Possible Snow Gradient Explanation

[HM]

I'm going to try and look at some +QBO gradient years later...there are fewer of them, but they are still there like 1975-1976 as one example. I'm wondering if some of the same features in the PAC appear during those winters even if they aren't necessarily favorable for +QBO climo.

It would be awesome if that was that case. Looking forward to your post...

By the way, on 75-76...while the QBO was westerly, it was also a classic low solar/+QBO stratosphere. I think the PV became so cold and so large that it forced all highs south. You will find that in 75-76, the Pacific High was very much displaced south. Last year would have been more like that if it wasn't for our unprecedented sun. In fact, overall, 10-11 was very cold in the stratosphere, especially in January and February. The North Pole mins were actually colder than 75-76 last winter!

[CoastalWx]

I brought up the Aleutian high connection to the NAO because it seemed like the natural teleconnections would favor a -NAO with a nice cold PV located in western or central Canada. The two features seemed to feed off each other, or perhaps the unprecedented sun and subsequent NAO forcing was so strong, that it created almost a backup effect and helped create conditions favorable for an Aleutian ridge? I guess we enter the chicken or the egg argument here. In any case these two features seem very much in sequence with each other, especially with the graphics Will posted. Of course there are exceptions, but it was an interesting connection.

[HM]

I brought up the Aleutian high connection to the NAO because it seemed like the natural teleconnections would favor a -NAO with a nice cold PV located in western or central Canada. The two features seemed to feed off each other, or perhaps the unprecedented sun and subsequent NAO forcing was so strong, that it created almost a backup effect and helped create conditions favorable for an Aleutian ridge? I guess we enter the chicken or the egg argument here. In any case these two features seem very much in sequence with each other, especially with the graphics Will posted. Of course there are exceptions, but it was an interesting connection.

Well it is a great connection. Not only does blocking help induce further blocking by affecting long waves /zonal winds but it also is all part of the bigger picture of Annular Modes--the AO. Delivering warmer air into the North Pole on one side of the hemisphere is more likely to make its way to the other side than let's say a heat transfer from the Plains or something. Once you get the ball rolling, it is usually hard to stop these processes, especially when the blocking is very anomalous.

[weathafella]

Outstanding thread guys. Thanks for the information! This winter presents one of the better learning opportunities we've had. Are we in "crapshoot mode" right now for the upcoming season?

[VAwxman]

I brought up the Aleutian high connection to the NAO because it seemed like the natural teleconnections would favor a -NAO with a nice cold PV located in western or central Canada. The two features seemed to feed off each other, or perhaps the unprecedented sun and subsequent NAO forcing was so strong, that it created almost a backup effect and helped create conditions favorable for an Aleutian ridge? I guess we enter the chicken or the egg argument here. In any case these two features seem very much in sequence with each other, especially with the graphics Will posted. Of course there are exceptions, but it was an interesting connection.

Yeah I agree they feed off one another. Which one is most responsible for forcing the other can be debated endlessly and probably is pointless since each can be the "driver" in certain circumstances, but it does seem that once both are established, it's tough to break. You can see it easily by separating nina winters by NAO phase (this doesn't even include some recent winters since I made these long ago).

Nina / -NAO

Nina / +NAO

[Ginx snewx]

Yeah I agree they feed off one another. Which one is most responsible for forcing the other can be debated endlessly and probably is pointless since each can be the "driver" in certain circumstances, but it does seem that once both are established, it's tough to break. You can see it easily by separating nina winters by NAO phase (this doesn't even include some recent winters since I made these long ago).

Nina / -NAO

Nina / +NAO

What are the parameters for NINA winters in these composites, weak , mod, strong? Can you run just moderates against NAO? or if you could is there a way to run these against AO? Thanks Brian, always learning.

[VAwxman]

What are the parameters for NINA winters in these composites, weak , mod, strong? Can you run just moderates against NAO? or if you could is there a way to run these against AO? Thanks Brian, always learning.

Yes you could run them by nina intensity, though once doing so, the sample size is so small that I'd worry about its validity.

[Ginx snewx]

Yes you could run them by nina intensity, though once doing so, the sample size is so small that I'd worry about its validity.

Thanks, I am terrible at that site.

[CoastalWx]

Yeah those are pretty telling Brian, thanks for posting.

[CoastalWx]

I don't have the graphics to back it up, but Nino/-NAO I think have more of a ridge over western NAMR, but the NAO ridging I think is displaced further north and more west based.

[VAwxman]

What are the parameters for NINA winters in these composites, weak , mod, strong? Can you run just moderates against NAO? or if you could is there a way to run these against AO? Thanks Brian, always learning.

By the way, sort of along these lines... The school of thought was that a strong nina, by virtue of strong anomalous westerly flow across the 50-60N belts of the Pacific and Atlantic made blocking tougher to come by, both the northward amplification of the NPAC high and in the NAO area. Last winter that line of thinking got roasted.

[Ginx snewx]

By the way, sort of along these lines... The school of thought was that a strong nina, by virtue of strong anomalous westerly flow across the 50-60N belts of the Pacific and Atlantic made blocking tougher to come by, both the northward amplification of the NPAC high and in the NAO area. Last winter that line of thinking got roasted.

Sure did , for 6 weeks anyway. JMHO but in my neck of the woods anyway, I think the AO state is the driver overcoming NINA effects. Obviously the further south and west the more the NINA impacts. There is some wonderful research dealing with AO state, Nina.(o's) which was originated in Alaska. I have lost the link, think it was an 80s paper. But the gist was the AO state was perhaps a bigger player than the Pacific at the further Northern climes. If I remember correctly they correlated AO state pretty well to winters in AK and NE despite Pac conditions being in either state.

[VAwxman]

Sure did , for 6 weeks anyway. JMHO but in my neck of the woods anyway, I think the AO state is the driver overcoming NINA effects. Obviously the further south and west the more the NINA impacts. There is some wonderful research dealing with AO state, Nina.(o's) which was originated in Alaska. I have lost the link, think it was an 80s paper. But the gist was the AO state was perhaps a bigger player than the Pacific at the further Northern climes. If I remember correctly they correlated AO state pretty well to winters in AK and NE despite Pac conditions being in either state.

I haven't plotted them yet, but I would imagine making maps sorted by AO phase would look similar to the ones I posted earlier, since the AO and NAO are highly correlated, especially when the NAO is negative. Of the 28 DJF periods with a -NAO of any value, only one did not have a -AO of any value, and that was 08-09, which barely registered negative on the NAO scale. A lot of folks do prefer the AO though since its domain reaches over to the Pacific side as well as the Atlantic.

[Ginx snewx]

I haven't plotted them yet, but I would imagine making maps sorted by AO phase would look similar to the ones I posted earlier, since the AO and NAO are highly correlated, especially when the NAO is negative. Of the 28 DJF periods with a -NAO of any value, only one did not have a -AO of any value, and that was 08-09, which barely registered negative on the NAO scale. A lot of folks do prefer the AO though since its domain reaches over to the Pacific side as well as the Atlantic.

This is chock full of info, great read too.

http://www.pmel.noaa.gov/foci/publications/2006/bondG700.pdf

[VAwxman]

This is chock full of info, great read too.

http://www.pmel.noaa...06/bondG700.pdf

Cool. I had not seen this. Thanks for posting! The images there are great to show the differences in ENSO events sorted by AO phase. Nice!

[Ginx snewx]

Cool. I had not seen this. Thanks for posting! The images there are great to show the differences in ENSO events sorted by AO phase. Nice!

Yea thats a sweet paper, no problem just us dumb SNErs ya know.LOL

[ORH_wxman]

Yeah I agree they feed off one another. Which one is most responsible for forcing the other can be debated endlessly and probably is pointless since each can be the "driver" in certain circumstances, but it does seem that once both are established, it's tough to break. You can see it easily by separating nina winters by NAO phase (this doesn't even include some recent winters since I made these long ago).

Nina / -NAO

Nina / +NAO

That is a sweet couple of maps there that show the difference in mean placement of the Aleutian high during -NAO and +NAO Nina winters.

[Ginx snewx]

Ok why was this moved?

[am19psu]

Ok why was this moved?

Will and I discussed moving it because it has a lot more relevance than just the snow gradient in SNE. There is a lot of good stuff in here that everyone can learn from.

[Ginx snewx]

Will and I discussed moving it because it has a lot more relevance than just the snow gradient in SNE. There is a lot of good stuff in here that everyone can learn from.

Gotcha, great thread.

[LakeEffectKing]

Good move on moving this thread! Moderation at it's finest!

[QVectorman]

Will and I discussed moving it because it has a lot more relevance than just the snow gradient in SNE. There is a lot of good stuff in here that everyone can learn from.

Thank you! Hope to see more of this type of moderating in the up coming weeks and months! Not all of us have the time to sort through the sub forums to find these great threads. Plus, as you kind of stated many times these types of threads contain info relevant to all regions. Thanks for bringing them to our attention

[usedtobe]

Thanks for moving the thread. It's an interesting one.

I guess my concerns and questions concern the qbo and the MJO and how they might impact on the Brewer Dobson Circulation and possibly precondition the atmosphere towards and negative nao. Wouldn't a truely negative QBO lead to deeper convection in the tropics which might allow the MJO to play a bigger role towards inducing a negative NAO during easterly qbo years?

The think I read something by Collemoreet al. (sp?) about the depth of convection being greater during easterly QBO years. I no longer can find where I stashed the paper but here's the abstract.

http://adsabs.harvard.edu/abs/2003JCli...16.2552C

and also read something by Geller and

http://adsabs.harvard.edu/abs/2009AGUFM.A51H0213G

Getting anomalous convection near the dateline is always a good thing for getting a negative nao going though it provides no guarantee that you will get one.

There is also this article on the role of the MJO in possibly preconditioning the atmosphere towards getting a negative NAO.

http://www.nature.com/nature/journal/v455/n7212/full/nature07286.html

It seems from these articles that it is the easterly QBO that might be the better phase for having an active MJO regardless of enso state.

Is my thinking OK or flawed.

[VAwxman]

Getting back to the QBO for a minute (since that was HM's idea for the thread anyhow)....

HM,

I'm a little confused on a couple of the years in the original post that were mentioned as La Nina / solid +QBO. I have both 55-56 and 64-65 as slightly neg QBO for DJFM, based on the 30mb QBO. The 50mb QBO I'm sure was + in those winters, but they would seem to belong more in the mixed camp to me.

[HM]

Getting back to the QBO for a minute (since that was HM's idea for the thread anyhow)....

HM,

I'm a little confused on a couple of the years in the original post that were mentioned as La Nina / solid +QBO. I have both 55-56 and 64-65 as slightly neg QBO for DJFM, based on the 30mb QBO. The 50mb QBO I'm sure was + in those winters, but they would seem to belong more in the mixed camp to me.

Yes, they should have been starred or something. You are correct that the 30mb numbers are a little on the minus-side. The way these years were selected was based upon my personal choice on how the entire QBO system behaved. I also cross-checked my analysis against the Berlin data. In some cases, I agreed with their assessments/classifications; but in other cases, I found too much of a difference in zonal winds to use them in a solid class (see below).

Overall, 64-65 and 55-56 had deep layer westerly flow over the Equator and NOV/DEC were at least on the plus-side (30mb) in both years. For the sake of sample size and their bias westerly, I lumped them in... sort of like a 2000-01 type of year.

But to calm your nerves, I analyzed all of the mixed years further and the results are still compelling:

55-56: Aleutian High. Classified westerly by Berlin. 30mb: weak +QBO to -QBO transition with an equatorial + anomaly at 50mb.

64-65: Aleutian High. Classified westerly by Berlin. 30mb: weak neutral to -QBO with an equatorial + anomaly at 50mb.

67-68: Aleutian High. Classified westerly by Berlin. 30mb: solidly -QBO with an equatorial + anomaly at 50mb.

88-89: Aleutian High. Classified westerly by Berlin. 30mb: weak -QBO with strong equatorial + anomaly at 50mb.

95-96: Aleutian High. Classified westerly by Berlin. 30mb: weak -QBO with a good westerly 50mb anomaly over equator and good easterly at 30mb.

83-84: Broad positive anomaly from N PAC to just off the West Coast. Classified w/e by Berlin. 30mb solidly negative with a weak DJFM equatorial negative anomaly at 50mb.

84-85: SE-displaced "Aleutian High" and classified easterly by Berlin. It was transitioning from -QBO to +QBO at 30mb. Strong negative equatorial anomaly at 50mb

98-99: No Aleutian High. Classified easterly by Berlin. It was transitioning from a -QBO to +QBO at 30mb. Strong negative equatorial anomaly at 50mb.

01-02: Displaced southward. Classified easterly by Berlin. It was a weak +QBO at 30mb with a strong negative anomaly at 50mb.

So, I would say that this is rather compelling that when you have a deep westerly descending QBO (perhaps 50mb is more important), you are most likely going to see a DJFM averaged Aleutian High with cold ENSO.

This would mean 2011-12 has a higher likelihood to see an Aleutian High based on how I think the QBO will behave.

[Ginx snewx]

This would mean 2011-12 has a higher likelihood to see an Aleutian High based on how I think the QBO will behave.

Taken from my earlier quoted paper, this would yield I would assume to a setup something like this?

[HM]

Guys, I am sorry about the original composites. I kind of did this quickly for the sake of tackling the snowfall gradient ideas being thrown around in the New England forum. In the original westerly composite, I forgot to add 73-74 which was a solid La Nina-west year. This fits in with 55-56 and 64-65 where 30mb was in the process of changing to a weak negative number but the entire layer was essentially westerly (Berlin agrees and the zonal wind averages are essentially westerly). This year had an Aleutian High and it was placed similarly to 55-56, perhaps slightly west.

[HM]

Guys, I am sorry about the original composites. I kind of did this quickly for the sake of tackling the snowfall gradient ideas being thrown around in the New England forum. In the original westerly composite, I forgot to add 73-74 which was a solid La Nina-west year. This fits in with 55-56 and 64-65 where 30mb was in the process of changing to a weak negative number but the entire layer was essentially westerly (Berlin agrees and the zonal wind averages are essentially westerly). This year had an Aleutian High and it was placed similarly to 55-56, perhaps slightly west.

I should add though: if your interest is just in the Aleutian High, I shouldn't have left 73-74 out. If your interest is in the New England snowfall gradient, I think it might have been wise to leave it out. The 73-74 La Nina was the strongest ever recorded. The entire state of the oceans were very cold and the Gulf of Alaska was also colder than normal. The warm anomaly associated with the -PDO was shunted well south/west. All of this combined lead to a very displaced Hadley/Walker circulation (west) and therefore a more displaced Aleutian Ridge.

The more west ridge allowed for more of a Southeast Ridge to develop. So, I am sure 73-74 was probably a good gradient year because the general circulation across the CONUS mimicked a -QBO La Nina.

But the deep-westerly QBO connection still holds to a more poleward Aleutian High, even in the strongest La Nina.

[HM]

Taken from my earlier quoted paper, this would yield I would assume to a setup something like this?

Yes, that type of Aleutian High would be favored if the lower stratospheric winds are westerly this winter. Should the easterly winds descend more quickly, then we may be looking at a more displaced high to the southeast. I just don't see the lower stratospheric winds going easterly fast enough.

[Ginx snewx]

Yes, that type of Aleutian High would be favored if the lower stratospheric winds are westerly this winter. Should the easterly winds descend more quickly, then we may be looking at a more displaced high to the southeast. I just don't see the lower stratospheric winds going easterly fast enough.

Nice block in NE Canada, would yield some pretty good Arctic outbreaks I would think especially in the Upper Midwest. Do not like the -PNA look but with a block set up the opportunity for a good gradient winter apperas to be on track. The classic 70-71 gradient appearing as an analog again this year is interesting. A midwinter warming event would be just what the DR ordered.