which is basically just one big deterministic run.  

[Daniel Boone]

5 hours ago, Carvers Gap said:

Unfortunately, the Aleutian Ridge has been a staple of recent past Nina winters - the big red ball on 500 maps.  If forces a Rex block.

Models have a very difficult time "knowing" when it ends - much like the NAO.  I don't think there is a lot of data in that area, and that can be a problem.  It seems like the Aleutian Ridge has a tendency to disappear with little notice, and the trough kicks almost immediately eastward. Those ice and snow storms that middle and west Tenn have experienced occurred when that Aleutians Ridge pattern relaxed.  It seems to me that usually occurs between the first and third weeks of January.  

I know some think the trough retrogrades and does not come back.  If the NAO goes negative, that could balance things out.  We lacked the NAO w/ recent analogs where the trough pulled back, and wouldn't budge.  

There is a lot of uncertainty going forward.  I generally like uncertainty, because that leaves room for crazy weather.  In winter, that could be anything from severe (which I don't like) to winter storms.  

I think the key going forward is the NAO going negative.  It is the ingredient in many EC storms.  That doesn't necessarily help you all just to the west...but it can force sliders in addition to coastals.

Yeah, la nina augmented you might say. Nina actually strengthened a little recently after a steady weakening. Should see a rather fast weakening from here on. I think i'll go back and look at some NPAC Charts from 95-96 and see how or if the AR was prominent then. 

[Daniel Boone]

 This is this day in 1995 

Plymouth State Weather Center   Compare to Christmas then :  Plymouth State Weather Center

I know it just shows Site link but it goes directly to Map.

[Holston_River_Rambler]

We desperately need to fill up the thunder in the mountains index. There is hope tonight. 

[Holston_River_Rambler]

I got this one from the NCEP reanalysis site for todays date in 1995:

[Daniel Boone]

2 minutes ago, Holston_River_Rambler said:

I got this one from the NCEP reanalysis site for todays date in 1995:

I used to get mine to post the map now just does Link. Anyway, look what a change by Christmas then.

[Daniel Boone]

Nina HP was well south then . By Christmas a +PNA with the HP centered over the NW and LP over Aleutians. Trough in East. We should further that Winter in increments in Time and see what evolution was.

[Holston_River_Rambler]

12 minutes ago, Daniel Boone said:

Compare to Christmas then :  Plymouth State Weather Center

That definitely looks better, but as far as I can tell, there's nary and Aleutian ridge o' death to be seen 

I had to go back to early December 1995 to see something similar:

[Holston_River_Rambler]

5 minutes ago, Daniel Boone said:

We should further that Winter in increments in Time and see what evolution was.

I was trying to pull the radar imagery from IEM as gif, but the file won't process. Here's a link if anyone wants to check it out:

https://mesonet.agron.iastate.edu/current/mcview.phtml?prod=usrad&java=script&mode=archive&frames=400&interval=60&year=1996&month=12&day=25&hour=0&minute=0

 I think most folks who were alive at that time in upper east TN and SW VA know where the pattern ends up about Jan 7 - 8, 1996. 

[Golf757075]

7 minutes ago, Holston_River_Rambler said:

I was trying to pull the radar imagery from IEM as gif, but the file won't process. Here's a link if anyone wants to check it out:

https://mesonet.agron.iastate.edu/current/mcview.phtml?prod=usrad&java=script&mode=archive&frames=400&interval=60&year=1996&month=12&day=25&hour=0&minute=0

 I think most folks who were alive at that time in upper east TN and SW VA know where the pattern ends up about Jan 7 - 8, 1996. 

Then feb 1-2 1996 was a heck of a winter storm in my area. Very cold after that 

[John1122]

9 minutes ago, Golf757075 said:

Then feb 1-2 1996 was a heck of a winter storm in my area. Very cold after that 

That was one of the most severe winter events for the entire Tennessee Valley, ever.  Huge ice storm, snow close to the blizzard of 93 levels, and cold close to 1985 levels. 

[*Flash*]

12 minutes ago, Golf757075 said:

Then feb 1-2 1996 was a heck of a winter storm in my area. Very cold after that 

I remember this storm. I was in 3rd grade. About 6-8" in Brentwood but the wind was howling which led to snow drifts up to my waistline in places!

[Carvers Gap]

3 minutes ago, *Flash* said:

I remember this storm. I was in 3rd grade. About 6-8" in Brentwood but the wind was howling which led to snow drifts up to my waistline in places!

Haha.  I was teaching 3rd grad that year.  We ran out of snow days in Knox Co...like ran waaaay out of snow days.  

[Daniel Boone]

41 minutes ago, Holston_River_Rambler said:

That definitely looks better, but as far as I can tell, there's nary and Aleutian ridge o' death to be seen 

I had to go back to early December 1995 to see something similar:

I didn't think we had to deal with an AR that Winter. Blocking was a big thing that Winter though.  

[Matthew70]

14 minutes ago, Carvers Gap said:

Haha.  I was teaching 3rd grad that year.  We ran out of snow days in Knox Co...like ran waaaay out of snow days.  

You & I are close in age. 

[Daniel Boone]

39 minutes ago, Holston_River_Rambler said:

I was trying to pull the radar imagery from IEM as gif, but the file won't process. Here's a link if anyone wants to check it out:

https://mesonet.agron.iastate.edu/current/mcview.phtml?prod=usrad&java=script&mode=archive&frames=400&interval=60&year=1996&month=12&day=25&hour=0&minute=0

 I think most folks who were alive at that time in upper east TN and SW VA know where the pattern ends up about Jan 7 - 8, 1996. 

That link you posted Holston was December 96 and January 97. It's 95 and 96 we were looking for.

[Matthew70]

Well gotta say.  This line of rain & storms is slow moving & dumping. 

[Golf757075]

1 hour ago, John1122 said:

That was one of the most severe winter events for the entire Tennessee Valley, ever.  Huge ice storm, snow close to the blizzard of 93 levels, and cold close to 1985 levels. 

I watched dan satterfield, who was the chief met out of Huntsville AL on YouTube clips for that winter storm. It was wild. I lived in Hernando ms at the time and we barely got it where I was. We still managed quarter inch ice on the roads!

[Holston_River_Rambler]

32 minutes ago, Daniel Boone said:

That link you posted Holston was December 96 and January 97. It's 95 and 96 we were looking for.

Sorry about that:

https://mesonet.agron.iastate.edu/current/mcview.phtml?prod=usrad&java=script&mode=archive&frames=400&interval=60&year=1995&month=12&day=25&hour=0&minute=0

[Daniel Boone]

21 minutes ago, Holston_River_Rambler said:

Sorry about that:

https://mesonet.agron.iastate.edu/current/mcview.phtml?prod=usrad&java=script&mode=archive&frames=400&interval=60&year=1995&month=12&day=25&hour=0&minute=0

That Jan 6-7th Storm was a Monster ! Remember it well. Recorded 13" at the Radio Station amongst the buildings and Streets in Pennington gap. 16" outskirts of Town. 18 to 20" in Western Lee County in Rose Hill area(there was a deformation of sorts that ran across there ). Some Highest Elevations up to 24". As we all know, that went on to be a Major Blizzard in the mid Atlantic with over 40" in area's !

[housemtnTN]

Has anyone noticed the line of storms coming through? It's 60 degrees at my house, very windy. I cannot believe how warm it is right now lol.

[Reb]

25 minutes ago, housemtnTN said:

Has anyone noticed the line of storms coming through? It's 60 degrees at my house, very windy. I cannot believe how warm it is right now lol.

It feels awesome outside. MPING reports show shingle damage near Harriman and Decatur

[John1122]

That like blitzed through here. No thunder but incredible wind and heavy rain. 

[John1122]

No sooner had I said that than thunder boomed. TIMs activated. Of course this may end as snow flakes towards morning. 

[Reb]

Lights out here in Seymour

[John1122]

Cousin at 2400 feet in an exposed area said that at 10:50 they recorded a gust at 75mph then the aneometer broke off. 

Had some reports of roofs blown off. Huge trees are down too. Wide spread power outages.