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Winter 2021-2022


40/70 Benchmark
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10 minutes ago, George001 said:

This is very interesting, the polar vortex is forecasted to be the weakest we have seen in years. Last year, we had a severe polar vortex event in late dec, and severe North Atlantic blocking developed and stayed in place from early Jan to mid Feb, then the pattern broke down and we had a milder regime from then until early- mid April, too late for a return to winter (we had nice storm where I forecasted a massive blizzard for all of eastern mass in mid April, but the temps were just too warm and the snow did not accumulate. I forecasted 2 feet for my area, got a dusting).
 

This year it looks like we could see a polar vortex event as early as mid-late November if the models are correct, which makes me think we could have our first window of North Atlantic blocking from early December to mid Jan. The pattern then probably starts to break down leading to less North Atlantic blocking from late Jan to early March. It is very possible we see a thaw during that timeframe if the polar vortex does not cooperate. After the North Atlantic blocking regime breaks down, it will have done its job enough to force the polar vortex south, leading to a polar vortex intrusion during the second half of the first blocking regime to a couple weeks after. That probably sets in from late Dec to early Feb. If this window is accurate, the second half of Feb is probably going to suck (similar to 2017-2018). March is where things get really interesting, due to the timing of our polar vortex event, like 2018 while we are in a sucky late Feb pattern there will probably be enough time for another polar vortex event to occur, leading to the development of North Atlantic blocking throughout the entire month of March and into mid April. This is not a guarantee, but due to our winter thaw being from mid Jan-late Feb instead of mid Feb-mid March, that opens up a second window in March (like 2018) rather than last winter. That is the biggest difference between the 2017-2018 winter and last year, what happened in March.

what I am thinking we could see right now:

biggest windows (2010-2011 type potential due to blocking and a polar vortex intrusion at the same time) :  late Dec-mid Jan, early March- late March

other windows (high variance, could be epic could suck, really I have no idea yet. What I will try to figure out before my winter forecast in November): early Dec-late Dec, mid Jan-early Feb

Will likely suck: mid-late Feb

The biggest question for me looking at the models is will the polar vortex cooperate, or will it displace too far west? If it displaces too far west, the mid Jan- early feb window will probably suck due to lack of blocking and a trough in the west. If everything comes together, there is a real chance that we only have a hostile pattern for 2 weeks throughout the entire winter. If nothing breaks our way with the polar vortex, we still have early Dec-mid Jan and then another shot in March, with a 1 month period of suck from late Jan-late Feb.
That is our floor in my opinion, and that can still be a damn good winter. The 2017-2018 winter we had a month of suck in Feb. The 2012-2013 winter we had a month of suck in Jan, and the 2014-2015 and 2010-2011 winters we had at least a month of suck (2014-2015 was a month and a half of suck Dec to mid Jan, and 2010-2011 was 2 months of suck Feb-Mar). 2010-2011 in particular we wasted half the damn winter and still got 80 inches of snow in Boston. 2014-2015 we wasted the first half of winter and got hammered the second half. I see 2 good windows at least, which is not something that could be said about 2019-2020 or 2011-2012.

I actually agree with this, but think it may take a bit longer to become established in December.

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My personal view on what is really evinced by this particular rendering ...

https://www.americanwx.com/bb/uploads/monthly_2021_09/719318380_FranceDJFFORECAST.png.534edb15d30df997a0ecf1a84965e65e.png

 

..is that those garland positive anomaly bands along the mid latitudes ... N and S hemisphere, are really more a functional artifact of the heights tending to linger high there.   Quite possibly associated with the expansion into those latitudes, as discussed.

The "symmetrical" aspect of that is the tip-off; HC expansion is a global phenomenon, one where positive anomalies would theoretically base-line as a modest positive rest state, but then pattern modulation occasionally combine to cumulatively cause those warmer nodes.

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12 minutes ago, Typhoon Tip said:

My personal view on what is really evinced by this particular rendering ...

https://www.americanwx.com/bb/uploads/monthly_2021_09/719318380_FranceDJFFORECAST.png.534edb15d30df997a0ecf1a84965e65e.png

 

..is that those garlands positive anomaly bands along the mid latitudes ... N and S hemisphere, are really more a functional artifact of the heights tending to linger high there.   Quite possibly associated with the expansion into those latitudes, as discussed.

The "symmetrical" aspect of that is the tip-off; HC expansion is a global phenomenon, one where positive anomalies would theoretically base-line as a modest positive rest state, but then pattern modulation occasionally combine to cumulatively cause those warmer nodes.

Yea, I guess maybe HC expansion is augmenting things, but that is a shit pattern, too.

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6 hours ago, 40/70 Benchmark said:

Yea, I guess maybe HC expansion is augmenting things, but that is a shit pattern, too.

I have a question. Do you think we can get a more robust aleutian ridge to build up instead of the flat type, which doesn't bring any cold air to us this winter or is it too early to tell? I think last winter it was relatively flat and we depended on the ao/nao to get cold imo

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10 minutes ago, Mr. Kevin said:

I have a question. Do you think we can get a more robust aleutian ridge to build up instead of the flat type, which doesn't bring any cold air to us this winter or is it too early to tell? I think last winter it was relatively flat and we depended on the ao/nao to get cold imo

Well, there are two main reasons why you get a flat ridge in a la nina..

1) -QBO/La nina = flat Aleutian ridge

2) Modoki-west based la nina=flat ridge. 

We have the first one working against us, and the second one is kind of a neutral signal, but I think we have a shot to build it since la nina will remain weak.

I am not a huge proponent of #1, as that can be overcome.

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8 minutes ago, 40/70 Benchmark said:

Well, there are two main reasons why you get a flat ridge in a la nina..

1) -QBO/La nina = flat Aleutian ridge

2) Modoki-west based la nina=flat ridge. 

We have the first one working against us, and the second one is kind of a neutral signal, but I think we have a shot to build it since la nina will remain weak.

I am not a huge proponent of #1, as that can be overcome.

Just for my own benefit what are your sources? I'm interested in reading more about it/analyzing it closer via composite plots if you have those.

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38 minutes ago, It's Always Sunny said:

Just for my own benefit what are your sources? I'm interested in reading more about it/analyzing it closer via composite plots if you have those.

I don't have sources for number one....just going off of what others have said. Look at my last blog post for number two...the link is a ways back...I posted it yeaterday.

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On 9/23/2021 at 3:26 AM, snowman19 said:

Good write up. About the Aleutian ridge….HM wrote an article back in 2012 showing that La Niña/-QBO results in a flat Aleutian ridge while La Niña/+QBO results in a poleward Aleutian ridge. 

 

On 9/23/2021 at 3:47 PM, 40/70 Benchmark said:

 

23 hours ago, raindancewx said:

From the draft of my winter outlook.

Image

 

43 minutes ago, It's Always Sunny said:

Just for my own benefit what are your sources? I'm interested in reading more about it/analyzing it closer via composite plots if you have those.

 

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11 hours ago, 40/70 Benchmark said:

Well, there are two main reasons why you get a flat ridge in a la nina..

1) -QBO/La nina = flat Aleutian ridge

2) Modoki-west based la nina=flat ridge. 

We have the first one working against us, and the second one is kind of a neutral signal, but I think we have a shot to build it since la nina will remain weak.

I am not a huge proponent of #1, as that can be overcome.

Aren’t the overwhelming majority of 2nd year La Nina’s CP/Modoki? I remember reading a research article about that maybe 6 or 7 years ago. I’ll try to find it again

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9 hours ago, snowman19 said:

Aren’t the overwhelming majority of 2nd year La Nina’s CP/Modoki? I remember reading a research article about that maybe 6 or 7 years ago. I’ll try to find it again

Well, its basin wide now and looks to remain as such on most guidance....actually region 1.2 has slight positive anomalies, but my thought is that is negated by the fact that the coldest values are in region 3.

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The QBO has been a focal point of investigation in recent years. This upcoming season, La Nina + EQBO, is pretty interesting wrt the MJO. Here's a couple relevant points from the following article. 

 

Combined effect of the QBO and ENSO on the MJO:

https://www.tandfonline.com/doi/full/10.1080/16742834.2019.1588064

For each La Niña/QBOE year (Figure 3(c)), there are 1.7 MJO events, which is much larger than that in an El Niño year and La Niña/QBOW year. The last phase has only 0.6 MJO events (Figure 3(d)). During a La Niña/QBOE year, the MJO can propagate to the western Pacific without being suppressed over the Maritime Continent. During a La Niña/QBOW year, the existing MJO is observed to be enhanced over the Indian Ocean, while it is barely able to pass the Maritime Continent (Figure 3(d)).

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13 hours ago, 40/70 Benchmark said:

Well, its basin wide now and looks to remain as such on most guidance....actually region 1.2 has slight positive anomalies, but my thought is that is negated by the fact that the coldest values are in region 3.

Ray, i guess we hope for the weaker the better for laniña to have a chance at a colder outcome for us.

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27 minutes ago, raindancewx said:

Once the NAO value overall value is in for September I can see which years match best. I'm also curious to see if the huge dip actually verifies as severe as depicted. It's a little hard to eyeball a monthly value without knowing the severity of that dip.

nao.sprd2.gif

My guess is it comes in pretty similarly to last year....modestly to moderately negative.

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4 hours ago, snowman19 said:

This is the deepest -PDO we’ve seen in many years. You can see the classic “cold ring” developing over the last month. cdas-sflux_ssta_global_1.png

I haven't analyzed the PDO in a while and its affects as of late but for the sake of Northeast cold (and perhaps snow), wouldn't we want to see more of a +PDO signature to mitigate the strength of La Nina? Generally New England does better during weak La Nina/ENSO neutral setups. A -PDO would only enhance La Nina, and possibly make it more central Pacific based which is what we don't want.

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Does anyone think this winter will be extraordinarily bad ... ?   like, top 5 if not the lowest snow total in the collective basin history, marred often by near/at historic positive temperature anomaly episodes ...   mmm ??

It seems there's been what 15  winters since 1950 that were "just" very bad, to the point of being almost shockingly so to those that want winters...and gritting teeth with guilt for those that don't, and I bet you dimes to donuts ... those winters are 0 -15 in winter forecast - i.e., not a single soul has ever forecast those.    LOL

And I so I ask,    who has the ballz

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26 minutes ago, Typhoon Tip said:

Does anyone think this winter will be extraordinarily bad ... ?   like, top 5 if not the lowest snow total in the collective basin history, marred often by near/at historic positive temperature anomaly episodes ...   mmm ??

It seems there's been what 15  winters since 1950 that were "just" very bad, to the point of being almost shockingly so to those that want winters...and gritting teeth with guilt for those that don't, and I bet you dimes to donuts ... those winters are 0 -15 in winter forecast - i.e., not a single soul has ever forecast those.    LOL

And I so I ask,    who has the ballz

I don't see enough evidence that la nina will be centered far enough west to be a real stinker. Doesn't mean it can't happen...

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5 hours ago, It's Always Sunny said:

I haven't analyzed the PDO in a while and its affects as of late but for the sake of Northeast cold (and perhaps snow), wouldn't we want to see more of a +PDO signature to mitigate the strength of La Nina? Generally New England does better during weak La Nina/ENSO neutral setups. A -PDO would only enhance La Nina, and possibly make it more central Pacific based which is what we don't want.

Not really IMO maybe @CoastalWx and @40/70 Benchmarkcan chime in, but the 1960’s-1970’s saw an extremely negative PDO cycle and some of the deepest -NAO/-AO periods on record 

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