January 2026 Short/Medium Range Thread

[Scottie16]

Wouldn’t we see more of a Cold Air Damming affect with this system?


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[Weatheriscool]

9 minutes ago, Scottie16 said:

Wouldn’t we see more of a Cold Air Damming affect with this system?


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I would imagine that solutions will change multiple times between now and next weekend; at noon, it will likely be vastly different from what is currently depicted

[TellicoWx]

1 hour ago, John1122 said:

The current forecast of ice box cold, warm up and rain, back to ice box, then warm up and rain, is weather torture for our forum area. For it to happen in December and January is particularly brutal. Especially with a potential second year in a row of "once in 50 years" type snow possible near the Gulf due to the air behind our first rain maker tonight. 

Need a reset...have to punt that pesky Great Lakes low. We have had too much northern stream dominance, hopefully the models are starting to catch on to the southern stream wake up in the medium range..just a wait and see if guess the way some of the modeling has been off lately.

[TellicoWx]

29 minutes ago, Scottie16 said:

Wouldn’t we see more of a Cold Air Damming affect with this system?


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If there was a High sitting over the lakes then possibly. But a GL low aides any type of vort to draw just enough southerly flow in advance up the valley to wreck the lower thermals. You can overcome this after the vort passes, but need it to generate some type of lee side low close enough to us to pull down the cold and still close enough to assist with lift to switch the moist low/mid levels over before they naturally dry out. Despise GL lows worse than SER...more ways to overcome the latter.

[Holston_River_Rambler]

For tonight, do we really buy the models showing snow at onset for some lower elevations and continuing throughout? This is basically a front swinging through with a low level jet nosing into the TN Valley, right?

I just can't think of a time when this kind of a set up produced snow recently for any lower elevations. 

Interestingly the 3km NAM has CAD for eastern escarpment of the plateau:

 

 

If someone rides just the right side of whatever boundary there is, they cold get some good rates though. 

[Holston_River_Rambler]

For some reason my CAD plateau gif isn't working, so I will post a static image here 

 

Now, Tellico ninja'd me with that explanation of CAD, so to be clear this is not a normal CAD set up as Tellico describes. The above is some weird microclimate mess that may or may not play out. 

[TellicoWx]

1 minute ago, Holston_River_Rambler said:

For some reason my CAD plateau gif isn't working, so I will post a static image here 

 

Now, Tellico ninja'd me with that explanation of CAD, so to be clear this is not a normal CAD set up as Tellico describes. The above is some weird microclimate mess that may or may not play out. 

It's picking up downsloping winds aiding the warm nose...could it pin the cold against the plateau..possibly, but it's rare...nose would have to be really weak.

[Holston_River_Rambler]

So is the consensus now that the Euro AI is the way to go for medium range (days 4-7 or so)? 

I like that is has a lower resolution like the NAVGEM, so it concentrates more on the general pattern than trying to get fancy with mesoscale features. 

[GBOVolz]

For some reason my CAD plateau gif isn't working, so I will post a static image here 

 
Now, Tellico ninja'd me with that explanation of CAD, so to be clear this is not a normal CAD set up as Tellico describes. The above is some weird microclimate mess that may or may not play out. 

Unless the winds are out of the SE, those temps don’t make sense to me.


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[GBOVolz]

It's picking up downsloping winds aiding the warm nose...could it pin the cold against the plateau..possibly, but it's rare...nose would have to be really weak.

I can’t remember what year, less than 10 years ago, but on the NW side of a line from Morristown to London got hammered from a event that was forecasted to be snow, rain, snow but CAD kept everything snow NW of that line. I ended up with 9” and the temps never got above 28°. At the same time, Sevierville was all rain in the mid 40’s.

Edit this to change NE to NW of the line.

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[Jed33]

I think it was in 2015. The further N and W you went, the more they got to a point. The CAD worked for the valley but the foothills and mtns got blasted with WAA. It was literally snowing and in the 20’s in the valley and raining and 45-50 degrees in the foothills and mtns. I’m not sure what it did to the plateau at the top elevations? Some of the heaviest snow I had ever seen until the MLK day 2024 over running event, which had some similarities in the foothills and mtns but was not quite exactly the same.

[GBOVolz]

I think it was in 2015. The further N and W you went, the more they got to a point. The CAD worked for the valley but the foothills and mtns got blasted with WAA. It was literally snowing and in the 20’s in the valley and raining and 45-50 degrees in the foothills and mtns. I’m not sure what it did to the plateau at the top elevations? Some of the heaviest snow I had ever seen until the MLK day 2024 over running event, which had some similarities in the foothills and mtns but was not quite exactly the same.

I was thinking 2015 also but I’m terrible with dates


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[Jed33]

That contributed to that 2014-2015 season being one of the best that I’ve seen since we moved to E TN in 2011. That year we exceeded 20in total snowfall, but it didn’t really get going until late Jan and ramped up in Feb. and into March.

[GBOVolz]

That contributed to that 2014-2015 season being one of the best that I’ve seen since we moved to E TN in 2011. That year we exceeded 20in total snowfall, but it didn’t really get going until late Jan and ramped up in Feb. and into March.

One of the analogues that I continued to see back in late summer to early fall for this winter was 2013-14. (I think) lol


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[Carvers Gap]

The biggest issue is widespread drought.  It has picked up steam this winter regardless of weather pattern.  Reminds me of 17-18 which was so cold at times but the STJ was not there.   The other thing is the northern stream is out of sync with the STJ…meaning its vortices are not connecting with STJ impulses.  I see some signs of that relenting after the 25th.  I am not sure how long that window lasts.   Some modeling has Feb holding a SE trough w a PNA ridge.   The GOA low is present on some modeling late, but generally that has been a red herring. 
 

I still remain optimistic that we see wintry conditions.   There is a lot of cold air in modeling right now.  I have to think we score with that on the table. 

[Scottie16]

WRF2 trending cooler for tonight’s wave.


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[*Flash*]

9 minutes ago, Scottie16 said:

WRF2 trending cooler for tonight’s wave.


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Indeed, we have pivoted from needing westward trends to cooler trends. Still have my eye on the plateau tonight. National guidance is modest, but those high-res short-term models are suggesting multiple inches in some parts. 

[GBOVolz]

So it’s moving towards 10 o’clock and we are stuck at 24° with a decent cloud deck that has moved in. WAA can overcome a solid cloud deck, but it’s gonna have to be a decently strong WAA.


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[Holston_River_Rambler]

Rediscovered a neat site when going through our links to see if I could find the site that shows how aircraft observations differed from model initialization conditions. I'm going to keep looking for that, but in the meantime, check the meridional flow into AK: (this is a precipitable water layer)

 

Link:

https://re.ssec.wisc.edu/?products=MIMICTPW2.100&center=11.178401873711785,-157.14843750000003&zoom=2&width=1316&height=780&basemap=bluemarble&labels=line&view=leaflet&timeproduct=MIMICTPW2&timespan=-24t&animationspeed=100&animate=true

 

A little bit of a learning curve to use, but it has a lot of views of the earth and atmosphere. 

[Daniel Boone]

25 minutes ago, *Flash* said:

Indeed, we have pivoted from needing westward trends to cooler trends. Still have my eye on the plateau tonight. National guidance is modest, but those high-res short-term models are suggesting multiple inches in some parts. 

Right with you man. Its looking that way.

[GBOVolz]

Rediscovered a neat site when going through our links to see if I could find the site that shows how aircraft observations differed from model initialization conditions. I'm going to keep looking for that, but in the meantime, check the meridional flow into AK: (this is a precipitable water layer)

 
Link:
https://re.ssec.wisc.edu/?products=MIMICTPW2.100&center=11.178401873711785,-157.14843750000003&zoom=2&width=1316&height=780&basemap=bluemarble&labels=line&view=leaflet&timeproduct=MIMICTPW2&timespan=-24t&animationspeed=100&animate=true
 
A little bit of a learning curve to use, but it has a lot of views of the earth and atmosphere. 

That is cool


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[GBOVolz]

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[Daniel Boone]

32 minutes ago, Scottie16 said:

WRF2 trending cooler for tonight’s wave.


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Started to post last night irt the WRF being as warm as it was. It seems it's been the warmer outlier 

 

43 minutes ago, Carvers Gap said:

The biggest issue is widespread drought.  It has picked up steam this winter regardless of weather pattern.  Reminds me of 17-18 which was so cold at times but the STJ was not there.   The other thing is the northern stream is out of sync with the STJ…meaning its vortices are not connecting with STJ impulses.  I see some signs of that relenting after the 25th.  I am not sure how long that window lasts.   Some modeling has Feb holding a SE trough w a PNA ridge.   The GOA low is present on some modeling late, but generally that has been a red herring. 
 

I still remain optimistic that we see wintry conditions.   There is a lot of cold air in modeling right now.  I have to think we score with that on the table. 

Exactly. We need the STJ to become active out of the Pacific and across Mx the SW and Southern Plains. That dryness there helps extend that ever present SW Heat Ridge, if you will, Eastward to the Gulf. That hinders our moisture transport and LP development there as well. 

[WintryMixmaster]

31 minutes ago, GBOVolz said:

So it’s moving towards 10 o’clock and we are stuck at 24° with a decent cloud deck that has moved in. WAA can overcome a solid cloud deck, but it’s gonna have to be a decently strong WAA.


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Satellite shows clearing skies to our west unfortunately, hopefully we can hold in as much cold air as we can ahead of the southwest winds. The temperature has been steadily climbing at my house, up to 28.6 degrees now

[Daniel Boone]

1 hour ago, Jed33 said:

I think it was in 2015. The further N and W you went, the more they got to a point. The CAD worked for the valley but the foothills and mtns got blasted with WAA. It was literally snowing and in the 20’s in the valley and raining and 45-50 degrees in the foothills and mtns. I’m not sure what it did to the plateau at the top elevations? Some of the heaviest snow I had ever seen until the MLK day 2024 over running event, which had some similarities in the foothills and mtns but was not quite exactly the same.

2015... We'd only got an inch in January before the February onslaught of which didn't start until the 13th. Totalled about 33" that Month at my place in Jonesville then. Northern Section of Lee County Totalled over 40" . Higher Eles 50" for the Month !

[*Flash*]

Seems to me this winter (and I know we're only half-way through) may go down as a textbook example of all the things that generally go wrong in a Nina/weakening Nina setup. The December Chinook, the historic cold in Alaska, misplaced Atlantic blocking, the stubborn Great Lakes lows, so many things have contributed to split flow and lack of phasing. You can sort of see the past 30/40 days how one issue has played into the next, even through the pattern resets. We have modest cold air supply rest of the month. Just have to hope the river and flop work in our favor regarding precip and timing. 

As for the weekend threat, I can't recall such a huge whiff on American models, notorious as they may be, within 24-48 hours. I try to not let recency bias get the best of me, but I lack relative remembrance. Truly, the absence of overhead blocking played a huge role in the weekend threat evaporating and will be a legacy to the archive. We've seen this storyline before many times, so it confuses me why so many neglected the writing on the wall. Kinda feel for our Piedmont brothers. They spew a lot of crazy stuff over on Southern but they're long overdue. Rooting for you, @GaWx! Not to sound to straight-forward but send pics if things out for you. 

[Daniel Boone]

1 hour ago, GBOVolz said:

I can’t remember what year, less than 10 years ago, but on the NW side of a line from Morristown to London got hammered from a event that was forecasted to be snow, rain, snow but CAD kept everything snow NW of that line. I ended up with 9” and the temps never got above 28°. At the same time, Sevierville was all rain in the mid 40’s.

Edit this to change NE to NW of the line.

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That particular Event was Feb 21, 2015 the day after the Record Arctic Blast brought a low of -20 in Pennington Gap.

    Model's all showed precip starting as a brief period of Snow quickly going to Rain(except the Para GFS, it showed 8-9 here ) with less than an inch forecasted . It started here around 1 A.M . With the Temperature in the Teens. Got up around 7 and just over 4 inches had fallen and snowing moderately. I called the NWS and they couldn't believe it as Models were showing Rain. It was raining there. 

      It increased intensity and by 10 over 7" had fallen. I reported that. At this point they were like it should change over soon.

    It continued heavy until about 4 O'clock. Then started the changeover with Temp in upper 20's. 15" at my place had fallen. 20" just about 2 statute miles north of me near Stone Mountain.

There was moderate rain on top of the snow that night that froze within it as the ambient Temperature rose to just above freezing. There were Carports and Porches collapsed from the Weight. 

[Carvers Gap]

The worst winters are super Nino or super Nina.  I still think we end up doing ok this winter due to the amount of cold in NA and its ability to get south this winter.  We have had many winters which were late bloomers.  We have also had several dry La Nina years recently.  I think folks in NE TN kind of already know the drill w/ these recent La Nina winters.  Mid-state and west Tenn have done decently well with Nina winters.  TRI is on the end of the state where everything kind of fizzles out during La Nina winters.  Sorry to share our "riches" with the rest of forum this winter!  Haha.  Again, I think things perk up.  Things can change quickly for better or worse!

[Carvers Gap]

21 minutes ago, Daniel Boone said:

2015... We'd only got an inch in January before the February onslaught of which didn't start until the 13th. Totalled about 33" that Month at my place in Jonesville then. Northern Section of Lee County Totalled over 40" . Higher Eles 50" for the Month !

I'd have to go back and look in the thread, but I think we ended up with 25-30" here.  Crazy, crazy month.  

[Holston_River_Rambler]

At 150 hours the GFS had blessed us with another temptation.