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December/January 2019/20 Winter Speculation Thread

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I think someone in one of the upslope areas should create an event thread or at least consider it.  If it winds up being a bust, no problem.  I think the Smokies are going to get sauced.  Looks like Roan Mountain already has a heavy band up.  I talked to someone in the foothill communities and they have rain already(prob will switch over).   I will be shocked if actual valley locations get too much.  That said, we could get a dusting to an inch.  I never do well with upslope.  Northwest facing communities on the Plateau and near the Smokies might do well enough to make a thread necessary. Heck, I will be living vicariously through you all anyway.  Planning on maybe making a run up to Roan Mountain on Tuesday to see if I can get some snow pics.

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Think I am kidding about the warm overnight suites and afternoon?  Look at the 18z 5 day C temp anomaly for days 10-15 on the GEFS.  Then toggle it back to 0z from last night.  Night and day differences for a five day period.  And it is day10-15, so I cut the model some slack for sure.  Just wanted to illustrate how different those two runs are.  Now, if we can just get that 18z run to hold!

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3 hours ago, Carvers Gap said:

I think someone in one of the upslope areas should create an event thread or at least consider it.  If it winds up being a bust, no problem.  I think the Smokies are going to get sauced.  Looks like Roan Mountain already has a heavy band up.  I talked to someone in the foothill communities and they have rain already(prob will switch over).   I will be shocked if actual valley locations get too much.  That said, we could get a dusting to an inch.  I never do well with upslope.  Northwest facing communities on the Plateau and near the Smokies might do well enough to make a thread necessary. Heck, I will be living vicariously through you all anyway.  Planning on maybe making a run up to Roan Mountain on Tuesday to see if I can get some snow pics.

,Last minute before Midnight I suppose I'll do it!

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0z EPS with yet another flip overnight to warm in the d8-15 range.  The 0z and 6z GEFS OTH look much improved and more than workable.  I still lean warm for December, and I do give the EPS more weight at this time of year.  So, let's see if the GEFS can hold at 12z....I also think the Dec 10-15 is still a time to watch for a storm to pull sharply out of the GOM.  

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Yeah the next big cold shot (11-15 day) may dive into the West first. Therefore a Midwest cutter would not surprise me. Note I'm skipping next week and talking 11-15 day.

KCMO TV Met Gary Lezak released his public winter forecast. The really good stuff is behind a paywall; but, I can infer plenty from the KC forecast. He's cold and snowy in KC. Unfortunately that is a Plains favorable storm track, which matches much of what has been observed since September. Said primary pattern is cutters, especially bad for southeast Tenn. However a secondary pattern is forecast. He does not discuss it on the public forecast; but, his system has a secondary pattern. That's the colder northwest flow when our region could benefit. Especially true if split flow and a slider or two from Texas through Georgia.

I figure all that good stuff is more likely Jan/Feb. Will try not to sweat a mild December. Pun intended? Only if we need AC at Christmas like four years ago, lol!

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40 minutes ago, nrgjeff said:

Yeah the next big cold shot (11-15 day) may dive into the West first. Therefore a Midwest cutter would not surprise me. Note I'm skipping next week and talking 11-15 day.

KCMO TV Met Gary Lezak released his public winter forecast. The really good stuff is behind a paywall; but, I can infer plenty from the KC forecast. He's cold and snowy in KC. Unfortunately that is a Plains favorable storm track, which matches much of what has been observed since September. Said primary pattern is cutters, especially bad for southeast Tenn. However a secondary pattern is forecast. He does not discuss it on the public forecast; but, his system has a secondary pattern. That's the colder northwest flow when our region could benefit. Especially true if split flow and a slider or two from Texas through Georgia.

I figure all that good stuff is more likely Jan/Feb. Will try not to sweat a mild December. Pun intended? Only if we need AC at Christmas like four years ago, lol!

No reason to waste a favorable pattern during the first half of December.  LOL.  I will say that when I was little, a cold/snowy Missouri and western KY were always good signs in my book.  Always seemed like if they could score early, we would get our share at some point.  Paducah, KY, was always a place I would keep an eye on.  If it snowed there, always seemed like we had a shot here(lived in Knoxville as a kid in the 70s).   I also like to watch the temp in International Falls.  It seemed like if the core of the cold went there, it would find a way here.  Now, I am looking at thunderstorm activity in the Indian Ocean and 500mb levels over Greenland and the eastern Pacific.  I have said this a few times...during the 70s it seemed like many of Knoxville's best snows would begin in Memphis(from a kid's perspective).  We know those as sliders now of course.  Would be interesting if we had one of those "old school" tracks...cutters and sliders. 

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Nice run of the 12z GEFS.  Dec 8-18 it has a nice EPO/PNA ridge.  Timing would be tough for a storm, but gulf systems don't seem to a problem right now.  I hesitate to say it...but nice trends over the past 3-4 runs on the GEFS.  Let's see what the EPS shows.

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16 hours ago, Carvers Gap said:

Think I am kidding about the warm overnight suites and afternoon?  Look at the 18z 5 day C temp anomaly for days 10-15 on the GEFS.  Then toggle it back to 0z from last night.  Night and day differences for a five day period.  And it is day10-15, so I cut the model some slack for sure.  Just wanted to illustrate how different those two runs are.  Now, if we can just get that 18z run to hold!

I haven't seen models this confused in years. They are good for about 7 days out with temps and 3-4 days with precip, anything beyond that is brutal. 

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27 minutes ago, BuffaloWeather said:

I haven't seen models this confused in years. They are good for about 7 days out with temps and 3-4 days with precip, anything beyond that is brutal. 

I think for one thing, we have been testing the limits as to how far into the future that we can use these models...I know I have.  D10-15 patterns shift a lot on ensembles anyway.  That said, there have been some wild shifts lately that often resemble the operational shifts.  I just like to see how far I can push the envelope.  D8-15 has been a mess for about 12-13 months.  Seems like when the Euro and GEFS locked into a pattern years ago, they didn't bounce around as much(but they were still prone to shifts).  I also suspect that we are seeing a somewhat substantial(but slow) hemispheric pattern change.  December '18 to October '19 seemed like one big, repetitive pattern.  Now, I think the pattern is changing, partly due to seasonal changes and partly because the atmosphere is now coupled with the weak El Nino.  I am not sure where the pattern goes.  It is a bit like playing the slots...just never know what is going to come up.  As Tellico said...probably best just to ride with climatology right now.  It actually has been pretty good.  

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41 minutes ago, Carvers Gap said:

I think for one thing, we have been testing the limits as to how far into the future that we can use these models...I know I have.  D10-15 patterns shift a lot on ensembles anyway.  That said, there have been some wild shifts lately that often resemble the operational shifts.  I just like to see how far I can push the envelope.  D8-15 has been a mess for about 12-13 months.  Seems like when the Euro and GEFS locked into a pattern years ago, they didn't bounce around as much(but they were still prone to shifts).  I also suspect that we are seeing a somewhat substantial(but slow) hemispheric pattern change.  December '18 to October '19 seemed like one big, repetitive pattern.  Now, I think the pattern is changing, partly due to seasonal changes and partly because the atmosphere is now coupled with the weak El Nino.  I am not sure where the pattern goes.  It is a bit like playing the slots...just never know what is going to come up.  As Tellico said...probably best just to ride with climatology right now.  It actually has been pretty good.  

The issue is Neutral Enso conditions result in a very up and down pattern. There are other drivers that are dictating the forecast. MJO, PV, AO. I don't expect anything to really lock in all winter. It's been a great "winter" for most of the midwest and northeast already. Almost everyone is way above normal snowfall totals for Dec 2nd.  

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ECMWF weekly charts are pretty benign, no matter what side one favors. The warm weeks 2-3 are already advertised in the ECMWF ensembles. While a loss to the GFS, it's no change within the European guidance.

End of December is shown seasonable for the most part. Clusters are all over the place, common for week 4 where accuracy drops. Main takeaway is no endless blowtorch. Euro looks too cold in the Rockies, perhaps its snow feedback issue. Southwest low for two weeks? Doubt that. 

Early January (weeks 5-6) is so far out of the range of skill for these products that I will withhold comment. Slightly mild but mostly meaningless. Instead will need to watch sub-seasonal drivers which are indeed a mess, as mentioned in previous posts.

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Good write-up, Jeff.  Yeah, looked like the Euro Weeklies which ran from the 0z run just basically went wash/rinse/repeat for the rest of the run.  It might be right as a new pattern is due and it might not be.  I couldn't see much difference between week 1 and week 6.  Looked like a northwest/western trough with an eastern ridge.  I am not even sure the Weeklies matched with the 12z run of the EPS.  Like you said, it "appears" that the low in the southwest is an error and caused the run to miss from that point on.  But I have seen it nail patterns where I was certain it was in error.  I tend to favor the GEFS just a bit because it seems to see eastern cold better...and it is not getting bogged down in the southwest.  But I tread carefully as the GEFS is less reliable in a stable winter pattern.  Not sure I would share a foxhole with either model right now.  LOL.  Some fairly major differences in how each are handling the MJO and that occurs fairly early in the Euro and American models.

Just general comments not directed as a reply to Jeff....Also, looks like the QBO dropped from 7.27 to 5.07.  That is its biggest drop since it began falling in June.  Pretty steady progression which is sort of unusual as it usually has one big drop as it descends.  So the trajectory is down and wind reversal is in progress at 30mb...still not there yet.  Makes me think the QBO will be negative during mid to late January or sometime in early February if this consistent trajectory persists.  If it drops quickly, we could be there by early January.  Would be interesting to see an actually splitting of the PV about the time it goes below zero.  Looks like with the QBO cross-section graph that there is usually a stall and then a drop and a stall and then a drop.  The double dip into positive during the last cycle had the first drop, and then it went back up.  Just look at the blue in the upper right hand corner...that is the current reversal working its way down.  You can see just to the left where it failed to reverse.  You can see the ones further to the left how they progressed.  This current cycle looks like it has survived the stall and is progressing downward again.

https://iridl.ldeo.columbia.edu/maproom/Global/Atm_Circulation/QBO.html

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1 hour ago, BuffaloWeather said:

The issue is Neutral Enso conditions result in a very up and down pattern. There are other drivers that are dictating the forecast. MJO, PV, AO. I don't expect anything to really lock in all winter. It's been a great "winter" for most of the midwest and northeast already. Almost everyone is way above normal snowfall totals for Dec 2nd.  

Yeah, I actually like the forecast(just referencing what Jeff has mentioned...I haven't read it yet but will) of a Plains storm track with cutters early.  That is fairly normal.  Then, as winter presses and El Nino sort of forces the trough eastward during January and February, I actually favor sort of what we are seeing now...cutters and coastals as a secondary track.  And we know on the EC that just one or two systems along or inside the coast can make for some memorable winter weather.  But yeah, I agree that we might not see a settled pattern this winter...but if we are, it would likely be a trough in the East for the second half of winter.  I am guessing the GEFS is likely right but just too quick.  I think we are going to have to have the Pacific in our favor as it just seems an Atlantic block during winter is difficult these days.

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10 hours ago, Carvers Gap said:

And today’s winner is the 18z GEFS temp anomaly map! 

Looks like the Euro tried to bring some serious cold deon south into the plains and Midwest next week.  Could have implications for us if it verifies.  

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Pretty funny to be talking about International Falls yesterday...and then the 12z GFS straight drops the hammer on the North Star State.  Source regions, anyone?  My favorite storm track is New Orleans/Mobile to inside Hatteras.  The track(take with a huge grain of salt) on that GFS run would be a close second and an old school one at that.  Again, crazy we were just talking about that yesterday.   

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1 minute ago, TellicoWx said:

12z Euro has trouble written all over it with a 1043 parked over the NE in a region with 1° temps at the end. CAD would be impressive with that setup 

Check out the thermal profile one the US on the GEFS after that.  But yeah, trouble written all over that pattern.  Pretty amazing shift in modeling during the past 48 hours.  I think the 12z GFS operational has a 1057 parked over western Canada on its run.  To me the GEFS is more impressive than the operational.  

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The 12z GEPS does offer a word of caution.  The EPO ridge gets so tall on it...that the GEPS tucks a trough under the big ridge.  So, that is the danger we need to be wary of in terms of the LR.  This actually happened last year.  Modeling went crazy for a cold East...and the trough tucked West.  I don't think the Nino will let that happen now that it is coupled.  However, there may be a window there for that to happen due to the IOD firing.  Long term, that tough likely gets kicked out of there.  Besides, park a 1050+ high over MT, and let's see what happens!  

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Check out the thermal profile one the US on the GEFS after that.  But yeah, trouble written all over that pattern.  Pretty amazing shift in modeling during the past 48 hours.  I think the 12z GFS operational has a 1057 parked over western Canada on its run.  To me the GEFS is more impressive than the operational.  
Yeah the teleconnections for that time frame has been interesting, think the OPs are starting to clue in. Even with a neutral/slight + AO..a crashed EPO can buckle the cold south...sprinkle in blocked pattern over the Atlantic to slow an system's and things should be interesting. Temps here normally lag the crashing EPO by a few days (unless the PNA doesn't cooperate).

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The 12z GEPS does offer a word of caution.  The EPO ridge gets so tall on it...that the GEPS tucks a trough under the big ridge.  So, that is the danger we need to be wary of in terms of the LR.  This actually happened last year.  Modeling went crazy for a cold East...and the trough tucked West.  I don't think the Nino will let that happen now that it is coupled.  However, there may be a window there for that to happen due to the IOD firing.  Long term, that tough likely gets kicked out of there.  Besides, park a 1050+ high over MT, and let's see what happens!  
Exactly, if PNA can't hold to assist the EPO, then its wasted

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Just now, TellicoWx said:

Yeah the teleconnections for that time frame has been interesting, think the OPs are starting to clue in. Even with a neutral/slight + AO..a crashed EPO can buckle the cold south...sprinkle in blocked pattern over the Atlantic to slow an system's and things should be interesting. Temps here normally lag the crashing EPO by a few days (unless the PNA doesn't cooperate).

Sent from my SM-S767VL using Tapatalk
 

PSU in the MA thread mentioned that if you look at the 850 temps on the Euro, it is moving towards the broad trough idea.  Bob Chill and FRD talk a little (they were just throwing it out there...not a forecast and more just fun speculation...forgive me if that is wrong!) about how an overrunning event could be derived from that broad trough look on the American model.  I tend to agree.  Long way to go, but a fun set of model runs, especially considering that modeling looked awful several days ago.  Definitely interesting.  

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back in the day I remember a southwest low not being a terrible thing.  Would spit out smaller disturbances and with enough cold provide lighter snow opportunities.  Then, when the main system kicked there would be a chance at a major system somewhere in the east. 

If the cold is tough to dislodge, ice becomes a much bigger concern.  Let's see how the pattern evolves.  Nothing but good vibes today, which is always fun...

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8 minutes ago, TellicoWx said:

Exactly, if PNA can't hold to assist the EPO, then its wasted

Sent from my SM-S767VL using Tapatalk
 

The problem with the Euro is that it messes around in the Southwest and is wrong about 2/3 of the time.  And that bias causes it to be slow sometimes.  The Euro has often been too warm this fall.  The GFS can sometimes be too quick with cold - right idea often but a few days too fast.  However, if one blends those two looks and the timing, that is a pretty good set-up for cold and snow in the East beginning about d10-12.  Probably also worth pointing out that often times modeling will underestimate how far south that cold gets.  I do think the ENSO set-up is going to force that trough out of the West.  I would not be surprised to see a big high settle into the front range and then spread out.  I don't mind seeing the core of the cold at the northern border of the US.  If that cold air mass is real, it likely verifies at about the latitude of roughly Chicago IMHO.  Not sure @John1122 can take another snowstorm in New Orleans.  LOL!

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