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Winter 2020-21 Discussion


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1 hour ago, WinterWxLuvr said:

That winter missed by an eyelash of being a really good one. There were January and Feb near misses too. There was also the good clipper that missed us to the south in December.

Id take my chances with those types of opportunities again.

Agree, 2011 was very close to a mini 1996 type Nina repeat just got really unlucky. Even the one good storm could have been much bigger if it hadnt come when the cold was stale and we wasted the front half of the storm.  

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On 9/7/2020 at 10:06 PM, WinterWxLuvr said:

My memory of the 96 storm is different. I remember it as a storm that formed in the western gulf that rode up through Georgia and the Carolinas and then off the coast. I don’t remember the 2010 storm being anything like that. I of course could have a faulty memory.

I should edit that to say I remember the 2010 storm as an eastern gulf, off the east coast late developer.

Everything you need to know:  http://www.raymondcmartinjr.com/weather/2011/26-Dec-10.html

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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  

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I’m ready to watch North Carolina get a foot of snow, while leaving Virginia and north with nothing.

Also, the stuff on this website (I’m sure it’s been posted a ton by now over time) is interesting. They made all the graphs, but it seems like they had to mention each time the data was above average for snowfall, because of some event that dumped a ton of snow everywhere. I do find it interesting that the Moderate Niña winters had usually close to average snowfall, and temperatures.

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