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Winter 2020-21 Discussion


CAPE
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14 minutes ago, WinterWxLuvr said:

But isn’t there some evidence out there that the NAO and perhaps the AO operate on decadal cycles? CAPE  and PSU would know this. If so what’s happening could just be part of that.

I believe there are -NAO cycles or periods when winter blocking in the NAO domain continued for several winters in a row. Lately as you know the -NAO during the heart of winter has been lacking. 

The real game changer for us and for a large part of the country has been the fast Pac jet causing warmth to dominant and responsible for a lack of phasing storms ( think East Coast , and Miller A s ) and the breaking down of West Coast ridging.  

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7 hours ago, WinterWxLuvr said:

But isn’t there some evidence out there that the NAO and perhaps the AO operate on decadal cycles? CAPE  and PSU would know this. If so what’s happening could just be part of that.

IMO, 18-19 was a decent winter, at least here. The other 4 were bad, with last year being a lol joke. But before that 09-10, 10-11, 12-13, 13-14, 14-15 were decent to extremely good winters. Again speaking for mby. So if I get on average 6 of 11 winters that are good, I’m gonna be ok with that.

Its not decadal. Unless you mean we see a -NAO an average of once a decade lol. That's probably about right over recent decades. There may be some cyclical nature to it, but with a longer period. The NAO has been predominantly positive since the early 1980s. The 40-50 year period preceding that, there were more negative phase years than positive. IIRC, the frequency of ++NAO years has increased since the early 1990s.

Somewhere in this thread I posted a long term time series of the NAO phase (or maybe it was the AO) for the winter months. I cant find it atm. There is a significant correlation between the AO and NAO though. A legit -NAO (not transient bootleg crap) typically occurs when the AO is negative.

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20 hours ago, frd said:

I know it is early,  but I go with 2015-2016 

 

16 hours ago, WinterWxLuvr said:

That’s a 4 year data set. Not sure I’d draw too many conclusions from that.

But hey I’m just posting thoughts not trying to challenge your ideas. You are a valuable contributor here.

I'd argue around 2006/2007 was when we started into a new era. Arctic sea ice loss (an indicator of Northern hemisphere warming) has really accelerated since then. There's obviously not a hard line in the sand, and downstream effects are going to play out over longer timescales, but these two graphs below emphasize it pretty well. 2020 just landed itself as #2 lowest on record after 2012. Link here if you want to mess with the data: https://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/

1997 - 2006

image.thumb.png.9f7fd7d7e7749f46c321abc681b6a892.png

2007 - Present

image.thumb.png.76dcc29dd037c930564da6039983e52c.png

 

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6 hours ago, TSG said:

 

I'd argue around 2006/2007 was when we started into a new era. Arctic sea ice loss (an indicator of Northern hemisphere warming) has really accelerated since then. There's obviously not a hard line in the sand, and downstream effects are going to play out over longer timescales, but these two graphs below emphasize it pretty well. 2020 just landed itself as #2 lowest on record after 2012. Link here if you want to mess with the data: https://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/

1997 - 2006

image.thumb.png.9f7fd7d7e7749f46c321abc681b6a892.png

2007 - Present

image.thumb.png.76dcc29dd037c930564da6039983e52c.png

 

Ok but we aren’t talking about sea ice. If this new regime is to be applied to winter outcomes then we basically can say that roughly half of the winters in this 14 or so year long new era have been decent to good to great. I’d be willing to wager that if you take the preceding 14 or so year period you’d probably find about half of those winters to be decent to good to great. In other words, I don’t think there’s data that links the warming to the winter outcomes. If there is I haven’t seen it. And I certainly don’t think you can link arctic sea ice to the outcome of winter. If that’s the case then explain the years 2012-2013 through 2014-2015.

Not seeing this new winter area, especially after just a handful of less than stellar winters.

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51 minutes ago, WinterWxLuvr said:

Ok but we aren’t talking about sea ice. If this new regime is to be applied to winter outcomes then we basically can say that roughly half of the winters in this 14 or so year long new era have been decent to good to great. I’d be willing to wager that if you take the preceding 14 or so year period you’d probably find about half of those winters to be decent to good to great. In other words, I don’t think there’s data that links the warming to the winter outcomes. If there is I haven’t seen it. And I certainly don’t think you can link arctic sea ice to the outcome of winter. If that’s the case then explain the years 2012-2013 through 2014-2015.

Not seeing this new winter area, especially after just a handful of less than stellar winters.

I'm not explicitly talking about sea ice either. I'm talking about the northern hemisphere warming overall which is undeniably happening whether you believe in AGW, or not. The Arctic sea ice extent is one way to look at that phenomenon as it is something we have solid data on for decades now. I'm not talking about what has happened in this tiny part of the globe the past 30-40 years.

It's quite possible we're seeing the downstream effects of a less frozen artic 5-10 years later. Of course one bad summer for sea ice doesn't mean some part of the Northern hemisphere is going to have a mild winter... there isn't any connection that simple, but decades of accelerating trends tell a story. Do we know exactly what that means for our backyards? No. Can we identify that things are changing and have been doing so at a higher rate than previously recorded since a certain point in time? Yes.

The Arctic is our source for cold and it's warming faster than any other part of the globe. If you don't think that's a sign that we can expect changes in what the average winter will be like moving forward, I don't know what to say.

EDIT: Adding some snow cover data since that seems it'll get better traction here. https://nsidc.org/cryosphere/sotc/snow_extent.html

Animation of June snow cover anomalies

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24 minutes ago, TSG said:

I'm not explicitly talking about sea ice either. I'm talking about the northern hemisphere warming overall which is undeniably happening whether you believe in AGW, or not. The Arctic sea ice extent is one way to look at that phenomenon as it is something we have solid data on for decades now. I'm not talking about what has happened in this tiny part of the globe the past 30-40 years.

It's quite possible we're seeing the downstream effects of a less frozen artic 5-10 years later. Of course one bad summer for sea ice doesn't mean some part of the Northern hemisphere is going to have a mild winter... there isn't any connection that simple, but decades of accelerating trends tell a story. Do we know exactly what that means for our backyards? No. Can we identify that things are changing and have been doing so at a higher rate than previously recorded since a certain point in time? Yes.

The Arctic is our source for cold and it's warming faster than any other part of the globe. If you don't think that's a sign that we can expect changes in what the average winter will be like moving forward, I don't know what to say.

You said since 2006. I said half of those winters have been good. I guess we can revisit this conversation in 14 years. 
 

 

 

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3 minutes ago, CAPE said:

CFS seems to be off the crack and now looks pretty much identical to the CanSIPS for early winter now.

cfs-mon_01_z500a_namer_2.png

I do have a serious question. Or two. That look is almost zonal but in the pacific it shows that same zonal flow as being much above normal. Is “normal” a trough there. I mean if you lower heights in a zonal flow wouldn’t that result in a trough?

Also, aren’t those heights in the arctic centered in such a way that it’s “leaning” toward eastern North America? Couldn’t that produce bouts of cold in the east from time to time with just a bit of transient ridging along the west coast?

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25 minutes ago, WinterWxLuvr said:

You said since 2006. I said half of those winters have been good. I guess we can revisit this conversation in 14 years. 
 

 

 

I said sometime around 2006/2007 was the potential start of a new "era" and then explained why I felt that way with data. If you want to say I'm wrong in that opinion, back it up bud. Your anecdotal evidence that things haven't seemed to change doesn't count.

 

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18 minutes ago, WinterWxLuvr said:

I do have a serious question. Or two. That look is almost zonal but in the pacific it shows that same zonal flow as being much above normal. Is “normal” a trough there. I mean if you lower heights in a zonal flow wouldn’t that result in a trough?

Also, aren’t those heights in the arctic centered in such a way that it’s “leaning” toward eastern North America? Couldn’t that produce bouts of cold in the east from time to time with just a bit of transient ridging along the west coast?

That is a pretty terrible look for a LR h5 height anomaly mean. But sure, its a smoothed mean, so there would obviously be some perturbations in the overall pattern. Big picture is crap though. The CFS,  CanSIPS. JMA, etc, might all have the wrong idea at this juncture, but it fits recent winters, and is characteristic of Ninas in general. It really is all about the placement/strength/orientation of the Pacific ridge. If we luck into a legit HL block, even if the EPAC ridge parks in an unfavorable location as currently advertised, the impact could be mitigated somewhat.

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46 minutes ago, TSG said:

I said sometime around 2006/2007 was the potential start of a new "era" and then explained why I felt that way with data. If you want to say I'm wrong in that opinion, back it up bud. Your anecdotal evidence that things haven't seemed to change doesn't count.

 

LOL your data was sea ice. Like everyone doesn’t already know that. I have no idea if you’re wrong. That’s my whole point. You can’t look at the past 5 years of winter and draw a conclusion that we’ve entered into a new era of winter weather. If you want to say we’ve entered into a new era with arctic sea ice then I’d say your data supports that.

See ya, bud.

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35 minutes ago, CAPE said:

That is a pretty terrible look for a LR h5 height anomaly mean. But sure, its a smoothed mean, so there would obviously be some perturbations in the overall pattern. Big picture is crap though. The CFS,  CanSIPS. JMA, etc, might all have the wrong idea at this juncture, but it fits recent winters, and is characteristic of Ninas in general. It really is all about the placement/strength/orientation of the Pacific ridge. If we luck into a legit HL block, even if the EPAC ridge parks in an unfavorable location as currently advertised, the impact could be mitigated somewhat.

Yeah but what I was saying is that that map shows extreme high heights in the pacific but the height lines don’t really show a pronounced ridge. So what I’m asking is would “normal” heights produce a trough there?

Not really commenting on whether what it shows is good or bad. It’s pretty clear it’s bad. I’m just confused why mega high heights (relative time normal) don’t produce a pronounced ridge.

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34 minutes ago, WinterWxLuvr said:

LOL your data was sea ice. Like everyone doesn’t already know that. I have no idea if you’re wrong. That’s my whole point. You can’t look at the past 5 years of winter and draw a conclusion that we’ve entered into a new era of winter weather. If you want to say we’ve entered into a new era with arctic sea ice then I’d say your data supports that.

See ya, bud.

The whole start of this was around the statement that looking at analogs from decades ago may be somewhat worthless as the global pattern drivers are changing. You are arguing that N. hemisphere warming, which is changing those pattern drivers, has no effect on what we can expect in terms of winter weather in the Mid-Atlantic and that's just false. No one knows what the exact effects will be, but I'm not making that argument...

Also, I pulled data for both snow and ice cover over the past ~40 years. The warming trend is clear and it's accelerating.  It wasn't me looking at the past 5. That was frd.

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@WinterWxLuvr I don’t think there has been some sudden flip and winters are all going to be crap now. That wasn’t my point at all. If I had to rank our issues bad shorter term patterns are primary and climate trends secondary. We will have a big winter again. We will have legit snowstorms. But if you go back and look at the snowfall records at most mid Atlantic locations outside the mountains it’s clear there is a warming trend and they are bleeding the wrong way. It’s not any sudden thing that you can say “that’s when it flipped”. But slowly 20”+ winters are becoming less frequent and <10” winters are becoming more frequent. And especially less than 5” total dud winters. They were extremely rare 100 years ago. Now they happen regularly.  4x in the last 9 years!!! Our median and avg snowfall is slowly decreasing at most recording stations. And Im sure urban heat island is some of that but not all.  Places in higher elevations in our region have been hanging on because big qpf events have been increasing. Places just cold enough have been offsetting the bad periods with some crazy good ones and some sporadic big storms.   But places outside those zones are slowly losing snow on the margins the last 100 years. 

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1 minute ago, cbmclean said:

The Pacific Doom Blob which haunted us all last winter is back like a horror movie villain.  It just won't die.

Nina or Nino simply does not matter.  As mentioned before the small area of cooler Pac waters is nothing compared to the HUGE global ocean impact specifically the Pacific.  And the CFS sucks. Even the monthly CFS is horrible until you get to the 20 th of the present month for the next month's forecast. 

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9 hours ago, WinterWxLuvr said:

Yeah but what I was saying is that that map shows extreme high heights in the pacific but the height lines don’t really show a pronounced ridge. So what I’m asking is would “normal” heights produce a trough there?

Not really commenting on whether what it shows is good or bad. It’s pretty clear it’s bad. I’m just confused why mega high heights (relative time normal) don’t produce a pronounced ridge.

That is simply a function of a smoothed mean. The primary takeaway on that panel is the location of the average positive and negative h5 height anomalies for the month. You cant just ignore the colors and focus on the height lines. The +(-)heights generally correlate with the temp anomalies at the surface. I wont bother posting that panel- you can imagine what that looks like lol.

Clearly these models are not very good at this range, so hopefully that area of +heights in the PAC ends up parking further NE, shifting the phase of the longwave pattern some. That would suppress the SER and give us a better chance for cold air delivery here.

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13 hours ago, CAPE said:

That' is typical. It will eventually hone in on the most likely solution though. It has pretty much been the only climate model pushing a half decent Pacific and favorable HL look.

The CFS is such a train wreck, always the very last one to get a clue. Pretty sad when American guidance is some of the worst out there

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7 hours ago, snowman19 said:

For anyone following; the QBO number for September just updated, it’s up to +7.95

You might as well stop monitoring this. It is clear where it is heading as we move into winter. There is nothing particularly good that can result from this, esp in a Nina.

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