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Pattern Oppressive Ornery Obstinate Opposite October

Webberweather53 said:
Some variables begin to reveal themselves by this time in the fall, and when you combine the long-term background state, warm background climates like this one and during the medieval warm period tend to favor less high latitude blocking over the Atlantic, background state inter annual tendencies which has favored a stronger than normal Greenland/Iceland Vortex, dynamical forcing (slight uptick in solar activity coupled w/ EQBO >>> less blocking), and ENSO which interferes w/ the standing planetary wave configuration and henceforth tends to reduce wave activity flux onto the polar vortex all are conducive to a stronger vortex. While some of the variables can certainly change, the ENSO forcing (NINA-esque) coupled w/ long term background state changes (AGW) and dynamical forcing all tend to skew the probabilities quite high for a warmer than normal winter around the SE US...
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I still think the NAO is the biggest wild card to what type of winter we could have. Sure it has been non existent for a while but the trends seem to be all or nothing like 2011. Also, while the warm trend has been there who can really say what will happen several weeks or months down the road with that much skill? I don't trust long range forecasting much.
 
Webber, another question I have is how do we really know the solar is going to throw a wrench in all this? The QBO is more favorable now than this time last year.
 
Webberweather53 said:
Some variables begin to reveal themselves by this time in the fall, and when you combine the long-term background state, warm background climates like this one and during the medieval warm period tend to favor less high latitude blocking over the Atlantic, background state inter annual tendencies which has favored a stronger than normal Greenland/Iceland Vortex, dynamical forcing (slight uptick in solar activity coupled w/ EQBO >>> less blocking), and ENSO which interferes w/ the standing planetary wave configuration and henceforth tends to reduce wave activity flux onto the polar vortex all are conducive to a stronger vortex. While some of the variables can certainly change, the ENSO forcing (NINA-esque) coupled w/ long term background state changes (AGW) and dynamical forcing all tend to skew the probabilities quite high for a warmer than normal winter around the SE US...
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Webber, despite a -QBO this winter, you don't think it will allow for times of blocking compared to last winter without the -QBO or has the winter pattern pretty much been established already? I feel that it's a legitimate question.
 
Mr. Golf, this is essentially what I'm alluding to as well. As good as Webber is at identifying the trends there are some things we can't accurately see far down the road. The NAO is one of those things that can't be predicted with much skill and that imo holds the key to this coming winter.
 
We're gonna get what we get, yet the speculation and analysis is fun ... but ... there are so many drivers and how they ultimately line up will be the key. Remember last year when all looked so good, only to have a half a world away turn the screw? It's still far too early to tell with any degree of certainty ... Now, off the soap box and back into the cave ... :confused:
 
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GaStorm said:
I still think the NAO is the biggest wild card to what type of winter we could have. Sure it has been non existent for a while but the trends seem to be all or nothing like 2011. Also, while the warm trend has been there who can really say what will happen several weeks or months down the road with that much skill? I don't trust long range forecasting much.
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There actually is some predictability in these phenomena at long leads as long as you understand the uncertainties, probabilities in certain regimes, etc, and what you can and can not say at particular leads, which goes hand in hand w/ understanding uncertainties. The literature and observations actually confirm that a +NAO is favored in a warmer background climate, and these regimes tend to persist for long periods of time, as we've been observing of late, the NAO has tended to be positive for the majority of winters the past several years, not just 2011...

Aside from the negative stint in 2009-10 and the first half of 2010-11, since the early-mid 1990s, the NAO has been primarily positive....
Screen Shot 2017-10-19 at 4.57.08 PM.png
 
Webberweather53 said:
There actually is some predictability in these phenomena at long leads as long as you understand the uncertainties, probabilities in certain regimes, etc, and what you can and can not say at particular leads, which goes hand in hand w/ understanding uncertainties. The literature and observations actually confirm that a +NAO is favored in a warmer background climate, and these regimes tend to persist for long periods of time, as we've been observing of late, the NAO has tended to be positive for the majority of winters the past several years, not just 2011...

Aside from the negative stint in 2009-10 and the first half of 2010-11, since the early-mid 1990s, the NAO has been primarily positive....
View attachment 1419
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looks like time to take a dip (in a manner of speaking) ... LOL
 
GSP still looking good for severe and 3-5" on Monday-Tuesday? Been a busy day on the golf course! :)
 
Mr. Golf said:
Webber, despite a -QBO this winter, you don't think it will allow for times of blocking compared to last winter without the -QBO or has the winter pattern pretty much been established already? I feel that it's a legitimate question.
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Punctuated periods of high latitude blocking are inevitable in nearly any winter and while the forcings can modify over the course of the winter, it takes several weeks for the atmosphere to respond significantly even if they change dramatically. Easterly QBO aids in high latitude blocking because it modifies the background upper level shear near the equator s.t. Rossby wave momentum flux deposition and heat fluxes are confined to the wintertime hemisphere. However, interaction with ENSO and solar activity modifies the impacts directly attributable to the QBO. The most favorable configuration with an easterly QBO is a warm ENSO event coupled with low solar activity. The easterly QBO intensifies the Brewer Dobson Circulation, while El Niño events reinforce the standing planetary wave configuration (featuring large scale upper level ridges and troughs occurring in quadrature with topography) and lower solar activity cools the top of the BDC and in the absence of major coronal mass ejections and solar proton events, warms the polar stratosphere, thereby intensifying the mean meridional circulation... All of these work in tandem to enforce a pattern that's favorable for high latitude blocking by maximizing the momentum flux deposition of the Rossby Waves and strengthening the meridional circulation that accompanies it. This year we have a weak La Niña event coupling with weak-moderate solar activity, in concurrence with the background state (warm climate + persistence) that's not conducive to -NAO regimes, I would lean towards a solution that keeps this index primarily positive for the majority of the winter especially in the latter stages ~ February and henceforth reinforces the idea for a warmer than normal winter in the SE US
 
Webberweather53 said:
Punctuated periods of high latitude blocking are inevitable in nearly any winter and while the forcings can modify over the course of the winter, it takes several weeks for the atmosphere to respond significantly even if they change dramatically. Easterly QBO aids in high latitude blocking because it modifies the background upper level shear near the equator s.t. Rossby wave momentum flux deposition and heat fluxes are confined to the wintertime hemisphere. However, interaction with ENSO and solar activity modifies the impacts directly attributable to the QBO. The most favorable configuration with an easterly QBO is a warm ENSO event coupled with low solar activity. The easterly QBO intensifies the Brewer Dobson Circulation, while El Niño events reinforce the standing planetary wave configuration (featuring large scale upper level ridges and troughs occurring in quadrature with topography) and lower solar activity cools the top of the BDC and in the absence of major coronal mass ejections and solar proton events, warms the polar stratosphere, thereby intensifying the mean meridional circulation... All of these work in tandem to enforce a pattern that's favorable for high latitude blocking by maximizing the momentum flux deposition of the Rossby Waves and strengthening the meridional circulation that accompanies it. This year we have a weak La Niña event coupling with weak-moderate solar activity, in concurrence with the background state (warm climate + persistence) that's not conducive to -NAO regimes, I would lean towards a solution that keeps this index primarily positive for the majority of the winter especially in the latter stages ~ February and henceforth reinforces the idea for a warmer than normal winter in the SE US
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I appreciate your analysis Webber. Is the winter pattern pretty much already determined, barring a big change before winter starts? Ive heard based kinda on what you alluded to, that nov-jan possibly cold before big flip in feb.That's what most people want to know to be quite honest with you.
 
Mr. Golf said:
I appreciate your analysis Webber. Is the winter pattern pretty much already determined, barring a big change before winter starts? Ive heard based kinda on what you alluded to, that nov-jan possibly cold before big flip in feb.That's what most people want to know to be quite honest with you.
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Not being derisive at all ... but IMHO, given so much that still needs to evolve and then settle, this will give you as good an October answer on February (or all of winter this early into the season) as anything else ...
http://www.indra.com/8ball/front.html
 
I'm going 200% of climo snowfall for mby! That would be between 10-14" depending on where you look!
#JBCLONE
 
pcbjr said:
I ask all the time -- the questions are always the same, it's the answers that keep changing ... :confused:
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Phil, I know we live in the south, but I don't think many people like warm winters. We like our excitement. Get our adrenaline going.
 
Back to watering the lawn and looking forward to Monday's system. CMC and Euro look like they have a second system close to the coast on Thursday too. Beyond that, very curious how the season unfolds. Fall color is very late here. Have a feeling I will be still dealing with leaves in Dec this year...
 
not to belabor the point, but CHA has had AN snowfall in the past 8 winters.. not sure of the overall temps though. It's all a crapshoot down below the Mason Dixon line, that hasn't changed ever. Eventually West Tn will get in line for some snow storms. Warm winters overall in the mid-south can also bring anomalous snow falls.
 
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