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November 2017 Discussions & Observations Thread


Rtd208

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I disagree with a relaxation until mid+ December. I think the temperature moderation is very transient prior to the reload. As mentioned last week, the wave 1 event will significantly weaken the SPV such that zonal winds are about 50% of their previous intensity in 10 days. This will downwell, subsequently inducing a renewed -NAM regime beginning later in the first week of December. Contemporaneously, weak LF forcing will be propagating back toward the Maritime continent, and the retracted jet / poleward -AAM transport will redevelop. All of these factors will lead to a cold to much colder than normal December across parts of the Central and Eastern US. Once the pattern sets up, I expect the first meaningful opportunity for coastal snow to appear thereafter (as stated in the outlook, I am expecting the Dec 15-30 period to offer potential for significant or major). This is the most interested I have been in the winter pattern in a few years, and since 2013 for December.

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17 hours ago, Neblizzard said:

The PDO is neutral ( actually +0.4) so you’re wrong about that.  

No, that was last month’s (October’s) number. And secondly, that is not “the blob” reappearing. That warm water out by the Aleutians and west of there is in a classic -PDO position. Look at the chart I posted comparing a -PDO signature to a +PDO signature. Here are maps of the blob; note the difference: 2015040900_054_G6_global_I_SEASON_tm@lg@  figure-14.png

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10 minutes ago, snowman19 said:

Don’t change the subject. The info you posted was wrong. It shows how little knowledge you have of basic weather. Do your research next time before you post inaccurate proclamations

What's the latest figure then if it's not +.04?  That's certainly not a "robust" -PDO as you have opined in the past.    You also argued for warmth this week, this week will be anything but warm around here and the next 10-15 days also look BN.  Looks like you should study up on the subject of "basic weather"

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4 minutes ago, snowman19 said:

No, that was last month’s (October’s) number. And secondly, that is not “the blob” reappearing. That warm water out by the Aleutians and west of there is in a classic -PDO position. Look at the chart I posted comparing a -PDO signature to a +PDO signature. Here is are maps of the blob; note the difference: 2015040900_054_G6_global_I_SEASON_tm@lg@ 

The PDO SSTA region is bounded by 30°N-50°N and 145°E to 150°W (see area enclosed in the black box) courtesy of: https://link.springer.com/article/10.1007/s00382-014-2364-5:

PDO Region.jpg

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3 hours ago, Brian5671 said:

What's the latest figure then if it's not +.04?  That's certainly not a "robust" -PDO as you have opined in the past.    You also argued for warmth this week, this week will be anything but warm around here and the next 10-15 days also look BN.  Looks like you should study up on the subject of "basic weather"

Wow. When you argue against warmth you know its going to be cold. 

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9 minutes ago, bluewave said:

We may also get a record low sea ice feedback boost to the blocking like we did with the record Kara to the North Pole block in January 2016. 

Here's the current (Nov 17) Bering Sea ice extent in the 40 year passive microwave perspective. Friday had the lowest extent for the date in the satellite record, but as importantly, look at the past five years! Data from @NSIDC #akwx #Arctic @Climatologist49 @ZLabe@DaveSnider pic.twitter.com/U5sPLxjt8f

As I scrolled down a ways he says that the low sea ice levels are due to excessive storminess rather than warm temps. There was another panel that showed some temps 10-20* above avg but that's still cold considering that the average is in the single digits. 

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10 minutes ago, bluewave said:

We may also get a record low sea ice feedback boost to the blocking like we did with the record Kara to the North Pole block in January 2016. 

Here's the current (Nov 17) Bering Sea ice extent in the 40 year passive microwave perspective. Friday had the lowest extent for the date in the satellite record, but as importantly, look at the past five years! Data from @NSIDC #akwx #Arctic @Climatologist49 @ZLabe@DaveSnider pic.twitter.com/U5sPLxjt8f

Great point, if I may ask a question. Did this prior feedback boost in Jan. 2016 lead to, or contribute anyway to the blizzard in the Mid Atlantic and Northeast regions ?  

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winters with an ao near or lower than -5...

winter.......AO min. date...............weather just before or after date...

1976-77...-7.433...01/15/1977...record cold with snow...

1969-70...-6.365...03/05/1970...cold all month with late snows...

1984-85...-6.226...01/19/1985...record cold with snow...

2009-10...-5.821...12/21/2009...snowstorm...

2012-13...-5.688...03/20/2013...snow...

1977-78...-5.291...02/05/1978...blizzard...

1968-69...-5.282...02/13/1969...blizzard...

2010-11...-5.172...12/18/2010...blizzard...

1965-66...-5.130...01/28/1966...record snow with cold...

1962-63...-5.010...01/21/1963...record cold...

2015-16...-4.916...01/17/2016...blizzard...

2000-01...-4.854...02/25/2001...snow...

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That low pressure is forming earlier and more west with each run. I think temps may be a problem but if it catches the vort early and more west, dynamic cooling and evaporative cooling will cool the column and produce wet snow. Each run the accumulated precipitation has been drifting west. Let’s see how early that low forms and how west in the future runs. Definitely something to keep an eye on!

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14 minutes ago, bluewave said:

There's an interesting correlation between La Nina Novembers and strong blocking near the Bering and Aleutians. All 9 La Novembers since 1950 with this pattern were followed by a -AO December. This would match the long range guidance shifting the primary NH blocking from the Bering and Aleutians to the North Pole or Greenland. This November so far has seen record 500 mb blocking near the Bering and Aleutians.

La Nina Novembers with a strong Bering and Aleutians block since 1950 and December AO.

2010...-2.631

1996...-1.721

1995...-2.127

1985..-1.948

1973...-0.181

1970...-0.399

1966...-1.401

1955...-0.444

1950..-1.928

 

Never realized December 96 had such a negative AO given it was so warm

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1996 was one of the exceptions that had a negative ao and nao in December with nothing to show for it...November 1996 was cold...

Decembers with an ao and nao -1 or lower...

year.....ao.....nao.....

1950...-1.928.....-1.02...snow 12/27...

1961...-1.668.....-1.48...snow 12/24

1963...-1.178.....-1.92...snow 12/23

1976...-2.074.....-1.60...snow 12/26

1995...-2.127.....-1.67...snow 12/20

1996...-1.721.....-1.41...no snow...

2009...-3.413.....-1.93...snow 12/20

2010...-1.749.....-1.85...snow 12/27

1996 was the only December that was mild without measurable snow in NYC...

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23 minutes ago, uncle W said:

1996 was one of the exceptions that had a negative ao and nao in December with nothing to show for it...November 1996 was cold...

Decembers with an ao and nao -1 or lower...

year.....ao.....nao.....

1950...-1.928.....-1.02...snow 12/27...

1961...-1.668.....-1.48...snow 12/24

1963...-1.178.....-1.92...snow 12/23

1976...-2.074.....-1.60...snow 12/26

1995...-2.127.....-1.67...snow 12/20

1996...-1.721.....-1.41...no snow...

2009...-3.413.....-1.93...snow 12/20

2010...-1.749.....-1.85...snow 12/27

1996 was the only December that was mild without measurable snow in NYC...

the pna was negative in 12/96...positive in 12/95...

further review shows 2010 with a very negative pna...it was close to neutral the time of the blizzard on the 27th...1961 had a negative pna most of the month...

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