Jump to content

cbmclean

Members
  • Posts

    2,591
  • Joined

  • Last visited

Posts posted by cbmclean

  1. On 3/15/2024 at 7:40 PM, psuhoffman said:

    Awesome find. It shows both the improvements and confirms there has been a bit of a plateau since 2010. Perhaps the advent of AI ushers in the next leap? 

    I'd like to understand what the y-axis represents.  It is labeled percentage, but percentage of what?  What does 100% mean vs 0%?  I know you didn't make the graphic.  Maybe @Ji has some more data from wherever he got this from?

  2. 54 minutes ago, stormy said:

    Regardless of your theory, I'm not convinced a positive PDO will be the magical elixir for snowfall because the 50's and 60's both witnessed a mostly negative PDO with a brief positive from about 1958 - 1962.  Under mostly negative conditions as we have witnessed since 2020, the 50's witnessed below normal snowfall and the 60's witnessed above normal snowfall.  I don't find any significant impact because of the PDO phase.  

    I don't think anyone has been touting the PDO flip as a magic elixir, at least not in any of the serious posts I have been seeing.  The general theory (and hope) is that some of the suck we have been seeing in the last ~8 years is due to a prolonged period of very negative PDO and that when that relaxes we may see some improvement.  I don't think many are expecting it to go back to "normal".  It just MAY not suck so bad.

    @psuhoffman has been the person I have talk most about this topic and he has made it VERY clear that he believes that at at best a +PDO will only mitigate the suck and that there are non-cyclical factors leading to an ever-worsening base state, which is my own belief as well. 

    What impact, if any will a +PDO have?  TBD.

    • Like 1
  3. On 3/8/2024 at 7:47 PM, WxUSAF said:

     

    A fascinating graphic: some musings:

    1. The east has clearly been hit harder than the west.  This actually gives me a bit of hope.  Yeah there is nasty background warming but perhaps there really is a multidecade cycle that happens to be "favoring" eastern NA for warmth.  

    2. On the other hand, the eastern CONUS is on average lower in elevation than the west which suggests that it is less able to rely on elevation for cold and is this more dependent on cold air advection from the source regions.  So it makes sense that combined trends of warmer source region and increased pacific influence are hurting the east worse.

    3. Man 1998-2000 looks like it was an ugly period.

  4. 8 hours ago, Rhino16 said:

    Does the hypsometric equation kind of relate to the question you’re asking?

    Yes, but that appears to pertain more to thicknesses as opposed to heights.  I know that thicknesses are closely related to virtual temperature, and I know that thicknesses are related to heights.  But if you look at maps of gph anomalies vs temp anomalies, you can tell they are related but never identical.  What I would like to understand is why they are different.

  5. 8 hours ago, psuhoffman said:

    Holy crap... if it was possible to explain wave physics in a paragraph I would put a lot of professors and text book writers out of business!  But... I think I can try to explain the basics of what you are getting at fairly briefly, at least I will try. 

     

    8 hours ago, psuhoffman said:

    Now to really get into this on the physics level we would have to discuss things like Bernoulli's principle and how speed and pressure factor into these equations but I'm not interested or qualified to teach that physics course on here lol.  If it could be explained in a forum post there wouldn't be whole courses on this.  

    I understand it is a big ask but I appreciate the attempt.  One thing I have noticed is that for many topics, for example Calculus, differential equations, planetary science etc., there is a large amount of material available for those who are beyond the basics but who aren't ready for the 4 year degree level.  For synoptic meteorology, not so much.  Most of the stuff I can find is the basic stuff.  I learn a lot lurking here.

  6. 18 hours ago, psuhoffman said:

     

    this shot here is why I wonder how much split flow blocking works in this regime. I know with the time of year it doesn’t matter but the same concept applies mid winter. If that energy in the west was less amplified and the ridge in front was slightly less that system would slide east under the block and 50/50 and be a threat. But there is a tipping point where the ridging in front of every pacific wave is too much and they amplify out west and then try to cut regardless of blocking. 

    I wanted to say something meaningful about this but realized i could not because I have very little understanding of what actually causes ridges or troughs.  If someone asked you to explain the mechanism(s) by which synoptic-scale variations in geopotential height arise and move around, how would you do it in a paragraph?  I know that thicknesses are highly correlated to average temperature in a column of air, but is it just that simple for heights: cold air = low heights and warm air = high heights?

    Assume your listener has a strong background in basic physics but very little detailed knowledge of fluid dynamics.  

  7. 1 hour ago, psuhoffman said:

    Ok if we’re being more realistic guidance does suggest there might be some pretty awesome snowstorms up in the mountains of Vermont, NH, Maine the last week of March and early April.  If you need to see one more snow that bad just plan a trip. I’m stoked for what it could mean for the late ski season. 

    Better get the knee in shape!!

  8. 21 minutes ago, Terpeast said:

    I get your frustration around the lack of discussion of what's causing the ridge/trough flip. I notice this more and more, but tbh I don't have any good answers to offer as to what's causing this. Really. Gun to head, I'll still say "I don't know." 

    I hope we get some real answers either from yet another shift in the pattern, or from climate scientists smarter than us publishing new papers on this.

    We could blame the MJO, but I think that's too convenient of a target. It could be the +EAMT since all the cold has been on the other side. It could be the Atlantic, but I'm not buying it 100%. Again, I hope the answers become clearer to us sooner than later.

    TNH?

  9. 2 hours ago, psuhoffman said:

    Something that's been bothering me though the last few days...the EPS wants to retrograde the NAO ridge very quickly and it ends up centered pretty far south in Canada...that used to work, but in recent years when that happens it's just been linking up with the mid latitude ridges which neutralizes the suppressive benefits of the -NAO.  Just something to look out for here.  On top of the fact its going to be late March by the time cold makes its way east.  

    Maybe we can manage a miserable cold, wet Easter.

  10. 35 minutes ago, psuhoffman said:

    q0NXUrvVFG.png.7cabce79913d972a52629dc6f78a5541.png

    This has been our reality for 9 years...

    Here is the thing about that...yes the PDO is killing us, putting a perpetual ridge over the east...but look out west at our latitude...even with a crazy -PNA most of the time, they aren't cold either.  At our latitude the variance across the northern hemisphere the last 9 years has been crazy unprecedented torch to at best slightly above normal temps, which for us isn't even good enough since our lowest average high temp is still in the 40's.

     

    I've witnessed this first hand...yea they have been "colder" and yes at times when a crazy trough sets up they do get cold for a bit...but I've been out west several times in the last 8 years and lower elevations were really really suffering in terms of snowfall with very warm temps between storms and during any modest ridging episodes.  Just a cautionary thing to keep in mind for when the PDO flips...it hasn't exactly been cold ANYWHERE at our latitude on the whole, no matter what the longwave pattern is.  This doesn't mean you can't get cold for a period, there are anomalies within that longer term avg...just saying...in general its just been warm everywhere at our latitude.  

    As you have mentioned many times it is likely that there are at least two additive factors at play in our recent snow woes

    1. The perma-SER courtesy of the -----PDO

    2. Pack puke episodes which are more frequent, stronger, and longer in duration due to pac warm pool/hadley cell expansion/Babar

    The PDO flipping should hopefully help with factor 1 but I don't know of any reason why it would help with factor 2.  

    So when the PDO flips it's a matter of do we get 80% back or 20% back (or whatever).  I think 100% is out of reach sadly.

    • Like 1
  11. 3 hours ago, CAPE said:

    I think Chuck might be referring to influences such as east Asian mountain torque on the earth's rotation. The hints in his post are mentions of friction and more high pressure. A +EAMT opposes the earth's rotation, and to conserve angular momentum there is an increase in westerly winds in the atmosphere(stronger jet stream). 

    I know I take things literally but I was not being serious about the infinitesimally slow decrease in rotation rate causing climate impacts on a decadal scale.  I was just poking a bit of fun at those mocking Chuck.

    • Like 3
×
×
  • Create New...