December/January 2019/20 Winter Speculation Thread

[Carvers Gap]

The 12z GEFS snow mean is impressive in addition to the cold.  @BornAgain13 the SE forum has a snow map posted.  Now, let's see where the Euro goes.  Starting to get some cold looks inside of d10 now.   Euro up next.

[nrgjeff]

I'm several pages behind on this thread, so I'll keep it brief. 

1. I want to make love to the Himawari satellite, literally the robot up in space. All kinds of convection in the Modoki El Nino zone. Just beautiful if you want some winter down here.

2. MJO index is also going into cold phases. Nice when it lines up with satellite photos.

3. SSTs have assumed the proper look for cold phases. Hopefully the atmosphere will settle there too.

4. Models remain consistent. Ensemble clusters are remarkably correlated. No guarantee correlation = correctness, but plenty of Pacific backing here.

5. Hesitate to post, but yeah the CFS (weekly crap shoot) lays down a defined swath of snow in the Valley about week 3.

I don't see anything in the 6-8 day window for lower elevations. Days 9-10 could always surprise, just because it's the mid-range. As usual it'll take 2-3 cold fronts for the cold air to settle in. 11-20 day is where I hope for some action.

[AMZ8990]

40 minutes ago, nrgjeff said:

I'm several pages behind on this thread, so I'll keep it brief. 

1. I want to make love to the Himawari satellite, literally the robot up in space. All kinds of convection in the Modoki El Nino zone. Just beautiful if you want some winter down here.

2. MJO index is also going into cold phases. Nice when it lines up with satellite photos.

3. SSTs have assumed the proper look for cold phases. Hopefully the atmosphere will settle there too.

4. Models remain consistent. Ensemble clusters are remarkably correlated. No guarantee correlation = correctness, but plenty of Pacific backing here.

5. Hesitate to post, but yeah the CFS (weekly crap shoot) lays down a defined swath of snow in the Valley about week 3.

I don't see anything in the 6-8 day window for lower elevations. Days 9-10 could always surprise, just because it's the mid-range. As usual it'll take 2-3 cold fronts for the cold air to settle in. 11-20 day is where I hope for some action.

 From far, do you think this could outbreak could be like the cold outbreak in 2017 that kept us under freezing for two weeks or so?  Just curious if you see similarities, I know we were really dry a lot of the time in 2017 and finally got lucky with the trowal event we had.  Just curious if HP could also ruin this cold outbreak as well

[Carvers Gap]

49 minutes ago, nrgjeff said:

I'm several pages behind on this thread, so I'll keep it brief. 

1. I want to make love to the Himawari satellite, literally the robot up in space. All kinds of convection in the Modoki El Nino zone. Just beautiful if you want some winter down here.

2. MJO index is also going into cold phases. Nice when it lines up with satellite photos.

3. SSTs have assumed the proper look for cold phases. Hopefully the atmosphere will settle there too.

4. Models remain consistent. Ensemble clusters are remarkably correlated. No guarantee correlation = correctness, but plenty of Pacific backing here.

5. Hesitate to post, but yeah the CFS (weekly crap shoot) lays down a defined swath of snow in the Valley about week 3.

I don't see anything in the 6-8 day window for lower elevations. Days 9-10 could always surprise, just because it's the mid-range. As usual it'll take 2-3 cold fronts for the cold air to settle in. 11-20 day is where I hope for some action.

LOL.  Bullet point one should be forever placed into TN Valley subform lore.  

[Carvers Gap]

The 12z EPS is not warm.  500 pattern is 12z GEFS-esque.  Let's fire-up the winter tracking bus and don't let Jeff sit next to the satellite!

[weathertree4u]

4 minutes ago, Carvers Gap said:

The 12z EPS is not warm.  500 pattern is 12z GEFS-esque.  Let's fire-up the winter tracking bus and don't let Jeff sit next to the satellite!

I just want a good old fashioned snow of 4" - 6" don't want to be transported to the movie Frozen 

[nrgjeff]

Just in European weeklies might. And the 12Z EPS is Frozen.

52 minutes ago, AMZ8990 said:

 From far, do you think this could outbreak could be like the cold outbreak in 2017 that kept us under freezing for two weeks or so?  Just curious if you see similarities, I know we were really dry a lot of the time in 2017 and finally got lucky with the trowal event we had.  Just curious if HP could also ruin this cold outbreak as well

Sadly I don't remember anything in 2017 though. Must have been the one that broke the snow drought for Mid Tenn. Southeast Tennessee was missed. Our last gems were 2015 and 2014. That does not count travelling to Calhoun, GA I think December 2017.

At any rate it's time for some action forum wide! Keep our fingers crossed. ECMWF weekly charts are lit for 3 straight weeks starting next week. Big AK ridge AND above normal heights Western Canada. It's +PNA though not textbook Bering Sea / Aleutians. Important thing is cold dumps east of the Rockies. None of that West tough BS. It's full tilt trough Greenland to SE USA.

Please be right. 

[weathertree4u]

23 minutes ago, nrgjeff said:

Just in European weeklies might. And the 12Z EPS is Frozen.

Sadly I don't remember anything in 2017 though. Must have been the one that broke the snow drought for Mid Tenn. Southeast Tennessee was missed. Our last gems were 2015 and 2014. That does not count travelling to Calhoun, GA I think December 2017.

At any rate it's time for some action forum wide! Keep our fingers crossed. ECMWF weekly charts are lit for 3 straight weeks starting next week. Big AK ridge AND above normal heights Western Canada. It's +PNA though not textbook Bering Sea / Aleutians. Important thing is cold dumps east of the Rockies. None of that West tough BS. It's full tilt trough Greenland to SE USA.

Please be right. 

Well, alrighty then.

[Holston_River_Rambler]

Happy hour GFS manages to spit out some front end snow (maybe a few flurries at the start?) for this weekend system:

[Daniel Boone]

1 hour ago, Holston_River_Rambler said:

Happy hour GFS manages to spit out some front end snow (maybe a few flurries at the start?) for this weekend system:

Wouldn't surprise me particularly for NE sections. 

[1234snow]

Interested to see if we can get some nice storms over the next couple of days. Seems like they have over-performed in the SE:

I'm guessing nothing severe and really don't want that anyway after Saturday, but some plain old thunderstorms might be fun.
 
 

Off topic but already some rumbles of Thunder this evening.

[Wurbus]

Nice Tennessee snow hole on the latest GFS.

[John1122]

2 minutes ago, Wurbus said:

Nice Tennessee snow hole on the latest GFS.

2018 all over again. 

[weathertree4u]

3 hours ago, John1122 said:

2018 all over again. 

Oh well I am sure will be 100% different next run, it is the gfs remember 

[weathertree4u]

Seems like we will have the needed cold in the LR but the moisture shuts off almost completely, such a strange pattern. 

[Holston_River_Rambler]

Maybe I'm wrong, but I want the GFS to have everything like 1000 miles south of us at range, lol. Gotta have room for the inevitable NW shift. I think we saw one go from Cuba to Michigan last year, over 10 days. 

[weathertree4u]

3 minutes ago, Holston_River_Rambler said:

Maybe I'm wrong, but I want the GFS to have everything like 1000 miles south of us at range, lol. Gotta have room for the inevitable NW shift. I think we saw one go from Cuba to Michigan last year, over 10 days. 

The model is just so volatile and variable with its solutions; we discuss it every year; not sure why we use it for forecasting honestly. 

[Carvers Gap]

17 minutes ago, Holston_River_Rambler said:

Maybe I'm wrong, but I want the GFS to have everything like 1000 miles south of us at range, lol. Gotta have room for the inevitable NW shift. I think we saw one go from Cuba to Michigan last year, over 10 days. 

Yeah, that STJ is likely going to be active.  Precip pattern probably favors E TN a bit more, but no way to be sure yet.  Suppression is always a factor, but El Nino winters really fight that off some.  If it was La Nina...big, big concern.   Also important to realize the GEFS/GFS have been too suppressed all winter...and too cold.  So, I bet this pattern modifies northward over time for all except the coldest days.  The GEFS mean is actually pretty strong for E TN and has been for several runs.  Even the putrid EPS has bumped up a bit.  It would likely be an understatement to say that I like where this is going.  Not trying to hype, but this look is showing up right when climatology favors bigger winter events.  Fingers crossed!  I will say this...if the pattern was perfect at 10 days out, I would say the actual pattern would likely be over the Ohio River once it verifies.  Keep it down there and we'll just have to take our chances.  At worst,  I get to see stories of people in Tallahassee playing in the snow.  LOL.

[PowellVolz]

If we don’t get a lengthy period of dry weather soon we’re gonna have another issue like last year.


.

[Carvers Gap]

The real danger is if we get a snowpack up in the mountains, the pattern breaks for even just a few days, and we get rain on that snowpack.  Fortunately, Cherokee is where it needs to be to catch the rain from NE TN.  If this switches to La Nina, were are going to need every drop.  Kind of weird to say that during record rainfall, but Nina summers are scorchers.  Not saying that is a given, but on the table as something that might even be a likelihood. 

As for the upcoming pattern.  I still think we get pulses of cold air that come down, sometimes much below normal.  I think we get less precip than we are getting now - pretty easy call.  Looks like there may be a warm-up(relative to where it is about to go...cold compared to the present) sometime in early February and then cold to follow.  The Weeklies tend to ease off the pattern around February 10th....I have my doubts about that.  I suspect this pattern lasts roughly 6 weeks with typical warm spells intermixed.  I think by the time this pattern is over, we will be ready for spring because the temps will have been cold.  What I think will be interesting is if we get a -NAO right as the Pacific relaxes.  I mean, this is the time of year it could do that.  The newest QBO is neutral between 30-40mb.  The MJO on the new LR MJO by the Euro takes the MJO into the COD and leaves it there - fine by me.  At this point the Pacific will be the driver w the potential for the Atlantic to help later as we close out the season.  Modeling a couple of days ago was very strong with blocking in eastern Canada.  Let's see if it picks that up gain.  There is potential that this pattern lasts into spring.  At any rate, big pattern shake-up appears to be on schedule.  I suspect we go BN on temps from January 20th - end of February.  I will roll with AN precip w/ some periods where things do dry out.  

 

[tnweathernut]

If you believe the models it appears we will soon have something to track.  I know the OP's haven't been throwing out snowy solutions for the southeast, but with all the ridging shown to occur in central Canada (Manitoba, Ontario, Hudson Bay, Nunavut) this SHOULD eventually force some of these storms under us.    That has historically been a pretty good spot for AN heights in correlation with a mid-south snow.  I am pretty sure it was Robert (WxSouth) who mentioned this in the past. 

I wouldn't sleep on the storm shown on the Euro OP around hr 168-180.  The height fields will almost certainly trend one direction or the other in the coming days and it wouldn't take an earth shattering amount of change to pop a winter storm somewhere from the coast toward east TN.  Even if that one misses, the pattern beyond this period is night and day better than where we have been........ and should produce additional opportunity somewhere in the southeast/mid-south as we close out January.

As always, any opportunity will come down to timing, but I think the odds we time something up with enough cold and a favorable storm track are better than 50/50 the last week or so of January.  

[Carvers Gap]

5 hours ago, Carvers Gap said:

The real danger is if we get a snowpack up in the mountains, the pattern breaks for even just a few days, and we get rain on that snowpack.  Fortunately, Cherokee is where it needs to be to catch the rain from NE TN.  If this switches to La Nina, were are going to need every drop.  Kind of weird to say that during record rainfall, but Nina summers are scorchers.  Not saying that is a given, but on the table as something that might even be a likelihood. 

As for the upcoming pattern.  I still think we get pulses of cold air that come down, sometimes much below normal.  I think we get less precip than we are getting now - pretty easy call.  Looks like there may be a warm-up(relative to where it is about to go...cold compared to the present) sometime in early February and then cold to follow.  The Weeklies tend to ease off the pattern around February 10th....I have my doubts about that.  I suspect this pattern lasts roughly 6 weeks with typical warm spells intermixed.  I think by the time this pattern is over, we will be ready for spring because the temps will have been cold.  What I think will be interesting is if we get a -NAO right as the Pacific relaxes.  I mean, this is the time of year it could do that.  The newest QBO is neutral between 30-40mb.  The MJO on the new LR MJO by the Euro takes the MJO into the COD and leaves it there - fine by me.  At this point the Pacific will be the driver w the potential for the Atlantic to help later as we close out the season.  Modeling a couple of days ago was very strong with blocking in eastern Canada.  Let's see if it picks that up gain.  There is potential that this pattern lasts into spring.  At any rate, big pattern shake-up appears to be on schedule.  I suspect we go BN on temps from January 20th - end of February.  I will roll with AN precip w/ some periods where things do dry out.  

That last line is probably not going to age well.  LOL and sorry.  I should have known better.  I am just going to own it now.  Pretty substantial changes to the 12z EPS today and not for the good in the LR.   The run-to-run trend in the d10-15 had trends that look like a textbook phase 6 MJO.  Maybe we get our pattern back tomorrow and this was a hiccup, but I definitely do not like that 12z run.  It was a major break from continuity.  As is, we could probably steal a storm or two from that look, but if that is a trend...that is not good.  Pattern shift is still a "go" but if that is a trend...the new pattern might not be what we think.

[John1122]

2 hours ago, Carvers Gap said:

That last line is probably not going to age well.  LOL and sorry.  I should have known better.  I am just going to own it now.  Pretty substantial changes to the 12z EPS today and not for the good in the LR.   The run-to-run trend in the d10-15 had trends that look like a textbook phase 6 MJO.  Maybe we get our pattern back tomorrow and this was a hiccup, but I definitely do not like that 12z run.  It was a major break from continuity.  As is, we could probably steal a storm or two from that look, but if that is a trend...that is not good.  Pattern shift is still a "go" but if that is a trend...the new pattern might not be what we think.

The Euro tries to loop the MJO into Phase 6 again at the end of day 14. The Australian model has it collapsing into the COD through February. GAWX indicated that Atlanta averaged -4 when the MJO was in the COD during Jan/Feb vs -1 if it was outside the COD in favorable phases. Normally if Atlanta is -4, we're likely to be cold as well. That said, it could warm again, though the EPS was only warm for a couple of days before going back to a more BN look at the end. Either way, a massive waffle for the Euro and not a good look at all for it's verification one way or the other.

[Carvers Gap]

Just now, John1122 said:

The Euro tries to loop the MJO into Phase 6 again at the end of day 14. The Australian model has it collapsing into the COD through February. GAWX indicated that Atlanta averaged -4 when the MJO was in the COD during Jan/Feb vs -1 if it was outside the COD in favorable phases. Normally if Atlanta is -4, we're likely to be cold as well. That said, it could warm again, though the EPS was only warm for a couple of days before going back to a more BN look at the end. Either way, a massive waffle for the Euro and not a good look at all for it's verification one way or the other.

The only good thing I can find is what I posted a few posts back which is that the EMON basically ended the MJO in the COD and doesn't bring it back.  What concerns me is the EPS run-to-run change at 500 looks like a trend towards phase 6.  I am not entirely convinced any model has the MJO correct as it is forecast to have a lot subsidence in the MJO regions.  Agree also, I don't mind the COD either....actually that is not a terrible solution as you point out.  What concerns me is the trend towards phase 6.  Hopefully that is just a hiccup or corrects to the COD.  However, I see some similar trends on the GEFS.  The CFS is much colder as it has an entirely different MJO progression after phase 7.   I believe a variable pattern is upcoming, and I should not have broken from that thinking this AM.  The EPS immediately made me pay for that line that I have in bold.  So, an immediate retraction seems wise.  I just get excited like the rest of us when I see all of those BN heights.  On a positive note, looks like suppression problems could be short lived.  LOL.  But again, I think a long term variable pattern is probably likely, though nothing is a certainty after next week's cold shot.  Looks like the 18z has tnweathernut's storm.

[Holston_River_Rambler]

Someone may have mentioned this earlier, but Bluewave had a good post earlier about the EPS backing off on the cold (I think you have to click "bluewave replied to a topic") to get to the post:

That analogue map looks very much like what the EPS was showing in the extended. I don't rally know that much about AAM, so not sure exactly how that impacts us? Maybe extra momentum = stronger N. hemisphere jets and that pushes through attempts at ridging? 

It's like the ridge wants to build, but the Pac jet keeps blasting it any ridging east. 

Although even with that added momentum, the control still manages to pop storm at the end:

 

Like Carver's said, maybe it's a hiccup and maybe it looks better tomorrow. 

Convection still looks hot in Jeff's erogenous zone:

 

 

 

 

[Carvers Gap]

As I understand it, a strong AAM is associated with El Nino.  When it is weaker, during La Nina, it is produces a trough in the West.  I have seen the AAM readings really misused on Twitter.   The strong AAM is likely playing a part in removing the western trough - not the other way around.  I could be wrong.   I am not expert on the topic, but some of the tweets give me some pause.  No knock on BlueWave...haven't read his post.

The 18z actually shows what I think the pattern will evolve to which is strong shots of cold air and storms with warm intermissions.  That is classic El Nino stuff right there.  That is what I think we don't have to worry about suppression for very long.  In fact my worry is the opposite.  

The EPS actually shows a true El Nino pattern with very weak ridging underneath and marginal cold.  That doesn't bother me.  That can work.  What concerns me is the massive shift.  In other words, is that the only shift or is it in the process of shifting to something far less wintry such as a phase 6 look?  When an ensemble breaks in continuity, usually means there are more changes coming or it reverts to the previous look...but rarely stays the same.  

Overall, definite concerns in the LR, but not enough to pull the plug on the variable pattern that should lean cold.  

 

 

[Holston_River_Rambler]

8 minutes ago, Carvers Gap said:

The strong AAM is likely playing a part in removing the western trough - not the other way around.

Yeah, on 33 and rain, someone just posted a GWO/AAM diagram and showed that it was going into phases conducive to Nino type forcing...I think. I'll try to draw it here with the cpc's explanation diagram. 

The Green line is the GFS forecast, no clue where I could find a Euro version. But indeed, it looks like it should drive Nino type convection. 

8 minutes ago, Carvers Gap said:

I have seen the AAM readings really misused on Twitter.

Agree too, that BAMMwx bunch or whatever have been really messing with people lately.

[Holston_River_Rambler]

The EPS apparently sees it as being off the charts, lol:

[Carvers Gap]

10 minutes ago, Holston_River_Rambler said:

The EPS apparently sees it as being off the charts, lol:

Something in the back of my mind makes me think that SSWs can be initiated with big spikes like that.  And I could be wrong.  

Rambler...this is not meant for you, just my general musings.  I was thinking today of all of the things that have to be right for us to get winter...MJO, QBO, ENSO, AO, PNA, etc.  And then I though, sometimes it just gets cold when it wants to get cold.  And sometimes it is warm in spite of good alignment of all of those.  To me, I think we can add the AAM to that list.  It may get warm and have nothing to do with that and it may have everything to do with that. 

[Carvers Gap]

At any rate, the sustained big eastern trough/western ridge(EPO) at 500 that was seen universally on modeling for days...has now mostly disappeared on the 18z GEFS and 12z EPS.  And when I mean disappeared...like it is barely on those runs at all.