January 2023 Medium/Long Range Pattern Discussion Thread

[Carvers Gap]

I managed to make it through December w/ a trace of snow, but severely cold temps.  I am beginning to wonder if this PNA ridge does NOT materialize or is too weak to be of any service.  Remember the comment above when I was saying that modeling was waffling between a PNA ridge and/or HB blocking?   It looks like the trend on today's modeling is for the HB block to hold.  The positive is that we see plenty of storms w/ a good track.  The negative is maritime air enters/stays in the pattern.  There is very little ridging showing up in the LR in the West.  Weeklies this evening will be interesting and needed.  The lack of a -NAO is going to be a problem

[Carvers Gap]

The 12z GEFS, GEPS, and 6z CFSv2 show the Hudson Bay block as the primary driver and NOT the PNA ridge.  I don't see that ridge being of any significant influence on LR modeling on todays runs.  That could easily change at this range, and probably will.  The HB block will work provided that it does not bridge to lower latitudes and form a ridge in the Plains.   The GEFS and GEPS do like they allow enough space for colder Canadian(not Arctic air) to get infected into the pattern.  The CFSv2 is maritime only.  The opportunities we do have will be somewhat thread the needle if LR modeling is correct.  I do want to see the Euro Weeklies as noted above....but they may not have the 12z trend away from the PNA.  

The pain in the neck right now the GOA low and Nina climatology which doesn't want to go to phase 8 of the MJO..  Those are the roots of the problem.  Those GOA lows can take weeks to dislodge, but we will see.  We are going to need the Atlantic to do what it did during this month...NAO block

[Carvers Gap]

Here is how fluid long range forecasting is.  The image on the right is 6z of the CFSv2.  The image on the left is 12z(most recent) of the same time frame.   It is possible that things are swing wildly like this due to cold wx about to enter the pattern.  Still, this is why things are far from certain.  I think the image on the left is likely as it matches its own MJO progression....but that is no slam dunk when the image on the right is only from 6 hours earlier.  Also, as you can see, the PNA is either absent or weak.  The colder solution occurs w/ HL blocking over Greenland.

 

[Carvers Gap]

12z comparisons EPS, GEFS, and GEPS.  Some big differences exist.  Scoreboard is 2 HB blocks vs 1 PNA ridge.   I lean EPS.  A storm signal is present from Jan7th-10th.

 

 

[Itryatgolf70]

You definitely want the eps to be right imo but so far out there in lala land

[Matthew70]

I can say I am happy for the warmer wx.  60’s will be short sleeves for sure.  54 & Sunny on Wednesday will feel great.  63 & Sunny on Sunday fabulous.  Actually might feel hot after this cold we just had.  With daughter soccer starting up especially first of February.  I will take the warmer wx.  We have a showcase tournament in Gatlinburg first weekend of February.  It is on turf so no cancellations. Please at least let it be sunny this year. 

[Carvers Gap]

The Euro Weeklies are a mixed bag.  The ensemble shows a window from Jan10-24th before the trough backs into the West for the foreseeable future.  Oddly, the Weeklies keep temps at normal or just below even after the trough digs into the west.  That tells me there is some variability in the pattern - meaning cold fronts push eastward at times.  Honestly, it is a classic La Niña progression - and I am glad to be seeing the last winter of that front loaded winter progression!

[Itryatgolf70]

12 minutes ago, Carvers Gap said:

The Euro Weeklies are a mixed bag.  The ensemble shows a window from Jan10-24th before the trough backs into the West for the foreseeable future.  Oddly, the Weeklies keep temps at normal or just below even after the trough digs into the west.  That tells me there is some variability in the pattern - meaning cold fronts push eastward at times.  Honestly, it is a classic La Niña progression - and I am glad to be seeing the last winter of that front loaded winter progression!

Just a pattern that's good enough for cold and storminess and hopefully not over bearing cold like we just went through. Overrunning events are my favorite providing enough cold is present 

[Itryatgolf70]

Carver, take a look at Dr. Jason Furtado post about what could lie ahead on Twitter when you get a chance. See if you can make any sense out of it.

[Daniel Boone]

53 minutes ago, Carvers Gap said:

The Euro Weeklies are a mixed bag.  The ensemble shows a window from Jan10-24th before the trough backs into the West for the foreseeable future.  Oddly, the Weeklies keep temps at normal or just below even after the trough digs into the west.  That tells me there is some variability in the pattern - meaning cold fronts push eastward at times.  Honestly, it is a classic La Niña progression - and I am glad to be seeing the last winter of that front loaded winter progression!

For real! Too bad we didnt get underwater volcanic activity in that area this fall..

[tnweathernut]

I'm beginning to see people in multiple places discuss a possible disruption of the stratospheric polar vortex.   I'm going to say I don't want a split to occur.   Let's jostle and move it around a bit, but let's keep it together.  Biggest concern for a split means sweating things out and having (what seems to be) an 80% chance the cold filters to a place that hurts us more than helps us.

[tnweathernut]

3 hours ago, Carvers Gap said:

I managed to make it through December w/ a trace of snow, but severely cold temps.  I am beginning to wonder if this PNA ridge does NOT materialize or is too weak to be of any service.  Remember the comment above when I was saying that modeling was waffling between a PNA ridge and/or HB blocking?   It looks like the trend on today's modeling is for the HB block to hold.  The positive is that we see plenty of storms w/ a good track.  The negative is maritime air enters/stays in the pattern.  There is very little ridging showing up in the LR in the West.  Weeklies this evening will be interesting and needed.  The lack of a -NAO is going to be a problem

If we can manage to realize the lower heights in the Aleutians, it should teleconnect to a +PNA.

[Carvers Gap]

Ditto @tnweathernut, no SPV split for me either!   

The 18z GFS speeds up the transition back to cold.  Instead of transitioning to cold between the 5th and 10th, it just flips cold(enough) on the 5th.  That is now within the 10 day window.

[Carvers Gap]

Food for thought....

 

[Daniel Boone]

3 hours ago, Carvers Gap said:

Ditto @tnweathernut, no SPV split for me either!   

The 18z GFS speeds up the transition back to cold.  Instead of transitioning to cold between the 5th and 10th, it just flips cold(enough) on the 5th.  That is now within the 10 day window.

Hopefully it's right. Don't want to go through another kick the can 2.5-3 weeks mild. 

[Carvers Gap]

4 minutes ago, Daniel Boone said:

Hopefully it's right. Don't want to go through another kick the can 2.5-3 weeks mild. 

This model waffling reminds me of early December.  Modeling at 12z and 18z seemed to be a little more aggressive w/ both the timeline and intensity of the cold.  I just posted above(must have been at almost the exact same time you post this), the transition that the Euro control (notably WARM bias) sees from early Jan to the end of Jan.  What I am looking for is whether the eastern trough can begin establishing around the 5th w/ likely a cutter.  If it can hold, the dam may break and the PNA pops...and we hold a cold pattern for a bit.  If the ridge can hold around the 5th, then we may be kicking the can.  Good signs today.  We will see what tomorrow brings. With models swinging so wildly right now, I have to think more cold is on the way into the Lower 48.  Part of me thinks this is just going to be one of those winters that finds a way to stay cold.  Fingers crossed.  If that pattern holds, you would very likely see multiple bouts of snow.  Is it right?  Time will tell.

[Daniel Boone]

48 minutes ago, Carvers Gap said:

This model waffling reminds me of early December.  Modeling at 12z and 18z seemed to be a little more aggressive w/ both the timeline and intensity of the cold.  I just posted above(must have been at almost the exact same time you post this), the transition that the Euro control (notably WARM bias) sees from early Jan to the end of Jan.  What I am looking for is whether the eastern trough can begin establishing around the 5th w/ likely a cutter.  If it can hold, the dam may break and the PNA pops...and we hold a cold pattern for a bit.  If the ridge can hold around the 5th, then we may be kicking the can.  Good signs today.  We will see what tomorrow brings. With models swinging so wildly right now, I have to think more cold is on the way into the Lower 48.  Part of me thinks this is just going to be one of those winters that finds a way to stay cold.  Fingers crossed.  If that pattern holds, you would very likely see multiple bouts of snow.  Is it right?  Time will tell.

Exactly my thoughts. Going to be crucial what happens that first week. If can begins to be kicked and trough deepens out west, may be same old cycle. 

[Carvers Gap]

1 minute ago, Daniel Boone said:

Exactly my thoughts. Going to be crucial what happens that first week. If can begins to be kicked and trough deepens out west, may be same old cycle. 

Robert, from WxSouth, had an interesting post on FB just a few minutes ago.

[Daniel Boone]

3 minutes ago, Carvers Gap said:

Robert, from WxSouth, had an interesting post on FB just a few minutes ago.

I'll check it out. Hadn't saw much from him in awhile. Robert always was good at pattern recognition. 

[John1122]

I'm a big believer in weather repeating. 

November 1983, wishy washy with very warm and very cold weather. Ended up -.2 here or basically normal. 

November 2022, wishy washy with very warm and very cold weather. Ended up -.5ish here. Or basically normal. 

December 1983. Warm with several days more than +10. Then big cold hit Christmas week. Single digits highs and well below 0 lows but barely any snow to show for it. It warmed to AN by Dec 28th but did get really cold for New Years. 

December 2023, very warm with multiple very above average temperatures. Then of course the extreme cold we've had with most of us not getting a lot of snow. Gonna warm up towards New Years 

 

January 1984 after a cold first couple of days, warmed to AN, peaking at the mid 60s by Jan 10th. Then the bottom fell out. 4 inches of snow on the 11th in an Anafrontal situation. Stayed just BN, which is plenty cold for Mid January, upper 30s and upper 20s. Then another 3 inches of snow fell on the 16th. Stayed cold, 7 inches fell on the 18th and the bottom dropped out on the thermometer. 3 days in a row with -10s for lows and teens for highs. Warmed up on the 23rd and the snow melted off by the 26th. Warm to the end of the month. 

 

February 1984. Mostly warm, but had 4 BN days in a row from the 5th to the 9th and it snowed 7.5 inches and we had a -4 and a -9 low. 

 

March 1984 was cold. Snow fell on 12 different days and there was 2.5 inches on March 22nd. Lows in the 10s 5 different days.  The March 22nd snow was two days after a 76 degree high on the 20th. 

 

So hopefully we can get a similar story to unfold here after a pretty similar late fall and first week of winter of 1983. 

[Daniel Boone]

You were more fortunate irt Snow in , 83-84. Only 1 really good snowfall in the Valley's up this way. That being the one on the January 18th. 6 inches. 

      Feb. was mild overall. Some days above 70. Several dustings and one 2-5" fluffy snowfall. March was rather cold but, once again most snow missed here. The 22nd one had alot of wind, thunder and lightning. It was snow/rain mixed below 2000 ft. 

    

[John1122]

10 minutes ago, Daniel Boone said:

You were more fortunate irt Snow in , 83-84. Only 1 really good snowfall in the Valley's up this way. That being the one on the January 18th. 6 inches. 

      Feb. was mild overall. Some days above 70. Several dustings and one 2-5" fluffy snowfall. March was rather cold but, once again most snow missed here. The 22nd one had alot of wind, thunder and lightning. It was snow/rain mixed below 2000 ft. 

    

I would have never thought you missed out on the 3 Jan events in 1984. I know Tazewell got less snow from each but that they had snow each time out. I think 1 inch in the Anafrontal, and 2 inches the 16th and 6.5 the 18th. 

February was warm overall but the 4 or 5 cold days were extremely cold with a big snow here. 

 

1989 is sort of similar to this time frame as well. Except 1989 had much more cold in December with multiple cold shots. 

That's something I've noticed over the years. We don't often have a single extreme cold shot. If we get an extreme cold shot, which to me us generally days where the high is low 20s or colder and the low is around 0 or less, we tend to get multiple shots of it. 

The last two years were snowy here but lacked any extreme cold imby. I know the western areas got extreme in 2021. 

In 1989 it happened but close together. We had sub zero lows. Went back to near 40 two days later and then another, bigger cold blast happened and extreme cold returned a week after the first. 

So I believe there is a good chance extreme cold returns at some point in winter. 

[Daniel Boone]

37 minutes ago, John1122 said:

I would have never thought you missed out on the 3 Jan events in 1984. I know Tazewell got less snow from each but that they had snow each time out. I think 1 inch in the Anafrontal, and 2 inches the 16th and 6.5 the 18th. 

February was warm overall but the 4 or 5 cold days were extremely cold with a big snow here. 

 

1989 is sort of similar to this time frame as well. Except 1989 had much more cold in December with multiple cold shots. 

That's something I've noticed over the years. We don't often have a single extreme cold shot. If we get an extreme cold shot, which to me us generally days where the high is low 20s or colder and the low is around 0 or less, we tend to get multiple shots of it. 

The last two years were snowy here but lacked any extreme cold imby. I know the western areas got extreme in 2021. 

In 1989 it happened but close together. We had sub zero lows. Went back to near 40 two days later and then another, bigger cold blast happened and extreme cold returned a week after the first. 

So I believe there is a good chance extreme cold returns at some point in winter. 

Yeah, apparently they teterred out as they moved east. Each of those smaller ones were less than an inch here. 

      Yeah, hopefully, we get an extended stretch of cold that has at least a couple decent systems to track through. Cold but not bitter would be great. 

[John1122]

That was the most bizarre storm evolution I've maybe ever seen on a weather model, on the 0z GFS. At one point it's snowing in literally a 360 degree circle around East Tennessee/SWVA and SE KY as this 24 hour snow map shows. The crazy thing is, it raining here, and in Western NC/Northern Georgia but changes to snow there while avoiding pulling cold air into just that small portion of our area and it avoids changing to snow here. It's not even a valley warm nose because Chattanooga changes and gets 3-4 inches while the snowhole continues along I-40/I-81 and into SE Kentucky. It'll be gone by 06, but it's just crazy how wild these model runs can get at times.

[Holston_River_Rambler]

WRT the strat, there have definitely been some signs that it is under stress at the top, but nothing showing a split just yet. 

The mean on the GEFS shows the warming and displacement, but no sign of a split yet:

I think this is tied to what Jason Furtado was tweeting yesterday. Here's the thread if anyone wants to read it:

My take on what he is saying is that as waves at H5 get tossed up to the strat from eastern Siberia they can either be reflected back down over Canada or that can bring warming and weakening to the the SPV from 30mb on up. Much like how the upcoming pattern may or may not play out, we just don't know yet which of the two options is more likely. 

Here's ye olden 3D vortex. You can see some shear at the top from these heat fluxes, but that's about it:

 

 

[Holston_River_Rambler]

3 hours ago, John1122 said:

That was the most bizarre storm evolution I've maybe ever seen on a weather model, on the 0z GFS. At one point it's snowing in literally a 360 degree circle around East Tennessee/SWVA and SE KY as this 24 hour snow map shows. The crazy thing is, it raining here, and in Western NC/Northern Georgia but changes to snow there while avoiding pulling cold air into just that small portion of our area and it avoids changing to snow here. It's not even a valley warm nose because Chattanooga changes and gets 3-4 inches while the snowhole continues along I-40/I-81 and into SE Kentucky. It'll be gone by 06, but it's just crazy how wild these model runs can get at times.

Your storm is still there at 6z John. 

 

If we can get it to pop up for 5 or 6 more runs, that should be money for a nice cutter. This might be your storm Itryatgolf! 

 

To be more serious, the pattern the GFS is showing is conducive for this sort of an outcome, several waves pushing the boundary a bit further south each time at peak climo. 

 

[Carvers Gap]

We continue to track a potential winter storm between the 7th and 10th.  The GFS continues to show a storm during that time range.  Last night, it went full Miller A.  Previously, it has been a ULL moving through after a big storm.  It has been on the GEFS for several days now.  Interestingly, the CMC and Euro have similar evolutions at 0z...but their pattern transition and storm window is 48 hours-ish later.   Notably, the EPS has a storm signal sliding across the Deep South just after the GFS does.  My guess is the GFS/GEFS is too fast.  However, big storms can/do form along cold outbreaks during January.  We are about to enter our best climatology during the second and third weeks of January.   For now, the GFS seems to favor a cutter and then a second storm on its heels which is further east.  My preliminary guess is that storm would again favor middle and western areas of the forum.  As we saw yesterday w/ the clipper, the eastern valley does best when cold is already in place.  But we will see, it is a LONG way out there, and we are going to likely see multiple scenarios on modeling.  

One thing I am noticing is that there is a cluster of runs w/ very weak ridging out west.  That has to be watched as noted above as that produces not so much cold here.  What is interesting is that there is split flow found in most solutions re: how tall that ridge is.  Split flow during January is normally playing w/ house money.  There is also a cluster of solutions w/ a very powerful PNA ridge out West, and produces deep cold here.  My guess is that we continue the same pattern as November.  A period of warmth followed by cold temps - wash, rinse, repeat.

[Carvers Gap]

Just digging through MJO plots this morning.  Most, not all, try to rotate the MJO at low amplitude through the colder phases.  There are cold outliers and very few warm outliers.  That said, the models w/ the worst rotation through the MJO is the colder - GEFS.  IF the MJO plots are correct, one would think some significant corrections to colder are upcoming.  That said, the HB block is a thorn right now in some modeling.  I have beaten that horse for days.  It creates zonal flow.  So, it is possible the MJO is about to lose influence, and we are about to enter a Wild West pattern where multiple teleconnections hold sway and forecasting is difficult.  

Short story:  We are reaching prime climatology.  The MJO is good.  There are flies in the ointment, but when isn't there?  

[Itryatgolf70]

3 hours ago, Carvers Gap said:

Just digging through MJO plots this morning.  Most, not all, try to rotate the MJO at low amplitude through the colder phases.  There are cold outliers and very few warm outliers.  That said, the models w/ the worst rotation through the MJO is the colder - GEFS.  IF the MJO plots are correct, one would think some significant corrections to colder are upcoming.  That said, the HB block is a thorn right now in some modeling.  I have beaten that horse for days.  It creates zonal flow.  So, it is possible the MJO is about to lose influence, and we are about to enter a Wild West pattern where multiple teleconnections hold sway and forecasting is difficult.  

Short story:  We are reaching prime climatology.  The MJO is good.  There are flies in the ointment, but when isn't there?  

Carver, you actually want that HB bock. That is typically a good position for it unless it connects to something we don't want kinda like the -nao connecting to the se ridge when it did at times. We unfortunately didn't get the good benefits out of the -nao being so strong and even west based

[Carvers Gap]

16 minutes ago, Itryatgolf70 said:

Carver, you actually want that HB bock. That is typically a good position for it unless it connects to something we don't want kinda like the -nao connecting to the se ridge when it did at times. We unfortunately didn't get the good benefits out of the -nao being so strong and even west based

Not necessarily.   We had and HB block a few years ago, and maritime air flooded the continent.   They can be really good re: storm track, but we have to have help from the Pacific or temps wash out.   

We got great benefits from the NAO - two snow events and record low temps.  We are just going to have to disagree on that.  I really don't want to go round and round on that anymore.  There really is no disputing its benefits this month.  Again, it doesn't want to snow in the forum area during December no matter what the set-up.  That is the last I will discuss that as it is just beating a dead horse.  The NAO brought near record cold, winter storms, and a great event to track for much of the country from the Rockies to the Apps.