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Winter 2020-21 Discussion


CAPE
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5 hours ago, CAPE said:

Just looking back at 2017-18, the QBO(u30) was moving into the negative phase in Fall and stayed significantly negative through the winter. That winter was decent wrt cold outbreaks/anomalous cold, at least for Dec and Jan. I think that was technically a moderate Nina, but the QBO influence on the tendency for cold that winter may have been real.

The previous winter, also a Nina, QBO was moving into positive territory and stayed positive, and it was more the typical Nina eastern US torch. Again this is cherry picking one index in isolation, and so it is always difficult to determine the actual impact. The character of the Nina events were quite different between those 2 winters.

2017-18 was weak. Peaking at -1.0 on the tri monthlies. 2016-17 was actually borderline cold neutral as it peaked at -.7 in fall and dropped below Nina status by the DJF period!  But there is a lag and enough of the other factors were crap that it didn’t matter. 

I am not saying the correlation isn’t accurate. Although now I’m curious and will look when I get the chance. Simply saying off the top of my head knowing the enso of some years he included in his “weak Nina” dataset is flawed I wouldn’t take that product very seriously. But in general we do want the qbo negative. So the idea is correct. I doubt that map accurately depicts the correlation though. 

Wait for the “it’s never going to snow again” crowd to notice the QBO suddenly has tended to want to stay in unfavorable phases lately!  Just one more thing for them to pile on!  

Actually one thing positive to note from recent results. Despite a recent bias to spend a lot of tome in unfavorable phases of pattern drivers (qbo/NAO/AO/EPO/MJO) we have still managed to have a few snowy periods in the last 5 years. Is seems like we do hit more often when we do line up a good pattern. But getting a good pattern is less frequent. If we can ever get into a period of more favorable longwave pattern influences and keep the penchant for frequent big precip events...we could get an epic run!  Hopeful I know but why not inject some positivity now. 

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3 hours ago, Mersky said:

The risk from a changing climate is using analogs that existed in a different climate. While science has improved long range forecasting I believe climate change is going to make it much harder and more difficult for long range forecasts. What’s happening across the globe in 2020 is different then what was happening 30, 40, 50 years ago. The one constant that seems to exist in today’s world is go warmer than normal for every season and you have better than a 50/50 shot of being right. 

I don’t think the past 9.5 years are being used yet right? When will they be added does anyone have a guess?

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4 hours ago, Mersky said:

The risk from a changing climate is using analogs that existed in a different climate. While science has improved long range forecasting I believe climate change is going to make it much harder and more difficult for long range forecasts. What’s happening across the globe in 2020 is different then what was happening 30, 40, 50 years ago. The one constant that seems to exist in today’s world is go warmer than normal for every season and you have better than a 50/50 shot of being right. 

You’re right we should stick to the CFS 

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9 hours ago, PhineasC said:

Randolph, NH received 207" out of that putrid look. All snow weenies should head north if they want to escape the misery.

Kinda goes without saying, but cant beat the combo of latitude and elevation, not to mention having a persistent mechanism for orographic lift.

With the crappy pattern of last winter, even at this latitude places like Canaan still managed over 100" mainly because of the persistent NW flow induced snow. That usually happens even on the backside of mild inland tracking rain storms.

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On 7/25/2020 at 3:15 PM, CAPE said:

Epic HL blocking for the entire winter. It seemingly occurred so easily...effortless. It's like a fantasy now- something that simply cannot occur. Extinct.

And don't forget,  that was back in the day when a Nino did what a Nino was suppose to do. In this day and age with global warming the outcomes expected are no longer so simple.  Since 2010 there have been noted changes in various mechanisms that would typically deliver cold and snow to the East with a moderate to almost strong El Nino.  The use of analogs prior to 2010, to me, prove little value. A blended approach to forecasting the Winter IMHO might be the best way to go.  Of course they also need to be tweaked and modified for GW.   

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On 7/19/2020 at 11:06 PM, psuhoffman said:

I know a dropping qbo that’s transitioning to negative correlates to colder. Last year was pretty good wrt qbo but did us no good. We wasted it.  Frankly other than the solar minimum I see nothing that looks favorable att. There is always dumb luck though. 

There was a study years ago by Joe D’Aleo which showed a very strong correlation to a negative (easterly) QBO during a La Niña winter resulting in a cold eastern US. The exact opposite was true for positive (westerly) QBO during a La Niña winter, it resulted in a warm eastern US. Also, I believe there was some evidence from a different study which found that La Niña’s that occur during a solar minimum resulted in a colder stratosphere/stratospheric PV than the ones which occurred during periods of higher solar flux. I’m going to look back and see if I can find the links

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1 minute ago, snowman19 said:

There was a study years ago by Joe D’Aleo which showed a very strong correlation to a negative (easterly) QBO during a La Niña winter resulting in a cold eastern US. The exact opposite was true for positive (westerly) QBO during a La Niña Winter, it resulted in a warm eastern US. Also, I believe there was some evidence from a different study which found that La Niña’s that occur during a solar minimum resulted in a colder stratosphere/stratospheric PV than the ones which occurred during periods of higher solar flux. I’m going to look back and see if I can find the links

Here it is, go to page 126: https://books.google.com/books?id=PvJyVtw53Y4C&pg=PR4&lpg=PR4&dq=joe+d'aleo+nina+west&source=bl&ots=IZzwDpsLOl&sig=ACfU3U0KjJcmSsDgryXj2AK4mMRkfMomYg&hl=en&sa=X&ved=2ahUKEwidy63sxvfqAhX6gXIEHSDfC50Q6AEwGnoECAUQAQ#v=onepage&q=joe d'aleo nina QBO&f=false

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6 minutes ago, snowman19 said:

There was a study years ago by Joe D’Aleo which showed a very strong correlation to a negative (easterly) QBO during a La Niña winter resulting in a cold eastern US. The exact opposite was true for positive (westerly) QBO during a La Niña Winter, it resulted in a warm eastern US. Also, I believe there was some evidence from a different study which found that La Niña’s that occur during a solar minimum resulted in a colder stratosphere/stratospheric PV than the ones which occurred during periods of higher solar flux. I’m going to look back and see if I can find the links

Here’s another study: https://journals.ametsoc.org/jcli/article/29/24/8899/34342/The-Stratospheric-Pathway-of-La-Nina

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27 minutes ago, snowman19 said:

There was a study years ago by Joe D’Aleo which showed a very strong correlation to a negative (easterly) QBO during a La Niña winter resulting in a cold eastern US. The exact opposite was true for positive (westerly) QBO during a La Niña Winter, it resulted in a warm eastern US. Also, I believe there was some evidence from a different study which found that La Niña’s that occur during a solar minimum resulted in a colder stratosphere/stratospheric PV than the ones which occurred during periods of higher solar flux. I’m going to look back and see if I can find the links

I brought this up on the previous page, but the only info I found was from DT, and he has some of the years wrong. I will look at the links you provided. What I recalled was- wrt La Nina winters- there is a correlation to cold eastern US when there is a very negative QBO during winter, specifically during a weak Nina. It appears we are heading towards a weak Nina for fall/winter, but not so sure the QBO is going to cooperate(looking at current trends), so this may not matter.

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In theory, although it seems nebulous to me, a QBO that is trending negative heading into/during the winter months, favors a weaker PV, and increases chances for a -AO/NAO, in general. During a Nina, a +AO/NAO tends to be favored, so I suppose the idea is that if the QBO is extremely negative, and the La Nina event is on the weak side, those tendencies can be mitigated, and the chances of HL blocking episodes increase. I will leave it to someone else to dig into the data for previous Nina winters to see if this has any validity.

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28 minutes ago, CAPE said:

In theory, although it seems nebulous to me, a QBO that is trending negative heading into/during the winter months, favors a weaker PV, and increases chances for a -AO/NAO, in general. During a Nina, a +AO/NAO tends to be favored, so I suppose the idea is that if the QBO is extremely negative, and the La Nina event is on the weak side, those tendencies can be mitigated, and the chances of HL blocking episodes increase. I will leave it to someone else to dig into the data for previous Nina winters to see if this has any validity.

According to D’Aleo there is also an effect on the PNA. Westerly QBO/Niña favors more -PNA, easterly QBO/Niña favors more +PNA

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10 minutes ago, Mersky said:

So you are going warm and snowless this winter?? Color me shocked LOL 

His biases aside there isn’t much to be optimistic about ATT. But long range seasonal is low probability and things can change quick. But that’s not a reason to predict a cold snowy winter. I don’t see much to justify such a prediction right now. 

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