January 2021 Medium/Longterm Pattern Discussion.

[tnweathernut]

No clue if this pattern comes to fruition as portrayed, but if it does....... it's the type of pattern that can produce snow on snow (i.e. multiple winter events) for someone in the southeast.

[Holston_River_Rambler]

Here are all 50 EPS members as a gif:

 

A little bit for all, but TRI and SW VA look really good on this run. 

[Carvers Gap]

Euro Weeklies from Jan 9 - Feb 9 are normal for surface temps(minor miracle considering the warm bias of the Weeklies) and the 30 day 500 pattern for the same time frame looks like this:

[Carvers Gap]

Euro Weeklies have a that look(above) until they break during the second week of February and stick the trough back West.  We take - if real.

[Carvers Gap]

46 day snow mean.  Notice how far south it has snow.  That tells us there is some decent cold embedded in that run.  Looks like sliders, hybrid, and inland Miller As for that run as evidenced by the snow map.

[Holston_River_Rambler]

Some of the EPS member progression from days 10 - 15 are so nice. Here are some samples:

 

 

 

 

There were more too and even some of the misses were not rainers, but suppressed storms. There were some rainers in there too. None of these solutions is likely "The" solution, but at least some hint at what could be possible if the block develops nicely. 

 

 

[weathertree4u]

3 minutes ago, Holston_River_Rambler said:

Some of the EPS member progression from days 10 - 15 are so nice. Here are some samples:

 

 

 

 

There were more too and even some of the misses were not rainers, but suppressed storms. There were some rainers in there too. None of these solutions is likely "The" solution, but at least some hint at what could be possible if the block develops nicely. 

 

 

Looks great to me, sure beats last few seasons lol 

[jaxjagman]

2014 the strongest LOW on record during this time frame, into the Bering Sea  and western Aleutians was in a Nino year and the trough axis was further west unlike this year we are in a NINA,other drivers should be noted just as well,just pointing out the ENSO.

 

 

https://www.adn.com/alaska-news/weather/2020/12/31/bomb-cyclone-heading-toward-aleutian-islands-becomes-strongest-storm-ever-to-hit-alaska/

 

[Chattownsnow]

17 hours ago, Holston_River_Rambler said:

EPS

 

It has been so long since I have seen a pattern like that modeled with staying power. Dare I say 2009-2010 look there? Which is funny considering a completely opposite ENSO. 

[Carvers Gap]

One thing I am noticing at 12z...the cold air source is very lacking.  Growing concern.  Pattern at 500 is as advertised and even forecast to occur just a few days earlier than what was modeled just a few days ago - just very little cold air in Canada to pull from.  The 12z EPS actually has the cold in Canada rotating back to Siberia over the next several days.  Source for cold is the Pacific on modeling at 12z.  I think by later this month that improves, but waiting on a pattern is an all to familiar practice and risks losing the 500 pattern by the time the cold air gets here. Looks like a reload on the EPS is modeled to BEGIN mid-month for Canada.  Unless something major changes, think we are waiting until after the 20th for enough cold without having to thread the needle.  It can still snow with this block, but it is going to be finesse stuff.  Don't think we see a truly cold North American pattern until later this month at best - all of the cold is bottled up in Siberia and barely moving by the end of the EPS run which is Jan 16th.  Again, good pattern...cold air severely lacking.

[Carvers Gap]

That said, there are a couple of windows for storms, but the track is going to have to be perfect.  See one window around the 8th and another about 5-6 days later.  

[Carvers Gap]

One thing I am also noticing is that the strong cyclones over the Bering Sea/Aleutians are acting like a pump which turns counter clockwise and just evacuates the cold from central and western Canada back into Siberia during the next week.  So, we are left with marginally cold air in the SE of Pacific origins in order to get the job done.  That can happen, but just makes the job that much tougher.  And admittedly, some great snow patterns have occurred when cold sources were marginal.

[Carvers Gap]

What we need is what the Euro op is advertising is that we can get just enough feed in eastern Canada that sneaks into the eastern trough - essentially gets pinched off(yeah, I know!  LOL) as the cold air evacuates.  Would give us enough cold for storms until maybe Canada is re-seeded mid to late month.  

One positive note is that the NCEP MJO models "appear" to be moving to the colder Euro MJO.   The EMON yesterday goes into 2 and then rotates back through the colder areas of the COD and back towards colder phase - much different than the GEFS.

So, for me I am riding with the EPS almost completely in the LR.    The GEFS/GFS has really struggled of late.  

 

[Holston_River_Rambler]

We slosh?

 

Until the mythical slosh commences, I'm just going to pretend I live in Redding CA for the next 10 - 15 days. Weather isn't much different. 

[Carvers Gap]

4 minutes ago, Holston_River_Rambler said:

We slosh?

 

Until the mythical slosh commences, I'm just going to pretend I live in Redding CA for the next 10 - 15 days. Weather isn't much different. 

Are you able to do a gif of the Euro operational of just 850 temps (no anomalies) from the same pole view.  That would really show what is happening over western/central Canada.  

[Carvers Gap]

9 minutes ago, Holston_River_Rambler said:

We slosh?

 

Until the mythical slosh commences, I'm just going to pretend I live in Redding CA for the next 10 - 15 days. Weather isn't much different. 

Found it Holston....Watch the cold just get lifted out of Canada by the Bering Sea cyclones.  Also, watch a bit of cold slide down through eastern Canada.  Just click on "FRD replied to topic."  That might hold us over until Canada can become more favorable from a temp stand point later in Jan.

 

 

[John1122]

I'm still a fan of the EPS/Euro.  There's some bone chilling cold on there around D10, -10 to -12 BN 850s. The EPS mean for the last 6 runs has increased the snow mean for the area.  

I'm a big fan of the blocking showing up vs the SE ridge patterns we've had.  My normal is 41-21 over the January 15-31st period. The mean around freezing. So basically normal temps to even slightly AN can still produce snow here.  

The Euro also had a warm bias as a rule. So overall I'm still pretty excited vs the general hopelessness of the last 3 or 4 winters. 

[tnweathernut]

I’m not terribly concerned (at this point) about cold air with the 500 pattern projected. I suppose we could strike out over the 7-14 due to a little too much warmth, but it’s not like Canada can’t supply any cold if we pop a flow from our friends to the north. As always, time will tell.



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[Carvers Gap]

Definitely cold in northern Canada right now, that is not what I am saying.  What I am noting is that nearly all of it rotates over the pole between d3-10 - see FRD's gif which I shared.  So, that is basically going to delay the eastern trough having cold until maybe weeks 3-4 unless we can do what the Euro op does between d8-10 with cold draining alone eastern Canada.  And as noted, the GFS(not the para) is struggling.

The problem in valley areas, is we can't depend on elevation to get snow.  We usually have to have a decent cold source.   The past two snows are great examples of that.  Both had incoming cold sources which fueled the changeover.  I do agree (for now) that this appears to be a temporary problem or Canada which is solved by mid-month in regards to cold refueling Canada.  So the message is this...Cold is in northern Canada now...the coldest air is going to leave quickly due to the Aleutians low and head over the pole to Siberia...and then very gradually return after mid-month into NA.  Now, I am not making the claim that(when it returns) the cold comes into the East as the 500 pattern could change by then - not getting in a foxhole with a week 3 500 forecast from any model.  LOL.  Assuming the Weeklies are correct, the cold should feed into an eastern trough.  But memories of the November head fakes temper my expectations just enough, and that is not without minor model support.  The past two runs of the CFSv2 actually place a ridge(WAR) in the East after the 10th, but that model is swinging wildly.   0z was completely opposite for it.  Likely the CFSv2 is handling the MJO differently(maybe incorrectly).  Again, there are some big differences in the MJO between American and Euro modeling.  

We essentially need the 500 pattern which will be in place around Jan 5th to hold until the cold from Canada can reload the eastern trough mid-month.  I do think we need to watch any cold front that manages to form as the last two snows have been been along those fronts.

[Carvers Gap]

Just took a look at the 12z EPS snow mean - looks very elevation dependent IMBY.  Now, the 12z GEPS ensemble snow mean is a different story, It implies a very good pattern(north of I-40) after the 10th.  That pattern would be absolute money.  The one thing about Canadian modeling is that it has done really well with the past two snows IMBY.  

[BNAwx]

I recall a recent post from Griteater when he was taking about the upcoming SSWE saying that it’s possible the current blocking regime holds for a while, relaxes and then comes back (paraphrasing if you will).  If that happens, perhaps our best shots will be when the pattern reloads.  Maybe at that point we’ll have a better cold source to tap in Canada.  Wild guess at this point and I’d rather not wait for a pattern reload even if that does occur. 

[Carvers Gap]

11 minutes ago, BNAwx said:

I recall a recent post from Griteater when he was taking about the upcoming SSWE saying that it’s possible the current blocking regime holds for a while, relaxes and then comes back (paraphrasing if you will).  If that happens, perhaps our best shots will be when the pattern reloads.  Maybe at that point we’ll have a better cold source to tap in Canada.  Wild guess at this point and I’d rather not wait for a pattern reload even if that does occur. 

Yeah, very possible.  Grit is really good.  I kind of think the pattern at 500 holds(with maybe a ridge rolling through from time to time), but not saying that definitively - just spitballing.  The trick is can we get true cold into the pattern before it changes up - not cold front cold but cold that has 1-2 weeks duration?  Think it is very possible that we have a very good pattern from Jan 15 to Feb 5.  I just don't want folks to get their hopes up like the past few winters!  It is very possible we thread the needle prior to that.  GFS is way too progressive.  I think the Euro and CMC hold some promise late during week 2.

[jaxjagman]

Nice looking trough going through East Asia the next few days.Teles look like the NAO/AO is going to start climbing during this time so lots of uncertainty.Should potentiallly see a system effecting us MId Jan

[tnweathernut]

Good tweet thread here. Thought I’d share....

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[jaxjagman]

Think these maps are so cool,even tho it's 15-days out the GFS shows a split.

https://stratobserve.com/misc_vort3d

[Daniel Boone]

When the stratosphere ruins your seasonal model party Just a wee bit of adjustment for the January pattern on the new CanSips. New on the L, old on the R

 

 

4:03 PM · Jan 1, 2021·Twitter Web Appi

[Holston_River_Rambler]

I really think the models are just now starting to seen whatever the shake out is going to be from the SSW. My take: This -NAO is a product of something else, related to the cause of the SSW or not. We rain and maybe mix above 3000' and snow above 5000' and basically Nino in terms of how the weather seems until mid month. SSW really sinks the AO, screws with the Urals high/ Mongolian Death HPs and jet extension, and cold finally starts to build in Canada. Then a trough dumps west first and cold bleeds east. Maybe we severe too, once or twice. Better pattern then through Valentine's day, maybe a little later. After that, do we revert to this weird base state with blocking developing in a Nina? Is there a second SSW in late Feb? (It has happened) Or do we TNI and severe? 

 

AM ensembles:

 

 

 

 

 

[Holston_River_Rambler]

This SSW is a weird one (granted I've only followed 3 now, but it is different from the three I've seen). 

 

 

 

It's almost like we took last years super strong SPV and 2021 said, yeah.......that was a bad year, let's reverse that and see what happens

Last year:

[Windspeed]

[Carvers Gap]

Day10-15+ discussion...

I am probably one of the few, but I don't think what happens after the 10th(especially after the 15th) is settled.  There are basically two camps for the MJO this morning.  One camp is the ECMWF which holds in phase 2 right at the COD.  The GEFS rotates at decent amplitude into phases 3 and 4.  This likely explains the tendency of American modeling to try to more quickly move the trough into the West on some recent operational runs.   I think this is a less likely scenario than the EPS, but I can't rule it out.  Overall, there is a trend to retrograde the future trough westward.  Some, like the EPS, retrograde it into Texas.  Some, like the last several runs of the CFSv2extended, pop a ridge in the East and never look back - a solution which has yet to verify this winter I might add.   So, I still lean with the EPS/GEPS this AM, but can't rule out something completely opposite of those models due to MJO differences.   We are still dealing with cold source problems at this latitude.  I think the mid-Atlantic near DC, Maryland, and Virginia looks like it could score in this pattern.  

Yesterday, I talked about the flow of cold out of northern Canada.  Still very apparent today as Canada is pretty much emptied of seasonal and BN cold by the end of the upcoming week.  Around d13 the flow reverses back towards NA on most modeling, with the 6z GFS being the quite aggressive.  I think it is tricky business knowing where the cold will go once it returns.  I suspect that goes into the Mountain West and then moves eastward sometime after the 15th.  There is still a risk it could hold in the West if the CFSv2 is even halfway correct.  If American modeling of the MJO is correct, the cold dumps West.  If the Euro is correct, likely rotates into the East after first going into the Mountain West.  Again, this is the time of year in which the Euro/EPS combo is very good.  Some might say the Euro missed the Feb strat split and subsequent cold during March.  True, but that was shoulder season territory where the Euro struggles when wavelengths change IMO.  So interesting times.  

Short to midterm discussion...

Still some potential during the next couple of weeks for high elevation snows and maybe threading the needle in the valleys.  The operational 0z Euro is warmer than its 12z counter part from yesterday.  That said, there is a tendency to push a cold front through around the 10th-11th.  If real, that would a time to watch.  When we have had significant cold fronts this winter(early Dec and Christmas Eve), we have had our chances.  So, looks like a couple of windows, Jan 8/9 and Jan10/11 depending on your model of choice.  The CMC is fairly aggressive with the 8/9th system.   Agree with Jax, that is a bowling ball deal where it just "rolls from the Mountain West through a TBD track in the south.  Then, there is potential for another system right on its heals on the 10/11th as seen on the 6z GFS and 0z Euo.