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AMZ8990

December 2018 Pattern And Forecast Discussion

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I should have added to my "parts" above, a southern stream that just keeps on keeping. Remember when this system we were dealing with now, looked like it would cut to the lakes? If you'd told me that it would end up as a cut off rolling over our heads at that time, I wouldn't have thought it. Usually once we get a good storm (not trying to say everybody did, but it was favorable for some) we have to reset. We kind of are, but these lows taking the low road just don't want to stop. 

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Additionally, it is worth noting that it was the GFS nailed that strat warm last spring from nearly 16 days out, and it also modeled the pattern that followed quite well.  It is notable that its warm-up is quite muted when compared to the Euro right now.  So, after we get through the pre-Christmas warm-up, it appears I will be 1-1(one loss, one verification) on warm-ups during the past two months.  I have yet to cast a lean or vote on the post-Christmas 2-3 week warm-up.  I am also not saying that it won't snow.  I do think the scales tip in our favor by mid-Jan though. As noted in other sub-forums, getting that trough out of the west and getting Canada cold/snowy is going to take some time.  To echo others, just have to be patient.  That said, we do not want this pushed past the third week of January.  For now, I will enjoy running on pavement...my usually jogging routes have been a wreck!

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11 minutes ago, Holston_River_Rambler said:

I should have added to my "parts" above, a southern stream that just keeps on keeping. Remember when this system we were dealing with now, looked like it would cut to the lakes? If you'd told me that it would end up as a cut off rolling over our heads at that time, I wouldn't have thought it. Usually once we get a good storm (not trying to say everybody did, but it was favorable for some) we have to reset. We kind of are, but these lows taking the low road just don't want to stop. 

Yeah, the southern stream is rolling for sure.  Ninos are notorious for 50s for highs and upper 30s for lows along with a consistent amount of precip.  Should have a nice surplus of water by spring.  If we can get some cold to interact over a 2-3 week period w that southern stream...I think we all would be happy.  And I don't think winter is done by a long shot.  However, it may take a longer break than I had anticipated...and I didn't have winter getting rolling until mid-Jan anyway.  So, I think we are on track in terms of climatology.  The JAMSTEC flipping warm definitely gets my attention.  Also, the stubborn Nina-esque SOI is also an issue.  But as you noted, we need to know where this strat split is headed....

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7 minutes ago, Carvers Gap said:

it is worth noting that it was the GFS nailed that strat warm last spring from nearly 16 days out,

What's crazy about what it is showing right now is that it is not only showing one wave of warming, but another one, just as strong at the end, that pushes the SPV toward our half of the hemisphere. Maybe this is pretty subjective/ confirmation bias (i.e. maybe I've only paid attention when it was showing warming)  but, I feel like it's been pretty solid, from even long leads this/ last month with how all the SPV situation has progressed so far. 

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Just now, Holston_River_Rambler said:

What's crazy about what it is showing right now is that it is not only showing one wave of warming, but another one, just as strong at the end, that pushes the SPV toward our half of the hemisphere. Maybe this is pretty subjective/ confirmation bias (i.e. maybe I've only paid attention when it was showing warming)  but, I feel like it's been pretty solid, from even long leads this/ last month with how all the SPV situation has progressed so far. 

Where the cold goes will be key....if we get a split or heavy nudge, we need the cold over here or at least split evenly between hemispheres.  But I am about above my pay grade w strat warm stuff.  I follow Amy Butler on Twitter.  She is usually money with these things.

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Yep, Butler is the way to go. Wholeheartedly agree.  I think the cold usually goes to Eurasia, but not always. I think I remember reading that it has something to do with the fact that Eurasia has more land in the high latitudes, but could also be misremembering something else.  I think it did go to Eurasia at first last year and then it slowly bled west and helped create a block that retrograded into a big -NAO.  As the flow blocked up, the storm track drifted south and eventually we got a good track, but it was something like mid March.  I remember thinking, man, if that had only happened about Dec 25th... Well......

One of her papers suggests that on average SSWs in El Ninos, (no distinction made for displacements vs splits) tends to lead to Greenland blocking and -AO over the 60 days following and, if I'm reading it correctly, that this is more likely during a Nino winter than a Nina.

https://www.earth-syst-sci-data.net/9/63/2017/essd-9-63-2017.pdf

Of course a SSW still has to happen and Butler isn't sold that it will be a major one just yet. 

In terms of blocking I think I'd prefer a more amplified PNA ('93; hey I can dream) to get waves under us and aimed at the Gulf to reduce the risk of the dreaded Miller B or A/B hybrid (worse for my location because it gives false hope), but these can work for others in the area so I will be happy for them if they do well.  And if I can get snow out of some wonky Miller B with uber cold, I'll take it. 

EDIT Here we go: https://www.esrl.noaa.gov/csd/groups/csd8/sswcompendium/

Butler's compendium in the public domain. Anyone can go in, select a date for a SSW and an anomaly, and get a reanalysis plot for 0-30, 0-45, or 0-60 days

If nothing else it gives us a list of events for comparison.

 

 

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Finally managed to grab an EPS stratosphere map (from the NE forum) for comparison. I think it's happening. EPS, GEPS, and GEFS agree. Big question is how big (warm) is it and does this affect us (mid-late Jan- Feb)? And how does it all evolve as it happens? 

I think it offers a reshuffle, but the question is, which deck did we start the game with, and which game were we playing? 

eps strat .png

 

That is to say, how do our current and particular iteration of ENSO along with low solar and other base states this year impact and change this as it evolves?

 

 

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So this system next Friday/ Saturday looks a little interesting. Around half of the EPS members give some area in our region some snow with it, whether it be dynamic cooling snow as it wraps up the coast, or NW flow. 

As it stands now, it's not too far from being a big Gulf low riding up I 95.

Curious to see how it evolves over the next few days, for better or worse. I'll post an Fv3 image here. Euro a little further west/ more cut off with the energy dig. Not a terrible look for 5 - 6 days. 

fv3p_z500_mslp_us_27.png

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The biggest positive I see is a continuation of low pressures that want to try and track under us.  If that remains a winter constant, we likely have an interesting Jan-March coming up.

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Both the 12z GEFS and GEPS show the way out of this upcoming warm-up around the New Year.  JB commented in a post today that the 0z EPS was finally beginning to depict an eastern NA that is compatible w a phase 5 MJO.  Once we get the 500 pattern to switch-up around Jan 1, then it will take about 7-10 days IMHO before we see the first affects at 2m in the SE.  The huge wildcard in all of this is the SSW that is lurking.   Does the strat split?  How does it impact NA?  We saw last spring how abruptly things can change in terms of blocking.  Even the latest Weeklies depicted this abrupt switch w its teleconnections, but for whatever reason the mid-latitudes failed to respond in a way that one would think w those in place.  Of note, the pattern reshuffle has been pushed back a couple of weeks which is no surprise.  For my future reference...those deeply BN heights are a signal of a western cold shot that is very slow to mitigate.  Additionally, if the strat indeed splits...the antecedent warmth over eastern NA is remarkably similar to last spring before it split.  Again, is that a hint that the troposphere is responding in a symptomatic way to the upcoming change or is it proactive element at the lower levels of the atmosphere?  Finally, if we get a decent cold snap of duration during the second half of winter following a December warm-up...that is right out of the El Nino playbook.  I will probably go w Bob Chill in the MA forum(hopefully this is correct), I am not a huge fan of waiting on back-loaded winters.  Thankfully, we had some winter early on.  And I do remain fairly confident(as confident as one can begin when trying to predict chaos), that this winter will feature a second half that holds much winter wx potential.

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MJO just got out of the IO today into the more warm phases.Looks like a potential wet pattern upcoming.Towards the end of the month there should or could be a potential severe threat.I like what Carver said above.All signs seem to be going into the right direction.It really looks good especially towards mid Jan.,we'll see :)

RRWT   Consonant Chaos.png

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I think that's (Wayne Browning?) High Knob Landform (https://www.highknoblandform.com/)  guy. I love his blog. Based on topography I could see how High Knob could kill Big Stone Gap's snow. Still unbelievable how "microclimate" that must have been if Wise got snow and BSG did not.  Wise ought to be downsloped too, I think. I guess there is that big hill between the two on hwy 58. 

Awesome that a local paper is publishing info about things like ageostrophic forcing.  

Is "Thermally Indirect Mesoscale (TIM) Circulation" a thing? Works for me, but haven't heard it before. 

AND High Knob got 40" !!!!!

amazing. 

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4 hours ago, Holston_River_Rambler said:

I think that's (Wayne Browning?) High Knob Landform (https://www.highknoblandform.com/)  guy. I love his blog. Based on topography I could see how High Knob could kill Big Stone Gap's snow. Still unbelievable how "microclimate" that must have been if Wise got snow and BSG did not.  Wise ought to be downsloped too, I think. I guess there is that big hill between the two on hwy 58. 

Awesome that a local paper is publishing info about things like ageostrophic forcing.  

Is "Thermally Indirect Mesoscale (TIM) Circulation" a thing? Works for me, but haven't heard it before. 

AND High Knob got 40" !!!!!

amazing. 

At that point when we are talking about such localized areas the idea of microscale meteorology comes into play. Where even the hills begin to cause a significant effect on the weather in a given location. The truth is the effects of these mountains are always in play always affecting the weather. It's just that winter storms especially with borderline temperatures can better visualize this effect with the amount of snow. A difference between 72 and 75 degrees is negligible but a difference between 32 and 35 degrees can mean all the difference between a dreary day with some snowflakes passing by and being absolutely buried. In a few years time in this hobby I have learned to respect the influence of terrain on microclimates. This storm only furthered my perception of the importance of location especially in regions with mountainous terrain. It leaves me to wonder how anyone could accurately forecast for an area in a major mountain range like the Rockies or Alps.

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I'm hopeful for above 5000 feet Friday PM. Heading up Leconte to see what I can see. 

Late edit: And for what it's worth (probably not much below 5000 feet) the 12z NAM and 0z Euro are currently agreeing on the energy being much further south than the GFS or Fv3. 

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Always could be a surprise, but I think moving focus to January(in agreement w/ @*Flash*) in terms of winter weather is probably not a bad idea.  With that in mind, there are some nice drivers waiting in the wings for January which include increasing (but cautiously optimistic) potential for a strat split and a favorable MJO.  As a caveat, not all SSWs help, but they do tend to promote high latitude blocking.  Right now we have the SOI remaining peculiarly in La Nina territory along w a +QBO.  Not including the anomalous SOI situation, this winter is almost textbook for Nino winters.   If the Nino progression continues as expected, the last half of winter will indeed be winter.  @griteater posted an excellent synopsis in the SE forum.  Here is the link...

 

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Speaking of 2014. I went back and read through that Dec. thread and it is eerie how similar some of the progression was.  Chance at a storm mid month (didn't materialize that time, unlike our Dec. 8-10 storm did for some) then relax in the pattern. MJO was pretty similar, but seems to have been a little behind this year (i.e. progression into and through 4-5-6 came a little later that year, thus the storm chance when we were in 3 was slightly later than this year's, which was, oddly enough, just as we transitioned from 2 to 3). 

 

 

 

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I don't know if any of you follow Crankyweatherguy. He's New England focused but puts out some pretty good stuff. From what I can surmise he thinks deep winter hits all at once this year for a four to six week period(with no reloads) beginning around mid January followed by a normal spring by the first of March. Says we are in our "January Thaw" right now. 

Quote

When we look at the major hit the stratosphere looks to be taking it is entirely possible we see an event where the vortex is completely broken down and we get our dam burst now and all at once.

If so it rarely if ever reconstitutes into another viable entity that suffers another break down and an extension of winter (aka late winter weather into March and April) as we've seen more of in recent years.

I think there are plenty of signs to suggest we're about to see the major event and then that sends us into a rather unbroken six week or so period of winter weather events.

If so then there's no interludge midway, no pattern reload that then comes back, and instead you get it all in one string and then Spring arrives on schedule with no late period surprises.

It has been a while since we've had a winter go like that and there are some things here to suggest maybe that's just what we get. 

 

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Note much of this is not in direct response to you Coach B, but that post kind of gave me a kick start for something I've been thinking about. 

I'm a fan of Cranky (I like his approach of looking at overall N. hemisphere flow) and think what he's saying (strat. aside) pretty much lines up with what most are thinking in terms of the overall pattern  progression. RE: isotherm (not quite biting on a full SPV split); griteater, posted above; Carver's; Jeff, etc..., I say "strat aside" because not everyone is gung ho about the real time results of the strat.  It still is a big question for me, as much as I post about it.  The strat. stuff can be controversial because I think some (not Cranky and no one in our forum) use it or have used it as a "hail mary" type event for past winters that were looking bleak. The word "unicorn" has been used a couple of times today in the MA and SE regions.  

They are tough to predict but I think this one is more in folks' minds since last year's SSW. It eventually created a nice pattern from many in the east, but alas, too late in the season for our area (although Olhausen got a nice late season snow).  I think they are also poorly understood but are starting to be understood more by scientists like Amy Butler (mentioned by Carver's earlier in this thread).

With all that in mind, one thing that I worry about is, let's say best case scenario based on last year, we get a split and a major warming. Now, the pattern was pretty dismal last year with a mega ridge in Feb. Ninas are usually front loaded and one would normally expect an early spring. The MJO was in record territory in phase 6 when the GFS first sniffed the SSW out and in phase 7 when it happened. But as soon as the SSW happened and it's responses were felt, the weeklies/ other models did a big turnaround. Examples from Carver's much appreciated rundown of the weeklies taken from last February: 

"When we began talking about a return of winter w the SSW being part of the equation, I can think of no model that showed a return to cold as the Weeklies completely abandoned any 500 pattern that would support it." -Feb 18, 2018

"Nice to see the Weeklies retrograde the trough into the EC.  And honestly, the 12z run was faster and would likely have produced a colder Weeklies run." -Feb 19, 2018

 

This year, leaving aside for a moment any dramatic SSW or SPV splits, the Euro weeklies/ CFS weeklies are still looking not too shabby from mid-Jan on. Yeah we're in phase 5 of the MJO now and relaxing, but seems like it is a pretty typical Nino progression. What would unfold without a SSW?  2014 - 15 looks pretty similar as a recent analogue, but slightly better so far I would say based solely on the Dec 8 -10 storm. So, does any potential SSW destructively interfere with what was going to unfold? In other words, do we get a worse pattern in the long run because of the SSW? On the other hand, does it constructively help it along even more? Butler's research has shown that El Nino SSWs are associated with blocking in the AO and NAO regions.  

Maybe my "wait and see" from earlier in this thread could have covered all the above ;)  but sometimes writing it out helps me refine what I think. Maybe this is just an attempt at reverse psychologizing the weather?  

Also, since there isn't much else right now, anyone got any links to info on Mountain Torque as it relates to overall patterns? Last year the buzz word seemed to be GLAAM, this year I keep seeing Mountain Torque (MT). 

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I want say that we began talking about the strat split in early February last year.  It was pretty neat to see an event modeled that far in advance on the GFS, and to see it impact our weather as it did.   If it had come two weeks earlier, we would have been hammered.  And yes, it took wx models some time to see the high latitude blocking that would develop in its wake.   An SSW is similar to one of those recurving typhoons near Japan....you know it is going to shake-up and reshuffle things, but the models will be all over the place for some time.  

Yep, I have found at times the the Weeklies can really whiff on pattern changes, especially if it is a return to cold.  Sometimes they will also erroneously perpetuate a pattern.  The Weeklies also have a habit of following whatever base pattern(warm or cold) that the Monday or Thursday AM run had.  What they do a good job of is modeling the 500 pattern during non-shoulder season timeframes.  Last winter they had a cold December, then didn't, and then went full bore.  As noted the GFS suite nailed the strat split from 16 days last year.  This year, the CFS may have nailed it from 25(think that is correct) days out...crazy!  It is really tough to tell how the troposphere will be effected in this hemisphere.  Last year, it initiated incredible high latitude blocking and was present for most of the first half of spring....when it left, it flipped to summer.  If this happens, I suspect when it has run its course we flip to spring as noted above.  But that blocking held for a long time before the split.  Once the split happens, the affects on the stratosphere are instantaneous.  It takes sometimes a couple of weeks to induce high latitude blocking and thus impact the troposphere where we live.  It is basically a massive wrench that gets thrown into a set of spinning gears.  It is going to do some damage, but just no idea what.  (As for the Weeklies tonight, I will guess that they will be warm.  If they had been derived from the PM run, they might have a different progression.) The Weeklies last year flipped on that Monday run that you noted.   The Sunday prior is where I had noted that it seemed to be having trouble.  I think this is correct....the Weeklies did not model the pattern correctly until AFTER the split.  It was crazy how suppressed the actual pattern was for March.  Now just imagine how good that pattern last spring could have been w an active STJ like we have now....a fire hose into cold air.

Now, I do like a wx model that is on time.  Is the 12z Euro beginning to detect some changes?  Yes, but probably due to the MJO progression.  The EPS has been flipping around understandably w its progression during d14-15.  I really like where it went today at 12z.  It basically plopped the trough in the east on its 500 map around d14.  Hopefully that will hold in future runs.  The 2m temps did not respond as it will take a week or so to get cold back into Canada.   It had a source region problem.  Strat split or no strat split, that is exactly were we want the pattern to go.  That is a nice PNA ridge that develops on that run.  Honestly, the strat warm could really enhance what already would be good Nino climatology OR it could screw up what could have been a good timeframe.  My guess, if it happens, is that we will cycle through some very good MJO phases in early to mid-Jan just prior to feeling the strat affects.  Then the strat split affects might actually nullify the warm MJO phases that follow.  

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And again, the SOI staying positive(Nina state) is rare considering that SSTs are in a Nino state.  I am guessing there are very few analogs if any that can match where we are right now....

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31 minutes ago, Carvers Gap said:

My guess, if it happens, is that we will cycle through some very good MJO phases in early to mid-Jan just prior to feeling the strat affects.  Then the strat split affects might actually nullify the warm MJO phases that follow.

Hadn't thought of that approach. I like it!

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Euro Weeklies are rolling.  I can only see the weighted hindcast runs.  Looks like the 500 flips around Jan 4 w 2m temps following a week later.  Source regions has to build up.  We will see what the "normal" Weeklies look like within about an hour.  Will update this post.

**Update**Run was money.  Even better, it was derived from a warm run this AM.  The good thing is the timeline moved up and was not pushed back.  BN temps after roughly first week of Jan...might take until late in the second week at worst.

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Triplets? Just one run of the GFS, but I never thought there could be three. Take it for what it's worth, but I guess a possibility. And here's an interesting thought, would three be inherently more stable than 2? A triangle of little SPVs to keep the wind reversal in place over the pole?

gfs_Tz10_nhem_32.png

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On 12/17/2018 at 8:10 AM, *Flash* said:

Welp. This post didn't age well. 

Pretty unreal that a storm with that structure is going to be mainly rain.  The storm this weekend is a beauty...just very little cold.  It is literally a perfect set-up for a huge snow if it had even the slightest cold to work with.  I still look at each model run in amazement.  I wouldn't be surprised if higher elevations didn't get walloped by it, place like John's or our folks in SW VA at elevation.  The FV3 certainly likes that.  What I hope?  I hope these systems jettisoning out of the GOM keep going.  When we get to Jan/Feb, someone in the forum area scores with that look...

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