February Pattern and Storm Discussion

[MichaelJ]

With the MJO heading into phase 4 and 5 by March, I don't think we will see much cold then either regardless of the -NAO. Besides, this late in the season the -NAO mostly affects the NE part of the US and not so much here. What happens is the storms do come up and blow up off the Capes and pound the NE but it will be too warm here for anything but rain. I don't buy the cold the models are showing because they have shown that since December and it has not worked out for us with the Pacific controlling things with the PNA

[Tacoma]

man the average snowfall for the winter is 6.1 inches to date, but to date asheville has had only a trace.  all we need is one good snow to be over average, man a trace is sickening considering we're mid Feb.

[Bevo]

With the MJO heading into phase 4 and 5 by March, I don't think we will see much cold then either regardless of the -NAO. Besides, this late in the season the -NAO mostly affects the NE part of the US and not so much here. What happens is the storms do come up and blow up off the Capes and pound the NE but it will be too warm here for anything but rain. I don't buy the cold the models are showing because they have shown that since December and it has not worked out for us with the Pacific controlling things with the PNA

 

In my opinion, the MJO isn't even a second tier influence and is overrated.  I may be alone in that...wouldn't be the first time.

 

The problem I see is a -PNA that is modeled to be nasty.  So a - NAO would need to be superhero-esque to even have a shot at being relevant.  

 

*This has all been brought to you by "The PAC": Screwing Up Your Winter Since February 2011.

[franklin NCwx]

All of our cold shots have come from a - epo and plus pna. The Atlantic has been worse

[superjames1992]

With the MJO heading into phase 4 and 5 by March, I don't think we will see much cold then either regardless of the -NAO. Besides, this late in the season the -NAO mostly affects the NE part of the US and not so much here. What happens is the storms do come up and blow up off the Capes and pound the NE but it will be too warm here for anything but rain. I don't buy the cold the models are showing because they have shown that since December and it has not worked out for us with the Pacific controlling things with the PNA

 

We don't need sustained cold to have a good winter storm in the SE.  In fact, oftentimes when the deep freezer on, we end up cold and dry.

 

Just think of all of the recent snowstorms we've had in the SE.  In most cases, we were quite warm during the preceding day(s) and in many cases there wasn't exactly sustained cold.

[GaWx]

In my opinion, the MJO isn't even a second tier influence and is overrated.  I may be alone in that...wouldn't be the first time.

 

The problem I see is a -PNA that is modeled to be nasty.  So a - NAO would need to be superhero-esque to even have a shot at being relevant.  

 

*This has all been brought to you by "The PAC": Screwing Up Your Winter Since February 2011.

 

 Oh no, you're definitely not alone. I've made several posts just since yesterday poopooing the MJO's predictive value for the SE US as far as major winter storm chances are concerned. I posted some very revealing hard data: actual MJO phase for each of the 21 major S/IP's since 1974 (how far back MJO phase data that I've seen and used goes back) at KATL and KRDU. The conclusion is clear: very little help from the MJO in trying to determine the chance for a major SE winter storm during an upcoming period. In other words, "Where's the beef?" Basically, I'm saying that using the MJO for that purpose is a load of bollocks as you might put it.

[Tacoma]

I agree there have many a storm where the days just before were nice almost warm and then a big snowstorm to follow.  seen it many times here in the mtns.  like you said I too have seen just cold and dry which is what happens a lot if its to cold, keeps the storms suppressed to far to the south.

[GaWx]

With the MJO heading into phase 4 and 5 by March, I don't think we will see much cold then either regardless of the -NAO.

 

 On what are you basing this? Consider these SE US major winter storms (5 of the last 10 that included some real doozies like the 1993 blizzard and even included a second March storm) that were during MJO phases 4 and 5 (which may not even verify since MJO forecasts are not reliable):

 

- 1/9-10/2011: started in 6 and went to 5

- 12/25-6/2010: 5

- 3/1/2009: 4

- 2/26-7/2004: 5

- 3/13/1993: 4

 

 The MJO may have more predictive power in some other ways or in other regions like the NE US....I don't know and don't really care that much about whether or not it does. I just know it doesn't for SE US major winter storm chances. However, the MJO prediction constantly gets noted as if it is crucial in this regard. Using it for this for SE winter storm chances is a bunch of "malarkey" as Joe Biden might say.

[franklin NCwx]

Oh no, you're definitely not alone. I've made several posts just since yesterday poopooing the MJO's predictive value for the SE US as far as major winter storm chances are concerned. I posted some very revealing hard data: actual MJO phase for each of the 21 major S/IP's since 1974 (how far back MJO phase data that I've seen and used goes back) at KATL and KRDU. The conclusion is clear: very little help from the MJO in trying to determine the chance for a major SE winter storm during an upcoming period. In other words, "Where's the beef?" Basically, I'm saying that using the MJO for that purpose is a load of bollocks as you might put it.

thanks for those stats Larry , I have changed my thoughts on the mjo because of your info

[pcbjr]

What amazes me is that all models had us in a deep freeze for a couple to three days (Fri - Sun) just about 2 days ago, and now, we're not even getting to 33º (per GFS).

 

What is up with this?

[GaWx]

What amazes me is that all models had us in a deep freeze for a couple to three days (Fri - Sun) just about 2 days ago, and now, we're not even getting to 33º (per GFS).

 

What is up with this?

 

The GFS has a cold bias. The Euro also has been too cold on some runs though it doesn't have a clearcut cold bias like the GFS.

[MichaelJ]

 On what are you basing this? Consider these SE US major winter storms (5 of the last 10 that included some real doozies like the 1993 blizzard and even included a second March storm) that were during MJO phases 4 and 5 (which may not even verify since MJO forecasts are not reliable):

 

- 1/9-10/2011: started in 6 and went to 5

- 12/25-6/2010: 5

- 3/1/2009: 4

- 2/26-7/2004: 5

- 3/13/1993: 4

 

 The MJO may have more predictive power in some other ways or in other regions like the NE US....I don't know and don't really care that much about whether or not it does. I just know it doesn't for SE US major winter storm chances. However, the MJO prediction constantly gets noted as if it is crucial. Using it is "malarkey" as Joe Biden might say.

Well when you look at the temperature profiles for each phase of the MJO, you will see the SE (and the east in general) averages above normal temps during those phases and while it is still possible to get the timing just right, it is much less likely especially as we start seeing more daylight and sun angle heating us up by late Feb/March time period. Add a -PNA to that and your chances really fall off.

[GaWx]

Well when you look at the temperature profiles for each phase of the MJO, you will see the SE (and the east in general) averages above normal temps during those phases and while it is still possible to get the timing just right, it is much less likely especially as we start seeing more daylight and sun angle heating us up by late Feb/March time period. Add a -PNA to that and your chances really fall off.

 

 Michael,

 I just showed you hard evidence that the MJO is of very little, if any, help. I listed 5 of the the last 10 majors at KATL and/or KRDU that occurred during just phases 4 and 5! Also, of the 21 majors since 1974, slightly more occured during the so-called "warm" phases! I'm sorry but case closed! The MJO is way overrated for this purpose. If the MJO actually does go into phases 4 and 5 in early March, it will have little importance one way or the other in this regard, period. We may or may not have an actual major storm then. However, attributing either a storm or a lack thereof to the phase of the MJO would be nonsensical.

[franklin NCwx]

Well when you look at the temperature profiles for each phase of the MJO, you will see the SE (and the east in general) averages above normal temps during those phases and while it is still possible to get the timing just right, it is much less likely especially as we start seeing more daylight and sun angle heating us up by late Feb/March time period. Add a -PNA to that and your chances really fall off.

the mjo is only one piece of the puzzle. The sun angle nonsense is way over played. I have already posted the snowfall per month stats. And why should we write off winter in feb when the westerlies are at their lowest?

[franklin NCwx]

The GFS has a cold bias. The Euro also has been too cold on some runs though it doesn't have a clearcut cold bias like the GFS.

larry the euro is gonna verify too cold for the west this week. And too warm for us. This is from its op and ensemble forecast from last week.

[Bevo]

 Oh no, you're definitely not alone. I've made several posts just since yesterday poopooing the MJO's predictive value for the SE US as far as major winter storm chances are concerned. I posted some very revealing hard data: actual MJO phase for each of the 21 major S/IP's since 1974 (how far back MJO phase data that I've seen and used goes back) at KATL and KRDU. The conclusion is clear: very little help from the MJO in trying to determine the chance for a major SE winter storm during an upcoming period. In other words, "Where's the beef?" Basically, I'm saying that using the MJO for that purpose is a load of bollocks as you might put it.

 

Fantastic.  BTW I just went back a page or two and read your info.  Great stuff as usual.

 

Well when you look at the temperature profiles for each phase of the MJO, you will see the SE (and the east in general) averages above normal temps during those phases and while it is still possible to get the timing just right, it is much less likely especially as we start seeing more daylight and sun angle heating us up by late Feb/March time period. Add a -PNA to that and your chances really fall off.

 

Ooohh - the Sun Angle!  Another piece of the influencing bollocks in my opinion, at least until mid March.  Understand, this has nothing to do with you personally man.  I've just seen too much hard evidence to the contrary.  Not statistics, but actual snow.  On the ground.  In multiple Marches.

[GaWx]

larry the euro is gonna verify too cold for the west this week. And too warm for us. This is from its op and ensemble forecast from last week.

 

 

I'm talking about the Euro runs that had ~-12 to -13 C at 850 down to Atlanta for this weekend being too cold as it currently appears.

[Bevo]

larry the euro is gonna verify too cold for the west this week. And too warm for us. This is from its op and ensemble forecast from last week.

 

I believe I agree with this.  At least, in my case, the "Blue Tongue" has prevailed most of the winter.  Only once - during the first week of December - did I reach the warm temps progged at any point this entire season.  However, I have recorded the coldest temps during the coldest progged stretches.  I know, I know...how can this be?

 

A big part has been living in "Wedgeland".  But I am hesitant to call the long range models complete bollocks at this point in regards to temps.  It seems to me that the CFS and Weeklies did not do that poorly in regards to how January ended.

[superjames1992]

The sun angle can and does play a role in accumulating snowfall during the daylight hours (particularly if the snowfall is light), so I wouldn't totally right it off as meaningless.  Nevertheless, if we get a Big Daddy rolling in, it isn't really going to matter.  The sun angle didn't stop the snow from piling 1993 Superstorm.

 

If the snow falls at night, then it is basically totally meaningless.

 

The sun angle is most going to be felt after the storm when the snow withers away before our eyes at record pace during the day.

[franklin NCwx]

I'm talking about the Euro runs that had ~-12 to -13 C at 850 down to Atlanta for this weekend being too cold as it currently appears.

I was talking about our discussion from last week when the euro wanted to bury a trough in the west and pop a south east ridge. The ge. Had a very good foforecast from last week. And for tbat matter two weeks ago when it was the first to catch on to the building pna.

[Bevo]

The sun angle can and does play a role in accumulating snowfall during the daylight hours (particularly if the snowfall is light), so I wouldn't totally right it off as meaningless.  Nevertheless, if we get a Big Daddy rolling it, it isn't really going to matter.  The sun angle didn't stop the snow from piling 1993 Superstorm.

 

If the snow falls at night, then it is basically totally meaningless.

 

The sun angle is most going to be felt after the storm when the snow withers away before our eyes at record pace during the day.

 

Where do I sign?  Seriously, I'll buy that any day of the week.  Snow is problematic after 2 days of slush and refreeze and slush and repeat.

[Cold Rain]

I think we (including me) need to take a step back with respect to all these indices.  It's such an easy thing to do to get wrapped up in what a certain state of an index is supposed to do and then expect that thing to come about.  A west-based -NAO is supposed to help the SE get cold and keep the storm track suppressed, except when it doesn't.  A -EPO is supposed to support cold air in the east, except when it doesn't.  Certain MJO phases equal cold and stormy while others yield warmer, drier conditions, except when they don't.  The stratospheric warming episodes help increase the likelihood of blocking which increases the possibility of colder weather in the east, except when it doesn't.  I could go on.

 

I think we have a tendency to get so caught up in what the average state of an index is, and so excited when we see it moving into a "favorable" state, that we often fail to recognize that there are many different shapes and sizes and magnitudes of these things, not to mention how each variant of each index might interact with another index or group of indices or variants of those indices.

 

Take the MJO, for instance.  Larry has clearly shown that just as many winter events (if not more) happen in "unfavorable" MJO states. Yet, what do we all wish for?  Phases 7-2 or whatever.  Why?  Because we look at a map and see blue over the east and yellows and reds over the west and think, "Yay, cold for me!"  Here's the questions we need to be asking:

 

1) At what amplitude does the MJO have the most influence on the pattern?

 

2) What other atmospheric variables, or configurations of those variables (like PNA, PDO, ENSO, NAO, etc.) mute or enhance the effects of the MJO?

 

3) What is the average state of the atmosphere that yields the average state of the temperature/precipitation profile in any given MJO phase?

 

There are so many factors that work together in subtle ways that we don't fully understand.  As we have seen, a -NAO and 50/50 combo is something we'd want, can be negated by a brutal Pacific.  Why has the Pacific been so bad?  The PDO alone?  At what point does that get overwhelmed by something else?

 

I guess what I'm trying to say is that it's easy to see a chart of the MJO moving into a favorable state or a graph of the NAO tanking or a prog of a big ridge going up in the west.  But the timing, configuration, amplitude, placement, and interaction of those things independently and in concert with one another make all the difference when it comes to the weather we observe when we look out our windows.  It's not wise to look at a chart of what the atmosphere is "supposed" to do when an index is in a given state and then expect that to actually happen when the index moves into that state.  We have all this information available to us and we're just barely beginning to understand how to use it.  We have a long way to go yet.

[Cold Rain]

 You're welcome! My feeling about a good bit higher than average chance at a cold stretch somewhere within late Feb-mid March (which would most likely be most intense during a 1-2 week long period and could easily be the coldest 1-2 week stretch this winter...you don't need anything close to a wall to wall cold March to allow this to happen) is strictly based on past analogs of winters that were also warm much of the winter due to a lack of physical mechanisms allowing for those winters to get cold. The mechanisms obviously changed to allow for cold late. So, the suggestion is that there's a good chance for the current mechanisms to change, just as they did for the analog winters, to allow for the coldest stretch in the SE US to be between late Feb. and mid March.The specifics of those mechanism changes aren't important at this still early stage. I didn't get into that much detail and some of those winters are back far enough such that some of the indices that we follow aren't even known.

 

You need to keep in mind that the very mediocre medium range modeling barely reaches into March right now and it is changing so much from run to run for late Feb.! There are indications that the NAO may finally go negative...we'll see...but that obviously would be a big help if it persists. I've already made several posts that hopefully have convinced you that the forecasted MJO. which is not even that reliable in the first place, and only barely reaches early March, hardly matters as far as cold chances are concerned. I don't care if it is in phases 4-6 through early March. The blizzard of 3/1993, which was accompanied by the coldest of that winter for many, was during the "warm" phase 4. The big snow of early March of 2009 was also during phase 4. The big snows of 3/1983 and 3/1980 were when the MJO was within the COD. So, none of the major March winter storms since 1974 were even within the "favorable phases". I urge you to not read much into the MJO for these purposes. I do think it has been overhyped in recent years for its forecasting help in the SE US. It is only a tool, not a crystal ball. In this case, it isn't even much of a tool.

 

Regarding where the coldest air sets up shop: 1) On what are you basing it not being be on our side of the pole? Keep in mind the weakness of medium range modeling. 2) Even if it does stay on the other side, that doesn't mean the SE US can't have a quite cold period. 

 

Edit: none of the analogs were during El Nino. (3/1983 is not one of my analogs.)

 

Ok, I wanted to get back to this one.  I agree with you about the MJO and just made another post about it.  My main concern for an upcoming sustained cold pattern is the relaxing of the Pacific and all of the energy in the flow that has been bombarding the US and creating a fast northern stream, which seems to be a negative influence for a PNA, which I would argue that we need.  In addition, we've had little to no help from a real -NAO (which may also have some correlation to the fast flow...I don't know).  I would think that in order to have a shot at March ending up the coldest month of the winter, we'd want to first and foremost see the unfavorable Pacific change.  Then, we'd want a -NAO (a real west-based one, like is showing up in the modeling).

 

I definitely understand your concerns about the medium range guidance.  But if we look at just the H5 Ens Mean at 240 for both the EURO and the GFS, they both show the lowest heights on the other side of the pole, and they've indicated this for several runs now.  Assuming that is somewhat correct, that puts us near the end of Feb.  And if things turned right then at D11, it would still take some time to get the cold stuff back over here.  And all that other stuff like a better Pacific and a better Atlantic would still have to happen...which it could.  But you're right:  We don't have to have the coldest air over here to be below normal.  But it sure doesn't hurt.

 

But averages in March go up quickly and (just pulling a number out of the hat) a -5 average in March doesn't carry nearly the same weight of a -5 in January or early February.  So March could end up below normal, which would be the coldest relative to the other winter months and still not be all that cold.

 

Here are the maps.  240 Euro Ens Mean:

 

 

240 GFS Ens Mean:

 

 

Both continue to show a -PNA, the hallmark of winter 2012-2013.  If we're going to get cold enough to align with your analogue research, we're going to have to get rid of that in a hurry.

 

Anyway, just some thoughts.  Thanks again for the comments and all of the data you provide.

[franklin NCwx]

Cold rain, if you look at the observered data for the pna it has been mostly positive since dec 20th. It had its long stretch of negative during oct, nov, and the first half of dec. Its interesting that if you look at oct and nov. We had below normal months. During those two months we had a negative nao. Last years pattern was an exception with the Alaska death vortex. I think the biggest driver of north American weather is enso. 2nd I would put the nao. Going back and looking at great periods for us it was with a negative nao. Just take the back to back winters of 09-10 and 10-11. Negative nao for both of those winters.

[Bevo]

I think we (including me) need to take a step back with respect to all these indices.  It's such an easy thing to do to get wrapped up in what a certain state of an index is supposed to do and then expect that thing to come about.  A west-based -NAO is supposed to help the SE get cold and keep the storm track suppressed, except when it doesn't.  A -EPO is supposed to support cold air in the east, except when it doesn't.  Certain MJO phases equal cold and stormy while others yield warmer, drier conditions, except when they don't.  The stratospheric warming episodes help increase the likelihood of blocking which increases the possibility of colder weather in the east, except when it doesn't.  I could go on.

 

I think we have a tendency to get so caught up in what the average state of an index is, and so excited when we see it moving into a "favorable" state, that we often fail to recognize that there are many different shapes and sizes and magnitudes of these things, not to mention how each variant of each index might interact with another index or group of indices or variants of those indices.

 

Take the MJO, for instance.  Larry has clearly shown that just as many winter events (if not more) happen in "unfavorable" MJO states. Yet, what do we all wish for?  Phases 7-2 or whatever.  Why?  Because we look at a map and see blue over the east and yellows and reds over the west and think, "Yay, cold for me!"  Here's the questions we need to be asking:

 

1) At what amplitude does the MJO have the most influence on the pattern?

 

2) What other atmospheric variables, or configurations of those variables (like PNA, PDO, ENSO, NAO, etc.) mute or enhance the effects of the MJO?

 

3) What is the average state of the atmosphere that yields the average state of the temperature/precipitation profile in any given MJO phase?

 

There are so many factors that work together in subtle ways that we don't fully understand.  As we have seen, a -NAO and 50/50 combo is something we'd want, can be negated by a brutal Pacific.  Why has the Pacific been so bad?  The PDO alone?  At what point does that get overwhelmed by something else?

 

I guess what I'm trying to say is that it's easy to see a chart of the MJO moving into a favorable state or a graph of the NAO tanking or a prog of a big ridge going up in the west.  But the timing, configuration, amplitude, placement, and interaction of those things independently and in concert with one another make all the difference when it comes to the weather we observe when we look out our windows.  It's not wise to look at a chart of what the atmosphere is "supposed" to do when an index is in a given state and then expect that to actually happen when the index moves into that state.  We have all this information available to us and we're just barely beginning to understand how to use it.  We have a long way to go yet.

 

Very well oratorably written (new word score).  The past two winters have seen a constant changing of players on the filed - sometimes in the right position, sometimes not.  All of these things - the MJO, Strat Warming, PNA, NAO, AO, SE Ridge, etc - have at one point been positioned to field the ball and make a play during the last two seasons.  So why haven't they?  It seems there has been one common denominator really.  None of what I personally thought about the players and their orientation (on the field you pervs) have manufactured the results I would have expected, and I can only narrow it down in my mind the the PAC.

 

The PAC seems to be throwing some umpire interference into the game.  It is the one factor that has been established during both winters.  Last year there was no blocking, and the PAC was forceful.  This year, even with blocking, the PAC was dominant (although maybe to a very tiny lesser degree) .  In my opinion, it is the primary culprit given all the usual suspects either being present or riding the pine.  In fact, the PAC has been so influential that I think it deserves major consideration in future winter patterns and how we forecast them if it is set up the way it has been.

[Bevo]

Cold rain, if you look at the observered data for the pna it has been mostly positive since dec 20th. It had its long stretch of negative during oct, nov, and the first half of dec. Its interesting that if you look at oct and nov. We had below normal months. During those two months we had a negative nao. Last years pattern was an exception with the Alaska death vortex. I think the biggest driver of north American weather is enso. 2nd I would put the nao. Going back and looking at great periods for us it was with a negative nao. Just take the back to back winters of 09-10 and 10-11. Negative nao for both of those winters.

 

That's a fair assessment except that for me, both winters of 2010/11 and 2011/12 were La Ninas that behaved un-La Nina-ish in a couple of ways - but really in one major way.  During both of those ENSO states, I was the opposite of dry - a keystone to Nina.  We had the Christmas storm and the encore of January 10-11 of 2011 during a Nina.  She may not have been a strong one, but she was there none the less.  I keep arriving at the same conclusion - The PAC switched like a light in February 2011, and seemed to supersede any of the indices after that.  This is my opinion of course.

[dsaur]

What amazes me is that all models had us in a deep freeze for a couple to three days (Fri - Sun) just about 2 days ago, and now, we're not even getting to 33º (per GFS).

 

What is up with this?

I know   It's why I want to see the 0 line on the Gfs down in Fla.  If it's though you I might dip below 30.  It it's in southern Ala.  maybe not.  The brass ring is down in Miami, or Cuba, lol.  If th 0 line is in Cuba on the Gfs 3 days out, it'll probably get cold here, and last a day or two.  I had great hopes for tonights 0z's...now, not so much   T

[Cold Rain]

Cold rain, if you look at the observered data for the pna it has been mostly positive since dec 20th. It had its long stretch of negative during oct, nov, and the first half of dec. Its interesting that if you look at oct and nov. We had below normal months. During those two months we had a negative nao. Last years pattern was an exception with the Alaska death vortex. I think the biggest driver of north American weather is enso. 2nd I would put the nao. Going back and looking at great periods for us it was with a negative nao. Just take the back to back winters of 09-10 and 10-11. Negative nao for both of those winters.

Yeah, I can certainly see a case for ENSO being the key driver. It's been shown that a -NAO/-PNA combo can work out, but I think a lot of that has to do with how fast the flow is. I don't know what it was doing in the fall, but it's been cranking all winter. Also, that's a good point about the Alaskan Vortex last year...yet another example of looking beyond the given state of an index.

 

 

Very well oratorably written (new word score).  The past two winters have seen a constant changing of players on the filed - sometimes in the right position, sometimes not.  All of these things - the MJO, Strat Warming, PNA, NAO, AO, SE Ridge, etc - have at one point been positioned to field the ball and make a play during the last two seasons.  So why haven't they?  It seems there has been one common denominator really.  None of what I personally thought about the players and their orientation (on the field you pervs) have manufactured the results I would have expected, and I can only narrow it down in my mind the the PAC.

 

The PAC seems to be throwing some umpire interference into the game.  It is the one factor that has been established during both winters.  Last year there was no blocking, and the PAC was forceful.  This year, even with blocking, the PAC was dominant (although maybe to a very tiny lesser degree) .  In my opinion, it is the primary culprit given all the usual suspects either being present or riding the pine.  In fact, the PAC has been so influential that I think it deserves major consideration in future winter patterns and how we forecast them if it is set up the way it has been.

Thank you sir. And nice baseball analogy. I'm with you on the Pacific flow. Again, I think it can be negated by other things....but how they all have to align to efficiently negate it, I don't know. A super strong Greenland block certainly can't hurt.

[franklin NCwx]

That's a fair assessment except that for me, both winters of 2010/11 and 2011/12 were La Ninas that behaved un-La Nina-ish in a couple of ways - but really in one major way. During both of those ENSO states, I was the opposite of dry - a keystone to Nina. We had the Christmas storm and the encore of January 10-11 of 2011 during a Nina. She may not have been a strong one, but she was there none the less. I keep arriving at the same conclusion - The PAC switched like a light in February 2011, and seemed to supersede any of the indices after that. This is my opinion of course.

you are correct, both of those years were ninas. Imo the only reason we had a great first half of winter in 10/11 was because of the deeply negative nao. When we lost that in mid jan 11 is when the fun ended. I posted a chart earlier showing how dec 10 was the most negative pna dec in history. The nao was also deeply negative and centered over the davis straits which gave us our cold and snow. Since then the nao has been mostly positive in winter.

[Bevo]

you are correct, both of those years were ninas. Imo the only reason we had a great first half of winter in 10/11 was because of the deeply negative nao. When we lost that in mid jan 11 is when the fun ended. I posted a chart earlier showing how dec 10 was the most negative pna dec in history. The nao was also deeply negative and centered over the davis straits which gave us our cold and snow. Since then the nao has been mostly positive in winter.

 

I'm even curious to know if this year's super PAC had a hand in essentially making sure that the progged weak to neutral Nino never materialized this winter.  I'm sure someone somewhere has that answer and chart.

 

***Edited to expound***

 

At the end of the day, I'll still be comfortable with resting on the basic ingredients for most winters: a solid -AO/-NAO relationship.  But in future winters that have a good -AO/-NAO relationship, yet also feature a super charged PAC, that equation is worth nil.