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Winter Speculation 17/18 -December Thread


AMZ8990

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3 hours ago, nrgjeff said:

It might get ugly on non-managed rivers, creeks and streams. Fortunately the WPC has lower qpf than the Euro chart above. GFS is of course all over the place!

Long-Term the Euro weeklies are probably too warm weeks 3-4. While I'm not really excited about the SSW, we are also not going to blowtorch. -NAO starts east-based but retrogrades for North America iff the model is right.

Northeast Asia trough (downstream of Ural Mountains ridge) also returns, fixtures during cold periods. Ural Mtns ridge is quite believable with the SSW. However shorter wavelength may break USA hearts. Does the snow track skip over us from the Deep South to the Midwest? Northeast Tenn still looks OK but I continue quite bearish below 1,000 FT.

At least TGIF!

Glad you are posting again in this thread.  Thanks for the information and have a great weekend.  Yeah, the urban creeks and mountains streams might get a workout.  I feel confident that there is room in area managed lakes as it is still late winter and they have been drawn down to winter levels.  Obviously, you know all of that!  This may be a rough spring fishing in mountain streams during the spring.  But that may mean good water deep into summer if it keeps up.  Long way to go until then.  Talk about a flip.  Record dry period followed by a deluge....but definitely a common piece of climo for the Tennessee Valley.  Big swings in river levels were a huge problem before the dam system was put into place.  

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While reading today’s discussions here and in the MA forum I felt like I noticed some similarities to discussions earlier in Winter, so I went back and started at page 1 of this thread. By page 5 and especially 6 and 7, similar questions about the pattern to what I see now were being asked then, although with perhaps a little more hope ;) 

Example: on page 6 there is discussion of a trough from the Southwest US to Greenland and the bias of the Euro to hold back energy was noted.

This sounds similar to what the EPS 12z and GEPS are showing at 240 hours today at 500mb.  The GEFS were sort of on board with that look at 12z, but not so much at 18. 

I understand that this is a different season and a different set of circumstances, but maybe the base state that was established early is fighting the recent agitators? I also remember a series of epic, long range overrunning ice and snow events modeled for some eastern US areas around this time that ended up super suppressed.   Well, wouldn’t you know it, the 18z GFS (only one run) is showing a crazy ice/ snow in the mid Mississippi Valley between hours 210 and 260 on what I’m guessing is an arctic front with some 1040-50 highs dropping in behind it.  The CMC is similar at 240, but holds energy back and the front is farther west and north. Euro is pretty flat at 500mb compared to the CMC and GFS.  I do remember those December runs were more oriented W to E than N to S.

I guess my point here is not to look so much for sensible weather at 240 hours, but overall model biases and possible pattern similarities or differences. I can’t go back and look at those model runs as far as I know and I definitely don’t have the pattern recognition skills and experience with model biases that many on here have.  This may be a totally different scenario on a global scale and I could just be trying to find something to hug, but would like to see if any of you think there is any merit to this line of thinking: comparing how things have trended this winter for how they might trend in the future.

 

Also, I'm ready for some epic waterfall hikes soon!

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Good stuff for sure, Holston.

This is off the top of my head...Back in December, the pattern evolution had different drivers than what is coming up.  The -EPO established and the Euro/EPS erroneously put the trough in the West over and over again.  The trough verified in the East.  The EPS has also really wanted a SER and that has not verified often, but it is now and for good reason.  The cold in eastern Canada has been extremely difficult to budge.  It has been a very bad winter for all LR models.   The fast flow and the dry 500 pattern out of Canada in Dec/Jan were just too much.

Upcoming...what is in play now is a -NAO which has been a rare bird during winter in conjunction w a -EPO and -AO.  But the -EPO may weaken a bit.  The SSW is also a major driver and major wild card.  Now, the Euro has a major bias of a trough in the West.  However, it should be there during phase 7 of the MJO which we are in now.  As the MJO rotates into 8 and 1 and maybe 2 and 3...the trough should correct east.  Now, what is different is the Nina wants to really put a ridge in the SE and that may indeed be correct as it fits climo. This is a major league reshuffle on a grand hemispheric scale.  Additionally, the -QBO really favors colder than normal winters in the East.  That is still TBD.

The 12z and 18z GEFS now place the trough in the East and it looks correct given the teleconnections and indicators that we have beaten like a dead horse for the past week.  I would suggest that the EPS is now maybe in error w where the trough is after d10.  It will be interesting to see the GEFS can hold....then if it holds, will the Euro again cave to the GEFS w the MJO potentially entering phased 8.  But this SSW is a big deal and there is a tone of uncertainty.  This pattern could get crazy....not necessarily meaning snow, but just tons of variability.  

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I will add that the 12z GEPS is in line w the 12z/18z GEFS w the return of the eastern trough after d10 and a -NAO.  The EPS is now on its own at that range...and that has usually meant a cave by it this winter.  We will see.  I am not even sure I would say the GEFS/GEPS is a solid trend yet.  Need a few more runs.

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11 hours ago, Carvers Gap said:

I will add that the 12z GEPS is in line w the 12z/18z GEFS w the return of the eastern trough after d10 and a -NAO.  The EPS is now on its own at that range...and that has usually meant a cave by it this winter.  We will see.  I am not even sure I would say the GEFS/GEPS is a solid trend yet.  Need a few more runs.

I certainly hope we do not get a pattern flip early March when everything is in the process of trying to bud out. What is most worrisome to me is that I have seen very few solutions of any model for the next ten days, give or take, that does not include several more inches of rain for the TN Valley region. Great if we can get some of that as snow but we need to seriously turn the tap off for a few days!

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Fortunately, I don't have much budding out right now.  I think TRI is still BN for Feb.  Rain looks like it is in the equation during the short, medium, and LR.  Not super trends overnight on the GEFS and GEPS...but long way for that pattern being reality.  When one looks at the day 5-10, one can see a trough deepen into the East.  To my best recollection, that was not present in the d10-15 forecast of the EPS.   I am to the point that I give it no more weight than the GEFS.  As JB just posted...w the GEFS stalled in MJO phase 7, the current pattern will continue ad nauseam.  The pattern looks exactly like phase 7.  Needs to move to 8,1,2 for winter to return. The GEFS has been much more accurate than the Euro w the MJO.  On a side note, watching it snow on TV right now in South Korea as the luge goes into the finals. Weather making an impact in that event.  Amazing how the geography there looks so much like E TN.  Back to our weather, my thoughts remain unchanged until we see the fallout from the SSW.  I still think it very likely that the models are not handling that well.  

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I hope I'm wrong, but I think barring some kind of ULL or very outside the climo norm events in March, winter is basically over as far as any sustained cold/snow goes. It may get colder than average at times but it will be so late in the year that colder than average will at best be marginal for snow in the region below 2000 feet or so.  Just have to hope for a miracle event. I am slightly ahead of last year snowfall wise, but still low enough to be the 2nd lowest snow total winter in 80 years.  Pretty crazy since late December and most of January were well below normal and we had a 2 week stretch of below freezing weather in the heart of winter. Completely different winter than last year but my area arrived at basically the same place snowfall wise. 

Got cold, couldn't buy moisture. Got moisture, couldn't buy cold. Life in the Tennessee Valley. Congratulations to those in the Western forum, as you guys are probably  at or above normal for snowfall and got to see some nice events this year. 

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31 minutes ago, John1122 said:

I hope I'm wrong, but I think barring some kind of ULL or very outside the climo norm events in March, winter is basically over as far as any sustained cold/snow goes. It may get colder than average at times but it will be so late in the year that colder than average will at best be marginal for snow in the region below 2000 feet or so.  Just have to hope for a miracle event. I am slightly ahead of last year snowfall wise, but still low enough to be the 2nd lowest snow total winter in 80 years.  Pretty crazy since late December and most of January were well below normal and we had a 2 week stretch of below freezing weather in the heart of winter. Completely different winter than last year but my area arrived at basically the same place snowfall wise. 

Got cold, couldn't buy moisture. Got moisture, couldn't buy cold. Life in the Tennessee Valley. Congratulations to those in the Western forum, as you guys are probably  at or above normal for snowfall and got to see some nice events this year. 

Didnt track it last year or this year but have to say that comparing the two winters, if we got no more snow this year, we would come out slightly, I mean slightly ahead of last year. The big difference this year was that two week period of cold, take that out and it has been a carbon copy of last except with more rain.

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I am with Bob Chill...I am not calling off winter on Feb 11th.  And also to paraphrase him...been plenty of bad hemispheric setups that still resulted in snow throughout the history of the TN Valley.  In NE TN, we have about five more weeks of legit climatology favoring snow, then it drops off quickly.  Obviously, that is less for areas in the southern extent of the region.  We had snow to rain just last Sunday....Like a broken record, I do suspect the models are not handling the medium to LR well due to the SSW.  Once that shakes out and some sort of set pattern re-establishes...then I think we will know better what will be the new pattern.   And also a steal from the MA forum...since this is a speculation thread and not a forecast thread, feel free to throw stuff out there.  I have not problem being wrong with the idea that cold will return. I also have no problem looking at the flip side potential for it not coming back.  I look at weather as trying to solve a puzzle.  Sometimes, one has to move around pieces to see where they fit.  And with the long range forecasts being pretty unreliable lately, I am not taking anything off the table.  But thankful for the rain at the moment....though a break is needed here.  We do have some urban flooding at the usual areas here in town.  But with energy consistently now tracking from the GOM to the NE...I can't rule out anything.  Kind of has a Nino feel to it.

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I will add that MBY sits at 1-1.5" of snow for the entire winter.  I have seen recent winters with over 20" of snow.  This winter will be its own analog, though very similar to 83-84 I think.  Probably will have to go back to 98-99 (off the top of my head) to find so little snow.  But those snowless winters do pop-up here from time to time.  If we can ditch this Nina, I think next winter will be much improved.  Seeing signs of that already.  Moderate to strong Ninas are the kiss of death in the eastern Valley.  Generally, here we need weak ENSO states one way or the other.  I just have seen too many late season snows in the eastern Valley to call things off yet.    

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The cold shot this winter was impressive with its old school cold, and will be spoken of for years to come.  The super Nino had finally worn off and the extremes (which are often expected w Ninas) took hold.  Also, this past summer was very tolerable.  We have an outside shot at BN for the winter here at TRI.  So for me, this winter was much different if one does not factor in snow.  My bushes and shrubs are still just fried from that month long cold snap. But no post mortem for this winter just yet....still roughly a third of winter to go here.

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Two weeks ago...did anyone expect these totals?  We were on the drought monitor with no relief in site.  Below is a 72 hour rainfall total map that the Euro came very close to nailing a few days back.  Now within a 3-4 day period, the Euro is still king...but has lost a bit of its shine now in the longer range.  Things can change quickly when dealing with chaos.  

5a80c1d338ac7_ScreenShot2018-02-11at5_19_47PM.png.c9bd9dbbc08bf7621e432d0555d88bd9.png

 

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1 hour ago, Carvers Gap said:

The cold shot this winter was impressive with its old school cold, and will be spoken of for years to come.  The super Nino had finally worn off and the extremes (which are often expected w Ninas) took hold.  Also, this past summer was very tolerable.  We have an outside shot at BN for the winter here at TRI.  So for me, this winter was much different if one does not factor in snow.  My bushes and shrubs are still just fried from that month long cold snap. But no post mortem for this winter just yet....still roughly a third of winter to go here.

Yea, that cold snap was rough on things like the Southern Magnolia, noticed several with leaf burn; honestly, my attention is turning more to what seems to be an emerging pattern of heavy rain events every four or five days. I am guardedly hopeful for next Winter, I mean, one would think that statistically, eventually, we would get a winter that would feature a couple of good snow events. Take for example, the year after the awful season you referenced, 83' - 84'. That next winter had some good snows from roughly mid January to first half of February.

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Interesting to see very light frozen precipitation for west and middle TN popping up on the 18z GFS and NAM.  It is inside of 24 hours.  RGEM is probably most pronounced.  

GFS has a light to moderate event around 126 for the entire forum area.  Kind of a rain chasing cold event.  Most models have this.  Basically all models have a stalled from that does not get out of the way at that time frame.  I am skeptical but cannot ignore what the models depict.  Been there for a few days.  18z GFS was decently robust compared to recent runs.  

Again...with all of this precipitation running around, it really reminds me of a Nino.  Mostly run, but look out if it ever gets cold.

84-85 is my favorite winter.  But as some in the SE forum will say...they missed out east of the mountains.  We cashed in that winter.

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Couple of morning notes....

The GEFS MJO has moved considerably during the past 48 hours from a stalled look for phase 7 of the MJO to either COD or low amplitude phase 8.  The Euro wants to make the winter tour through phases 8,1,2 at low amplitude. 

Models are still quite warm w a SER really getting established and not wanting to budge.  Let's see how this verifies.  The troughs coming through the East have been undermodeled all winter, even in the current pattern.  I still suspect that we see a trough in the East some time after the 20th.  If that MJO does rotate into phase 8, there could easily be a flip in modeling.

The SSW is now underway per the folks on Twitter.  Let's see what happens to modeling when the split is completed.  I strongly suspect that the pattern after the SSW is probably not being modeled correctly.  Not sure anyone can say with certainty what that new pattern will look like. 

The NAO still looks as if it may try to go negative.  Not a certainty, but likely IMO.  If so, that changes the dynamic.  Now, it can be warm w a -NAO.  It is no magic bullet.  But it strongly correlates to EC late season snowstorms.  

Flooding...pretty crazy that two weeks ago we were all complaining about the drought. Currently, the areas that I run are under 3-4 feet of water.  They were frozen solid one month ago.  So, that is another reason I don't panic when I see modeling looking one way or another at long range, especially when LR modeling has been very suspect this winter.  Thanks to @1234snow and @BlunderStorm for the updates in the observations thread.  The water is rolling down the N Fork of the Holston this AM.  Reedy Creek in Kingsport is also well out of its banks.  I suspect this may now be an ongoing problem this spring.  When flooding starts early in spring...it is just tough to get creeks to say in their banks.  Definitely not a great look if you like fishing in the mountains.  These creeks may stay "blown out" for a bit.   Get those streamers and BH nymphs rigged up.  Hey, one time we decided to fish the South Holston during muddy water - not generating, just muddy. I hooked a fish in Rock Hole that at first I thought was a rock.  I had always heard rumors that big browns are easier to catch in muddy water...I have no idea what I had on the line(might have been a carp as well), but it fell like I was hooked to the back bumper of a UPS truck making Christmas deliveries. Needless to say, I never saw the fish.  No way I fish today.  Also, I never wade fish when the generator water hits.  I always check the generation schedule, and know the time that the water is supposed to rise in my area, and get out(and always have a quick way out if it gets there early).  I have only been caught once in rising water, but that was no major event as we had our way out planned and used it.  There are definitely some scary stories from folks who fished too long once the water began to rise.   I also watch a rock or two as a benchmark just in case water is not released as scheduled.  Now, unannounced generation can be dangerous...probably also good to know if they are working on the generators.  Sometimes they test them.  I also watch fishermen up stream.  They get out if water is rising.  Another thing is to be aware of the sound of the river and fog.  The river will get louder up stream as each hole begins to fill.  Also, the water gets very cold right before the generated water hits and creates fog.  But it is much safer to know how fast water travels to your area of the river.  Also, the fish quite rising.

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Looking at the 12z ICON and GFS I'm starting to root for the SE ridge to flex more the next couple of weeks to push the endless rain train a little bit north and give us at least a few days of downslope, sunny, and dry. Starting to feel like I live in Seattle. And this is only after a week or so of it...

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1 hour ago, Holston_River_Rambler said:

Interesting continuation of an earlier twitter conversation from last week about the SSW, branches of PAC jet, and Southeast Ridge: (not much speculation for the future here, more of an educational post-mortem of how it has played out)

 

Definitely been some back and forth today.   Seemed to me that he was getting frustrated with some comments directed his way....I was definitely interested in this comment below.  Though, I encourage everyone to read the entire conversation.  Lots of wiggle room in most of those Twitter comments.  Nobody knows anything for sure right now.  The LR models are spitting out some solutions that provide a very wide range of solutions.  

 

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7 minutes ago, Carvers Gap said:

Definitely been some back and forth today.   Seemed to me that he was getting frustrated with some comments directed his way....I was definitely interested in this comment.  Though, I encourage everyone to read the entire conversation.

 

Indeed. Hope was kindled. Crankyweatherguy (http://www.stormhamster.com/entry/e021218.htm ; mostly forecasting for the 95 corridor) also helped light the beacons by showing the Bering Straight Rule for 3/1 - 3/5. Not too confident in how I read these BSR maps, but superficially it looks good. 

BSR 3:2.png

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1 minute ago, Holston_River_Rambler said:

Indeed. Hope was kindled. Crankyweatherguy (http://www.stormhamster.com/entry/e021218.htm ; mostly forecasting for the 95 corridor) also helped light the beacons by showing the Bering Straight Rule for 3/1 - 3/5. Not too confident in how I read these BSR maps, but superficially it looks good. 

BSR 3:2.png

That is @jaxjagman territory right there.   It will very interesting to see where high latitude blocking sets up, where the MJO is at the time, and how the changing wavelengths of the season interact.  

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Honestly, I still don't think anything past Feb20 is in focus...even less so than normal.  So many variables in play...give me that block and let's play ball.  Could be a strikeout, but hey...when is that not off the table at this latitude.  -NAO's in late February are rarely boring.  Time will tell.  Still a couple of weeks away from that window.

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