Winter 2024/2025 January Thread

[Carvers Gap]

Nice storm on the 12z GFS after 300.  Pretty typical of what ensembles have been showing the past few days on their snow maps.  

[Carvers Gap]

Pretty respectable 5-15” of snow over the eastern forum area for that run.  TRI had 10-15”.

[Carvers Gap]

Two small events and one bigger event.  I suspect we nickel and dime this, but a bigger storm would have snow on the ground for a while if the pattern stays as cold as the GFS portrays.  Is it right?  

[Daniel Boone]

8 minutes ago, Carvers Gap said:

Two small events and one bigger event.  I suspect we nickel and dime this, but a bigger storm would have snow on the ground for a while if the pattern stays as cold as the GFS portrays.  Is it right?  

Agree. If we can get some STJ and NS phasing we can get that '96 like Big Dog. With the Polar Jet digging that far South there's a decent likelihood of at least a Miller B to A transfer providing Trough dives far enough West .  If the NS were to dive to the Gulf it could create cyclogenesis in the Gulf even without the STJ. Although rare these days the possibility is still there.

[Carvers Gap]

12z Euro is thus far back to general continuity after a weird hiccup at 0z

[Carvers Gap]

The 0z Euro must have had something go sideways overnight - was really warm  compared to the past gazillion runs.  The 12z run was SIXTY degrees colder after 300!!!

[Carvers Gap]

To clarify…apparent temp changes.  Below zero for most of TRI…single digit actual temps.    60 degrees colder for apparent and 40-50 degrees colder for actual temps.

[Carvers Gap]

Real feels are in the -10s for NE TN late in the 12z Euro.

[Carvers Gap]

Last nights Euro/EPS was strange.  The multiple runs before it and the 12z run after it - not the same.  Had to have been some model input or a week.  The 12z ensembles are about as cold as you can get at this range.  Big signal for a very cold air mass.  I am like Bob Chill in the MA...just give the cold, and let's roll the dice so to speak.

[John1122]

I hope we can get a storm worked up at some point during the cold. The overall pattern has been dry for most of the last year. (ironic to have historic floods during a dry pattern) and the first cold shot is dry on the Euro/Canadian. Possibly a similar pattern to early this month when we got some light snow but not much else.  Jan 10th and beyond may afford more opportunities.

[Carvers Gap]

It will be interesting to see how things play out.   Both the 12z Euro and GFS have multiple events ranging from small to boomers.  The Euro has a slider and an anafront.  The GFS has 2 sliders and the fantasy land big dog.  I would look for some snow in he air by the 3rd or the 4th.  For me in E TN, this definitely looks like a nickel and dime pattern...but the 12z Euro gives me a bit more confidence this pattern will deliver at some point.   It really is going to depend on confluence.  There is some 14-15 in how this looks.  Lots of small pieces of energy rotating through the northern stream as the EPO really locks in.

[AMZ8990]

1 hour ago, John1122 said:

I hope we can get a storm worked up at some point during the cold. The overall pattern has been dry for most of the last year. (ironic to have historic floods during a dry pattern) and the first cold shot is dry on the Euro/Canadian. Possibly a similar pattern to early this month when we got some light snow but not much else.  Jan 10th and beyond may afford more opportunities.

 Definitely seems like the Euro and GFS are on the same page about that 2nd week of January, both showing similar setups in that January 6th-10th timeframe.  Long ways out but impressive to see nonetheless 

[Carvers Gap]

GFS Happy Hour rarely disappoints.

[Carvers Gap]

I am going to use the GEFS ext weeklies today since the 0z weeklies were so wonky(back to normal at noon...so hopefully not a trend).  The 0z runs are what the Weeklies are derived from.  So far, the GEFS ext is about halfway out....frigid for Jan 7-14 and colder than yesterday's run.

[Carvers Gap]

Man.  Can you draw it up any better?  This is the 18z GEFS.  The Weeklies from this morning looks almost exactly like this as well, and is out to 1/15.

 

[Carvers Gap]

Still rolling.....EPO, NAO(but slightly east so no WAR), trough east of Hawaii(important).  Anyone have any daily PDO numbers?  I heard it was approaching neutral last week.  That look right there opens up the potential for the PV to be trapped.

 

[Carvers Gap]

I don't know if this January is that time, but one day we are going to track another memorable pattern and maybe historic pattern.  That is why we show up each winter.  Give me that above, and let's roll.  We need the Euro to stay in the fold overnight!

[Carvers Gap]

This is a 360 map from the Euro AIFS - proceed with caution.  It was super warm at 0z, but has rapidly cooled off.  This is 12z.  We will see what 18z has in a bit.  It ended with a setup that was sending and Arcitc air mass straight down the middle of the Canadian Prairies - due south.  I think we are going to have some northern stream smaller systems and maybe we get an STJ system.  Clippers appear to embedded in this.  I will add(very cautiously), sometimes BN precip can reflect snowfall areas...and sometimes it is just dry.  With this type of look as a potential...no way modeling has the details even remotely worked out. 

That is confluence over the Tenn Valley right there.  Northern MS to DC would be happy with that setup and 200 miles either side of that line IMHO.  We'll see....

Dig up some great snowstorm maps.  Looks a lot like that.

[John1122]

45 minutes ago, Carvers Gap said:

Man.  Can you draw it up any better?  This is the 18z GEFS.  The Weeklies from this morning looks almost exactly like this as well, and is out to 1/15.

 

I wish the trough was centered a little further West. That's a clipper look though so hopefully we can score either way. 

[Carvers Gap]

10 minutes ago, John1122 said:

I wish the trough was centered a little further West. That's a clipper look though so hopefully we can score either way. 

I think in 2018, the issue was the EPO got so tall, we were just pulling cold, dry air from the Arctic.  Modeling this time does hint at multiple short waves coming out of the northwest.   These look like 1-2" quick hitters.   I know you know this, but for others new to this.....in very cold air those shortwaves can have 15:1 or better rations.  

Was 84-85 northern stream driven?  I was a high schooler at the time, and wouldn't have known the answer to that.  It seemed northern stream driven as my dad was hauling a load from Missouri to Tenn.  He was racing a massive snowstorm home - barely made it.  He got the rig into to town, jumped in the care, and rolled in with about 4-6" of snow already on the ground.  In my mind, that storm came from the northern Plains....

[Carvers Gap]

Finally figured out how to make a tweet work.  Just copy the twitter link, past it into notepad, change the x to twitter, and copy link into post - will automatically update.  MA had shared this.  Now, we certainly don't live in the Mid-Atlantic...but E TN and NE TN do sometimes cash-in on the beginnings of their storms.

 

[John1122]

48 minutes ago, Carvers Gap said:

I think in 2018, the issue was the EPO got so tall, we were just pulling cold, dry air from the Arctic.  Modeling this time does hint at multiple short waves coming out of the northwest.   These look like 1-2" quick hitters.   I know you know this, but for others new to this.....in very cold air those shortwaves can have 15:1 or better rations.  

Was 84-85 northern stream driven?  I was a high schooler at the time, and wouldn't have known the answer to that.  It seemed northern stream driven as my dad was hauling a load from Missouri to Tenn.  He was racing a massive snowstorm home - barely made it.  He got the rig into to town, jumped in the care, and rolled in with about 4-6" of snow already on the ground.  In my mind, that storm came from the northern Plains....

'85 was a series of Miller A's if I recall correctly. 

[Carvers Gap]

Might have been a phaser where he was racing the northern stream in from St Louis? 

I normally don't use the CMC weeklies a ton, but I do look at them from time to time.  Sometimes the CMC is the only model which can really handle very cold patterns.  It does have a cold bias, so maybe scale that back a degree or two.  GEFS ext is taking forever to load tonight.

 

[John1122]

28 minutes ago, Carvers Gap said:

Might have been a phaser where he was racing the northing stream in from St Louis? 

I normally don't use the CMC weeklies a ton, but I do look at them from time to time.  Sometimes the CMC is the only model which can really handle very cold patterns.  It does have a cold bias, so maybe scale that back a degree or two.  GEFS ext is taking forever to load tonight.

There was a southern stream system then another on January 17th. January 20th was the arctic front that was northern stream related I believe. Extremely high ratios. Around 6-8 inches of snow on .3ish qpf. 

[Daniel Boone]

11 minutes ago, John1122 said:

There was a southern stream system then another on January 17th. January 20th was the arctic front that was northern stream related I believe. Extremely high ratios. Around 6-8 inches of snow on .3ish qpf. 

Yeah, remember that well. The January 20 85 Arctic Front Snowfall was amazing in that it dumped a swath of 2-8 inches along it's path all the way from Illinois, Missouri, western Tn and Ky across Indiana and Ohio down through our area and east to Western NC. I measured 7 inches. I think Knoxville recorded 7 and I believe Ktri 5".  Flurries floated around the afternoon before the front came through that night with temps in middle 30's. Temps crashed after front passed around 9 p m. and by Midnight was already below Zero ! 

[beavis1729]

57 minutes ago, Daniel Boone said:

Yeah, remember that well. The January 20 85 Arctic Front Snowfall was amazing in that it dumped a swath of 2-8 inches along it's path all the way from Illinois, Missouri, western Tn and Ky across Indiana and Ohio down through our area and east to Western NC. I measured 7 inches. I think Knoxville recorded 7 and I believe Ktri 5".  Flurries floated around the afternoon before the front came through that night with temps in middle 30's. Temps crashed after front passed around 9 p m. and by Midnight was already below Zero ! 

Good stuff. 1/20/1985 was Chicago’s all time coldest temperature, -27F. 

[Holston_River_Rambler]

Kind of a non sequitur from me this AM but we finally have the MJO as plotted on the RMMs moving out of 6:

I don't really put a ton of stock in the RMMs alone, but from the perspective of model watching, I think they can kind of give us a plotted idea of the "numerical" part of Numerical weather prediction, i.e. models and where they're coming at the pattern from. 

I just found it interesting that whatever slew of variables it looks at had the value stuck in 6 for almost 10 days, despite model forecasts consistently trying to move it out and now it is finally chugging along. 

[Carvers Gap]

Overnight model runs and 6z continue to paint a pretty cold picture over our region to begin January.  Interestingly, the cold appears to have moved up to late in New Year’s Day.  Instead of Jan 3.  Though details are murky for individual events, the CMC has a pretty stout upslope event well inside of d10.  Let’s see if that shows up in other modeling.  The 6z GFS has brought back the slider for Jan 2.  No other model has that…so proceed with caution.

[Carvers Gap]

I suspect the GFS woes from late last week were probably due to that model mishandling the MJO.

The Euro Weeklies tonight should be interesting as the 0z run was very cold and didn’t have the PNA displaced into the Plains as yesterday’s 0z did.

[Carvers Gap]

9 hours ago, Daniel Boone said:

Yeah, remember that well. The January 20 85 Arctic Front Snowfall was amazing in that it dumped a swath of 2-8 inches along it's path all the way from Illinois, Missouri, western Tn and Ky across Indiana and Ohio down through our area and east to Western NC. I measured 7 inches. I think Knoxville recorded 7 and I believe Ktri 5".  Flurries floated around the afternoon before the front came through that night with temps in middle 30's. Temps crashed after front passed around 9 p m. and by Midnight was already below Zero ! 

Great info beavis, John, and Boone.  We had 1-2’ drifts from that in Scott, Co, Virginia.  The wind chills with that front in SW VA were insane.  I don’t want to embellish, but maybe in the -50s?  Our farm thermometer got to -26F.