December 2018 Pattern And Forecast Discussion

[John1122]

Interested to see if we can squeeze a storm with potential in the brief overlapping forecast -NAO/+PNA combo the ens forecast shows. Outside of that, we look to stay chilly for the next couple of weeks. We are easily in the window where snow can fall here with the proper track in early December. Getting that track seems to be an issue, as models generally forecast a parade of cutters in the near term. If the Euro is to be believed we could have a severe event in the day 8-10 time frame rather than any snow.

 

[Holston_River_Rambler]

 

@Daniel Boone here is December 1977: https://imgur.com/a/ukZ1bNJ  

Went ahead and threw in a storm from mid Jan. 78, since it was so close 

[Carvers Gap]

High winds predicted in the mountains tomorrow with decent gusts in the valleys. 

As for the LR, nothing really new to report.  I will add that the models have the cold in early December...a bit delayed and no surprise as the "delay" has been a trend for years on LR models.  I do wonder about the staying power of the trough over the AK(per wxusaf in the MA thread) that is depicted in LR forecasts.  While it is not unusual for Dec to be slightly warmer than normal during Nino years(w some notable cold Decembers as well), I am not sure that I buy that depiction.  Having a trough stuck there goes against the atmospheric weather pattern during analogous Nino years unless I am mistaken.  So, while I lean on the slightly warm side(that is my seasonal "forecast" which I don't change) for December...I am not sure that is how it gets done(meaning warm).  I still like a backloaded winter from mid-January to early March.  It certainly would be nice to score some snow IMBY before January...but my confidence would be considered average at best for snow before Christmas or even below.  I do think we deal with Pacific air this winter as that seems to accompany most Nino winters.  How much is debatable. I think we will see some in December....again, how much is debatable.  So right now, a ton of question marks as we enter December regarding higher latitude atmospheric patterns.  For now, it seems like the pattern is base cold...and I have a tough time seeing that broken for long periods of time.  Tomorrow's Weeklies will be interesting.  If they go full bore warm after week 2 of December, might be time to look into what is driving that as there could be implications going into January.  That said, the Weeklies are notorious for missing cold(though they did nail the December/Jan cold last year and the early spring cold).  So really, nothing new at this point as most of that is a total rehash.   Most years, I am not even looking at wx models this early for snow.  Truly, we are still about four weeks out from the window being "dependable" from a climatology perspective, though within a couple of weeks the window opens slightly.  Anything prior to New Year's is always a bonus in my book.

addendum:  A few thing that I remember doubt Nino winters.  Many of them just have these cold and cloudy and rainy days.  Often the cold air is not optimal, but the weather is just soggy.  Some years, things connect and we get plenty of snow.  Others, it feels like Seattle or London.  

[jaxjagman]

We're in a wind advisory.The winds have been pretty good with some gust around 30mph.The cold front is still just getting into West Tn off of RAOBS AT 9 PM right now.They should get howling here in a few hours

[Carvers Gap]

Just for kicks and giggles as they are way out there and likely not anywhere close to being right...both the FV3 and GFS at 12z do show some chances for snow next week.  No way am I buying that at this time...but worth a mention as the cold shot that may come in early December is pretty stout.

[Carvers Gap]

Seems there are a several waves and a few take the low road.  I think the details are likely wrong...but the idea that we have waves of slp pressed further south is not without precedent and would be expected with that type of cold and pattern.  Absolutely not calling for a winter storm, but there is a weak signal on the American suite at 12z.  Looks very much like a repeat of the pattern that brought snow to western Tennessee.  I think the number of storms will make it unlikely that weather models will nail this down anytime soon.  Mentioning next week as another potential window...that is all.  And windows of opportunity do not equal storms.

[tnweathernut]

10 minutes ago, Carvers Gap said:

Seems there are a several waves and a few take the low road.  I think the details are likely wrong...but the idea that we have waves of slp pressed further south is not without precedent and would be expected with that type of cold and pattern.  Absolutely not calling for a winter storm, but there is a weak signal on the American suite at 12z.  Looks very much like a repeat of the pattern that brought snow to western Tennessee.  I think the number of storms will make it unlikely that weather models will nail this down anytime soon.  Mentioning next week as another potential window...that is all.  And windows of opportunity do not equal storms.

Good post and I agree.  With so many shortwaves involved the modeling will likely be much less reliable anyway.  Prudent to point out an early season window of opportunity, IMO.

[John1122]

If you look at the reanalysis animations Holston posted last week, of Decembers past, you'll see some memorable snow events on one or two of them.  They often took essentially the same exact path the storm on the GFS takes from 222-234.  To say the least, it's likely to change a million times, but I'd take the path from near Panama, to near Charleston to over Eastern NC every time. I believe there'd be more snow than the GFS puts down with that path. I know there would be if it were December 20th instead of December 5th.

[Carvers Gap]

Even the Euro is showing a suppressed wave around d7 followed by an prolonged upslope event.  Again, the details are iffy.  However, the way that trough looks on the 12z suite is suitable for winter events.  That will likely change with each run.  The biggest thing to watch is whether threats continue to pop.

@John1122, I am going to have to go back and re-read the thread.  LOL.  I will go check out Holston's posts.  I am just now getting tuned back in after chilling last week.

[Holston_River_Rambler]

After watching all these December patterns, I think the thing we need in the pattern we're in now for any chance at all is a big old ridge somewhere in the west to force energy beneath us toward the Gulf. I don't think sliders or overrunning or clippers or -NAOs are going to get it done in the split flow, fast Pac. pattern we're in. (Not saying anyone is saying that they will, just trying to point out how the pattern could work in our favor this time of year). Sure enough a big ridge is there at around 200 hours on the GEFS and GEPS. And the 0z EPS (and 12z Euro at 192), to quote Bob Ross, has an "almighty" one. Of course it still has to be there when we get to 200 hours in the future and we have to have energy to ride down that ridge and it has to be timed right, but without the steep ridge to aim it south and east, the energy will always cut to our west and north. I don't think suppression is a worry here since there is so much evidence things want to cut. They are cutting all over the place on the models, but they are still cutting. It all depends on the initial trajectory and where the cut happens. Get it to the Gulf, and then let it move NE. The further south we can get the energy, the better for us. Look at the N. Hemisphere 12z Euro at 500mb height anomalies at hour 192. If the Atlantic ridge was flexing a little bit more, that would sharpen the trough and help energy bottom out before it cut.  NW trend? What causes that usually? Stronger SE/ Atlantic ridging. 192 hours is only Dec 4 after all. 

Am I saying there is going to be something? Am I saying any of this will happen? Not at all. Just my two cents on what sorts of things we need with what we've got right now. 192 hours is a lot of time for ifs, maybes, and buts. 

Now watch me have to eat all this when the coastal plain or deep south gets a storm. It's there on 12z GEFS ensemble member 16. 

[John1122]

Looks like the Euro has a clipper system in the same time frame that the GFS has the gulf system. Lots of time to go, but both models are at least showing somewhat favorable temperatures for snow to fall in parts of the valley, GFS scenario favors the Plateau and west for now (though I think it'd be good for all of us) and the Euro is Plateau and East, above 40 for the most part, as clippers tend to favor those areas.

[AMZ8990]

35 minutes ago, John1122 said:

Looks like the Euro has a clipper system in the same time frame that the GFS has the gulf system. Lots of time to go, but both models are at least showing somewhat favorable temperatures for snow to fall in parts of the valley, GFS scenario favors the Plateau and west for now (though I think it'd be good for all of us) and the Euro is Plateau and East, above 40 for the most part, as clippers tend to favor those areas.

Nice to have possibilities for sure.  Definitely looks like cold air could be in place next week!

[Carvers Gap]

Regarding week 3:  Interesting to see both the 12z Euro and GEFS with a huge NA ridge and very BN heights over AK.  I still think that "should" be fairly short-lived given the ENSO state, but sometimes the weather does exactly what we think it should do.  Will it be a muted warm-up or relaxation similar to the "miss" by the Weeklies or are the two models now right?  Not sure...but they are fairly adamant now w that big ridge.  The "bad" thing about that ridge is that it will scour Canada of any cold air and force Canada to reload so to speak.  That is a major Chinook.  Now, let's see if it moves forward in time.  Last time, it was delayed, delayed, delayed...until it went poof.  Sure, it would likely make my December call look pretty good of slightly AN.  But those are doing to be some serious negative departures during week two that will have to be erased.  Still, this fits Nino climatology like a glove.  Zonal winds and chinooks are the real deal during those winters in many cases.  And I have said often that warm-ups during recent winters have been really warm which is why I have trouble going w BN temps for any winter now.  Honestly, I get a bit grouchy about warm weather over Christmas.  I get that it doesn't snow often around Christmas...but AN temps is not my favorite at that time of the year.  

Anyway, some seasonal to well BN cold before any of that is even on the medium range....and maybe a window of opportunity next week.  Just wanted to give a heads up that some changes may occur after the next cold snap.  Nothing a given yet.  If the mid-Dec warmup goes "poof," we may be in business all winter.

[Carvers Gap]

Euro Weeklies skinny....warm from mid December through the first week of January w increasing variability in that time frame.  We have seen this warm signal before.  No idea if it is right...but as a lover of winter, I am not a fan.  It would likely make my December idea correct.  I will let you in on a secret...I really want my December idea to bust(meaning it is cold).  Again, it does fit Nino climatology.  Nothing in that run says that winter is not coming...just looks backloaded.  And as last time, the end of the run looks pretty good around the second week of January.  I still question the run though...there is blocking in areas that don't really align w the Pacific ENSO set-up.  One nice caveat...it does get show some potential around Christmas...big grain of salt though!  This is a good test.  With the seasonal change almost behind us, the Weeklies should dial in.  If they whiff on this warm-up, not sure they can be depended upon this winter.  No knock on the model....just seems the Euro can struggle during cold patterns.  My gut says a warm-up is probably right....but I was not correct about November.  Hope I go 0-2!

Update:  Go check out the New England discussion about it.  Basically, the Euro Weeklies have officially flipped warm after mid Dec.  MUCH discussion about the length of the warm-up if it is even right.  Seems like a lot of discussion is that we do not want that pattern to get established as it is the type of look that can lock in because it is stable when it does.  We need it to be transient.  Still...it fooled me once....so gonna have to see it to believe it.

[Holston_River_Rambler]

I love that the NE folks have a name for the +EPO (giant upper low in Gulf of Alaska): the one eyed pig (took me a while to figure out what they were talking about, explaining it here for readers who may not know, so they don't have to, like me, spend a day trying to figure it out). I do not like that possible pattern, though it does make me want BBQ. 

I'm with you on this...I think. A lot of the discussion there (and elsewhere) has been:

 

Poster 1: "Oh God, it's the one eyed pig.!.!" 

Poster 2: "Weren't these the same weeklies showing wall-to-wall cold a week or two ago?"

Poster 3: "Probably need to take it seriously since it is a possibility, but with a grain of salt, since it is 12-15 days out"

 

Seems like a lot of handwringing over possibilities. I was 100% guilty of that over the holiday weekend.  Yes, the pattern is showing up on the EPS and GEFS and GEPS. Let's say worse case scenario, it verifies for 30 - 45 days. I'd rather have it now than later.  Other scenarios: it verifies in a slightly different way; it verifies after a nice storm in the east that tides people over; it verifies, but for a short period of time and somehow contributes to a better pattern evolution in the long run; it never fully materializes. Maybe I'm being too optimistic. 

When this pattern first started popping up over the holiday weekend, Isotherm offered an update to his Winter forecast that basically said: this was expected as part of the seasonal transition (hope I'm not misrepresenting that), keep calm and carry on. Crankywx on the twitterwebs has also been advertising a step down as part of the transition to winter that would feature a relax toward week one or two of December, although now he seems bent on trolling people on Twitter who hyped the -NAO/ Modoki as an intro to a new ice age.

I think that you're right Carvers in your assessment. We are in a cooler than normal and wetter than normal base state and that will have its say before its over. Jeff has also nailed the overall pattern over the past few months: cool and wet, relax and dry (hope I'm not misrepresenting either of y'alls thoughts). I think we relax after/around the 8-10th or so and this is what the weeklies are picking up on, and then (I hope) we step down  and start to see how things will develop after that.  I know, still wringing my hands a bit. It's been a long time since 2014/ 15 in Knoxville. 

I'm also interested in ENSO assessment for the pattern going forward. I've seen some different assessments today that show different interpretations of anomaly levels for the Nino regions and different assessments of the significance/ endurance of those anomalies (compare 40/70's take to Raindancewx's on page 22 on the El Nino 2018-19 on the Weather Forecasting and Discussion section of the larger forum). I've not usually paid much attention to ENSO other than the base state, but reading up on the current conditions and different people's perceptions of them, it makes me think that there is more variability in global pattern results than the usual "El = this" or "La = that" accounts for. 

 . 

[Holston_River_Rambler]

The GFS is getting fiesty with the SPV in its long range: https://imgur.com/a/J7bgOS3.

See also:

 

[Carvers Gap]

2 hours ago, Holston_River_Rambler said:

The GFS is getting fiesty with the SPV in its long range: https://imgur.com/a/J7bgOS3.

See also:

 

Good share.  Now(edit), I am not saying it is going to split.  I don't think I have read anything on that...However, it getting dislodged is a possibility.  Now, something to think about was the massive WAR (Western Atlantic Ridge) that we saw late last winter that preceded the split.  If we see that NA ridge roll through and hook-up w the Atlantic ridge...then maybe that is something to keep an eye on.  All of that would fit with the timing on the Euro with winter taking a break during mid-December and returning in mid-January.  I think it was Roger Smith who has something similar on his winter forecast...big warm-up followed by winter.  Again, that is all speculation on my part.  Prior to all of that, plenty of cold.  A bird in the hand is worth two in the bush...maybe that applies here.

And remember the big ridge that was supposed to be here this week that was on the EPS and Weeklies...well, I have a dusting of snow right smack in the middle of that timeframe.  I do think a difference here is that the GEFS is also showing something similar in the LR.  I am not sure(could be wrong) that the GEFS ever really bought into the pseudo warm-up for this week.  Now, we will see some warm...but nothing like original modeled.  However, the counter to that...a warm December fits Nino climatology.   Plenty in play here.  I will lean warm for the time frame from Dec 10ish-end of the month, but not totally bought in to that yet.

[Carvers Gap]

9 hours ago, Holston_River_Rambler said:

I love that the NE folks have a name for the +EPO (giant upper low in Gulf of Alaska): the one eyed pig (took me a while to figure out what they were talking about, explaining it here for readers who may not know, so they don't have to, like me, spend a day trying to figure it out). I do not like that possible pattern, though it does make me want BBQ. 

I'm with you on this...I think. A lot of the discussion there (and elsewhere) has been:

 

Poster 1: "Oh God, it's the one eyed pig.!.!" 

Poster 2: "Weren't these the same weeklies showing wall-to-wall cold a week or two ago?"

Poster 3: "Probably need to take it seriously since it is a possibility, but with a grain of salt, since it is 12-15 days out"

 

Seems like a lot of handwringing over possibilities. I was 100% guilty of that over the holiday weekend.  Yes, the pattern is showing up on the EPS and GEFS and GEPS. Let's say worse case scenario, it verifies for 30 - 45 days. I'd rather have it now than later.  Other scenarios: it verifies in a slightly different way; it verifies after a nice storm in the east that tides people over; it verifies, but for a short period of time and somehow contributes to a better pattern evolution in the long run; it never fully materializes. Maybe I'm being too optimistic. 

When this pattern first started popping up over the holiday weekend, Isotherm offered an update to his Winter forecast that basically said: this was expected as part of the seasonal transition (hope I'm not misrepresenting that), keep calm and carry on. Crankywx on the twitterwebs has also been advertising a step down as part of the transition to winter that would feature a relax toward week one or two of December, although now he seems bent on trolling people on Twitter who hyped the -NAO/ Modoki as an intro to a new ice age.

I think that you're right Carvers in your assessment. We are in a cooler than normal and wetter than normal base state and that will have its say before its over. Jeff has also nailed the overall pattern over the past few months: cool and wet, relax and dry (hope I'm not misrepresenting either of y'alls thoughts). I think we relax after/around the 8-10th or so and this is what the weeklies are picking up on, and then (I hope) we step down  and start to see how things will develop after that.  I know, still wringing my hands a bit. It's been a long time since 2014/ 15 in Knoxville. 

I'm also interested in ENSO assessment for the pattern going forward. I've seen some different assessments today that show different interpretations of anomaly levels for the Nino regions and different assessments of the significance/ endurance of those anomalies (compare 40/70's take to Raindancewx's on page 22 on the El Nino 2018-19 on the Weather Forecasting and Discussion section of the larger forum). I've not usually paid much attention to ENSO other than the base state, but reading up on the current conditions and different people's perceptions of them, it makes me think that there is more variability in global pattern results than the usual "El = this" or "La = that" accounts for. 

 . 

Coastal, a red tagger, has some very good comments.  But yeah, just wanted to point out that others were seeing similar things in terms of a potential warm-up.  I always read other forums just to get different perspectives.  Sometimes, like most folks, I can get locked-in in to an idea...so I like to read what other folks are saying. 

[Holston_River_Rambler]

Sorry if what I wrote came out wrong.  I apologize if it did. I ramble too much sometimes. That whole post was basically me saying, I think your original idea was right. The whole reason I brought in the NE stuff the way I did was that I was reading it too (probably to an unhealthy level) over the weekend and when their "pig" started to show, I started think, uh oh... I also thought the way they call it a pig was funny. 

To me their consensus now is that hopefully it doesn't linger and I wholeheartedly endorse that sentiment. 

I'm starting to think we may break even in December (0 on temp anomalies), so your warm up may be right. Hard to argue with some sort of-EPO showing up for at least a bit and as I mentioned, Isotherm seems to think its all part of interseasonal forcing. I think the more important thing is what the long range starts to look like once that gets established. 

Also, if I came off as saying you were arguing for a Strat PV split, I apologize. Ever since I saw the Ventrice tweet (somewhere in one of our recent threads) I've been watching the GFS strat on Tropical Tidbits and maaaaan did it look different today and wanted to share this AM. Still way out there but I can't say I wouldn't love a split and warming similar to what we had last Feb, but this time in Dec! 

 

[Carvers Gap]

3 hours ago, Holston_River_Rambler said:

Sorry if what I wrote came out wrong.  I apologize if it did. I ramble too much sometimes. That whole post was basically me saying, I think your original idea was right. The whole reason I brought in the NE stuff the way I did was that I was reading it too (probably to an unhealthy level) over the weekend and when their "pig" started to show, I started think, uh oh... I also thought the way they call it a pig was funny. 

To me their consensus now is that hopefully it doesn't linger and I wholeheartedly endorse that sentiment. 

I'm starting to think we may break even in December (0 on temp anomalies), so your warm up may be right. Hard to argue with some sort of-EPO showing up for at least a bit and as I mentioned, Isotherm seems to think its all part of interseasonal forcing. I think the more important thing is what the long range starts to look like once that gets established. 

Also, if I came off as saying you were arguing for a Strat PV split, I apologize. Ever since I saw the Ventrice tweet (somewhere in one of our recent threads) I've been watching the GFS strat on Tropical Tidbits and maaaaan did it look different today and wanted to share this AM. Still way out there but I can't say I wouldn't love a split and warming similar to what we had last Feb, but this time in Dec! 

 

Nah, didn't take it that way in the least.  That first post had a typo in response to the tweet...should have been "now" and not "no."  

Also, was a good share.  I didn't read anything as negative and would have been fine if it was.  Sometimes written words just get in the way!  LOL.

 

[John1122]

Looking back on the Decembers following the 10 coldest Novembers over the last 60 - 70 years. 7 of the 10 of these years were 7 of the snowiest winters in my area.

2014 - December was a month long warm fest that finished about +4 AN. The lowest temp in the entire month was 22 degrees. The coldest day was the 31st when the big cold front/severe event moved through and ushered in a frigid January start.

1997 - December finished at -1.4 with another month of up and down temps. 1st week warm, second week cold, third week warm, final 5 days of the month were cold. The warmth was muted and the highest temp was only 60 but it was never rock bottom cold either, lowest temp was 10. Was mostly a dry month with about 50 percent of normal precip.

1995 - December ended at -2.5 as temps rode the roller coaster. There was a big warm up during the 1st 6 days of the month with temps in the upper 60s. The bottom fell out and there was a 24-3 degree day in the middle of a 7th-13th cold snap. After that the roller coaster went back up, with a 69-55 degree day by the 15th. It stayed above normal until the 20th and the coaster went back down again. Spent the 20th - 28th mostly below freezing, had a white Christmas from snow showers that fell every day from the 23rd-27th.

1996 - December ended at +2.6 with more wild temp swings. Had a low of 18 on December 9th and it was in the 60s on the 10th. 18th-20th were cold and snowy with temps in the lower 20s for highs. It was in the upper 50s by the 23rd. Final week of the month was in the upper 60s and pushed it from a BN month to an AN month.

1976 - December was a roller coaster this month too. It finished at -4 even with the yo-yo temps. There were stretches of +10-14 AN weather and stretches of -20 BN weather. Snow fell on multiple days.

1969 - December started cold and stayed that way until the end of the month. Finishing at -6 degrees. Snow fell multiple days of the month with a big time White Christmas storm.

1967 - December was another warm one, +3.5 degrees. Warm most of the month and then it turned cold around Christmas with several inches of snow falling the day after Christmas into the 27th.

1959 - December was  mostly steadily near normal with a couple of spikes up and down,  it finished at +1.5 for the month. The coldest temp for the month was 17 and the warmest was 62 and they both happened in the first week of the month. The 17 happened due to 5 inches of snow falling the day before. That was the only snow event for the month, the rest of the month was mostly mild to normal and very wet. Almost 8 inches of rain for the month.

1955 -  December was -2.5 in another roller coaster of a month. Temps were all over the place with a -10 from normal day and a +15 in the first 3 days of the month. It bounced around then got cold through the middle of the month. By Christmas it warmed up and was in the upper 60s on Christmas eve and Christmas day. By New Year eve there was snow on the ground and the high was in the 30s with a low of 10.

1954 - December came in at -3.5 in a month where the cold was never extreme, merely steadily cold most of the month. Lowest low was 13 degrees. There were 7 days with lows in the 10s and 11 with highs in the 30s. Very wet month,  almost 10 inches of snow fell and almost 10 inches of rain fell. 

 

 

[nrgjeff]

Keep calm, and listen to that chain as the roller coaster takes the cars up the hill. Guess that is not really a calming sound, lol!

Anyway I'm going roller coaster December. I do not believe 4 weeks of torch. First it looks warm this weekend. Next week cold should verify. Transition timing is up in the air even more after 12Z runs, but it'll get cold next week. Fewer Deep South lows are shown, little disappointing, but we have discussed December is generally not our month for snow anyway. 

Middle of December looks warm for a couple reasons. Cold dropping into the West is a SER signal. We have a Kelvin wave trying to come out into a warm zone. Ensembles and weeklies pick up on the warm signal.

Now I doubt the warm will last as long as weeklies predict. Yet another dateline flare-up is starting; and, it could be a cool signal. If it becomes another tropical storm or typhoon, it would strengthen the cold signal here. This late in the season the tropical cyclone does not need to be strong. Just needs to merge up with the jet stream off Asia. Two have done so ahead of and during current cold.

Back to the weeklies, though majority warm, they have cold clusters starting as early as before Christmas. Cold clusters increase (still minority) Christmas week. I would not be surprised if the cold clusters become majority Christmas week. Then, the trend would be a friend.

Will December overall verify AN or BN temps? Looks variable averaging near normal first 3 full weeks. That last week starting around Christmas may determine the outcome. Regardless, plenty of cold Oct/Novie and warm December have been cold Jan/Feb. This snow lover has no concerns attm.

UPDATE: Forgot to mention, I love the one-eyed pig. Huge LOL!

[Carvers Gap]

I don't get too worked up about warmth during winter anymore...I know pretty much it is going to happen most winters due to latitude.  Most Nino winters have warmth, especially early.  It is important to note that it is not even winter yet, but it might as well be.  Here are a few evening thoughts:

1.  I have from the beginning thought this winter has been hyped a bit too much(not by anyone in our subform...or even the forum's other major contributors and/or seasonal forecasts).   Most know I have been a bit skiddish.  My memories of Nino winters are rarely of bitter cold.  I always remember how cloudy and rainy they are and how many just have high temps that seem to hover in the 40s and 50s for what seems like months on end.  Plenty of cold rain.

2.  I have great memories of some Nino winters and some lousy memories.  The 90s were chocked full of Nino winters. For those of us in the valleys with no elevation they were not as snowy as the decades that preceded them, those glorious winters of the 70s and a few monster cold winters during the 80s.  Remove the blizzard of 93, the winters of 93-94 and 95-96...and that decade was not the best compared to the ones that preceded it.  Now, localized areas of TRI had two BIG snows(the last of their kind) during the late 90s.  But recent weak Nino winters have proved to be pretty good.  Basically, I am saying a weak Nino is not a magic bullet and is not automatically a great winter.  However, they statistically are a good signal.  It is good to remember that sometimes things seem to line up perfectly, and we just don't do well.

3.  Back to the Weeklies and the really ugly(if you like winter) run of the 12z EPS(days10-15 progression).  We just have to hope they are wrong or short-lived.  BN heights when they get established over AK can be an absolute bear to move no matter the pattern.  My guess is that feature will last 2-4 weeks if it actually occurs.  We need to beware of the LR modeling right now.  This week is a great example of a total bust by the EPS.  Now to be fair, the flooding of NA by Pacific air and the scouring of cold from Canada is shown on many models.  I was reading some of Bob Chill's comments...basically said that if that unfolds in that manner, it will take significant time to reload Canada once it is over.  Not to put words in his mouth, but he seems on the fence about whether it actually happens and about the duration.  Either way, it is realistic to say that the feature over AK has been a common feature for many winters that were less than ideal.  

4.  So what now?  Sit and wait and enjoy the next few weeks of cold.  I think the MJO is a big driver right now.  It would be wise to watch it.  My guess is that the mid Dec warm spell probably coincides w warm MJO phases.  What is good about that?  Well, if the MJO follows it recent pattern...it will cycle out of those warm phases during later December or early January.  As Jeff said, the warm-up does not really change anything about many winter forecasts.  Many are backloaded.  And right now, I still fully believe that winter will return for a good 2-4 week period with plenty to track(those times may be split into two time frames).    I am thinking a really good shot at winter in mid January followed again by mid-late February.  That is off the top of my head based on the current MJO cycle.  Now it is also not guaranteed that cold cannot happen during warm phase of the MJO....I am guessing that this past month included some warm phases that were accompanied by cold here.   Also, need to really watch and see if those BN heights set-up shop over AK.  They should move eventually due to the ENSO state...but that is a strong signal and AK has taught me harsh lessons in the past in how hard it is to get that cold dislodged and moved into the eastern U.S.

5.  I still think winter is on track and agree w Jeff.  Our mets are the best out there...not sucking up, just speaking the truth.  My call has been slightly AN temps for Dec, normal for January, and BN for February.  I did call for a warm November, because I thought the last ten days would be warm....and we know how that will turn out.  LOL.  I will get some warmth, but not as billed....a warm weekend and not a warm week(minor differences - Ha!).  We may also get some sever weather this weekend. December will be a close call.  As I noted earlier, the cold during the first half of the month will be truly cold and will take some pretty incredible departures to eat away at that.  But if the EPS is right...if, if, if....then there is some pretty incredible warmth to follow the cold.  Big warm-ups have been a common features for the past three decades during winter.  I also noted that we would likely get slightly AN snowfall for the winter....that is almost always an educated guess at this latitude.  As for the overall DJF winter...I think we are close to normal for temps(slightly AN or slightly BN).

6.  And lastly, I have also noted that Nino winters require patience because they seem to often begin later than we are used to.  However, once the season is over, we are glad it finally warmed up!  To close, we want that AK feature showing up on LR models to be short lived or an error.   And it "should" move on due to the Nino...

[Maestrobjwa]

14 hours ago, Carvers Gap said:

I don't get too worked up about warmth during winter anymore...I know pretty much it is going to happen most winters due to latitude.  Most Nino winters have warmth, especially early.  It is important to note that it is not even winter yet, but it might as well be.  Here are a few evening thoughts:

1.  I have from the beginning thought this winter has been hyped a bit too much(not by anyone in our subform...or even the forum's other major contributors and/or seasonal forecasts).   Most know I have been a bit skiddish.  My memories of Nino winters are rarely of bitter cold.  I always remember how cloudy and rainy they are and how many just have high temps that seem to hover in the 40s and 50s for what seems like months on end.  Plenty of cold rain.

2.  I have great memories of some Nino winters and some lousy memories.  The 90s were chocked full of Nino winters. For those of us in the valleys with no elevation they were not as snowy as the decades that preceded them, those glorious winters of the 70s and a few monster cold winters during the 80s.  Remove the blizzard of 93, the winters of 93-94 and 95-96...and that decade was not the best compared to the ones that preceded it.  Now, localized areas of TRI had two BIG snows(the last of their kind) during the late 90s.  But recent weak Nino winters have proved to be pretty good.  Basically, I am saying a weak Nino is not a magic bullet and is not automatically a great winter.  However, they statistically are a good signal.  It is good to remember that sometimes things seem to line up perfectly, and we just don't do well.

3.  Back to the Weeklies and the really ugly(if you like winter) run of the 12z EPS(days10-15 progression).  We just have to hope they are wrong or short-lived.  BN heights when they get established over AK can be an absolute bear to move no matter the pattern.  My guess is that feature will last 2-4 weeks if it actually occurs.  We need to beware of the LR modeling right now.  This week is a great example of a total bust by the EPS.  Now to be fair, the flooding of NA by Pacific air and the scouring of cold from Canada is shown on many models.  I was reading some of Bob Chill's comments...basically said that if that unfolds in that manner, it will take significant time to reload Canada once it is over.  Not to put words in his mouth, but he seems on the fence about whether it actually happens and about the duration.  Either way, it is realistic to say that the feature over AK has been a common feature for many winters that were less than ideal.  

4.  So what now?  Sit and wait and enjoy the next few weeks of cold.  I think the MJO is a big driver right now.  It would be wise to watch it.  My guess is that the mid Dec warm spell probably coincides w warm MJO phases.  What is good about that?  Well, if the MJO follows it recent pattern...it will cycle out of those warm phases during later December or early January.  As Jeff said, the warm-up does not really change anything about many winter forecasts.  Many are backloaded.  And right now, I still fully believe that winter will return for a good 2-4 week period with plenty to track(those times may be split into two time frames).    I am thinking a really good shot at winter in mid January followed again by mid-late February.  That is off the top of my head based on the current MJO cycle.  Now it is also not guaranteed that cold cannot happen during warm phase of the MJO....I am guessing that this past month included some warm phases that were accompanied by cold here.   Also, need to really watch and see if those BN heights set-up shop over AK.  They should move eventually due to the ENSO state...but that is a strong signal and AK has taught me harsh lessons in the past in how hard it is to get that cold dislodged and moved into the eastern U.S.

5.  I still think winter is on track and agree w Jeff.  Our mets are the best out there...not sucking up, just speaking the truth.  My call has been slightly AN temps for Dec, normal for January, and BN for February.  I did call for a warm November, because I thought the last ten days would be warm....and we know how that will turn out.  LOL.  I will get some warmth, but not as billed....a warm weekend and not a warm week(minor differences - Ha!).  We may also get some sever weather this weekend. December will be a close call.  As I noted earlier, the cold during the first half of the month will be truly cold and will take some pretty incredible departures to eat away at that.  But if the EPS is right...if, if, if....then there is some pretty incredible warmth to follow the cold.  Big warm-ups have been a common features for the past three decades during winter.  I also noted that we would likely get slightly AN snowfall for the winter....that is almost always an educated guess at this latitude.  As for the overall DJF winter...I think we are close to normal for temps(slightly AN or slightly BN).

6.  And lastly, I have also noted that Nino winters require patience because they seem to often begin later than we are used to.  However, once the season is over, we are glad it finally warmed up!  To close, we want that AK feature showing up on LR models to be short lived or an error.   And it "should" move on due to the Nino...

Are there any records for an el Niño year where it DIDN'T move and remained a feature?...

[Carvers Gap]

@Maestrobjwa, great question.  I generally adhere to the idea that a great question is always better than a good answer.   Without looking, I would say there are years where El Nino's go a bit rogue.  Most of what I have read says there is great variability with ENSO events.  To quote one of our mets, each year is its own analog.  Even if there was not an exception to the rule, this year could become the analog for that.  There are folks who don't like analog years for just that reason - chaos is capable of new solutions even within a given pattern.  I follow the rule that there are exceptions to every rule in weather but within the constraints of actual physics.  That would take some pretty serious research to find which years had persistent BN heights over AK during an El Nino along w low solar, a QBO switching positive, etc.  It may be that the data set is so small (once all of the climates information is inputed) that there may be no analog.   However, I would guess that there are years w weak El Ninos that featured AN temps in the east and cold in AK for the DJF time frames.  Those are likely moderate to strong events.  I would suggest that some weak Nino events are probably also included.  The problem right now is that we don't know how strong the Nino will be.  I saw someone yesterday(maybe Ventrice on Twitter) note that the Nino may have peaked...  I also read a post by Judah Cohen that the MJO/tropical forcing may have too much weight in global forecast models.  He felt like drivers at higher latitudes were not given enough weight.  JB mentioned this morning that there are some analogs to the warm December.  One is '06 and the other is '14.  Both of those featured different trajectories, but were both weak Ninos at the time.  After December of '06, a La Nina would soon follow.  After '14, a very strong Nino would develop.   Not sure if those featured the big blue blob over AK, but those are probably good places to begin.  Might not hurt to look at the 90s data sets.  The overall idea is that with the ENSO setup over the Pacific, that a ridge should respond to that over western North America that gets pumped by a low in the GOA.  So here is a really long answer as to what might be going on...and where we might be headed...

1.  The SOI is not in the negative range yet as it should be for El Nino events.  My understanding is that is unusual.  That is a very slight lean La Nina. 

https://www.longpaddock.qld.gov.au/soi/

 

2.  Here is the most recent MJO BOMM forecast from the Australia met office...Considering Cohen's discussion about tropical forcing being given to much weight, there is some variability among the models as to where the MJO goes.  The progression of the MJO would seem to signal that the BN heights over AK will cycle through.  I think we want to be in 8, 1, and 2 for December - I could be wrong there, just off the top of my head.  Also, see Jeff's most recent comments above...I took that to mean that the MJO will cycle back in our favor.

 

3.  Here is the link to Cohen's discussion regarding tropical forcing along with a quote.  This might explain the recent whiff regarding the November warm-up.  The article itself seems contradictory as to how this sorts itself out, but I may just not understand his semantics or just don't understand some of the concepts enough...

https://www.aer.com/science-research/climate-weather/arctic-oscillation/

It seems to me that the model forecast reversal is related to Madden Julian Oscillation (MJO) activity.  The MJO forecast is for it to quickly rifle through phases 7, 8, 1, 2 and possibly 3 over the next two weeks.  In Figure ii, I include the geopotential height anomaly related to MJO phase 1 and it looks very similar to the GFS forecast for early December.  Therefore it seems to me at least the predicted December circulation pattern in the dynamical models is in large part attributable to the MJO.  I have argued in several papers now that the dynamical models are overly sensitive to tropical forcing and insensitive to Arctic forcing including stratospheric PV variability (for example Cohen 2016 and Cohen et al. 2016).  My own instinct is to weigh more heavily the pattern suggested by the configuration of the stratospheric PV with ridging near Alaska and downstream troughing and relatively cold temperatures in eastern North America and weigh less the pattern suggested by the MJO phase with troughing across Alaska and into the Gulf of Alaska with downstream ridging and relatively mild temperatures in eastern North America while I would argue the model weighting is just the opposite.

4.  The following is from the CPC regarding the weather pattern for El Nino and La Nina.  With that in mind, remember the SOI number above....it is not in El Nino territory yet.  It is ever so slightly La Nina.  Maybe that explains the tendency for BN heights to be potentially in AK for a portion of December.  Additionally, your original question was about whether there were years where the BN heights stayed over AK.  I feel fairly certain the graphic below was likely made w analog ideas for common Nino and Nina years.  That is why I think it will eventually get kicked out.  Also note where the "wet" notation is for La Nina.  There was just a blizzard that went to Chicago taking a similar path.  

 

 

5.  Here is the Ventrice tweet.  I take that to mean that the Nino is not over, but it is as strong as it is going to get.

 

6.  Below is the d10-15 500 map from the 0z EPS. The anomalies are in exactly the wrong places when we look at the Nino map above.

7.  Here is the link to the ENSO state map for multiple years from DaculaWx and excellent link for all things related to El Nino and La Nina.

https://www.daculaweather.com/4_nino_graphs.php

8.  Here are the December maps that JB mentioned that had weak El Ninos at the time for '06 and '14.  Neither are perfect analogs.  However, I made these maps so that we could compare them.  The winter of 2014-15 would feature a great reversal.  Its January and February would feature significant cold east of the Mississippi and would have a significant, reoccurring tough in eastern NA.  January and February of 2006-2007 would feature some cold in the nation's mid-section with BN heights found persisting in western Alaska.  ***That is likely a possible answer to your question.  06-07 featured a winter where it did persist.  January was warm and Feb cold...hence the cold in the nations mid-section for the composite of both months together.  It peaked and then went to a Nina FYI.*** Both analogs would see cold return by February.  I have said often, waiting on Nino winters makes me pull my hair out.

9.  So what does this all of that mean?  The 0z EPS pattern is suspicious in nature because it does not fit the general El Nino atmospheric structure for winter, and the models just recently missed with the November pseudo warm-up. Could it be that Cohen is correct in the wx models give too much weight to tropical forcing and not forcing at higher latitudes? The Ventrice tweet above might mean that the Nino has peaked?  If so, maybe there is a reason for seeing some Nina like characteristics in the LR models.  Remember also that the SOI is not in Nino territory.  Could it be that the AK BN heights is being modeled to reflect that?  Overall, it is well within the wheelhouse of Nino progressions to have warm Decembers.  So, the 0z EPS could be correct.  It may not be.  That said, I "think" a possible answer might be 06-07...with the caveat, we could always be in new territory.  I think the pattern will last somewhere between 1.5 and 4 weeks if it comes to pass, followed by a return to winter.  Best case scenario is that it lasts about ten days and rolls on through.  Worst case, list that it lasts all winter but I consider that unlikely...so maybe the realistic worst case is that winter returns in mid-January.

 

...And if you made it this far into that long post, kudos!!!

 

[Carvers Gap]

4 hours ago, *Flash* said:

Don't have time to break this down this morning, but I still think next weekend's pattern is favorable for a southern tracking storm. Speaking purely from a 'something to track' perspective, it sure seems signal continuity is increasing. Compass is set for cold rain here, but if this indeed turns into Winter Storm Diego, I don't think we'll be far from some fun & games.

 

12z GFS and FV3 look decent.  Still looks like a window of opportunity.  

[John1122]

GFS and Euro continue to be at odds over next Tuesday. The GFS has various southern stream solutions, from a favorable Gulf track to a cutter over the last 24-48 hours. Euro is consistent with a clipper from the northern stream of varying strength.  Canadian is a weak southern stream system as well.

[John1122]

Through yesterday November temps are at around -4 to -6 across the western 2/3rds of the valley. Today will lower those a bit. Tomorrow will be near normal on average and the final day of the month will be above normal. So we should see -2ish around Tri. -3.5 to -4 around Knox. -4.5 around Cha. -5.5-6 along the Plateau from London Ky to Huntsville. -4 around Nashville. -6 around Clarksville and Memphis. November will be a top 10 coldest ever at Huntsville, Crossville, Jackson Tn, Clarksville, Jackson Ky and Memphis (top 5 ever for some of these areas). Top 15-20 coldest for BNA, CHA, London, Ky.  Top 20ish for TYS. I think it's 21st right now before today's -15 to -20 comes in.

This doesn't lock down a cold/snowy winter. But it is a characteristic of the greater majority of memorable winters here. 59-60, 62-63, 76-77,  84-85, 95-96, 13-14, 14-15 show up among these. At Crossville Jan 77 is the coldest ever. It followed the coldest November ever in 76. Jan 2014 is the 3rd coldest ever at Crossville. It followed the November of 13 which is about .5 degrees warmer than this November so far at -5. Jan of 85 is the 4th coldest at Crossville. It followed November of 84 and it's -4.5 anomaly at Crossville. The 5th coldest January at Crossville was 1970. November of 1969 was -6.8 at Crossville. The 7th coldest January ever at Crossville is 1963. November of 62 was -4 at Crossville. Rounding out the top 10 coldest Januarys at Crossville are 2003, 1981, and 1961.  There we find that November 2002 was -5 at Crossville. November 1980 was -3 at Crossville. November 1960 was -2 at Crossville.  So 8 of the 10 coldest Januarys ever recorded in Crossville were following Novembers that were at least -2 degrees. Of the two others, one was -.4 from normal and only one of the 10 was AN for November. That was November 1970 and it was +2.

So 9 of the 10 coldest Januarys ever at Crossville followed Novembers that were below normal, several of those were very similar to this November.

 

[Carvers Gap]

1 hour ago, John1122 said:

Through yesterday November temps are at around -4 to -6 across the western 2/3rds of the valley. Today will lower those a bit. Tomorrow will be near normal on average and the final day of the month will be above normal. So we should see -2ish around Tri. -3.5 to -4 around Knox. -4.5 around Cha. -5.5-6 along the Plateau from London Ky to Huntsville. -4 around Nashville. -6 around Clarksville and Memphis. November will be a top 10 coldest ever at Huntsville, Crossville, Jackson Tn, Clarksville, Jackson Ky and Memphis (top 5 ever for some of these areas). Top 15-20 coldest for BNA, CHA, London, Ky.  Top 20ish for TYS. I think it's 21st right now before today's -15 to -20 comes in.

This doesn't lock down a cold/snowy winter. But it is a characteristic of the greater majority of memorable winters here. 59-60, 62-63, 76-77,  84-85, 95-96, 13-14, 14-15 show up among these. At Crossville Jan 77 is the coldest ever. It followed the coldest November ever in 76. Jan 2014 is the 3rd coldest ever at Crossville. It followed the November of 13 which is about .5 degrees warmer than this November so far at -5. Jan of 85 is the 4th coldest at Crossville. It followed November of 84 and it's -4.5 anomaly at Crossville. The 5th coldest January at Crossville was 1970. November of 1969 was -6.8 at Crossville. The 7th coldest January ever at Crossville is 1963. November of 62 was -4 at Crossville. Rounding out the top 10 coldest Januarys at Crossville are 2003, 1981, and 1961.  There we find that November 2002 was -5 at Crossville. November 1980 was -3 at Crossville. November 1960 was -2 at Crossville.  So 8 of the 10 coldest Januarys ever recorded in Crossville were following Novembers that were at least -2 degrees. Of the two others, one was -.4 from normal and only one of the 10 was AN for November. That was November 1970 and it was +2.

So 9 of the 10 coldest Januarys ever at Crossville followed Novembers that were below normal, several of those were very similar to this November.

 

Do you mind checking TRI’s ranking?  I think -2 sounds about right. We hit 60s on Saturday and Sunday which will roughly balance today.  So whatever we were as of yesterday will be pretty close.  Are you hand crunching those or do you have a website?  

[Carvers Gap]

For kicks and giggles...On the 12z EPS, looks like roughly 10 have sliders over some portion of the forum area during week two.  If I use a looser translation, I could probably get a couple of more.