December/January Medium/Long Range Discussion

[yoda]

6 minutes ago, psuhoffman said:

EPS starting to get colorful day 10-15

 

Those look pretty nice... did the other half of the EPS members just not have that many pretty colors as this half does?

[showmethesnow]

1 minute ago, yoda said:

Those look pretty nice... did the other half of the EPS members just not have that many pretty colors as this half does?

Yeah, he picked the better members.  The other 25 members have some good hits as well but not to the degree these do. Like seeing a continual improvement on the mean though. Keeps inching up slowly but surely where we now have 2 1/2 inch mean through the cities and 4 inch on the PA line.

[frd]

This is highly relevant and most interesting, as I was wondering about this myself, regarding the consequences of a major strat warming ( with wind reversal ) versus a split. 

I copied and brought this over here as I think you guys might enjoy it.  This is an exchange between the co-founder of the site and Earthlight 

Posted 46 minutes ago

  1 hour ago, 33andrain said:

Well, we've lost a sizable chunk of GEFS members over the last 3 runs. We've dramatically lost the GEPS today. I mean...major changes toward PV consolidation. And the Euro is delaying any split day by day; now back to d10, after showing 3 days earlier just a couple of runs ago. Not saying it's not happening, but it's not trending the way of a split. Other people are content with the reversal. I am not content relying on that. A reversal yields a few weeks of Winter. A split keeps us in deep winter through February.

 

The bolded parts of this statement above are not correct. I think there is a bit of a misconception here regarding the stratosphere and the effects of a split. First of all, there is no trend toward SPV consolidation. The SPV is at an extremely weak state on all models and uwind at 65N at 10hPa is forecast to drop dramatically. The SPV is, at the very dramatic least, going to be extremely disrupted, displaced, and abnormally and anomalously weak for this time of year. Second, there is no research or data backing up what you're saying in regards to a reversal vs a split.

 

A significant reversal of zonal winds at the pole is a major warming event of the stratosphere. While impacts are not guaranteed, it almost always suggests high latitude blocking and a propensity for colder than normal air to move into unusual position. A split of the stratospheric polar vortex at multiple levels is an entirely different thing and can lead to varying impacts depending on where the split ends up, how the troposphere is involved, the heat flux involved, downwelling, etc. It's just not as simple as what's bolded above. Here's the deal. The stratosphere is about to undergo significant warming and a very, very notable zonal wind reduction and perhaps reversal. The stratospheric polar vortex is going to be extremely disrupted and displaced, perhaps split. Research suggests that during these significant warming events - even if a split doesn't occur right away - the likelihood of high latitude blocking and cold in the North/Eastern USA and parts of Europe increases dramatically. 

 

My suggestion: Worry less about whether a split happens or not on the OP models. It's going to happen eventually, just a matter of time. The signal we consistently see moving up in time is a major warming event and major reduction of westerlies near the pole. This is more than sufficient to suggest that high latitude blocking will develop and the pattern across North America, particularly the Northern 1/3 of the USA and Canada, will turn colder and more stormy. 

 

 

[Maestrobjwa]

5 minutes ago, frd said:

This is highly relevant and most interesting, as I was wondering about this myself, regarding the consequences of a major strat warming ( with wind reversal ) versus a split. 

I copied and brought this over here as I think you guys might enjoy it.  This is an exchange between the co-founder of the site and Earthlight 

Posted 46 minutes ago

  1 hour ago, 33andrain said:

Well, we've lost a sizable chunk of GEFS members over the last 3 runs. We've dramatically lost the GEPS today. I mean...major changes toward PV consolidation. And the Euro is delaying any split day by day; now back to d10, after showing 3 days earlier just a couple of runs ago. Not saying it's not happening, but it's not trending the way of a split. Other people are content with the reversal. I am not content relying on that. A reversal yields a few weeks of Winter. A split keeps us in deep winter through February.

 

The bolded parts of this statement above are not correct. I think there is a bit of a misconception here regarding the stratosphere and the effects of a split. First of all, there is no trend toward SPV consolidation. The SPV is at an extremely weak state on all models and uwind at 65N at 10hPa is forecast to drop dramatically. The SPV is, at the very dramatic least, going to be extremely disrupted, displaced, and abnormally and anomalously weak for this time of year. Second, there is no research or data backing up what you're saying in regards to a reversal vs a split.

 

A significant reversal of zonal winds at the pole is a major warming event of the stratosphere. While impacts are not guaranteed, it almost always suggests high latitude blocking and a propensity for colder than normal air to move into unusual position. A split of the stratospheric polar vortex at multiple levels is an entirely different thing and can lead to varying impacts depending on where the split ends up, how the troposphere is involved, the heat flux involved, downwelling, etc. It's just not as simple as what's bolded above. Here's the deal. The stratosphere is about to undergo significant warming and a very, very notable zonal wind reduction and perhaps reversal. The stratospheric polar vortex is going to be extremely disrupted and displaced, perhaps split. Research suggests that during these significant warming events - even if a split doesn't occur right away - the likelihood of high latitude blocking and cold in the North/Eastern USA and parts of Europe increases dramatically. 

 

My suggestion: Worry less about whether a split happens or not on the OP models. It's going to happen eventually, just a matter of time. The signal we consistently see moving up in time is a major warming event and major reduction of westerlies near the pole. This is more than sufficient to suggest that high latitude blocking will develop and the pattern across North America, particularly the Northern 1/3 of the USA and Canada, will turn colder and more stormy. 

 

 

So essentially...the strat warming is gonna happen regardless (and the PV remains weak)...and the only real debate is over this "split"?

[pasnownut]

@frd thanks for sharing. Very informative and helpful in understanding this SSW voodo. Sounds like disruption is better for us. Disrupt away then. 

[dallen7908]

6 hours ago, frd said:

Wonder what the accuracy of the Euro is to the GFS in this area of the strat.

I would simply assume that the superior physics of the Euro would equate to a better, more accurate forecast. 

 

I  am not sure about the outcomes here for our areas versus a split or no split. Seems the Euro and the Canadian have it and the GFS no . 

Judah says too difficult to tell at this time.

I know a couple days ago the GFS ensembles vs the op were not even on the same page.  

Alexey Karpechko gave a talk on SSW predictability. He found that last year's event was hinted at by EPS members 12-13 days out, predicted by 30% of ensembles 11 days out, predicted by 100% of ensembles 4 days out. 

 

 

[pasnownut]

1 minute ago, Maestrobjwa said:

So essentially...the strat warming is gonna happen regardless (and the PV remains weak)...and the only real debate is over this "split"?

Correct. 

[frd]

9 minutes ago, Maestrobjwa said:

So essentially...the strat warming is gonna happen regardless (and the PV remains weak)...and the only real debate is over this "split"?

Yes, overall things are progressing well for sensible weather impacts here.

There are three outcomes regarding the strat and I highly recommend you check out Isotherm's answer to my question he posted a few minutes ago, on his seasonal outlook post.  

You will get all the answers you need there. 

In a nut shell one specific outcome would raise the ante for a more severe sensible weather outcome, as Isotherm mentioned we just have to see how things progress. 

Again please go and read the update, its very informational and you will see a tie in to the MJO and a historical reference to something that happened before when the MJO was in a similiar location as to where it is now .  Isotherm's update is great as always.   

[psuhoffman]

The strat stuff is interesting and frd I love your updates so please don't mistake this for me saying I don't like your posts...but some are placing way too much emphasis on just the ssw. We have had some extremely snowy periods without a ssw. We have had blocking without a ssw. There are tropospheric forces that can disrupt the PV and we have seen those working so far also. The long range seasonal guidance was already predicting a blocking pattern well before a ssw was on the radar. There is also a chicken or the egg factor here. And I've seen some mention that there may be some correlation between a ssw and warm mjo phases so there might be a link between our warm intermission right now and this ssw.  But before the mjo and soi decides to throw up on us for 2/3 weeks the pattern was progressing just fine. And it now looks to resume where it left off around New Years. 

Now this is like all volcanoes are mountains but not all mountains are volcanoes. Yea a ssw is a good thing. We need a weak PV to sustain a block but not every ssw results in a nao block and not ever nao block is from a ssw. 

Additionally the obsession with the split is irrelevant to our snow chase. I think I would actually prefer it not to split. A severely weakened and perturbed PV is good enough and more predictable and stable. When the underlying factors are lined up favorably anyways stable is good. A total split could lead to a lot of volitility and perhaps even make it harder to get a stable favorable longwave pattern to lock in. Yea there could be some crazy results like a superstorm or arctic blast but it might not be here and it's less likely to be a stance 5-6 week pattern. Be careful what you wish for. We don't need exteme. Everything is lined up in our favor pattern wise to begin with. 

This stuff is fascinating and it's great to track and a ssw can help but I don't think it's the end all be all some seem to be making it. 

[Ji]

I heard the weeklies were good. Now we now to transfer this good to the OP runs

[Wxdavis5784]

1 hour ago, psuhoffman said:

EPS starting to get colorful day 10-15

 

All in with E48 FTW!

[frd]

15 minutes ago, psuhoffman said:

The strat stuff is interesting and frd I love your updates so please don't mistake this for me saying I don't like your posts...but some are placing way too much emphasis on just the ssw. We have had some extremely snowy periods without a ssw.

Of course psu, likewise I love your updates, and there have indeed been many great winters without a SSW. There is way more to the upcoming pattern than just the evolution of this SSW event, or even the event itself. I still find the topic fascinating though, mother nature at her best.   

We have a lot to look forward to, and all the signs, even from months ago, gave us hope this winter would deliver, long before the strat stuff even showed up.  

Wishing we both get our wish of active tracking and and a snowy winter :

[psuhoffman]

1 minute ago, Ji said:

I heard the weeklies were good. Now we now to transfer this good to the OP runs

Patience grasshopper 

[showmethesnow]

7 minutes ago, psuhoffman said:

The strat stuff is interesting and frd I love your updates so please don't mistake this for me saying I don't like your posts...but some are placing way too much emphasis on just the ssw. We have had some extremely snowy periods without a ssw. We have had blocking without a ssw. There are tropospheric forces that can disrupt the PV and we have seen those working so far also. The long range seasonal guidance was already predicting a blocking pattern well before a ssw was on the radar. There is also a chicken or the egg factor here. And I've seen some mention that there may be some correlation between a ssw and warm mjo phases so there might be a link between our warm intermission right now and this ssw.  But before the mjo and soi decides to throw up on us for 2/3 weeks the pattern was progressing just fine. And it now looks to resume where it left off around New Years. 

Now this is like all volcanoes are mountains but not all mountains are volcanoes. Yea a ssw is a good thing. We need a weak PV to sustain a block but not every ssw results in a nao block and not ever nao block is from a ssw. 

Additionally the obsession with the split is irrelevant to our snow chase. I think I would actually prefer it not to split. A severely weakened and perturbed PV is good enough and more predictable and stable. When the underlying factors are lined up favorably anyways stable is good. A total split could lead to a lot of volitility and perhaps even make it harder to get a stable favorable longwave pattern to lock in. Yea there could be some crazy results like a superstorm or arctic blast but it might not be here and it's less likely to be a stance 5-6 week pattern. Be careful what you wish for. We don't need exteme. Everything is lined up in our favor pattern wise to begin with. 

This stuff is fascinating and it's great to track and a ssw can help but I don't think it's the end all be all some seem to be making it. 

Great post. Considered writing something similar up as well but deferred because I didn't want to seem critical. I enjoy reading his posts because he does provide much useful information that I otherwise normally wouldn't see. Always seems that pv splits and ssw's are brought up when things seem dire but I think that is very far from the case here as everything looks promising for a great winter as is. I would be perfectly happy with just a continual disruption of the pv which seems to be the case for the foreseeable future anyway. So split or no split I am perfectly content where we stand at this point. And as you said, we see a split it and we are essentially rolling the dice on the outcome. Could roll a 7 and get a block buster winter but we could also roll snake eyes. 

[RitualOfTheTrout]

1 hour ago, psuhoffman said:

Aren't you under water yet?

Per the panel Bob posted with the wave heights he will be by the 27th, no climate change required.

[pasnownut]

18 minutes ago, psuhoffman said:

The strat stuff is interesting and frd I love your updates so please don't mistake this for me saying I don't like your posts...but some are placing way too much emphasis on just the ssw. We have had some extremely snowy periods without a ssw. We have had blocking without a ssw. There are tropospheric forces that can disrupt the PV and we have seen those working so far also. The long range seasonal guidance was already predicting a blocking pattern well before a ssw was on the radar. There is also a chicken or the egg factor here. And I've seen some mention that there may be some correlation between a ssw and warm mjo phases so there might be a link between our warm intermission right now and this ssw.  But before the mjo and soi decides to throw up on us for 2/3 weeks the pattern was progressing just fine. And it now looks to resume where it left off around New Years. 

Now this is like all volcanoes are mountains but not all mountains are volcanoes. Yea a ssw is a good thing. We need a weak PV to sustain a block but not every ssw results in a nao block and not ever nao block is from a ssw. 

Additionally the obsession with the split is irrelevant to our snow chase. I think I would actually prefer it not to split. A severely weakened and perturbed PV is good enough and more predictable and stable. When the underlying factors are lined up favorably anyways stable is good. A total split could lead to a lot of volitility and perhaps even make it harder to get a stable favorable longwave pattern to lock in. Yea there could be some crazy results like a superstorm or arctic blast but it might not be here and it's less likely to be a stance 5-6 week pattern. Be careful what you wish for. We don't need exteme. Everything is lined up in our favor pattern wise to begin with. 

This stuff is fascinating and it's great to track and a ssw can help but I don't think it's the end all be all some seem to be making it. 

It’s just another piece of the meteorological pie,but when it occurs, it can have a lot of influence...arguably more than other indictes that we look for.  Hence the “weight” of the discussion. I didn’t think anyone was over the top with it fwiw. Not that my opinion matters.  Just fascinating to me and as it affects long range I thought this was the place to discuss.

Unfortunately it’s a rarity, and largely not discussed by most (and part of that is because many no little about it (me included). If you think about it...NAO is a rarity of sorts. We chat all the time bout it. Just my .02

[psuhoffman]

19 minutes ago, frd said:

Of course psu, likewise I love your updates, and there have indeed been many great winters without a SSW. There is way more to the upcoming pattern than just the evolution of this SSW event, or even the event itself. I still find the topic fascinating though, mother nature at her best.   

We have a lot to look forward to, and all the signs, even from months ago, gave us hope this winter would deliver, long before the strat stuff even showed up.  

Wishing we both get our wish of active tracking and and a snowy winter :

Your strat updates are great and save me the time of having to search for the stuff. And I wasn't meaning you are making too much. I totally get that your just tracking it. I just hear some people talking about it like it's going to save winter or how it's going to lead to this or that and now some obsessing over split vs no split and I want to be careful we don't put too much into just one factor. That said things look good. Keep beating down the PV by whatever means necessary and it can only help!

[psuhoffman]

13 minutes ago, pasnownut said:

It’s just another piece of the meteorological pie,but when it occurs, it can have a lot of influence...arguably more than other indictes that we look for.  Hence the “weight” of the discussion. I didn’t think anyone was over the top with it fwiw. Not that my opinion matters.  Just fascinating to me and as it affects long range I thought this was the place to discuss.

Unfortunately it’s a rarity, and largely not discussed by most (and part of that is because many no little about it (me included). If you think about it...NAO is a rarity of sorts. We chat all the time bout it. Just my .02

It's more people on twitter than here that are over the top with it but since some of those posts come up associated with links here I wanted to make sure people don't get the impression that we're sunk without a ssw associated PV split. 

[Chris78]

Happy hour delivers!

[pasnownut]

8 minutes ago, psuhoffman said:

It's more people on twitter than here that are over the top with it but since some of those posts come up associated with links here I wanted to make sure people don't get the impression that we're sunk without a ssw associated PV split. 

Fair point. It is exciting to see things starting to look good...Maybe really good. 

[psuhoffman]

37 minutes ago, Ji said:

I heard the weeklies were good. Now we now to transfer this good to the OP runs

Understatement of the year. They look amazing January 10 on. And almost an identical look every week through into feb with no relax in sight.  Never seen anything like it on guidance honestly.  I actually like this run even more than last. Same general idea. Perfect blocking. Less suppressive look the end of January into feb through. We don't necessarily want a big blue ball over us to get snow. 

[psuhoffman]

3 minutes ago, pasnownut said:

Fair point. It is exciting to see things starting to look good...Maybe really good. 

Euro weeklies are an Ian  worthy. 

[psuhoffman]

Visuals 

Jan 7-14 

Jan 14-21

Jan 21-28

Jan 28-feb 4

[Bob Chill]

Weeklies look like we'll miss 49 miles to the north weeks 3-4 and 86 miles to the south weeks 5-6. 

[dallen7908]

EPS gives DCA a 34% chance of >3" of snow between days 10 and 15. 40-50% chance in northern Maryland

[Bob Chill]

18z gefs starting to look more promising for the period around NYE. Eps looks pretty good as well. Imho- that's the first chance we have at something decent. It's tricky though because much will hinge on how far south the departing rain storm can drag the boundary. We usually struggle until the cold establishes and this potential event is at the very beginning of a colder regime. Prime climo season though so it's worth some optimism. 

[weathafella]

I’m salivating over those weeklies...thanks for posting them!

[Ralph Wiggum]

22 minutes ago, weathafella said:

I’m salivating over those weeklies...thanks for posting them!

Nice seeing ya Jerry!

[Bob Chill]

Meteograms are great graphics for showing timing clusters. Around a third of the eps members are showing a similar cluster of solutions for the NYE potential. 18z gefs is the first gefs run that shows this much agreement. An important feature to track is the storm before. We want that to shift as far south and east as possible so the cold boundary drags as far south as possible. 

[JBinStoughton]

1 hour ago, weathafella said:

I’m salivating over those weeklies...thanks for posting them!

Yeah looking good. But there’s a reason they’re called weeklies and not called tomorrow