December 2025 Short/Medium Range Forecast Thread

[Matthew70]

Webb is definitely good at what he does.  Only issue is he cliff jumps easily. In his defense many also do on that board. Negativity breeds more negativity.  We all just need to remember how hard it really is to get snow in these parts.  We have to have the temps first.  Which finally we do have those temps really close to tap into. I’ve learned so much from many on this board.  Carver has taught me to be patient & not live off every run of the models.  John is a wealth of historical data.  Jag is the MJO king. Gawx is the statics guru. Holston & Jeff are also great members of this forum. Come spring Jag & Jeff  are severe wx gurus.  The list goes on and on.  
 

[Carvers Gap]

After a super quick skimming of models.  The 0z Euro and 0z GEM are cold beginning sometime around Dec 28-29.  The GFS really does not like the idea of the Jan 2 cold front...but sends one a few days later.  Some of the AIFS models agree w/ the GFS...but for now, I am riding with the coldest models.  Why? We have seen a tendency for models to miss or under-do cold fronts.  I may try to update 500 here in a sec.  That update was pretty much surface focused.

As for snow?  I have to think one or more of these really cold fronts is going to produce winter precip.  It is worth remembering that models often lose systems in the the day 5-7 range...only to find them again, and they restrengthen.  We may have short lead times on fronts which bring snow with cold fronts.

[GBOVolz]

Looks like January 1982 is showing up as an analog at 500mb according to Webb. 
January 1982 was the year it snowed basically every day for a week.
The biggest was 3 inches, but it would snow 1/2 to 1 inch almost every day. We had accumulating snowfall on 9 of 10 days. Even Knoxville recorded 1.5 inches 3 days in a row. 
 
It was capped off by an epic ice storm on January 18th, that the NWS records for some reason, ignore for Knoxville.
It says Knoxville got .21 qpf of ice in the "official" record. 
This is from a KNS article about January 18th/19th 1982. 
 
"That Jan. 18th date was all about ice. The mother of all freezing rains turned the entire area into a skating rink with ice an inch or more thick in most places.
Law enforcement reported more than 150 wrecks. Power failures showed up across the grid. Schools and businesses were shut down. Downtown hotels filled up with ice-locked workers unable to get home. The less fortunate spent the night in their cars unable to do anything but spin their wheels.
The National Weather Service personnel called it the worst ice storm they'd seen in decades.
Stories abounded of people latching up their ice skates for a trip to the store or literally crawling from their cars to get back into their homes and offices."
 
Temperatures in the -10s here just before that ice storm. 

I remember that Ice storm in 82. What I remember about it is me and my dad had to go get my grandmother at her work, which was downtown at the city County building. I remember sitting on the overpass where 275 goes east on 40 and we sat there for what seemed like forever. However, we got my GM, got her home and we got home safe. Maybe the weather conditions got worse after we got home but at that time, only bridges and overpasses were iced up.


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[GBOVolz]

@John1122 i don’t remember the end of Jan snow storm though




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[John1122]

There's a good reason, it was nearly 70 by the end of January. No idea where that snow storm report came from.

The next snow event imby was February 5th/6th timeframe, with 2 inches. Then 1.5 around the 10th.

[Carvers Gap]

The 12z CMC and GFS in a bit of a model battle for Jan 1.  The 12z has snow and below zero temps.   My money is on the Canadian.

[John1122]

Here's an article about the snow leading up to the ice storm.

This was a southern slider that got all of us, and heavier snow fell into Alabama. Birmingham got 6 inches. Nashville 5 inches. Memphis 5 inches. Along and north of 40 in East Tennessee it was around 2-3 inches. But we'd gotten snow a couple days before this and it snowed in the NW flow area for days after it. 

We had 2 inches on the 10th, .5 the 11th, .75 the 12th, frigid with a high of 3 on the 11th and 10 on the 12th, lows below 0, the system from the article below came with that airmass in place, we got 3 inches of snow on the 13th, 1.5 on the 14th, .75 the 15th, .5 the 16th, .5 the 17th, as subzero cold squeezed out every drop of moisture, the ice storm on the 18th with .85 freezing rain. I remember smashed cedar trees that lined our driveway, and powerlines sagging towards the ground. It was solid ice on deeply frozen ground.

"January 14th, 1982

The epic Winter of '82 stunned the Deep South and East Coast Thursday with a new round of snow and icestorms -- the latest chapter in a continuing siege of severe weather blamed for more than 200 deaths. Blizzards again threatened the Midwest.

Dazed southerners suffered through their second storm in 72 hours - a 6-inch deep blanket of snow and ice.

New Yorkers barely had time to dry off their snow shovels before turning around to face the remnants of a second storm that began its attack on the city late Thursday. New snows from 3 to 6 inches were forecast on top of 4 to 7 inches of snow that hit late Wednesday before moving up the coast. At least 216 deaths have been blamed on the weather that set 20th Century records for low temperatures. The back-to-back winter storms claimed at least 60 lives in the South alone.

In New York two teenage youths fell through the ice-covered surface of Brooklyn's Prospect Park and drowned Thursday when they became trapped under a large chunk of ice. Two other youths also fell through the ice but were rescued. Seven police officers were injured in the rescue attempt.

A St. Louis police officer examining a parked car covered with snow and ice opened the door to check for a vehicle identification number and found a body frozen behind the steering wheel.

And an employee of New York's Sanitation Department suffered a broken leg when he was run over by his plow after his vehicle struck an object in the road and threw him from the cab.

The cruel storms have taken their toll of crops and poultry items, leaving consumers with expected price increases for citrus fruits, vegetables, eggs and chickens.

Snow fell in north Florida Thursday, but southern portions of the state were deluged by tropical thunderstorms and winds whipping up to 60 mph. A tornado cut a path a mile long and 100 yards wide in Fort Myers causing an estimated $300,000 in damages to homes. No serious injuries were reported.

Furious storms wreaked havoc on Massachusetts, dumping up to a foot of snow in some areas. Boston had almost a foot of snow and strong northerly winds were whipping the accumulations into near-blizzard conditions.

All along the east coast, especially southeastern New England, the second half of the storm was expected to hit during the night with forecasters calling for up to another foot of snow, gale-force winds and freezing temperatures.

'This one looks like a big storm with gale winds and considerable blowing and drifting snow expected,' a weather service spokesman said.

Connecticut received 6 to 8 inches of new snow, Rhode Island got 8 inches in northern portions of the state and about 6 inches in southern areas.

Higher prices for eggs and poultry loom on the horizon for consumers as a result of the bitter cold weather that froze much of the South.

'We're in some pretty tough times as far as poultry growing is concerned,' said Lionel Barton, a poultry expert with the University of Arkansas Cooperative Extension Service. Many baby chicks died in the cold weather and the hens that lived are laying fewer eggs.

Florida citrus growers estimated their losses at $500 billion. But in New York Richard Norton, a regional fruit specialist with the Monroe County Cooperative Extension, said a gradual cooling around the Finger Lakes and western New York area last fall helped prepare fruit trees and grapes for this week's subzero readings.

Six inches of snow fell on parts of southern Maryland and state police reported 4 inches of snowfall on the lower Eastern Shore.

Up to 6 inches of snow fell over Georgia, Alabama, Mississippi, Tennessee, and the Carolinas, making already slippery highways treacherous. An estimated 1 million people were left without power because of ice buildups on utility lines and trees -- 750,000 of those were in Alabama.

The weather did little to keep thieves in tow. Atlanta police said 19 people forced to walk home or seek shelter Tuesday night were robbed and dozens of motorists who abandoned their cars after the first snowstorm returned to find their batteries, radios and other valuables had been looted.

One Atlanta woman barely made it to the hospital in time to deliver her baby. 'I was worried,' said Gretchen Rehlin, mother of a new daughter. She was forced to walk the last half mile to the hospital because of stalled traffic. 'But my husband was more worried because he was the one who would have had to deal with it (the delivery)."

[Carvers Gap]

The 12z GEM would shatter some records.  Crazy run.  A few places would have all time records at risk.

[Icy Hot]

1 minute ago, Carvers Gap said:

The 12z GEM would shatter some records.  Crazy run.  A few places would have all time records at risk.

Highs or lows?

[Carvers Gap]

22 minutes ago, Icy Hot said:

Highs or lows?

Record lows.   Seems to be an outlier at 12z, but…it caught the Dec 29th front first.   Teens below zero.

[Matthew70]

44 minutes ago, Carvers Gap said:

The 12z CMC and GFS in a bit of a model battle for Jan 1.  The 12z has snow and below zero temps.   My money is on the Canadian.

I wish.  The Canadian sadly is never right.

[Holston_River_Rambler]

Euro has the dreaded La Nina qpf firehose look to it:

[John1122]

We will see if it holds, but the Aleutian ridge is basically eliminated by the end of the Euro run and it looks like a +PNA is building. If that happens, January 10th and beyond could be plenty of Pacific driven good times. Traditionally when it collapses extreme winter periods of 2 to 3 weeks can happen. 

[Golf757075]

3 hours ago, John1122 said:

We will see if it holds, but the Aleutian ridge is basically eliminated by the end of the Euro run and it looks like a +PNA is building. If that happens, January 10th and beyond could be plenty of Pacific driven good times. Traditionally when it collapses extreme winter periods of 2 to 3 weeks can happen. 

Don't want too much pna because the core of the cold will be east of us imo

[Carvers Gap]

4 hours ago, Matthew70 said:

I wish.  The Canadian sadly is never right.

Sorry, we have been traveling for most of the day....

It has been very right for the 29-30th event...scored the coup.  The 18z AIGFS has the Jan 1-2 cold front.  The run-to-run for the 18z GFS is MUCH colder.  Do I think it gets below zero without snow?  Unlikely as the GEM is often too cold.  But it ofter correctly sees cold fronts during winter when other models do not - just add back a few degrees for the cold bias.  The 18z AIGFS is basically the 12z GEM but just not on steroids...one cold front after another.

[Carvers Gap]

4 hours ago, Holston_River_Rambler said:

Euro has the dreaded La Nina qpf firehose look to it:

Now, merge that with the 12z GEM...and we are in business!!!

[John1122]

17 minutes ago, Golf757075 said:

Don't want too much pna because the core of the cold will be east of us imo

A true PNA will basically always work for cold here. It means drier weather in our area but as Jeff has noted, below normal precip doesn't mean it's not good for snow. Above normal precip here usually means the warm flow from the Pac or Gulf is coming, and all the issues they cause. 

[Golf757075]

5 minutes ago, Carvers Gap said:

Now, merge that with the 12z GEM...and we are in business!!!

I believe if the aleutian ridge is morphed with the Alaskan ridge at some point, we should be in business for better opportunity at winter weather. Its just tough in the south lol

[Carvers Gap]

The 18z GFS find the cold air mass.  All...winter...long -> so far.  It has almost 50 degree changes(colder) over the GLs.  Trending quickly towards what the GEM has had for days.  The 18z AIGFS is on board.  Honestly, there are so many cold fronts modeled...I have no idea how many there are.  Dec 29, Jan 2, Jan 5, Jan 8?.

[Carvers Gap]

1 minute ago, Golf757075 said:

I believe if the aleutian ridge is morphed with the Alaskan ridge at some point, we should be in business for better opportunity at winter weather. Its just tough in the south lol

Some great trends on modeling for the past week or so....still a tough pattern to model.  I like @John1122's analog discussion above about 1982.  It was one of only two Tenn winters which I missed while living in winter purgatory - Orlando, Florida.  I read the newspaper articles about the ice storm, and about Tennessee beating Alabama during the World's Fair.  I will say that it got crazy cold during those winters in Orland and wiped out many orange groves that were never replanted.

[Matthew70]

18 minutes ago, Carvers Gap said:

Sorry, we have been traveling for most of the day....

It has been very right for the 29-30th event...scored the coup.  The 18z AIGFS has the Jan 1-2 cold front.  The run-to-run for the 18z GFS is MUCH colder.  Do I think it gets below zero without snow?  Unlikely as the GEM is often too cold.  But it ofter correctly sees cold fronts during winter when other models do not - just add back a few degrees for the cold bias.  The 18z AIGFS is basically the 12z GEM but just not on steroids...one cold front after another.

No reason to apologize.  Safe travels.

[Golf757075]

4 minutes ago, Carvers Gap said:

Some great trends on modeling for the past week or so....still a tough pattern to model.  I like @John1122's analog discussion above about 1982.  It was one of only two Tenn winters which I missed while living in winter purgatory - Orlando, Florida.  I read the newspaper articles about the ice storm, and about Tennessee beating Alabama during the World's Fair.  I will say that it got crazy cold during those winters in Orland and wiped out many orange groves that were never replanted.

Surprised Eric webb would use that analog imo

[Carvers Gap]

I have found that the Euro coupled with the GEPS(Canadian ensemble) has been decent this winter.  When the two are singing the same song...good thing.  When the GFS starts to trend towards them...better thing.  The GEM only goes out to 240, so I kind of use the GEPS to see where it might have gone if it went past 300 hours at the deterministic level.  Both get to a pretty similar place.  

BTW, the ensembles have moved quite a lot over the past 48 hours.  Right now(rightly or wrongly), I don't trust any model which breaks the NAO down too quickly.  

Unrelated, it just kind of seems like about the time the NAO makes its exit...the EPO/PNA is gonna pop.  That has been a pattern for several winters.  NE TN folks have generally not benefitted from this, but with the cold pool so strong...I have to think the cold doesn't get held up at the Plateau or even the Apps.

 

[Carvers Gap]

The very definition as an outlier, but it deserves its moment since it is inside o 240.  Departures from normal....That would include -11F IMBY.  I have to look at chinook maps for a couple of weeks on modeling.  So, humor me...haha.

[Carvers Gap]

18 minutes ago, Matthew70 said:

No reason to apologize.  Safe travels.

I have been wanting to post that GEM map all day.  We were doing Christmas with some of my family...I definitely was sneaking a peak at models.  But my 12z model deep dive...just now happening.  

There is an interesting demarcation point after the 5th...does it warm up and we get a heavy rain event as Holston posted?  Or does end up frozen(not at those levels)???  I tend to think the cold hangs around, but that is an educated guess and by no means fact.

[Holston_River_Rambler]

I think a lot of it just depends on how the NAO evolves and how long it hangs around. Probably not getting an answer on that one soon. 

[Holston_River_Rambler]

And if the now advertised PAC jet extension can dislodge the Aleutian Ridge 

[Golf757075]

3 minutes ago, Carvers Gap said:

I have been wanting to post that GEM map all day.  We were doing Christmas with some of my family...I definitely was sneaking a peak at models.  But my 12z model deep dive...just now happening.  

There is an interesting demarcation point after the 5th...does it warm up and we get a heavy rain event as Holston posted?  Or does end up frozen(not at those levels)???  I tend to think the cold hangs around, but that is an educated guess and by no means fact.

Im ready for some action lol. At least one opportunity 

[Golf757075]

3 minutes ago, Holston_River_Rambler said:

And if the now advertised PAC jet extension can dislodge the Aleutian Ridge 

Do you think it will eventually?

[Carvers Gap]

Just now, Golf757075 said:

Im ready for some action lol. At least one opportunity 

Just looking at the 18z EuroAIFS....that is a pretty good look.  It is wild to see the Jan 2 cold front trend today.  I think we see several cold fronts forced south and east.  That seems like it has slider or clipper potential.  But with modeling bouncing around right now.....I hope today is the beginning of the ship being steadied, ie we get a fairly predictable pattern.