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Ghosts, Ghouls, Pumpkins, Autumn Chill?: October 2015 DISCUSSION/OBS


UnionWeatherWx

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Playing devil's advocate here. Not surprisingly, this October so far, doesn't look good for Greenland blocking for DJF average.

 

I gave up on trying to use the October pattern to predict the AO last winter. But in the end, it really didn't matter

since the blocking over Western North America compensated for the lack of blocking on the Atlantic side.

The AO and NAO have been more positive in general after March 2013. But this last summer we saw the

strongest 500 mb block over parts of the Arctic on record for July. So there was a a lot of volatility this year

from the winter to the summer.

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I gave up on trying to use the October pattern to predict the AO last winter. But in the end, it really didn't matter

since the blocking over Western North America compensated for the lack of blocking on the Atlantic side.

The AO and NAO have been more positive in general after March 2013. But this last summer we saw the

strongest 500 mb block over parts of the Arctic on record for July. So there was a a lot of volatility this year

from the winter to the summer.

Yup. But it would be nice to see more -AO/NAO this year with more amplification and phasing possibility with the strong nino enhanced STJ.

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we are due for an above normal November...the last three were below normal and 2011 already had a snowstorm...being due doesn't mean it will happen though...Novembers before our snowiest winters had a warm look to November...The last two years brought the average to slightly above...

post-343-0-35597500-1445693901_thumb.png

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Ugh not really a good morning read for a winter lover...but my thinking is mild and snowless this winter

This is exactly how the forecast could play out. Nov and Dec could and in my opinion (and has been in the ENSO thread ) torch and have no effect on Jan thru March.

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It's an opposite correlation so you want to have a +NAO in October to get a -NAO in the winter.

 

 

That's correct. While it isn't a robust correlation, there is an inverse correlation between the October NAO modality and ensuing DJF modality. The relationship predicts the NAO in approximately 64% of years from 1950-2015. The 500mb height pattern in the NPAC and NATL this month were fairly close to ideal in terms of correlations. Of course, they are some of the innumerable tools in the toolbox, but nonetheless, something to examine.

 

3450a37.png

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That's correct. While it isn't a robust correlation, there is an inverse correlation between the October NAO modality and ensuing DJF modality. The relationship predicts the NAO in approximately 64% of years from 1950-2015. The 500mb height pattern in the NPAC and NATL this month were fairly close to ideal in terms of correlations. Of course, they are some of the innumerable tools in the toolbox, but nonetheless, something to examine.

3450a37.png

Yes, having a good PAC (+PNA/-EPO)/bad ATL (+NAO) in October with significant cold shots seems to enhance the chances of a cold, stormy winter.

The Pacific ridge this month has been a little bit too far east to deliver optimal cold...the strongest troughing is going to be over eastern New England and up into the Canadian Maritimes. We can see this by how quickly the cold highs have moved offshore...quick cold shot last weekend, then 70s, cold yesterday/today but 65 tomorrow. I'm hoping the entire the Aleutian low/PNA pattern retrogrades in time for winter.

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My expectations are very low. You're always playing with fire when all bets are on a backloaded winter.

Last year was as amazing as it gets in that aspect and unlikely to repeat itself.

Most El Nino winters are backloaded so it actually makes sense. Saw this in 57-58 (huge Feb snowstorm, twin snowfalls late Mar), 77-78 (bad Dec, decent Jan, historic blizzard and wall-to-wall cold Feb), 82-83 (record warm Dec, Megalopolis storm Feb), 94-95 (decent Feb in bad winter), 02-03 (PDII in Feb after bland Jan), 09-10 (record Feb snows after mild Jan)...
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My expectations are very low. You're always playing with fire when all bets are on a backloaded winter.

Last year was as amazing as it gets in that aspect and unlikely to repeat itself.

2013-14 was also backloaded in many ways, so it's happened two years in a row. December was +1 with one modest snowfall (4-8" from City to suburbs). Then, we had a much colder January with several events, an 8-10" storm on Groundhog's Day and a 12-20" storm Valentine's Day, and near record cold in March with several days staying in the 20s for highs.
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Most El Nino winters are backloaded so it actually makes sense. Saw this in 57-58 (huge Feb snowstorm, twin snowfalls late Mar), 77-78 (bad Dec, decent Jan, historic blizzard and wall-to-wall cold Feb), 82-83 (record warm Dec, Megalopolis storm Feb), 94-95 (decent Feb in bad winter), 02-03 (PDII in Feb after bland Jan), 09-10 (record Feb snows after mild Jan)...

 

I wouldn't consider 02-03 and 09-10 back-loaded winters. December 2009 had a HECS from LI southwestward - a colder than normal month - and December 2002 had a significant snowfall the first week, and a significant Christmas event. The common denominator of those two months was a -AO / -NAO in the means. Although the statistical probability of an active Nino December is quite low, it can happen given a conducive northern annular mode and north Atlantic regime.

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I wouldn't consider 02-03 and 09-10 back-loaded winters. December 2009 had a HECS from LI southwestward - a colder than normal month - and December 2002 had a significant snowfall the first week, and a significant Christmas event. The common denominator of those two months was a -AO / -NAO in the means. Although the statistical probability of an active Nino December is quite low, it can happen given a conducive northern annular mode and north Atlantic regime.

The D 09 snowstorm getting erased by the pre Xmas rainstorm followed by an AN J makes it a bookend winter for me.

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The D 09 snowstorm getting erased by the pre Xmas rainstorm followed by an AN J makes it a bookend winter for me.

 

Disagree. Almost all of our December snowstorms are erased in 1 week, and January's temperatures were just marginally above normal (0 to +1). Additionally, the December 19th snowstorm was the coldest event of the winter with temperatures in the 20s. The Christmas rainstorm happened on Christmas night; I had a 7-8" depth Christmas morning.

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Disagree. Almost all of our December snowstorms are erased in 1 week, and January's temperatures were just marginally above normal (0 to +1). Additionally, the December 19th snowstorm was the coldest event of the winter with temperatures in the 20s. The Christmas rainstorm happened on Christmas night; I had a 7-8" depth Christmas morning.

So with an AN Jan after a D snowstorm and 2 in Feb , you don't classify it as a bookend or backend winter , how do you classify it ?

At KNYC

D 12.2

J 2.4

F 39.6

I view 09/10 as a bookend winter as there was dynamic system in D virtually nothing in J and 2 dynamic systems in F. So I can't call that wire to wire.

Looks like we differ here. No biggie.

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So with an AN Jan after a D snowstorm and 2 in Feb , you don't classify it as a bookend or backend winter , how do you classify it ?

 

 

A front to back winter with a break in the middle. I recorded 23" of snow total in the month of December. I've only seen a 20"+ December in one other Dec in my life (2010). That's a phenomenal month and certainly qualifies as a sufficient front part of the winter in my eyes.

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A front to back winter with a break in the middle. I recorded 23" of snow total in the month of December. I've only seen a 20"+ December in one other Dec in my life (2010). That's a phenomenal month and certainly qualifies as a sufficient front part of the winter in my eyes.

I would think that qualifies as bookend. Great in the front , a break then great in the back.

I didn't say backend ... I don't disagree with your description of its evolution , I just thought that looks bookend to me.

Not important. Let's repeat 09 in 15 and we will fight about its definition in march.

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I would think that qualifies as bookend. Great in the front , a break then great in the back.

I didn't say backend ... I don't disagree with your description of its evolution , I just thought that looks bookend to me.

Not important. Let's repeat 09 in 15 and we will fight about its definition in march.

 

 

Paul, long week. I was misreading "bookend" as "backend." I agree. Here's hoping it repeats.

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