Winter 2020-2021

[VanCitySouth]

'Twould be helpful if someone knowledgeable posted a matrix of all the phases and their effects. Much gratitude to whomever can whip one up.

[Typeing3]

Correct me if I'm wrong, -Enso (La Nina) and +QBO (Westerly winds) plus low solar, are good combos for the west to be colder/snowier than normal?

Generally.

Here's a list of all -ENSO(cold neutral or la nina)/+QBO/low or descending solar winters since 1950:

1961-62
1964-65
1971-72
1973-74
1975-76
1985-86
1992-93
2008-09
2010-11
2016-17

500mb height anomalies for these years:

97oFwM21BJ.png

850mb temp anomalies for these years:

850mbtemp.png

Surface temp anomalies for these years:

temp3.png

[tyweather]

With record low ice coverage and with that ice at record low thickness in the arctic ocean looking back at past data will help less and less to see what the upcoming winter will look like. If the jet stream is stuck in one position a lot we could win or lose.

[stuffradio]

Brrrr
https://twitter.com/bamwxcom/status/1306240856685510657

[Catnip]

Brrrr

Lots of early indications that we may actually have some excitement come this winter.

#Winter2020/21

[AbbyJr]

Moderate-Strong La Nina by December?

20200915.nino_summary_4.png

[VanCitySouth]

Moderate-Strong La Nina by December?

I have often read that we don't want strong Ninas for snow and cold, and that the sweet spot is a weak one.

[Typeing3]

Moderate-Strong La Nina by December?

20200915.nino_summary_4.png

Moderate nina is pretty much a lock already. Whether we meet the criteria for a strong event is still up in the cards. I don't think we'll get any lower than -1.6c on the trimonthlies but we'll see.

[AbbyJr]

Moderate nina is pretty much a lock already. Whether we meet the criteria for a strong event is still up in the cards. I don't think we'll get any lower than -1.6c on the trimonthlies but we'll see.

Do you agree with the idea that weak Nina's are better for cold and snow here versus strong ones?

[Typeing3]

Do you agree with the idea that weak Nina's are better for cold and snow here versus strong ones?

Generally.

Stronger Nina's seem to lack amplified blocking in the GOA...resulting in a very active chilly NW flow (maritime polar airmass) with well above average amounts of of mountain snow and many sloppy snowfalls for the lowlands.

Weaker Nina's generally seem to feature an amplified GOA ridge which helps with our access to cold continental airmasses.

Overall though, it's a mixed bag. Here's a list of all Nina's back to the mid 19th century with their corresponding intensities.

[AbbyJr]

Generally.

Stronger Nina's seem to lack amplified blocking in the GOA...resulting in a very active chilly NW flow (maritime polar airmass) with well above average amounts of of mountain snow and many sloppy snowfalls for the lowlands.

Weaker Nina's generally seem to feature an amplified GOA ridge which helps with our access to cold continental airmasses.

Overall though, it's a mixed bag. Here's a list of all Nina's back to the mid 19th century with their corresponding intensities.

Thanks I wonder if a +QBO would help with amplifying the GOA ridge during a moderate or strong Nina?

I'd be interested in finding out how many moderate and strong Nina/+QBO combos resulted in a cold snowy winter for the low elevations versus moderate and strong Nina's with a -QBO.

[Typeing3]

Thanks I wonder if a +QBO would help with amplifying the GOA ridge during a moderate or strong Nina?

I'd be interested in finding out how many moderate and strong Nina/+QBO combos resulted in a cold snowy winter for the low elevations versus moderate and strong Nina's with a -QBO.

Again, looks like a mixed bag. Ironically the moderate/strong nina and -QBO combo actually looks better from an analogue perspective. However some of these winters would be removed if we take solar into consideration as well.

Moderate/strong Nina and +QBO
1955-56
1973-74
1975-76
1999-00
2010-11

Moderate/strong Nina and -QBO
1970-71
1984-85
1988-89
1995-96
1998-99
2007-08
2011-12

[AbbyJr]

Again, looks like a mixed bag. Ironically the moderate/strong nina and -QBO combo actually looks better from an analogue perspective. However some of these winters would be removed if we take solar into consideration as well.

Moderate/strong Nina and +QBO
1955-56
1973-74
1975-76
1999-00
2010-11

Moderate/strong Nina and -QBO
1970-71
1984-85
1988-89
1995-96
1998-99
2007-08
2011-12

So generally our best winter's are weak Nina/+QBO/Low solar combos?

[Monty]

I think generally with the low solar and +QBO in our favour I would expect to see some favourable blocking at times even with a moderate to strong Nina. The problem seems to come when we see a roided up North Pacific jet that squashes any attempt to strengthen a N Pacific ridge. 2010-11 might be an okay analog though solar will be lower this time. If we look at moderate ninas with +QBO and low solar we don’t have enough data to really draw any conclusions

[Typeing3]

So generally our best winter's are weak Nina/+QBO/Low solar combos?

Generally, yes. Unfortunately QBO data (from what I can find), only goes back to around 1950. ENSO and solar data go much further back than that.

The problem we get when using parameters such as moderate nina/+QBO/low solar, we're left with only a couple analogue years. As Monty mentioned, it just isn't enough data to help us when trying to draw any conclusions.

Weak Nina/+qbo/low solar isnt the be all to end all though. Looking at the list I posted earlier, the vast majority of moderate and strong Nina's are cooler than normal with above average snowfall.