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Winter 2020-2021


ORH_wxman
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4 hours ago, Chrisrotary12 said:

Because the Hadley cell. At least I think that's what Tip told me over in the September thread. I mused about how recent fall seasons from mid-September to mid-November the last few years featured winter-like patterns with continuous low pressures passing near or through the northeast bringing us bountiful rain opportunities which had they been 3 months later would have been a weenies dream.

Suppositionally - yes.. 

The NAO could be "transitively" influenced...   

What we know:  The HC is expanded(ing) ... as I've outlined before and it can be found here: https://science2017.globalchange.gov/     ... note, this publication may be getting onwards to a couple years old, so it may be mirrored and or sophisticated further by follow-up efforts that I am less than aware of - will leave that to the reader research using the "stellar trustworth WWW" that the "intrinsically ethical nature of man" hasn't by any means corrupted -ha.. 

Anyway, right off the bat .. conceptually, 'what in hades does the Hadley Cell have to do with the NAO, considering the latter domain space is N of the Hadley..?'    

Directly?  nothing...  Indirectly?  perhaps - 

The expanding HC causing higher winds in the westerlies ( because there's more in situ gradients between 30N and 70 N in the general hemisphere...), would tend to augment the rest state PNAP structure... Which returning to 101 Synoptics, that features a modest ridge over the terrain of western N/A and a coupled, modest trough down stream over the east.  This has to do with forced topographical ascent, turning right by Coriolis ... .and that causes UVM and ridging to evolve...   Naturally, if we enhance the westerlies...it is conceptually acceptable to assume these orientations would also be augmented.

So, we have a slightly exaggerated ridge it the west, ... coupling wave/balancing we have increasing trough tendencies in the east... Down streams of troughs... we have the transitive higher height response ... and that ignites the -NAO ... 

But this gets complicated/washed out, as the season grows deeper into winter, and said gradient gets rather extreme... It's like we sinusoidally go the other way with so much maelstrom and high velocity, the balancing locks into the next sign - viola!  +PNA winters... with very high velocities situates the NAO blocks east or zonal... tending to reduce the west-based variant. 

Not all the time... no. but as a base line...?   mmm

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I'm excited for this season's outlook. My process will be a little bit different this season, as I am going to supply links to background information throughout the finished product, so that folks can actually read the damn thing. The previous format was mind numbing, and I appreciate that many of you pointed that out.

@Ginx snewx had a great suggestion to link the basic background information, which I am implementing in a series of addendums detailing major atmospheric drivers.

Addendum one is ENSO.

https://easternmassweather.blogspot.com/2020/09/winter-outlook-2020-2021-addendum-1.html

I am really starting to hone in my thoughts early this season and will have more season specific information out tonight.

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2 hours ago, 40/70 Benchmark said:

I'm excited for this season's outlook. My process will be a little bit different this season, as I am going to supply links to background information throughout the finished product, so that folks can actually read the damn thing. The previous format was mind numbing, and I appreciate that many of you pointed that out.

@Ginx snewx had a great suggestion to link the basic background information, which I am implementing in a series of addendums detailing major atmospheric drivers.

Addendum one is ENSO.

https://easternmassweather.blogspot.com/2020/09/winter-outlook-2020-2021-addendum-1.html

I am really starting to hone in my thoughts early this season and will have more season specific information out tonight.

always in awe of what you produce and grateful to have a chance to see it.

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2 hours ago, 40/70 Benchmark said:

I'm excited for this season's outlook. My process will be a little bit different this season, as I am going to supply links to background information throughout the finished product, so that folks can actually read the damn thing. The previous format was mind numbing, and I appreciate that many of you pointed that out.

@Ginx snewx had a great suggestion to link the basic background information, which I am implementing in a series of addendums detailing major atmospheric drivers.

Addendum one is ENSO.

https://easternmassweather.blogspot.com/2020/09/winter-outlook-2020-2021-addendum-1.html

I am really starting to hone in my thoughts early this season and will have more season specific information out tonight.

How much of a monkey wrench do you think this may throw into things?

 

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6 hours ago, 40/70 Benchmark said:

I'm excited for this season's outlook. My process will be a little bit different this season, as I am going to supply links to background information throughout the finished product, so that folks can actually read the damn thing. The previous format was mind numbing, and I appreciate that many of you pointed that out.

@Ginx snewx had a great suggestion to link the basic background information, which I am implementing in a series of addendums detailing major atmospheric drivers.

Addendum one is ENSO.

https://easternmassweather.blogspot.com/2020/09/winter-outlook-2020-2021-addendum-1.html

I am really starting to hone in my thoughts early this season and will have more season specific information out tonight.

Ray, like many others have stated, look forward to your outlook and "first call/final call" etc enjoyable read...

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6 hours ago, 40/70 Benchmark said:

Not so preliminary thoughts....but looong was from anything definitive. I offer up composites as coalesce my thoughts throughout the fall. Not at all a forecast.

This is evolving quickly IMO.

https://easternmassweather.blogspot.com/2020/09/structural-changes-observed-in.html

Really nice write up Ray.  Tough call!

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6 hours ago, 40/70 Benchmark said:

Not so preliminary thoughts....but looong was from anything definitive. I offer up composites as coalesce my thoughts throughout the fall. Not at all a forecast.

This is evolving quickly IMO.

https://easternmassweather.blogspot.com/2020/09/structural-changes-observed-in.html

Torch! Mild and dry enroute 

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7 hours ago, 40/70 Benchmark said:

Not so preliminary thoughts....but looong was from anything definitive. I offer up composites as coalesce my thoughts throughout the fall. Not at all a forecast.

This is evolving quickly IMO.

https://easternmassweather.blogspot.com/2020/09/structural-changes-observed-in.html

Very Impressive job. Obviously took you a lot of time and effort. Interesting write up

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1 hour ago, 40/70 Benchmark said:

While the hindsight composite could reflect that, it doesn't mean we can't get a good stretch....especially early. Also keep in mind that the dry stretch haas to end at some point.

I tend to agree. December can be good. Perhaps even like Dec 80 and then ends quickly 

IMO we are in a mid 1960’s type of drought . Long term

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1 hour ago, Fozz said:

The 500 mb composite seems to indicate a combination of some decent years (1965, 2009) and some :axe:  years. Let's hope it's at least much better than last year. Well done and good luck Ray!

We will need some luck as far as the timing of the highs etc, but it can be done.

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I've often thought that altho that early Dec snow last year was within the Met designation of winter that doesn't mean much ... It still to me appeared to really be a part of an autumnal hemispheric setting ...and fitting in with the recent decadal propensity to fold the heights over western Canada ... which tends(ing) to deliver early cold snaps ..etc...  A factor that may also be hidden because it is couched in modestly > normal monthly means ..Or not.  Octobers and Novembers may actually have been closer to normal or approaching so ...while hosting nested cold incursions that plumb departures some -6 to -12,  ....enough so to even snow or be supportive of snow, but rolling out in comparatively briefer time spans - such that by arithmetic weighting, the +3, 10 days intervening "hides" them in the averages..etc..

I feel pretty strongly about that early Dec event as being part of that.  I was in careful observance of the southern tier height compression around the time and moving past ( the weeks) of that event; the hypsometric gradient grew steeper over the ambience, as well .. the isohypsotic counts rose by 3 to 6 gradient lines by mid month, and never 'decompressed' until July frankly... kidding a little.  Within 10 days or so after that early month slow roller quasi-cut-off last December, that spit out a coastal wave for 9-12", then came through with a mid level snowball to double-dutch us for a total 30 hour stint ...  things changed.  Commercial air traffic began reporting the unusual ground-based velocities along .. concurrent with the arrival of that apparent gradient compression. And whether it can be proven geo-physically connected or not, it's hard to ignore that the winter sucked as those observations came about.  It went on to be a distracted mess of busted ravioli systems and sheared out messes...Or at best, modeling bombs that were always correcting 1000(s) of KM(s) east of original projections when at D7-10 leads ( when/where ensemble signals first began to emerge;  the Euro always had Del Marva genesis' ending up flatter or up near NF by D3...etc.. something like that..).  

I think it is important, but the the thematic arc of winters the past 10 years ( and really ... vestiges of this going back to 2000 ) seems to be more than ephemeral ... showing enough sample size to move the climate in insidious ways.  For example, we think of climate in terms of average temperature, #'s of sunny vs cloudy days, precipitation ...wind. Aspect the really are more 'sensible' ...  But, any geophysical variable that is an emergent result of the atmospheric machinery can be metrically analyzed.   Like, 'geopotential gradient' - there probably is normalized/averaged climate values of these lesser known/esoteric aspects, but it is in that obscure realm where climate changes seems to be more colorful.   But, if the 'theme' of winters is changing, and seeing these physical observations to back that .. probably should ignore the possibility that whatever forcing is causing that climate modality, might also do the same for this winters hemisphere.   

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1 minute ago, Typhoon Tip said:

I've often thought that altho that early Dec snow last year was within the Met designation of winter that doesn't mean much ... It still to me appeared to really be a part of an autumnal hemispheric setting ...and fitting in with the recent decadal propensity to fold the heights over western Canada ... which tends(ing) to deliver early cold snaps ..etc...  A factor that may also be hidden because it is couched in modestly > normal monthly means ..Or not.  Octobers and Novembers may actually have been closer to normal or approaching so ...while hosting nested cold incursions that plumb departures some -6 to -12,  ....but by arithmetic weighting, the +3 10 days intervening "hides" them in the averages..etc..

I feel pretty strongly about that early Dec event as being part of that.  I was in careful observance of the southern tier height compression around the time and moving past ( the weeks) of that event; the hypsometric gradient grew steeper over the ambience, as well .. the isohypsotic counts rose by 3 to 6 gradient lines by mid month, and never 'decompressed' until July frankly... kidding a little.  Within 10 days or so after that early month slow roller quasi-cut-off last December, that spit out a coastal wave for 9-12", then came through with a mid level snowball to double-dutch us for a total 30 hour stint ...  things changed.  Commercial air traffic began reporting the unusual ground-based velocities along .. concurrent with the arrival of that apparent gradient compression. And whether it can be proven geo-physically connected or not, it's hard to ignore that the winter sucked as those observations came about.  It went on to be a distracted mess of busted ravioli systems and sheared out messes...Or at best, modeling bombs that were always correcting 1000(s) of KM(s) east of original projections when at D7-10 leads ( when/where ensemble signals first began to emerge;  the Euro always had Del Marva genesis' ending up flatter or up near NF by D3...etc.. something like that..).  

I think it is important, but the the thematic arc of winters the past 10 years ( and really ... vestiges of this going back to 2000 ) seems to be more than ephemeral ... showing enough sample size to move the climate in insidious ways.  For example, we think of climate in terms of average temperature, #'s of sunny vs cloudy days, precipitation ...wind. Aspect the really are more 'sensible' ...  But, any geophysical variable that is an emergent result of the atmospheric machinery can be metrically analyzed.   Like, 'geopotential gradient' - there probably is normalized/averaged climate values of these lesser known/esoteric aspects, but it is in that obscure realm where climate changes seems to be more colorful.   But, if the 'theme' of winters is changing, and seeing these physical observations to back that .. probably should ignore the possibility that whatever forcing is causing that climate modality, might also do the same for this winters hemisphere.   

I never, ever would have guessed....lol

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On 9/9/2020 at 6:30 PM, frd said:

 

As many here already know, the QBO is currently positive and looks to continue to become more so in the months ahead.

There is some research that points out a tendency for a more poleward based and oriented North Pacific Ridge during  +QBO winters. HM mentioned that, along with a couple other mets as well. @griteater recently mentioned it  too in a detailed and revealing post. I found it so interesting as to share it here. Nice job with this ! 

Here is the post below :

The QBO is utilized in various ways with respect to seasonal forecasting, but IMO, it's best use with winter forecasting is not so much with the AO/NAO, but rather, with the configuration of the North Pacific High/Ridge that is common during La Nina winters.  A North Pacific ridge is almost certain to be present in the mean pattern during Cool ENSO / La Nina winters when the Jul-Oct averaged AAM is negative (which has been the case thus far for Jul-early Sep).

 

Anthony Masiello's findings from 2012 showed that more poleward north pacific ridges were favored during +QBO winters, while north pacific ridges that were suppressed to the south were more favored during -QBO winters.  A key element here is that the designation of the QBO for this purpose was in the lower stratosphere (roughly Nov-Feb averaged at 45mb) as opposed to the typical level used with QBO analysis which is at 30mb. 

 

While the QBO began to behave much more erratic than normal at the first part of 2020, it appears to have resumed with a more typical progression as the positive QBO has more firmly established itself in recent months in the middle stratosphere and descending into the lower stratosphere.  For the upcoming winter, I would anticipate the QBO to average positive for Nov-Feb averaged at 45mb - most similar to the winter of 2010-2011 when compared to other cool ENSO winters. 

 

See QBO Charts:

NASA QBO Chart

Free Univ of Berlin QBO Chart

 

Below is a list of what I have for the last 11 La Nina winters that followed El Nino, along with the Nov-Feb avg 45mb QBO, then the placement of the north pacific ridge averaged for Dec-Mar.

 

La Nina Winter That Followed El Nino Winter / Jan-Feb avg QBO at 45mb / Placement of North Pacific Ridge avg for Dec-Mar

2010-2011 / Positive QBO / north/poleward north pacific ridge (specifically, displaced to the NW)

2007-2008 / Negative QBO / south/suppressed north pacific ridge (specifically, displaced to the SW)

2005-2006 / Negative QBO / south/suppressed north pacific ridge (specifically, displaced to the SW)

1998-1999 / Negative QBO / south/suppressed north pacific ridge (specifically, displaced to the SW)

1995-1996 / Positive QBO / north/poleward north pacific ridge (specifically, displaced to the NW)

1988-1989 / Positive QBO / north/poleward north pacific ridge (specifically, displaced to the NE)

1983-1984 / Neutral QBO / no clear distinction overall in the north pacific

1973-1974 / Positive QBO / north/poleward north pacific ridge (specifically, displaced to the NW)

1970-1971 / Negative QBO / north/poleward north pacific ridge (specifically, displaced to the NW)

1964-1965 / Positive QBO / north/poleward north pacific ridge (specifically, displaced to the NW)

1954-1955 / Negative QBO / south/suppressed north pacific ridge (specifically, displaced to the SW)

 

Of the 11 winters, the only one that didn't follow the QBO/North Pacific Ridge placement theory was the winter of 1970-1971.

 

Here are 500mb Height / U.S. Temperature composites of the Positive QBO winters from the list: 

 

543070605_Sep9NinaPosQBO.png.b08d595893ad92d0f7876bd96c35464e.png

 

 

And here are 500mb Height / U.S. Temperature composites of the Negative QBO winters from the list (I left off the 70-71 winter):

 

795617113_Sep9NinaNegQBO.png.8098135465eea56fc7a9085a93bad00f.png

 

Clearly, the Positive QBO composite with the more poleward north pacific ridge offers more potential for cold air intrusion into the lower 48 east of the Rockies compared with the Negative QBO composite.

 

One other thing to look for is the Oct-Nov 500mb pattern over the NE Pacific / Alaska / NW Canada.  Winters with a more poleward north pacific ridge tend to be absent of negative height anomalies in the Bering Sea, Alaska, and NW Canada during Oct-Nov....while, winters with a more southward displaced north pacific ridge tend to contain solid negative height anomalies in the eastern Gulf of Alaska extending up into portions of the Bering Sea, Alaska, and/or NW Canada.

 

Bottom Line: I would expect the upcoming winter to exhibit a more poleward north pacific ridge in the mean pattern as long as: 1) the QBO progression continues in a more typical manner as seen in the past few months, and 2) the Oct-Nov averaged 500mb pattern doesn't contain negative height anomalies in the eastern Gulf of Alaska extending up into portions of the Bering Sea, Alaska, and/or NW Canada  

 

3 minutes ago, 40/70 Benchmark said:

Wow....GREAT stuff.

Food for thought, and it makes sense in that we use the QBO as a predictor for the polar fields, however, I have aways known the +QBO to favor less blocking (+NAO/AO). However, if it were to favor more N PAC blocking during la nina seasons, then that could change things.

Only thing with 2010-2011 is that we also had some NAO assist.

Interesting...

Looks more and more like the path to a very good winter may be though the NPAC....interesting perspective in relation to the QBO shared in the mid atl forum.

I really like griteater's stuff.

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I would just like to see less of a black hole across Greenland as that has been killing the east over the last two seasons. If we get North Pac ridging (west of the PNA domain) that's usually when the cold charges into the Plains and the response more often than not, are for lows to move into NY state. Not always the case, but a little confluence to the north would really help. Pacific is always King, but a little help from the Atlantic Queen of Greenland would be nice.

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1 hour ago, CoastalWx said:

I would just like to see less of a black hole across Greenland as that has been killing the east over the last two seasons. If we get North Pac ridging (west of the PNA domain) that's usually when the cold charges into the Plains and the response more often than not, are for lows to move into NY state. Not always the case, but a little confluence to the north would really help. Pacific is always King, but a little help from the Atlantic Queen of Greenland would be nice.

Or just get a black hole so strong and displaced south that we get Dec 2007.....:lol:

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