AO Forecast to Plunge

[Matt Rogers]

I am among those who are convinced solar is a much larger factor than fall snowcover. I think the overall evidence clearly indicates that. If we do not see solar activity pick up much before next winter, we will probably see major blocking yet again.

I am with you Tacoman. We had bigger snow cover in the 1970s and 1960s, but yet weaker blocking...particularly in terms of this amazing duration of blocking.

[VAwxman]

I am with you Tacoman. We had bigger snow cover in the 1970s and 1960s, but yet weaker blocking...particularly in terms of this amazing duration of blocking.

Yeah I think everyone should agree solar is a big factor. It's just that no one has been able to really connect the dots physically. You can make correlations, but when it comes to explaining the "whys", that's where answers are lacking. Last winter was a slam dunk for blocking, since everything pointed that way more than any year I can recall. This year is the one where the solar factor has to be carrying more weight.

[okie333]

Yeah I think everyone should agree solar is a big factor. It's just that no one has been able to really connect the dots physically. You can make correlations, but when it comes to explaining the "whys", that's where answers are lacking. Last winter was a slam dunk for blocking, since everything pointed that way more than any year I can recall. This year is the one where the solar factor has to be carrying more weight.

Makes one wonder what next winter will be like, since the solar cycle has been... hey who took the solar cycle? I swore it was right he-- oh wait there it is... kinda easy to lose it with how small it is!... anyway, the QBO will be negative next winter, and the ENSO will likely be near neutral (both strong El Niños and strong La Niñas tend to reduce blocking).

[Rainshadow]

Yeah I think everyone should agree solar is a big factor. It's just that no one has been able to really connect the dots physically. You can make correlations, but when it comes to explaining the "whys", that's where answers are lacking. Last winter was a slam dunk for blocking, since everything pointed that way more than any year I can recall. This year is the one where the solar factor has to be carrying more weight.

I would agree, from what I looked at, I would have WAG that the NAO was going to average neutral this winter.

[NJwinter23]

Yeah I think everyone should agree solar is a big factor. It's just that no one has been able to really connect the dots physically. You can make correlations, but when it comes to explaining the "whys", that's where answers are lacking. Last winter was a slam dunk for blocking, since everything pointed that way more than any year I can recall. This year is the one where the solar factor has to be carrying more weight.

Great point. I was just discussing this with someone actually.. The topic of the persistent blocking came up and then so did the question of why so many winter forecasts were all based heavily on strong/mod nina climo when last winter proved that the NAO/AO can completely overwhelm a strong ENSO event. My answer was pretty much what you just said, in that there were so many various forcing/factors signaling the blocking for winter 09-10, that the strong/persistent blocking that occurred was inevitably accepted as a result of these forcings. When a lot of those signals dissapeared going into 10-11, a lot of people understandably figured the mechanism for blocking would no longer be present in the upcoming strong/mod nina winter.

In hindsight though, the blocking of last winter was sooooo ridiculously extreme that perhaps more of us could have realized that something else bigger (Like the extreme solar min) may have been at play enhancing it (other than the earth climate indices). With this realization that something else is forcing the NAM to be extremely negative, and hence overwhelming 2 straight strong ENSO signals, a lot of Winter forecasts that were closely following mod/strong nina climo could have been saved. You are right that it is more obvious now that the blocking continues to persist though.

By the way, I realize that their were a few forecasters that did reflect the AO/NAO regime as a big factor in their winter forecast. I also realize that a lot of the forecasters who went heavily based on strong/mod nina climo for their forecast at least recognized the amazing stretch of -AO/NAO regime that was ongoing, and that it could screw things up big time for them if it persisted through the winter.

[NJwinter23]

Makes one wonder what next winter will be like, since the solar cycle has been... hey who took the solar cycle? I swore it was right he-- oh wait there it is... kinda easy to lose it with how small it is!... anyway, the QBO will be negative next winter, and the ENSO will likely be near neutral (both strong El Niños and strong La Niñas tend to reduce blocking).

Perhaps the severity of last year's blocking in spite of the strong El Nino event should have been more of a warning sign going into this strong La Nina winter? Easy to say that now of course. Personally, I definitely believed at the time that the warm pool being west-based towards the dateline last winter enhanced MJO forcing in the -NAO favorable phase 8 region, and played a big part in the blocking.

[Rainshadow]

Great point. I was just discussing this with someone actually.. The topic of the persistent blocking came up and then so did the question of why so many winter forecasts were all based heavily on strong/mod nina climo when last winter proved that the NAO/AO can completely overwhelm a strong ENSO event. My answer was pretty much what you just said, in that there were so many various forcing/factors signaling the blocking for winter 09-10, that the strong/persistent blocking that occurred was inevitably accepted as a result of these forcings. When a lot of those signals dissapeared going into 10-11, a lot of people understandably figured the mechanism for blocking would no longer be present in the upcoming strong/mod nina winter.

In hindsight though, the blocking of last winter was sooooo ridiculously extreme that perhaps more of us could have realized that something else bigger (Like the extreme solar min) may have been at play enhancing it (other than the earth climate indices). With this realization that something else is forcing the NAM to be extremely negative, and hence overwhelming 2 straight strong ENSO signals, a lot of Winter forecasts that were closely following mod/strong nina climo could have been saved. You are right that it is more obvious now that the blocking continues to persist though.

By the way, I realize that their were a few forecasters that did reflect the AO/NAO regime as a big factor in their winter forecast. I also realize that a lot of the forecasters who went heavily based on strong/mod nina climo for their forecast at least recognized the amazing stretch of -AO/NAO regime that was ongoing, and that it could screw things up big time for them if it persisted through the winter.

Its too bad that the stuff from Eastern is gone, I might have it at work from our winter weather workshop, but there was a graph about how an extremely negative nao the previous winter (granted not as extreme as last) almost always rebounded to neutrality or greater the enusing winter something like 80% of the time. I'm not well adversed in solar activity, so coincidentally in the past, the solar end of the equation year to year may have been a zero sum gain/non factor.

[Rainshadow]

Perhaps the severity of last year's blocking in spite of the strong El Nino event should have been more of a warning sign going into this strong La Nina winter? Easy to say that now of course. Personally, I definitely believed at the time that the warm pool being west-based towards the dateline last winter enhanced MJO forcing in the -NAO favorable phase 8 region, and played a big part in the blocking.

We also had the qbo in our favor, almost as if all of the pieces of the puzzle fell together.

[cpickett79]

seems like in the last ten days the tide has really turned in favor of the -NAO blocking persisting.....do we need some more continuity for another week or so to really gain confidence that this will be the driver thru the end of january into early feb.

[NJwinter23]

Its too bad that the stuff from Eastern is gone, I might have it at work from our winter weather workshop, but there was a graph about how an extremely negative nao the previous winter (granted not as extreme as last) almost always rebounded to neutrality or greater the enusing winter something like 80% of the time. I'm not well adversed in solar activity, so coincidentally in the past, the solar end of the equation year to year may have been a zero sum gain/non factor.

Interesting statistic Tony, and right you are about all that eastern data going bye bye...

We also had the qbo in our favor, almost as if all of the pieces of the puzzle fell together.

When we had that (record?) 1 month drop in the QBO a few months back, the initiial "emotional" reaction for me was that our chances of a good winter were pretty toast. As the fall went on though and we continued to see the record streak of -NAO months keep going and going and getting into November now, there started to be a lot of discussion about old time mod/strong ninas that featured respectable -NAO episodes as the better analogs. I was also getting a bit weary about whether the NAO would ever stop being negative lol..There was also a lot of discussion at that time though on how la nina keeping the tropical forcing in phase 3-5 during the Fall promotes a -NAO, but not when the wavelengths change in the winter months. That definitely made a lot of sense to me too right into the early December NAO period. But then when the severe blocking episode showed up again for mid-month as we started seeing the ensembles dip the AO to -5,-6 levels (giving La Nina the middle finger as Isotherm so eloquently put it), and Don Sutherland came out with a topic (that's when you know it's official ), I thought to myself "ut oh, it's happening all over again!".

[okie333]

Thought I'd show everyone my posts I found on Accuweather forums regarding this winter. I got the ENSO state wrong (said weak Niña or neutral), but my main idea was that the highly (possibly record-breaking) negative AO would overpower the ENSO pattern. I have included the full text of the posts below the links.

http://forums.accuwe...34

http://forums.accuwe...48

http://forums.accuwe...92

http://forums.accuwe...46

http://forums.accuwe...15

http://forums.accuwe...90

http://forums.accuwe...0

I've found 5 analogs for next winter based on the NINO 3.4 Peak/DJF values and the JFM AO: 58-59, 66-67, 69-70, 77-78, and 87-88. This was based on every El Niño that had an AO -1.0 or lower.

Winter...Peak 3.4...DJF 3.4...JFM AO...Modoki?
09-10.......1.8.......1.7......-1.9......YES
57-58.......1.7.......1.7......-1.5......YES
65-66.......1.6.......1.2......-1.4......YES
68-69.......1.0.......1.0......-2.0......YES
76-77.......0.8.......0.6......-1.3......NO
86-87.......1.3.......1.2......-1.0......YES

58-59: Pros: Best match by far; even the graph of the trimonthly Niño progression matches up closely. Cons: None, except AO was slightly higher 57-58 than in 09-10.

66-67: Pros: Good Niño and AO match. Cons: AO slightly higher 65-66, Niño progression timetable does not match much at all.

69-70: Pros: Best AO match, OK Niño match. Cons: Niño not nearly as strong.

77-78: Pros: AO matches fairly well. Cons: Worst match of the bunch. Niño was very weak and not a Modoki, and AO was a bit on the high side.

87-88: Pros: Good Niño match, OK AO match. Cons: AO not as good of a match: only down to -1.0.

I looked at the Tulsa data for those analogs, and 3 of the 5 are in the top 10 for snow since 1950 (that is, the top sixth of the data). In addition, of the winters FOLLOWING the analogs, 4 of the 5 are in the top 10. That is, statistically there is a 92% chance that one of the two next winters will be a top-10 for Tulsa, and 48% chance that BOTH will be. Also, of all those 10 years (next year's analogs and the years after them), only 1 had a positive DJF anomaly, and that one was only 0.3 degrees above average. Two of the 10 were the two coldest winters ever. In every case the analog year was colder than the year before ("year before" being the 09-10 representative), and in all but one case it was snowier. In all but one case the winter AFTER the analog was colder and snowier than the year before the analog. Considering 2009-2010 was one of the coldest, snowiest winters in Tulsa, I can only imagine what 2010-2011 and 2011-2012 will be like.

Oh, and for those of you in the Central/Southern Plains:

Tulsa, OK, snowfall (average: 9.1"):

58-59: 19.5"

66-67: 5.8"

69-70: 20.4"

77-78: 11.7"

87-88: 18.2"

10-11: ???

All of them, save for 66-67, were snowier than the winter before

YEARS AFTER:

59-60: 19.4"

67-68: 17.0"

70-71: 6.5"

78-79: 18.9"

88-89: 16.5"

11-12: ???

Every one of these, except 70-71, was snowier than the pre-analog winter. Red years were in the top 10 in terms of snowfall for the 50/51-09/10 period.

TEMPERATURES (average: 39.5):

58-59: 37.3

66-67: 38.6

69-70: 36.8

77-78: 31.2

87-88: 38.5

10-11: ???

All colder than the corresponding pre-analog winter. 77-78 was 2nd coldest ever.

59-60: 36.0

67-68: 37.6

70-71: 39.3

78-79: 30.4

88-89: 39.8

11-12: ???

All but 70-71 colder than pre-analog winter. 78-79 coldest winter ever.

PRE-ANALOG YEARS:

Year Snow Temp

57-58 17.2 40.1

65-66 9.4 39.6

68-69 8.0 38.3

76-77 11.3 36.5

86-87 13.3 40.3

09-10 22.8 34.8

And I'm in the exact correct location on the yellow storm track in the video on the site (WeatherAdvance's first prediction). The words for the gray area (including Tulsa) on the map in the video are "Colder than average. A few more snows than average." Just so happens I agree with that forecast in more ways than one.

Most of the forecasts I've seen, including the one from Accuweather's own Joe Bastardi, have predicted that 2010-2011 will be miserable for my area and the rest of the South and Central US. However, I do not agree with that. EVEN IF THIS DOES TURN OUT TO BE A LA NINA (a big if), it will still be colder than average for Tulsa, since as far as the ENSO goes, all that matters for the winter temperatures here is whether the Nino 4 (west) or Nino 1+2 (east) is warmer. West warm, good winter. East warm, bad winter. IN ADDITION, the ENSO/TNI is not all that matters. The AO/NAO matters too (particularly during ENSO-neutral years), and it has recently entered a (in my opinion) solar-induced decadal negative period. Also, you cannot forget the statistics for winters following ones like the last (particularly 57-58/58-59/59-60, which is both my top analog for 09-10/10-11/11-12 and also by far the snowiest 3-year period in Tulsa's history). To recap, the ENSO is not the only pattern that affects the weather on a yearly basis.

1957-1958 is the best match for THIS LAST WINTER. 1958-1959 is thus the best analog for the upcoming winter.

All 2010-2011 analogs:

1958-1959 only:

THE FOLLOWING MAP IS A QUICK GUESS AT POSSIBLE 2011-2012 ANALOGS AND IS NOT TO BE INTERPRETED IN ANY WAY AS BEING RELATED TO THE 2010-2011 WINTER SEASON

YEARS AFTER ANALOGS:

The "other small differences" include the anomalies in the Atlantic. I believe that this will be key to forecasting the winter in the United States. The correlations with that anomaly show that the winter will likely have a negative AO and NAO, and they show it very strongly so. The low solar activity agrees with this, as the vast majority of low solar years have had -AO/-NAO winters following. So far the sunspot number has only been half of the low-solar-cycle threshold. Call me crazy, but I think there is a chance that this winter may end up with more of a negative AO/NAO than last winter. Regardless of whether it goes this low, I think it is a safe bet to say the AO and NAO will average negative this winter.

Maps 1 and 3 are MJJ SST's, maps 2 and 4 are the correlations with the DJF NAO. Basic primer on correlations: If maps 1 and 2 look alike and maps 3 and 4 look alike, expect a +NAO this winter. If maps 1 and 2 look opposite and maps 3 and 4 look opposite, expect a -NAO this winter. Note that 2009-2010 was an exception to this rule, but there were some definite wildcards that influenced the index negatively (these wildcards will likely affect the index negatively this year too, but not quite as much influence... still, expect a --NAO this winter, possibly similar to last in intensity).

[Cyclonicjunkie]

Thought I'd show everyone my posts I found on Accuweather forums regarding this winter. I got the ENSO state wrong (said weak Niña or neutral), but my main idea was that the highly (possibly record-breaking) negative AO would overpower the ENSO pattern. I have included the full text of the posts below the links.

I have followed your posts here and on accuwx long range thread, and I must sat I am impressed. Great job

[Isotherm]

Yeah I think everyone should agree solar is a big factor. It's just that no one has been able to really connect the dots physically. You can make correlations, but when it comes to explaining the "whys", that's where answers are lacking. Last winter was a slam dunk for blocking, since everything pointed that way more than any year I can recall. This year is the one where the solar factor has to be carrying more weight.

I don't know if last year carried less weight in terms of solar, or maybe we just didn't realize the main driver behind all the record blocking. The QBO was strongly negative, tropical forcing was favorable, and sure that definitely aided in the negative NAO, but I strongly believe that the high latitude blocking would've been much less impressive if the solar environment was different.

[Isotherm]

Thought I'd show everyone my posts I found on Accuweather forums regarding this winter. I got the ENSO state wrong (said weak Niña or neutral), but my main idea was that the highly (possibly record-breaking) negative AO would overpower the ENSO pattern. I have included the full text of the posts below the links.

Yeah you and I were in the same camp on the -NAO this winter. However I thought the La Nina would be moderate to strong, which is why I muted the -NAO signal somewhat compared to your forecast. If I thought we'd see a weak ENSO I probably would've gone all out on record blocking as well (but it turns out it's happening regardless).

[tacoman25]

Yeah I think everyone should agree solar is a big factor. It's just that no one has been able to really connect the dots physically. You can make correlations, but when it comes to explaining the "whys", that's where answers are lacking. Last winter was a slam dunk for blocking, since everything pointed that way more than any year I can recall. This year is the one where the solar factor has to be carrying more weight.

Perhaps, but I remember there being some concern based on ENSO strength (much as there was prior to this winter). After all, we'd never seen a strong Nino with anything close to that level of blocking.

[tacoman25]

By the way, I realize that their were a few forecasters that did reflect the AO/NAO regime as a big factor in their winter forecast. I also realize that a lot of the forecasters who went heavily based on strong/mod nina climo for their forecast at least recognized the amazing stretch of -AO/NAO regime that was ongoing, and that it could screw things up big time for them if it persisted through the winter.

Yup. That was the biggest caveat to my forecast.

[ORH_wxman]

Perhaps, but I remember there being some concern based on ENSO strength (much as there was prior to this winter). After all, we'd never seen a strong Nino with anything close to that level of blocking.

'57-'58 had pretty severe blocking, esp in the 2nd half of that winter and it was of similar strength ENSO. (at least ONI)

But you are right, I do remember a bit of concern over the strength of the Nino at times. Though it did finally level off in late November or early December putting to rest any chance of a +2C type trimonthly.

[tacoman25]

'57-'58 had pretty severe blocking, esp in the 2nd half of that winter and it was of similar strength ENSO. (at least ONI)

But you are right, I do remember a bit of concern over the strength of the Nino at times. Though it did finally level off in late November or early December putting to rest any chance of a +2C type trimonthly.

That's a good point about 1957-58 (though I believe it was still significantly less -NAO/AO than 2009-10). But the stats clearly showed that blocking tends to favor neutral/weak ENSO state. One of those stats that is apparently close to meaningless now in the current regime.

[VAwxman]

I don't know if last year carried less weight in terms of solar, or maybe we just didn't realize the main driver behind all the record blocking. The QBO was strongly negative, tropical forcing was favorable, and sure that definitely aided in the negative NAO, but I strongly believe that the high latitude blocking would've been much less impressive if the solar environment was different.

Yeah "carrying less weight" wasn't really a good way to put it. I think you and NJWinter said it better by saying that it was easier to overlook given all the other signals that strongly suggested blocking. If it is as big of a factor as it now appears it may be, it was big last year too but was easier to overlook with all the other stuff going on.

[VAwxman]

Perhaps, but I remember there being some concern based on ENSO strength (much as there was prior to this winter). After all, we'd never seen a strong Nino with anything close to that level of blocking.

Given the orientation of the warm water though, even that favored blocking. It was as textbook of a setup as you could get IMO.

[HM]

The best theory out there (perhaps it's not yet there?) I think has to do with the susceptible lower stratosphere/tropopause level and the wave 1/2 amplification. We saw before the monster -AO tank, the wave 2 response (squeeze play on the vortex). I'm still in the process of searching but the catalyst looks to be a combination of the forcing from the convection and the solar wind anomalies...at least that is where I'm starting to hedge. I'll post about it soon.

[wxmx]

The best theory out there (perhaps it's not yet there?) I think has to do with the susceptible lower stratosphere/tropopause level and the wave 1/2 amplification. We saw before the monster -AO tank, the wave 2 response (squeeze play on the vortex). I'm still in the process of searching but the catalyst looks to be a combination of the forcing from the convection and the solar wind anomalies...at least that is where I'm starting to hedge. I'll post about it soon.

Yeah, I'm in the same boat as you are...great min....oops...

Post 1

Post 2

[HM]

Yeah, I'm in the same boat as you are...great min....oops...

Post 1

Post 2

LOL.. it's like there is something on the tip of your tongue.

Great post man. The next step is finding the catalysts...and as usual...it is a combination of several factors.

[Snow Wizard]

Thought I'd show everyone my posts I found on Accuweather forums regarding this winter. I got the ENSO state wrong (said weak Niña or neutral), but my main idea was that the highly (possibly record-breaking) negative AO would overpower the ENSO pattern. I have included the full text of the posts below the links.

At some point this strong of a Nina is bound to take over. -1.7 on the last update is a big time Nina.

[nzucker]

At some point this strong of a Nina is bound to take over. -1.7 on the last update is a big time Nina.

You hope....

[Snow Wizard]

The best theory out there (perhaps it's not yet there?) I think has to do with the susceptible lower stratosphere/tropopause level and the wave 1/2 amplification. We saw before the monster -AO tank, the wave 2 response (squeeze play on the vortex). I'm still in the process of searching but the catalyst looks to be a combination of the forcing from the convection and the solar wind anomalies...at least that is where I'm starting to hedge. I'll post about it soon.

Do you think this low solar activity means we should basically throw all of the old "rule" books out the window? I am also curious what forcing mechanisms might be able to put a big and persistent trough in the West instead of the East. There has to be a way the West can still do well with massive blocking going on.

[Snow Wizard]

You hope....

To some extent.

[Harry]

Do you think this low solar activity means we should basically throw all of the old "rule" books out the window? I am also curious what forcing mechanisms might be able to put a big and persistent trough in the West instead of the East. There has to be a way the West can still do well with massive blocking going on.

If history has a say ( look at the data of the 1800s/early 1900s out that way ) then yes it is still possible to get cold and snow in the PAC NW with the solar impact. Keep in mind too not all blocking is created equall. Personally i would give much better odd's to cold and snow now/for a few years to come and maybe longer vs what we had in the 80s/90s/early 2000s.

Hopefully now ALL puts away those 80s/90s analogs once and for all.

As for the rule books i guess it depends on what you are referring to? As to how they relate to Nina/Nino impacts etc?

[Snow Wizard]

If history has a say ( look at the data of the 1800s/early 1900s out that way ) then yes it is still possible to get cold and snow in the PAC NW with the solar impact. Keep in mind too not all blocking is created equall. Personally i would give much better odd's to cold and snow now/for a few years to come and maybe longer vs what we had in the 80s/90s/early 2000s.

Hopefully now ALL puts away those 80s/90s analogs once and for all.

As for the rule books i guess it depends on what you are referring to? As to how they relate to Nina/Nino impacts etc?

Yeah...I was refering to Nino = good winter in the east...Nina = good winter in the west type stuff. Of course that is extremely simplistic. I also wonder how this will effect the impacts of the MJO. I think we will all have to do a lot of learning in the coming years.

I do see your point about the NW doing really well in the 1800s and early 1900s with the low solar cycles. I guess I just can't get the -NAO means the NW is screwed out of my brain. It also really spooks me that the east coast seems to score no matter what these days.

[HM]

Do you think this low solar activity means we should basically throw all of the old "rule" books out the window? I am also curious what forcing mechanisms might be able to put a big and persistent trough in the West instead of the East. There has to be a way the West can still do well with massive blocking going on.

The best thing to do instead of throw out old rules is to use what you have learned and begin to develop amendments or new rules. Some signals were stronger in the 1980s/1990s than others. As we continue to head into different decadal swings, climate shifts etc. we are going to have to adjust. I agree that the golden era of simple ENSO climo for long range forecasting is over. But those that are well read and keep up will adjust and that's all we can ask for from anyone...that they are willing to continue to to be open minded and adapt.