January Medium/Long Range Disco Thread

[dallen7908]

... but the impressive WAFz spans the troposphere and stratosphere suggesting that the upcoming SSW is occurring in an atmosphere pre-disposed to troposphere-stratosphere coupling, which may make the winter storm track further south than normal either here  or in Asia as early as the last week of January - perhaps that elusive HA storm - given how low and stable the NAO/AO are forecast to be.

... Alternatively, we can skip the acronyms and focus on the January 3/4 period

 

 

[CAPE]

8 minutes ago, WinterWxLuvr said:

Noticed that the actual numbers for the AO and NAO have been above the forecasted numbers for the past week or so. They don’t appear to be at the levels desired just yet.

As long as the models get those numbers to the desired levels at day 15, perpetually, we good!

[Maestrobjwa]

8 minutes ago, CAPE said:

People pay more attention to the esoteric voodoo shit when the LR pattern doesn't look so good.

With all the mixture of pessimism and impatience in here...I'm losing a sense of where we are here...Are folks impatient or are the LR looks actually not looking as good as they were a week ago?

[CAPE]

Just now, Maestrobjwa said:

With all the mixture of pessimism and impatience in here...I'm losing a sense of where we are here...Are folks impatient or are the LR looks actually not looking as good as they were a week ago?

Both are true to some extent.

I was just effing around a bit with that post, although it is accurate..to some extent.

[MD Snow]

14 minutes ago, Maestrobjwa said:

With all the mixture of pessimism and impatience in here...I'm losing a sense of where we are here...Are folks impatient or are the LR looks actually not looking as good as they were a week ago?

Imo, we have two opportunities for wintry precip over the next 9 days. There's a chance the new years system changes over as it heads out, especially for northern and western areas. And there does seem like a window in the pattern for a coastal next Sunday/Monday before the trough builds into the western US. This appears to lead to a brief warm period before possibly a good pattern sets in for middle to end of January. This is based off the super long range guidance which isn't always the most dependable. Another thing, I get the whole decent pattern with no real cold around...but if there was a time we could score with limited cold it would be in January. 

[psuhoffman]

53 minutes ago, CAPE said:

Judah has his explanation for the modeled mild period in the east for early Jan. Ofc it is related to SPV disruption. What else could it be?!

 

Full disclosure I am not an expert of the strat so everything I’m about to say relies on stuff I’ve read about it from others I trust. But this might be a case of a blind squirrel finding a nut. I did see some evidence that the precursor periods to a SSW tend to be mild in the CONUS.   On a very basic level it makes some sense. The largest source of heat added is the tropical pac. If that heat is being transported poleward we are kinda in the way.  That’s just speculation. I’ve not seen enough on the “why” of the correlation just that it’s there. 

[CAPE]

1 minute ago, psuhoffman said:

Full disclosure I am not an expert of the strat so everything I’m about to say relies on stuff I’ve read about it from others I trust. But this might be a case of a blind squirrel finding a nut. I did see some evidence that the precursor periods to a SSW tend to be mild in the CONUS.   On a very basic level it makes some sense. The largest source of heat added is the tropical pac. If that heat is being transported poleward we are kinda in the way.  That’s just speculation. I’ve not seen enough on the “why” of the correlation just that it’s there. 

I am sure there is something to it, but ofc in his world everything ties to the PV. All above my pay grade. Just looking at h5 though, the advertised mildness would appear to be more directly related to the big ass trough sitting near AK, in combination with the Pac jet.

[Isotherm]

21 hours ago, frd said:

We need at @Isotherm to come in here and do a little updating. 

I believe according to his seasonal forecast , January held the highest probabilities of colder with normal to above normal snowfall for our area. 

 

@frd, not sure if you have been reading my updates in my winter outlook thread, but my thoughts remain the same as those expressed there (and not much disparate then initially w/ January). January still appears to offer the most conducive wintry potential in the Northeast/Mid-Atlantic of the winter, in my view (my initial thoughts were normal to snowier than normal and slightly colder than normal - I don't see compelling reason to abandon this). Those thoughts were, and continue to be expressed irrespective of the outcome of any SSW technical event, a phenomenon which receives too much focus in my view. Speaking generally in the meteorological community, I think sometimes there is a propensity for expectations to be set too high, and when modelling doesn't accord with those overly heightened expectations, disappointment ensues (E.g., it was never wise to set the bar at "epic" January - while that outcome can happen - it's still somewhat low probability). The current contemporaneous wave-1 hit on the SPV + multiple robust Siberian high descents-->+EAMT--> jet extension should be more than sufficient to tilt the NAO/AO negative for much of January. As the initial jet extensions begin to relax post the medium range, I anticipate amelioration in the PNA domain beyond the 5th or so of January. The "good" news is that the troposphere has evidenced receptivity to stratospheric alterations this winter, meaning, coupling and feedback strat-trop is present, so even if a technical SSW occurs (again, not needed to reach my expectations for a decent January), it will tend to feedback and promote/maintain tropospheric blocking. Overall, I do not see substantial reason to panic from a winter enthusiast's perspective for the month of January in particular.

[Ji]

Central Ohio is going to get a white Christmas and new year. Complete bs

[frd]

2 minutes ago, Isotherm said:

multiple robust Siberian high descents-->+EAMT--> jet extension should be more than sufficient to tilt the NAO/AO negative for much of January. As the initial jet extensions begin to relax post the medium range, I anticipate amelioration in the PNA domain beyond the 5th or so of January.

Tom, in your view, can there be too much of a +EAMT event?  Meaning, having multiple events is it a net plus or minus to a desired Eastern cold state in time?

 

[frd]

6 minutes ago, Isotherm said:

if a technical SSW occurs (again, not needed to reach my expectations for a decent January), it will tend to feedback and promote/maintain tropospheric blocking. Overall, I do not see substantial reason to panic from a winter enthusiast's perspective for the month of January in particular.

Last thing, if we have a favorable SSWE for example whether it be a displacement event, or a split, of combination is it possible that under certain circumstances it can create its own regime, over-powering say even the Pac influences or is that not a valid possibility ? 

I ask because HM alluded that the strat may be able to create its own regime under certain circumstances  in a recent post several days ago. Thanks 

[MD Snow]

8 minutes ago, Ji said:

Central Ohio is going to get a white Christmas and new year. Complete bs

Not according to the GEM. Oklahoma/Kansas snowstorm. Totally different evolution than GFS. Screws our chances of any coastal development on Jan 3-4. 

[Yeoman]

11 minutes ago, Ji said:

Central Ohio is going to get a white Christmas and new year. Complete bs

Still plenty of time for it trend west

[Isotherm]

31 minutes ago, frd said:

Tom, in your view, can there be too much of a +EAMT event?  Meaning, having multiple events is it a net plus or minus to a desired Eastern cold state in time?

 

 

25 minutes ago, frd said:

Last thing, if we have a favorable SSWE for example whether it be a displacement event, or a split, of combination is it possible that under certain circumstances it can create its own regime, over-powering say even the Pac influences or is that not a valid possibility ? 

I ask because HM alluded that the strat may be able to create its own regime under certain circumstances  in a recent post several days ago. Thanks 

 

As you know, examination of one variable in a vacuum is typically complex given there are always/invariably numerous constructively and destructively interfering forcing agents. That said, all else being held equal, generally +EAMT events are a net positive as far as enhanced favorability for downstream z500 patterns in the E US. The overall momentum budget right now is one of near parity to slightly above neutral, so we do not have a situation akin to 2016 w/ extremely high momentum precluding all ridge formations upstream (note, even in Jan 2016's very high momentum, the PNA was positive). Furthermore, the subseasonal forcing [e.g., MJO incoherence] also argues against prolonged -PNA. The mean state forcing thus far has promoted a neutral to positive PNA (which I expected until Feb) with a positive EPO. I would err toward model guidance improving on the PNA as we move past the New Year. As to your other inquiry - the location of the daughter vortices post split (or vortex post displacement) would govern location of coldest anomalies, but there are also gradations of SSW events -- some which briefly reverse z10/60N zonal winds, and those (more rare) which destroy the vortex. The latter tend to be better at creating their own regimes for about a month, sometimes even 40-45 days. But yes, hypothetically, sufficiently robust AO/NAO domain blocking would be able to countermand a much less conducive Pacific. Right now, modelling depicts the blocking action center slightly too far south on the Atlantic side to countermand. I think you'll find some of these z500 depictions changing somewhat over the next several days. Model chaos is further heightened in times of significant vortex assault as well.

[aldie 22]

44 minutes ago, Ji said:

Central Ohio is going to get a white Christmas and new year. Complete bs

My sister is sending me pictures of her sledding 

[frd]

8 minutes ago, Isotherm said:

I think you'll find some of these z500 depictions changing somewhat over the next several days. Model chaos is further heightened in times of significant vortex assault as well.

Excellent info, thanks.  

 

[psuhoffman]

1 hour ago, CAPE said:

I am sure there is something to it, but ofc in his world everything ties to the PV. All above my pay grade. Just looking at h5 though, the advertised mildness would appear to be more directly related to the big ass trough sitting near AK, in combination with the Pac jet.

You are totally right that he ignored other factors and focuses all on his baby the strat.  Nothing is one thing in weather.  It's so many variables working together...and when things are wrong its always more then one thing.  But this is interesting to me...in the sense I am always trying to learn and this is an area I can definitely understand better.  

The N Pac vortex is definitely our most direct "problem" but I think it might be symbiotic to an extent with what he is talking about.  I saw some posts from strat "experts" who implied that the anomalously strong vortext in the WPO and EPO domains are part of the process in getting a January SSW.  Additionally getting a strong heat flux from the tropics in conjunction and you have the perfect setup to transport that heat poleward.  Unfortunately we are in the way of that transport.   There is some "evidence" of this on the 6z GEFS.

This is a 5 day mean.   From about 24 hours to 144 hours the N PAC vortex actually pulls back enough that we COULD have had a better outcome.  And we might sneak in a snow event somewhere in there if we get VERY lucky...but the ridge over the northeast really screws it up.  But that ridge has its inception in the tropics...if you go back and look at where a LOT of that heat got added it originated in the tropical pacific and was drawn up by the PAC trough so its symbiotic. 

 But that ridge prevents systems from amplifying into the 50/50 region where it could help to retrograde the Atlantic blocking into a favorable spot.  Instead systems cut way too far west and get stuck...and actually help to prevent the blocking from retrograding west.  Basically because of that ridge in the northeast the block alignment gets systems stuck WEST of the block instead of UNDER the block.   That gets the trough stuck in the west and cannot progress east UNDER THE BLOCK...like we want.  I don't know how much of that ridge is amplified by the heat flux coming from the pacific...but whatever amount it is...it ain't helping that's for sure.  So you are 100% right this is way more complicated then just saying its all about the SSW...but there may be a component here.  

Looking ahead...after 144 the N PAC vortex shifts east and that is lights out for a little while.   It's obvious that the combo of the central pac ridge under the N pac vortex is going to create that pac jet problem...and its likely going to last all winter.  But that N PAC is a net positive IMO.  At times it shifts into AK and thats no good...but at times it has been far enough west to give us a shot.  Mid December was a great example.  It's centered far enough west coming up this week but that NE ridge...we just covered that.  When the N PAC trough pulls back again...if the Block has shifted west enough and we don't have that ridge in the NE it could work.  Looking out to the end of the run...

Similar setup to this week...but this time the blocking has migrated far enough west to set up better alingment to the "blocking" to get the flow to progress east UNDER the block v get stuck west of it.  This is still not a truly cold pattern...I don't think that is in the cards this year.  The pac is not right...but a direct flow from the YUKON in mid January better work...and I mean this...if a direct discharge of domestic air from the Yukon (even absent cross polar flow) is no longer good enough in dead mid winter...we are in big trouble snow climo wise...and I am not having THAT debate on this just stating a fact.  The issue is...does the blocking retrograde...and that is the thing.  If that blocking remains more of a WAR we will likely get similar results.  All the guidance says it does retrograde.  And the way it progresses kinda makes sense it would...the PAC trough crashing into the west actually helps...its gets the trough stuck so far west for a time that it allows the WAR to retrograde on its own even absent much wave breaking simply beause there isnt strong low pressure stuck north of the lakes preventing it.   But it all comes down to that...if when the pac back off again the blocking is centered in the western NAO domain we will get a good pattern.  If it is still a WAR we won't imo.  

[snowfan]

44 minutes ago, losetoa6 said:

Didn't it snow a coating to  1-2 inches in many places around here  yesterday and almost forum wide saw at minimum flurries yesterday . Asking for a redneck friend 

And NY is 6 days away ...just saying 

Many places definitely did not see 1-2 inches yesterday.

[WinterWxLuvr]

Seems like a good time for me to say, again LOL, that for just cold wintry weather, the Pacific is far more important that the Atlantic. I guess if you’re looking for big snows the Atlantic may be the king.

[psuhoffman]

Just now, losetoa6 said:

Definitely not.  But many areas saw a dusting to as much as 1-2" locally . Point being it was a white Christmas for the majority of the forum and a wintery look and feel on Xmas  

Ji isn’t chasing car toppers and 1” events.  And I kind of get it. He likes the thrill of the chase. The model runs that show some big hit. He isn’t in it for a cold day with snow showers. 

[cbmclean]

10 minutes ago, WinterWxLuvr said:

Seems like a good time for me to say, again LOL, that for just cold wintry weather, the Pacific is far more important that the Atlantic. I guess if you’re looking for big snows the Atlantic may be the king.

The Atlantic may be mitigating the effect of the Pacific somewhat, which is better than nothing.  But three straight years of crappy Pacific gets old.

[WinterWxLuvr]

5 minutes ago, psuhoffman said:

Ji isn’t chasing car toppers and 1” events.  And I kind of get it. He likes the thrill of the chase. The model runs that show some big hit. He isn’t in it for a cold day with snow showers. 

It may be different where you are, but in the northern tip of Va we don’t do cold day with snow showers. We get the cold day with snow flurries some but true snow showers on a cold day accumulate a bit. That’s the part of living on the west side of the apps that I miss. There you can get those convective type snow showers that can be pretty amazing if you like an inch of snow in 20 minutes type deal.

[psuhoffman]

13 minutes ago, WinterWxLuvr said:

Seems like a good time for me to say, again LOL, that for just cold wintry weather, the Pacific is far more important that the Atlantic. I guess if you’re looking for big snows the Atlantic may be the king.

For arctic cold yes. Need epo ridging. Historically we could snow fine without that. The majority of the warning events in my case study happened with temps near 32. Some above 32. A lot mixed at some point. Most of our snow historically wasn’t cold smoke. I do wonder if more recently the pacific isn’t becoming more important if warming has rendered domestic non arctic origin cold in effective for snow chances. That’s just speculation at this point. 

[cbmclean]

Tropical Tidbits has limited euro products.  Does the Euro agree with the Alaska vortex?

[WEATHER53]

Best pattern ever for mild rain followed by cold followed by mild rain.  There is pattern discussion and then pattern recognition 

[WEATHER53]

2 hours ago, leesburg 04 said:

Maybe today?

SSW is theoretical with no proven track record and for every 4 that are forecasted as the saviorof the mid atlantic about one materializes and then the excuse  making about some other interfering  factor, Pacific, and repeat cycle.  These  guys get some following with these elaborate technical discussions that go mostly nowhere for mid atlantic

if I could run NOAA I would put all  the money into the 5 day or inside, never forecast for the east coast a low that has not reached west coast yet, stick with what we know works which is mostly the AO and NAO, and quit coming up with new, novel theories presented as the latest exciting, and frequently false,  fact. Also, the sudden unreliability of the ENSO now needs to be factored in and stop conjuring up how  mountain torques in Peru effect east coast USA. 

[WinterWxLuvr]

Euro is nothing like the gfs for the end of the week. LOL don’t know why I said two weeks

[Ji]

8 minutes ago, WinterWxLuvr said:

Euro is nothing like the gfs for the next couple of weeks.

got the CAD. Where is the storm

 

[Ji]

the euro run is a disaster lol

[Ji]

not even sure what we are tracking at this point. It might be pull down the blinds for a few weeks?