Winter 2021/22 December Thread

[AMZ8990]

Figured it was time to start our monthly winter threads again.  Hope everyone is doing well!  

[Mr. Kevin]

2 hours ago, AMZ8990 said:

Figured it was time to start our monthly winter threads again.  Hope everyone is doing well!  

I think once the pna goes negative, it will warm up for a while. We can always get the -nao to force storms south  but it would take a strong nao/ao combo to allow that to happen. 

[nrgjeff]

Yeah it's time to start the bearish winter thread, haha!

Looks like December will start mild. Perhaps if the MJO wakes up or a Western US ridge pops up, cold can be delivered. GOA and NAO seem to check out after week 2. However Nina climo would favor some sort of cold in December. I have to favor toward Christmas, given this mild 6-15 day forecast. 

Full basin La Nina is a pretty solid signal for a mild back half of winter. Though La Nina is notoriously variable. 

[Carvers Gap]

Yeah, I think Nina climatology wins in this regard....there should be a substantial cold shot at some point during December, and then again during late January.  Agree that winter will be likely be base warm.  Aren't most of them?  The real wild card here is that some second year La Nina's tend to turn cold and hold that look.  So, I am really wary of what I am seeing on LR modeling.  Could just be a warm winter upcoming.  Could be models are wrong in the d10+ which we saw repeatedly last winter, sometimes to our benefit and sometimes not.  The back half of winter, as Jeff notes, should be warm.  However, it seems that analogs have been squirrelly of late.  If in doubt though, roll with the ENSO state.  I still think our chances for winter are on the front end of the season.  That said, this is what makes following wx so much fun and frustrating - predictability is no a given!  I am definitely willing to sacrifice a cold start for cold/winter around Christmas.  MJO is locked in the same 4-5-6 rotation that it has been for several seasons....I think things will improve once this La Nina is over and maybe a chance for an improved SST gradient which has been lacking during the past decade or so.  If December is warm in totality, I am not sold the rest of winter will be warm.  It seems like there are some second year La Nina's which have a decidedly cold Jan/Feb cluster.  Maybe @John1122 would care to comment on that?  

[Icy Hot]

Just a friendly reminder before everyone gets warm winter depression. Winter doesn't begin until December 21. Lets enjoy the current below norm temps and chase a chance of snow Thanksgiving night. 

[John1122]

Follow up Nina's since 1950

Dec 1950 - cold, -6 to -8 in the area. Snow fell on 6-10 days according to your location in the state. 

Jan 1951 AN slightly, but from the Plateau west the end of month had the brutal ice/snow storm that crippled Nashville.

Feb 1951 was around normal to slightly below normal the further west you went, but it was a brutal cold 1st half of the month and very warm back half. February had a -11, -10, and -5 here as well as a -1 and a 4. The back half had some near 70 degree weather.

Dec 1955 was cold, -2 to -4 across the area. Several snowy days before and after Christmas but it hit nearly 70 on Christmas day.

Jan 1956  was cold -4 to -6 across the state. Also snowy. Nice snows happened state wide. Most notable was a 5-8 inch event late month that got everyone except Chattanooga, who only got a trace.

Feb 1956 flipped warm and was +3 to +5.

Dec 1971 had a few cold days but was mostly a torch. +6 to +8

Jan 1972 was slightly cooler but still finished around +2

Feb 1972 was around -1 to -2. The whole winter didn't feature much in the way of cold or snow in the valley areas but the Plateau from here to Crossville picked up around 8-10 inches in February. It was a very wet month with over 9 inches of precip.

Dec 1974 was around -1 and there were several snow events here, the biggest on Dec 1st.  Snow fell on 9 days with 9 inches total. 6 on Dec 1st.

Jan 1975 was overall warm but with some cold days thrown into the mix. Around +4 to +5

Feb 1975 was also warm but with a few colder and snowy days. It was around +2 to +3

We know well how 84-85 went. Slow start in Dec, January was legendary with several shots of record cold and snow for the entire valley. February remained cold and more big snows came around Valentines day. It finally torched late in Feb.

Dec 1999 was near normal here and we pulled off a White Christmas with an inch of snow imby

Jan 2000 had a nice cold and snow shot late month here.

Feb 2000 was AN and not wintery.

2011-12 was not good for winter lovers at all. 

So basically follow up Ninas run the gamut, two of the most incredible winter periods from a cold and wintry precip standpoint, in the history of the state happened during follow ups.  Several were just warm and blah, several were in the middle with warm and cold periods that delivered snow for some and not for others.

[Carvers Gap]

3 hours ago, John1122 said:

Follow up Nina's since 1950

Dec 1950 - cold, -6 to -8 in the area. Snow fell on 6-10 days according to your location in the state. 

Jan 1951 AN slightly, but from the Plateau west the end of month had the brutal ice/snow storm that crippled Nashville.

Feb 1951 was around normal to slightly below normal the further west you went, but it was a brutal cold 1st half of the month and very warm back half. February had a -11, -10, and -5 here as well as a -1 and a 4. The back half had some near 70 degree weather.

Dec 1955 was cold, -2 to -4 across the area. Several snowy days before and after Christmas but it hit nearly 70 on Christmas day.

Jan 1956  was cold -4 to -6 across the state. Also snowy. Nice snows happened state wide. Most notable was a 5-8 inch event late month that got everyone except Chattanooga, who only got a trace.

Feb 1956 flipped warm and was +3 to +5.

Dec 1971 had a few cold days but was mostly a torch. +6 to +8

Jan 1972 was slightly cooler but still finished around +2

Feb 1972 was around -1 to -2. The whole winter didn't feature much in the way of cold or snow in the valley areas but the Plateau from here to Crossville picked up around 8-10 inches in February. It was a very wet month with over 9 inches of precip.

Dec 1974 was around -1 and there were several snow events here, the biggest on Dec 1st.  Snow fell on 9 days with 9 inches total. 6 on Dec 1st.

Jan 1975 was overall warm but with some cold days thrown into the mix. Around +4 to +5

Feb 1975 was also warm but with a few colder and snowy days. It was around +2 to +3

We know well how 84-85 went. Slow start in Dec, January was legendary with several shots of record cold and snow for the entire valley. February remained cold and more big snows came around Valentines day. It finally torched late in Feb.

Dec 1999 was near normal here and we pulled off a White Christmas with an inch of snow imby

Jan 2000 had a nice cold and snow shot late month here.

Feb 2000 was AN and not wintery.

2011-12 was not good for winter lovers at all. 

So basically follow up Ninas run the gamut, two of the most incredible winter periods from a cold and wintry precip standpoint, in the history of the state happened during follow ups.  Several were just warm and blah, several were in the middle with warm and cold periods that delivered snow for some and not for others.

Thanks for the update.  Always great information.

[Carvers Gap]

Ensembles look quite a bit different this morning.  Will take some time later and dig through them later.  There is a full latitude trough showing up on the EPS now.  The GEPS has flipped back to a good solution.  Not sure I trust any solution at this point.  Again, a lot of volatility in LR modeling.  Just looking at this AM's suite, looks like something as moved the needle just a hair back into the cold camp to start December.  Not sure what has changed, but they look a bit different than yesterday.  The 6z GFS is not exactly warm, and even attempts to send a piece of the PV south late in fantasy land.

[Carvers Gap]

GEFS at 6z has the stubborn ridge in the nation's mid-section.  But we are again where the 6z GFS, 0z EPS, and 0z GEPS are showing a sharp cold shot during early December.  Interestingly, the EPS/GEPS combo has almost all of the cold air in the northern hemisphere(in regards to departures) over North America.  That may well be forcing the cold eastward regardless of the SER.  Crazy look.  Been a while since we have seen the major hemispheric cold pool on this side of the planet....no idea if that occurs.  I can say this, if true, models likely don't have that ironed out yet.

[Daniel Boone]

5 hours ago, John1122 said:

Follow up Nina's since 1950

Dec 1950 - cold, -6 to -8 in the area. Snow fell on 6-10 days according to your location in the state. 

Jan 1951 AN slightly, but from the Plateau west the end of month had the brutal ice/snow storm that crippled Nashville.

Feb 1951 was around normal to slightly below normal the further west you went, but it was a brutal cold 1st half of the month and very warm back half. February had a -11, -10, and -5 here as well as a -1 and a 4. The back half had some near 70 degree weather.

Dec 1955 was cold, -2 to -4 across the area. Several snowy days before and after Christmas but it hit nearly 70 on Christmas day.

Jan 1956  was cold -4 to -6 across the state. Also snowy. Nice snows happened state wide. Most notable was a 5-8 inch event late month that got everyone except Chattanooga, who only got a trace.

Feb 1956 flipped warm and was +3 to +5.

Dec 1971 had a few cold days but was mostly a torch. +6 to +8

Jan 1972 was slightly cooler but still finished around +2

Feb 1972 was around -1 to -2. The whole winter didn't feature much in the way of cold or snow in the valley areas but the Plateau from here to Crossville picked up around 8-10 inches in February. It was a very wet month with over 9 inches of precip.

Dec 1974 was around -1 and there were several snow events here, the biggest on Dec 1st.  Snow fell on 9 days with 9 inches total. 6 on Dec 1st.

Jan 1975 was overall warm but with some cold days thrown into the mix. Around +4 to +5

Feb 1975 was also warm but with a few colder and snowy days. It was around +2 to +3

We know well how 84-85 went. Slow start in Dec, January was legendary with several shots of record cold and snow for the entire valley. February remained cold and more big snows came around Valentines day. It finally torched late in Feb.

Dec 1999 was near normal here and we pulled off a White Christmas with an inch of snow imby

Jan 2000 had a nice cold and snow shot late month here.

Feb 2000 was AN and not wintery.

2011-12 was not good for winter lovers at all. 

So basically follow up Ninas run the gamut, two of the most incredible winter periods from a cold and wintry precip standpoint, in the history of the state happened during follow ups.  Several were just warm and blah, several were in the middle with warm and cold periods that delivered snow for some and not for others.

Great info and work John !

     The 71-72 one sticks out to me...There was a major late November Snowstorm here (8 inch). Dec...very small events here. Jan. Mild, basically snowless. Feb., An Alaskan born major cold shot mid Month sparked a major east coast Snowstorm 17-19th. 8" on the 17th here.

   Interesting 500 mb charts on all those Winters and events you presented on Plymouth.

[Carvers Gap]

Indeed, late in the forecast time frame the MJO is shown on American modeling to swing into phase 7 which is cold for NDJ(source is CPC site).  I read in the MA forum that DT had noticed the MJO beginning to move on the Australian site.  So, I made a mental note to check the CPC site to see if there was similar movement.   The GEFS for the past several runs is pulling the eastern ridge back into the southwest.  The 5-day 500 anomaly (d10-15) on the 0z EPS stretches from Juneau to the west slopes of the Apps.  That looks an awful lot like phase 7(even phase 8) of the NDJ MJO.  GEPS has a different look.  The GEFS is trending away from its solutions of the past several days.  Just something to watch.  Huge grains of salt as always.

 

[nrgjeff]

Yeah I'll take the EPS over the GEFS and we'll be right 9/10 times. Euro is markedly colder than the GFS. Can we get a December 2008? Note the large sample size, though it's days not weeks or months. Do not share outside this Region. 

Also the ABNA is somewhat steady with Aleutians Bering Sea ridge, and troughs in China and parts of Eastern North America. ABNA impacts shift a little south compared to summer (Canada) into the USA. ABNA had been reverse in summer, warm in Canada and mild in the Southeast US. Current mirror image Mongolia / Canada (and it does shift around) would be cold Southeast US.

So while I'm bearish winter overall, the 11-15 day overnight flip is more evidence of a volatile pattern in the mid-term. Hopefully @Carvers Gap is right that we could get the December cold and a reload in January - before the January thaw that holds and ushers in that warm Feb.

[Carvers Gap]

1 hour ago, nrgjeff said:

Yeah I'll take the EPS over the GEFS and we'll be right 9/10 times. Euro is markedly colder than the GFS. Can we get a December 2008? Note the large sample size, though it's days not weeks or months. Do not share outside this Region. 

Also the ABNA is somewhat steady with Aleutians Bering Sea ridge, and troughs in China and parts of Eastern North America. ABNA impacts shift a little south compared to summer (Canada) into the USA. ABNA had been reverse in summer, warm in Canada and mild in the Southeast US. Current mirror image Mongolia / Canada (and it does shift around) would be cold Southeast US.

So while I'm bearish winter overall, the 11-15 day overnight flip is more evidence of a volatile pattern in the mid-term. Hopefully @Carvers Gap is right that we could get the December cold and a reload in January - before the January thaw that holds and ushers in that warm Feb.

Thanks for the great post!  I think this winter will be potentially super similar to last winter.  Base warm, but with some cold shots embedded - maybe severely cold at times due to the QBO flip from late summer.  Right now, I am just super wary of model output.   I think La Nina lends itself to cold which arrives abruptly and leaves abruptly.  Total crapshoot on timing, but generally December has better odds.  All of that is based on the ENSO state.  Seems like the last few winters have had modeling show cold barreling into the East at d10-15 only to have favored areas in the northern Rockies get the lion's share.  That may be what the EPS is indeed doing again.  IDK.   However, given that December "should" have some cold, have to think the actual solution is probably somewhere in between the Euro and American suites - warm interludes w/ AN heights with 3-4 day cold shots arriving regularly.  In other words, the pattern is one where a southwest ridge pops and sends cold eastward.   Once the trough in the east exits, the ridge rolls forward.  So, maybe a blend of the two gets us to something which works?  Best case is a full NA trough.  Been a long time since we have seen that.  Have a great Thanksgiving, man! 

[Mr. Kevin]

5 hours ago, Carvers Gap said:

Thanks for the great post!  I think this winter will be potentially super similar to last winter.  Base warm, but with some cold shots embedded - maybe severely cold at times due to the QBO flip from late summer.  Right now, I am just super wary of model output.   I think La Nina lends itself to cold which arrives abruptly and leaves abruptly.  Total crapshoot on timing, but generally December has better odds.  All of that is based on the ENSO state.  Seems like the last few winters have had modeling show cold barreling into the East at d10-15 only to have favored areas in the northern Rockies get the lion's share.  That may be what the EPS is indeed doing again.  IDK.   However, given that December "should" have some cold, have to think the actual solution is probably somewhere in between the Euro and American suites - warm interludes w/ AN heights with 3-4 day cold shots arriving regularly.  In other words, the pattern is one where a southwest ridge pops and sends cold eastward.   Once the trough in the east exits, the ridge rolls forward.  So, maybe a blend of the two gets us to something which works?  Best case is a full NA trough.  Been a long time since we have seen that.  Have a great Thanksgiving, man! 

I heard the afternoon models were colder also. Maybe a blip? Guess we will find out. 

[Carvers Gap]

3 hours ago, Mr. Kevin said:

I heard the afternoon models were colder also. Maybe a blip? Guess we will find out. 

18z GEFS was super warm.  We better hope the EPS hangs on!!!!

[Mr. Kevin]

1 minute ago, Carvers Gap said:

18z GEFS was super warm.  We better hope the EPS hangs on!!!!

Euro and eps havent been doing as good as years ago unfortunately. Gfs is somewhat better with many updates it's had. Hopefully we can get into a pattern for cold and storminess eventually this winter

[Holston_River_Rambler]

I don't quite feel like this winter has, as Carvers would say, "shown its hand" yet. To be fair, it is November 24 though.  There just isn't anything that has jumped out to me as a death knell or a reason to be very excited. There have been things that have looked horrible in the medium to long range (Pac configuration) or awesome, (-NAO), but neither has turned out to be a deal breaker or maker in the short range. 

Currently, both OP models have some things of interest in the medium to long range:

Euro Pac jet looks interesting:

 

500 mb on GFS looks interesting in the AO region:

 

There are some interesting things on the GFS's OP longish range (10 -15 day) tropical forecast that are reflected on some EPS members, but not sure how much stock to put in them at this time. 

 

 

No Isotherm outlook yet either. He suggested in his critique of his own work that he would have benefited from waiting until the end of November last year, so maybe that's what he is doing.  

[nrgjeff]

Here's another bullish take for our region, but the national picture if flipped compared to my previous teleconnection mixer. I trust we have no commercial lurkers here. Please do not share outside this sub-forum. Happy Thanksgiving!

[Carvers Gap]

Happy Thanksgiving, everyone!

Welp, it looks like the Euro and GFS have sort of met in the middle.  Interesting points....It is waaaay out there, but some hints at a major trough amplification over the east between d8-10.  This time of year, trough amplifications have to be watched as the GOM could fuel sever and/or winter activity.  Looks like modeling is beginning to converge on the time frame of Dec 10-20 as a time of warmth.  This does not surprise me as much of November has been below normal, and we are due a break in the below normal pattern.  Euro Weeklies, after the 20th go into a pattern where there are cold swings and warmth in equal doses.  Again, would not surprise me to see some extreme temps in terms of cold this winter.  Maybe the timeframe from Dec 20-Jan10 has some potential for that?  But hey, let's not rule out the potential amplification in the 9-10 day timeframe.  HUGE grains of salt!!!  

[Daniel Boone]

1 hour ago, Carvers Gap said:

Happy Thanksgiving, everyone!

Welp, it looks like the Euro and GFS have sort of met in the middle.  Interesting points....It is waaaay out there, but some hints at a major trough amplification over the east between d8-10.  This time of year, trough amplifications have to be watched as the GOM could fuel sever and/or winter activity.  Looks like modeling is beginning to converge on the time frame of Dec 10-20 as a time of warmth.  This does not surprise me as much of November has been below normal, and we are due a break in the below normal pattern.  Euro Weeklies, after the 20th go into a pattern where there are cold swings and warmth in equal doses.  Again, would not surprise me to see some extreme temps in terms of cold this winter.  Maybe the timeframe from Dec 20-Jan10 has some potential for that?  But hey, let's not rule out the potential amplification in the 9-10 day timeframe.  HUGE grains of salt!!!  

Happy Thanksgiving!

     Sounds like a probable occurrence this Winter as I think blocking will be prevalent and that in combination with La nina and -PDO should result in swings.

[Mr. Kevin]

1 hour ago, Carvers Gap said:

Happy Thanksgiving, everyone!

Welp, it looks like the Euro and GFS have sort of met in the middle.  Interesting points....It is waaaay out there, but some hints at a major trough amplification over the east between d8-10.  This time of year, trough amplifications have to be watched as the GOM could fuel sever and/or winter activity.  Looks like modeling is beginning to converge on the time frame of Dec 10-20 as a time of warmth.  This does not surprise me as much of November has been below normal, and we are due a break in the below normal pattern.  Euro Weeklies, after the 20th go into a pattern where there are cold swings and warmth in equal doses.  Again, would not surprise me to see some extreme temps in terms of cold this winter.  Maybe the timeframe from Dec 20-Jan10 has some potential for that?  But hey, let's not rule out the potential amplification in the 9-10 day timeframe.  HUGE grains of salt!!!  

The thing I'm concerned about is if niñas are mostly front loaded, and dont get a cold pattern early on, will we get in one at all this winter? I always like to get a winter storm early in case it gets warm and stays that way all winter 

[John1122]

42 minutes ago, Mr. Kevin said:

The thing I'm concerned about is if niñas are mostly front loaded, and dont get a cold pattern early on, will we get in one at all this winter? I always like to get a winter storm early in case it gets warm and stays that way all winter 

Looking back at Ninas I've not found a pattern to suggest they are front loaded in our region. They cluster about equally with cold/wintry periods from Dec 1st to February 20th over the course of the last 70 years that had a Nina. About 2/3rds of them feature cold and wintry outbreaks and about half of those have long (10 days or longer) severe winter outbreaks. About 1/3rd are wall to wall warm, those tend to be stronger Ninas. 

[Mr. Kevin]

12 minutes ago, John1122 said:

Looking back at Ninas I've not found a pattern to suggest they are front loaded in our region. They cluster about equally with cold/wintry periods from Dec 1st to February 20th over the course of the last 70 years that had a Nina. About 2/3rds of them feature cold and wintry outbreaks and about half of those have long (10 days or longer) severe winter outbreaks. About 1/3rd are wall to wall warm, those tend to be stronger Ninas. 

2011-12 winter is always a concern with such a +epo currently and hideous Pacific 

[Daniel Boone]

23 minutes ago, Mr. Kevin said:

2011-12 winter is always a concern with such a +epo currently and hideous Pacific 

1 in a bunch. Yes, a possibility but, not likely, imo. Qbo blocking and odds are against it.

[Carvers Gap]

11 hours ago, Mr. Kevin said:

2011-12 winter is always a concern with such a +epo currently and hideous Pacific 

I like analogs, but they are fickle companions.  Lot of ground to cover before I would be willing to mail it in this winter(especially since it hasn't started).  There is always the risk of non-winters.  Generally, strong El Nino's and strong La Nina's are notorious for those.  The late 90s were terrible with the exception of a couple of monster snows.  Lots of variables still to sort out right now as I am not sure the base winter pattern has shown itself yet.  There are always good and bad exceptions to the rule.  It is a good sign that November will likely end-up BN.  I have generally found that record setting cold shows-up IMBY during weak La Ninas.  It is often followed by a break for spring or an extended thaw.  Of note, the GFS(the model that was warm for so long) is spitting out some 1040+ highs in early December.  The 18z run was extreme in terms of trough amplification - single digits and low teens showing up between Dec 5-7 and highs below freezing IMBY.   I like the GFS when it begins to hint at those types of events.  It is definitely not always right nor is the timing always exacting....but, it does sometimes sniff out those types of events.  12z Euro had it as well.  I suspect we will see those features come and go on modeling.  If the frequency increases on modeling, it will have my attention.

[Carvers Gap]

Today's MJO from the CPC shows some modeling which takes it into phase 7 after a bout with phase 6.  Let's see if we can take a run through the cold phases.  If that MJO look is legit, modeling should begin to reflect that.  Lots of plates to juggle right now in regards to getting something out there that makes sense regarding December/early January ideas.

[John1122]

It didn't work out for us last time we had a cold November but it has a very good shot in our region. I looked at all those Novembers a few years ago and came up with a pretty good idea about the relationship. I've since found this map that shows a moderate Correlation between November and winter temps for most of our area.

 

No correlations are 100 percent and they can blow up in our faces from time to time but here are the QBO trends. It was -19 for October, down from -16 in September. It normally falls for about 12-15 months in a row and peaks downward around -26 to -28. Here are the QBO stats in weak Nina years and in years where it was falling through winter, and years where it was below -15 for the winter. We are in A on the bottom chart and hopefully we can remain there with the drop continuing. It should based on past history. October was the 5th month in a row it fell. In 2009-10 it actually blipped up a little from September into October but then it started falling again into winter and we had a nice winter. It was falling in 1993-94 and January 1994 was very cold. It was falling in winter 1995-96 which is an all time great winter here. It was falling in 2014-15 which was a brutal winter in the area too. The 2014-15 winter is the only one where we've timed it right to be falling to below -20 in January and February since 1979 when CPC has records for it. The bottom map is Jan-Feb of 2015. Maybe, if we are lucky, it will do it again this year. 

[Carvers Gap]

May be worth beginning to consider Dec 5-10 as a potential window for the first accumulating snows for someone in the forum area.  

[Carvers Gap]

The 12z operationals for the Euro, GFS, and CMC all show potential in the d8-10 range.  This is an amplification that was missed by the GEFS if I remember correctly.  Now obviously, at this range no model run is right or wrong.  The 12z Euro has a 1-2 punch late in its run.  Way out there, but something to consider.

[Carvers Gap]

Bit of a suppressed storm track on the 12z suite of models.