Jump to content
  • Member Statistics

    15,508
    Total Members
    7,904
    Most Online
    kgottwald
    Newest Member
    kgottwald
    Joined
Sign in to follow this  
weathafella

The early speculation on winter 2013-14

Recommended Posts

It may be my own ignorance claiming (  :P ) ...but I don't see how the Pac and AO are very correlated.   In fact, my own experience shows that that polarward field indices (less the EPO) are rather disconnected, and have oft' trumped seasonal outlooks that were more dependent on Pac, particularly, the ENSO's impact on the flow.  Even NCEP has in recent autumns begun to capitulate to the stochastic nature of these northern indices in modulating temperature and precipitation departures, in their seasonal outlooks.  

 

Also, I am having a problem seeing why this is an +AO winter.  I am getting a lot of this and I don't see why that is.  As Cohen (and others, such as myself) have noted for years that positive AO tendencies in autumns, tend to reverse in DJF.  Early studies related that to early cryosphere snow/ice production kinematics, but I suspect there are other factors, such as ozone in the stratosphere and solar fluxes.  

 

Anyway, the multi-decadal oscillation would offer a linear suggestion (trend) that negative is preferred.  The QBO is the only reason I can see that supports a positive AO, and that may very well prove to be the dominating factor, okay.  But, there are a lot of years where the positive QBO phase broke down.  2010-2011 is suspect, but there are others.  Papers, also about that, show that the positive phase of the QBO is the weaker correlation vs the negative.  

 

I still think this could be a good winter for the NP-GL-NE and yes, the MA.  But, this is admittedly based only what I have noticed is scale-able.  

Tip,

 

I wasn't suggesting that the Pacific and AO are correlated. I'm stating that an AO+ winter appears likely. How the Pacific pattern sets up will have an impact on the overall outcomes in combination with the AO+, particularly whether northern sections of New England and northward have smaller warm anomalies than those farther south.

 

My thoughts that things lean toward a predominant AO+ winter, which does not rule out some periods of blocking or even a switch late in the winter, is based on the SAI, new OPI, QBO, etc. I expect less blocking than last winter.

Share this post


Link to post
Share on other sites

Tip, I don't see how you can think the Pacific doesn't influence the AO domain. In the more fundamental sense, take the distribution of tropical forcing in the equatorial Pacific, sketch a Hadley circulation accordingly, which will move the "Ferrel cell" ball bearing, thus putting some vertical torque on the polar cell.

 

Or just take tropical forcing and the polar jet and see where the lower wavenumber Rossby rays go.

 

All sorts of interaction. And unfortunately no matter how many three letter acronyms someone wants to come up with, it will always be a nonlinear system.

Share this post


Link to post
Share on other sites

The definition of the AO, at least given by the CPC shows that 1000 mb height anomalies over the Aleutian region project onto the eof. So there is a direct influence of the Pacific on the AO value, aside from any physical forcing.

 

new.ao.loading.gif

Share this post


Link to post
Share on other sites

Tip, I don't see how you can think the Pacific doesn't influence the AO domain. In the more fundamental sense, take the distribution of tropical forcing in the equatorial Pacific, sketch a Hadley circulation accordingly, which will move the "Ferrel cell" ball bearing, thus putting some vertical torque on the polar cell.

 

Or just take tropical forcing and the polar jet and see where the lower wavenumber Rossby rays go.

 

All sorts of interaction. And unfortunately no matter how many three letter acronyms someone wants to come up with, it will always be a nonlinear system.

 

 

Actually, I did not say that.  I said, "not very correlated"   In plain English that means there is a disconnect, at least from what I have observed over the years and have read in refereed sources.   And it makes sense when considering the Brewer-Dobson circulation model.

 

As far as the EPO ... it should be mentioned because the EPO, similar to the NAO, shares domain space with AO.   Should changes in the Pacific hugely effect the EPO, than yes .. the AO would at least in quadrature (and by logic) register some of those changes.   But, in the absence of that over-lap in domain space, the purer arctic region is above the Brewer-Dobsin circulation boundary.  

 

Of course ... we should all keep in mind that there really aren't physical boundaries in the atmosphere, and nothing is absolute. 

Share this post


Link to post
Share on other sites

The definition of the AO, at least given by the CPC shows that 1000 mb height anomalies over the Aleutian region project onto the eof. So there is a direct influence of the Pacific on the AO value, aside from any physical forcing.

 

new.ao.loading.gif

 

Right ... I just mentioned that the shared domain space of the EPO with the AO can effect the AO -- agreed.

Share this post


Link to post
Share on other sites

Tip,

 

I wasn't suggesting that the Pacific and AO are correlated. I'm stating that an AO+ winter appears likely. How the Pacific pattern sets up will have an impact on the overall outcomes in combination with the AO+, particularly whether northern sections of New England and northward have smaller warm anomalies than those farther south.

 

My thoughts that things lean toward a predominant AO+ winter, which does not rule out some periods of blocking or even a switch late in the winter, is based on the SAI, new OPI, QBO, etc. I expect less blocking than last winter.

 

 

It's a good point about the SAI and the OPI.  I was just telling Scott the other day that I am less familiar with those.   The QBO, however, can be more easily trumped by other factors when it is in particular, in the positive phase.  

Share this post


Link to post
Share on other sites

Actually ... I was being stupid.  I was just thinking about the troposphere by mentioning the Brewer-Dobson model, and forgot about the stratospheric component and transport of ozone from the tropics to the poles.  

 

Neglecting that crucial factor was/is tantamount to colossally dumb.  

 

Having said that, I don't believe the Pac "directly" influences the AO.   That would have been vastly better   :) 

Share this post


Link to post
Share on other sites

A few quick things regarding my early thoughts:

 

1. The rolled-forward partial analogs are used largely to observe possible trends e.g., are things looking colder/warmer based on those cases.

2. ENSO and teleconnections help shape my overall thoughts. I usually look at those factors 1-2 weeks before the start of a month. I did post what things look like a little earlier with respect to December, but had noted that neither the CFSv2 nor those cases have demonstrated much skill from this far out.

3. The sample of seasonal forecasts I've seen over the years suggests that some skill may exist in the area of temperature anomalies, but neither precipitation nor snowfall forecasts have consistently been skillful. A better idea about regional snowfall does become evident during December.

 

Having said that, my early thoughts are that the region's temperature anomalies will probably be colder than 2011-12 and warmer than 2012-13, but some potential for warmth closer to 2011-12 exists. The farther north on goes, the closer anomalies in New England could be closer to normal. The state of the Pacific could be key to what happens in what very likely looks to be an AO+ winter (some periods of blocking are possible, but much less than what occurred last winter).

 

My biggest worry about snowfall: Ongoing dry conditions might persist and warmth could predominate leading to fewer opportunities for snow. A big storm or two could still have a big impact on seasonal accumulations.

I get your overall thoughts, but that sentence really doesn't tell anyone much lol.

 

In other news, I expect the 2014 season to be less successful than 2013, and more successful then 2012 for the Red Sox.

Share this post


Link to post
Share on other sites

I get your overall thoughts, but that sentence really doesn't tell anyone much lol.

 

In other news, I expect the 2014 season to be less successful than 2013, and more successful then 2012 for the Red Sox.

 

 

Well last winter was above normal for temps...despite the big snow amounts in many spots. So saying it will be between 2011-2012 and 2012-2013 for temperatures means it will be solidly above normal.

 

 

 

Snowfall OTOH is a much tougher forecast. Though with above normal temperatures, you would tend to cut back the snow amounts much more in southern areas vs northern.

Share this post


Link to post
Share on other sites

I get your overall thoughts, but that sentence really doesn't tell anyone much lol.

 

In other news, I expect the 2014 season to be less successful than 2013, and more successful then 2012 for the Red Sox.

I'll have my final thoughts later this month. Right now it looks milder than normal. While I'm fairly confident in a predominant AO+ pattern this winter and neutural ENSO, I'm still not very sure about the predominant state of the PNA and EPO.

Share this post


Link to post
Share on other sites

Welp, fwiw -- I just finished up with Cohen primer on the SAI developed index (AER)... . 

 

----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

 

Winter-Severity-Index-699x366.gif

 

  •  When there is more Eurasian snow cover in October, the following winter N/AO is low and there is an increased frequency of severe weather in the mid-latitudes.
  •  When there is less Eurasian snow cover in October, the following winter N/AO is high and there is a decrease in the frequency of severe weather in the mid-latitudes.

AER Researchers demonstrate how the Snow Advance Index predicts the N/AO

Until now only a moderate relationship has been demonstrated. However in a paper published in Geophysical Research Letters by myself and Justin Jones, a new Snow Advance Index is developed that is derived not from October mean snow cover extent, but rather as a function of how slowly or quickly the snow cover advances across Eurasia in October. This new Snow Advance Index is highly correlated with the N/AO or winter severity index (see Figure).

  • When snow cover advances rapidly across Eurasia in October, this is an indication that the upcoming winter will be more severe for the Eastern US, Europe and East Asia.

---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

 

What actually irks me here a bit is that I was hammering that "rate of recovery" as being much more telling about the/a system than the scaler values, because that differential tells more about the dynamics of the system in question.  I said this ...like 4 or 5 years ago, when we were still over at Eastern up through last year at American.   Sometimes I wonder how some of these well-financed organizations get some of their ideas.   Anyway, because their science strikes such chord, I'm going to have to go ahead and agree with them.  Wtf does it take to get noticed in this racket

 

That said, -NAO should evolve in time and perhaps rule more than 50%.  October's rate of recovery of snow was fantastic this year ... if the study works out.

 

ims_data.jpg

Share this post


Link to post
Share on other sites

it's the rate of change that matters... why is this so hard to understand?

 

It isn't -- not for me, anyway.  Never has been... This rather obviousness occurred to me like 7 years ago, when some of those cryosphere studies were gaining popularity.  

 

So Cohen from AER releases a study and now it's gospel.  Okay.  I guess who ever caries the loudest trumpet gets the ear.  It's called life.... 

Share this post


Link to post
Share on other sites

Well last winter was above normal for temps...despite the big snow amounts in many spots. So saying it will be between 2011-2012 and 2012-2013 for temperatures means it will be solidly above normal.

 

 

 

Snowfall OTOH is a much tougher forecast. Though with above normal temperatures, you would tend to cut back the snow amounts much more in southern areas vs northern.

I hadn't even realized.

Wasn't paying close attention to weather.

Share this post


Link to post
Share on other sites

For the Cohen paper - I can only get to the abstract - what was the correlation constant, pearson r or r^2 value for the correlation?

 

I'm wondering exactly how powerful the SAI index is in predicting the NAO.

 

I'm becoming gradually more hopeful for a good winter after just two weeks ago thinking this would be well below average winter.

 

Edit to add:  Why does the total ice curve end October 1?  Does anyone have full curve data?  I'm interested in the sinusoidal shape as well as differences in the x-offset of the curve year over year.

Share this post


Link to post
Share on other sites

For the Cohen paper - I can only get to the abstract - what was the correlation constant, pearson r or r^2 value for the correlation?

 

I'm wondering exactly how powerful the SAI index is in predicting the NAO.

 

I'm becoming gradually more hopeful for a good winter after just two weeks ago thinking this would be well below average winter.

 

Edit to add:  Why does the total ice curve end October 1?  Does anyone have full curve data?  I'm interested in the sinusoidal shape as well as differences in the x-offset of the curve year over year.

 

The r value for the SAI and DJF AO Index over the last 10 or so years is 0.81. The r^2 value is 0.66.

Share this post


Link to post
Share on other sites

Well if you're reading ongoing thread of summer you now know that I'm going all in for a huge winter with epic snow and cold......maybe end to end but I need a bit more details. I'm liking the early signs and will give more details as summer gets later.

Working out in the sense of subnormal temp and above normal snow in most of sne. And signs point to rocking on into March. This post was entered on 4th of July weekend.

Share this post


Link to post
Share on other sites

Working out in the sense of subnormal temp and above normal snow in most of sne. And signs point to rocking on into March. This post was entered on 4th of July weekend.

Def not end to end...but if tomorrow AND Tuesday work out well, we can talk about epic snow. Excellent cold but epic is hard with the torches in between.

But overall, cold and snowy was a damn solid call. Of course, one could make the argument that it is winter so cold/snowy isn't going out on a huge limb. But I also don't remember the 80s.

Share this post


Link to post
Share on other sites

Def not end to end...but if tomorrow AND Tuesday work out well, we can talk about epic snow. Excellent cold but epic is hard with the torches in between.

But overall, cold and snowy was a damn solid call. Of course, one could make the argument that it is winter so cold/snowy isn't going out on a huge limb. But I also don't remember the 80s.

Has everyone had subnormal temps since 11/1? Yes

Are most in sne above normal snow? Yes

Torches were big but much less in the past month in terms of duration. Remember 1995-96? Huge torches yet most remember it quite fondly.

Share this post


Link to post
Share on other sites

Has everyone had subnormal temps since 11/1? Yes

Are most in sne above normal snow? Yes

Torches were big but much less in the past month in terms of duration. Remember 1995-96? Huge torches yet most remember it quite fondly.

No I was 9 lol.

It has been an above average winter for most in sne, espec after tomorrow. No argument from me there. I am part of the "spoiled by winter" generation.

Share this post


Link to post
Share on other sites

Has everyone had subnormal temps since 11/1? Yes

Are most in sne above normal snow? Yes

Torches were big but much less in the past month in terms of duration. Remember 1995-96? Huge torches yet most remember it quite fondly.

Jerry, this is not at all comparable to 1996....we had epic depth that season, and it was the snowiest on record.

 

We had the one epic torch, but the there weren't nearly as many cutters.

Share this post


Link to post
Share on other sites

Jerry, this is not at all comparable to 1996....we had epic depth that season, and it was the snowiest on record.

 

We had the one epic torch, but the there weren't nearly as many cutters.

Oh I know. But torches alone should not be weighted so heavily. NAO did the deed that year. My speculation was based in EPO and that has worked out beautifully.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

  • Recently Browsing   0 members

    No registered users viewing this page.

×