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Winter 2022-2023 Conjecture


40/70 Benchmark
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53 minutes ago, 40/70 Benchmark said:

Here is a bit of a refresher taken from last season's outlook that illustrates what I have alluded to above:

There exist some notable differences between these two disparate types of la nina events. Here are a couple of schematics outlining these differences:
Differences between east-based La Nina's & central-based La Nina's 
Figure A is east-based. Figure B is central-based
One.gif
DJF 500mb for East-based years:
New%2BEast.png
 
 
DJF Temps

New%2BEast%2B1.png
 
Ironically in east-based years JFM is colder than Dec. Dec is typically the warmest month in the
 east-based years, which runs counter to typical cold ENSO climo.

JFM 500mb east-based years
JM%2BEast.png
 
 
 
JFM Temps
 
 
New%2BEast%2B2.png
 
 

 
 
Compare all of that to central-based La Nina years:

DJF 500mb

 
DF%2BH5.png
 
 
 
DJF Temps
 
DF%2BModoki.png
 
 
December is the coldest month for central-based Nina's. 
One thing worth noting is not all East-based Nina's are frigid, as there is variability due to the relatively weak
 ocean-atmosphere coupling. This is because many east-based events, as is the case with modoki el nino events, are 
weaker. You can have warmth, especially if the event is weaker, and one such case is 2005-2006.
2005-06.png

Likewise, there were some weak modoki events that were fairly cold across the eastern US, such as 2000-20001.
2000.png
This is further proof that there does indeed exist a structural mechanism beyond strength that dictates the overall character of la nina events and one of the focal points of this writing is to elucidate that point.
There are some "hybrid" events that share both east-based and modoki traits. You can have a Nina that is a mix of east-based versus central-based, or "basin-wide", such as both this season and last.

While I do not think it will be a blockbuster season, I don't buy the rationale that this winter will automatically suck because of the la nina/+QBO couplet, assuming la nina remains weak.....at least not with respect to New England.

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2 hours ago, snowman19 said:

Are you buying the models showing a moderate Niña peak in December? 

 

16 minutes ago, 40/70 Benchmark said:

It could....I mean, its moderate now. Depends on how quickly it can decay later this fall and into early winter. I think the strongly negative IOD belies the ultimate intensity of the la nina this cold season....be careful about interpreting the rather robust -IOD as an ensuing major la nina event. The IOD is also influenced by the timing of ENSO events, not just the strength....thus earlier onset la nina is correlated to more robust -IOD events. This of course is a well-established, multi year cold ENSO. Its later onset ENSO events that are less likely to manifest in changes to the IOD.

I am finding some really interesting stuff concerning the IOD...I suspected that -IOD was correlated to el nino modoki due to the co occurrence of increased convection over the W PAC, and early returns are that I am right.

Just another feather in the cap of an el nino modoki once this cold ENSO decays during the coming winter.

Do you have a good link for IOD data?

 

6 minutes ago, snowman19 said:

The IOD links I have are from google searches over the years. HM and Isotherm may be able to guide you better on that, they are well versed in it. As far as the La Niña, every model has it falling apart completely come March/April and region 3.4 finally going neutral then. Still way out in fantasy land but I think this 3 year event is done for good come spring, 2023

 

5 minutes ago, 40/70 Benchmark said:

It will be a tricky season because we are backing out of the ENSO state, as opposed to the atmosphere riding the coat tails of a burgeoning event.....thus I do not feel as though the forcing will be commensurate with a lot of the global indicators that normally provide insight into the strength of ENSO.....kind of like seeing this big bulge of warmth in the GOA, but knowing that the pattern has already changed and the residual SST pattern is just a reflection of what was, not what will be.

 

3 minutes ago, 40/70 Benchmark said:

I am firmly in the cold-neutral to weak la nina camp for winter, but I would not rule out enough residual coolness lingering into early winter for a moderate "peak", though I don't think it would mean anything.

 

2 minutes ago, 40/70 Benchmark said:

I think the strongly negative IOD and MEI are a reflection of this past year, not necessarily of what will be several months down the line.

 

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23 hours ago, snowman19 said:

This -IOD event started independent of the La Niña a couple of months ago. It should max out sometime in October. I think it will definitely have an impact on the tropical forcing/MJO going into winter

 

1 hour ago, 40/70 Benchmark said:

The first mode (mode 1) of the Indo-Pacific SST covariation, shown in Fig. 1, explains 47% of the total variance. Also drawn in Fig. 1 are the regressed 850-hPa wind anomalies onto the principal component (PC) time series. This mode shows a developing phase of ENSO starting from boreal spring (Fig. 1a) and peaking in winter. SST anomalies first appear near the South American coast (Figs. 1a–c) before extending westward over the central-eastern Pacific. In the Indian Ocean, SST anomalies of the IOD pattern begin to form in early summer. Then, the IOD gradually develops with the developing ENSO and reaches its peak in boreal fall (Figs. 1g,h) and finally decays after October (Figs. 1i,j). This is a typical pattern of ENSO–IOD coevolution (Saji et al. 1999). El Niño excites an atmospheric teleconnection over the Indian Ocean and causes easterly wind anomalies conducive to the IOD during boreal summer and fall (Klein et al. 1999; Alexander et al. 2002).

Fig. 1.View Full Size
 
Fig. 1.

(a)–(j) First mode of the rotated S-EOF for tropical Indo-Pacific SST anomalies (shading) and 850-hPa winds (vectors) regressed onto PC-1, (k) PC-1.

Citation: Journal of Climate 30, 6; 10.1175/JCLI-D-16-0426.1

From what I am reading, there is nothing to suggest that this particular episode of negative IOD developed independent of la nina....it seems pretty standard for a given IOD episode to develop during the early portion of the summer and grow in tandem with ENSO.

The article goes onto state that IOD is usually tied to early onset ENSO events, and not later onset events. I would have to consider this one the former, since its a multi year event...the implication being that la nina likely provided the impetus for this particular round of -IOD.

 

56 minutes ago, 40/70 Benchmark said:

Actually, you are right....the IOD-ENSO link doesn't apply for year long la nina events...only ones that have their initial onset during the spring.

 

 

47 minutes ago, 40/70 Benchmark said:

"One may note that the El Niño in mode 2 evolves from the peak phase of La Niña and the Indian Ocean experiences a decaying process of basinwide cooling".

 

Doesn't seem to be a coincidence that we usually have a modoki following a prolonged stretch of la nina.

 

5 minutes ago, 40/70 Benchmark said:

It also makes sense that some of the la nina's that were kind of irregular from traditional la nina climo, such as 1995-1996 with the hyper active STJ and 2000-2001 with the huge ending, did not induce a concomitant IOD response, thus why the MJO likely strayed from traditional la nina favored phases.

 

Table 2.

 

1 minute ago, 40/70 Benchmark said:

My theory why they did not link with the IOD, base upon this article, is that the 1995 la nina did not really get going until the fall and the 2000 event was a triple dip deal....and as cited above, the ENSO event needs to DEVELOP early in the summer in order to be most likely to induce an IOD respose, NOT be a one that his persisted all year. So, once again, snowman was right and this la nina likely is not coupled with the IOD. We could have some deviation from typical la nina climo this year.

 

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2 hours ago, 40/70 Benchmark said:

 

 

 

 

 

 

This -IOD means business (getting stronger as we speak) and it’s going to make its presence felt on the global longwave pattern, it already is. It is also serving to help strengthen this Niña even more going into fall as we are seeing now, this EWB is pretty incredible: 

 

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15 minutes ago, George001 said:

I’m not a fan of the increasing solar and low ACE. That usually means a polar vortex centered over the North Pole which is really bad. It looks horrible right now but it’s still early, there is time for the ACE to increase. 

No reason yet to believe this’ll be a low ACE season in the Atlantic.

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17 hours ago, WxWatcher007 said:

No reason yet to believe this’ll be a low ACE season in the Atlantic.

I think it will.

I don't think the polar domain will be particularly conducive this season, however, I do expect a favorable Pacific early on in the season...if we can get some  NAO early on, then December could be very good.

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31 minutes ago, 40/70 Benchmark said:

I think it will.

I don't think the polar domain will be particularly conducive this season, however, I do expect a favorable Pacific early on in the season...if we can get some  NAO early on, then December could be very good.

Wow, that’s pretty bold. I still think despite the quiet period and meh MDR anomalies that tropical season in the Atlantic will be above average. 

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Just looking at ACE, originally I would have been inclined to say that the -ENSO alone puts us in a place where average ACE is a floor, but that'd be lazy analysis. In fact, @GaWxrecently posted some great stats that show there tends to be a dramatic drop off in activity in a third-year Nina, though the sample size is on the smaller side. That gives a little pause, but I didn't expect hyperactive to begin with.  

That said, while I think it's tempting to look at a slightly cooler than normal MDR and the incredibly quiet Atlantic as a harbinger of things to come, I don't think it's going to get in the way of a very active peak that should bring us to at least average. I know you know this, but we still have approximately 90% of climo to go with regard to Atlantic activity, and there have been numerous examples this century of long quiet periods and less than favorable eastern MDR conditions that fail to get in the way of a season with a favorable background state becoming above active. 

I still think the combination of a Nina, lower than normal shear driven by the Nina, and importantly, warmer than normal temperatures and TCHP/OHC throughout the western Atlantic suggest a season that gets the Atlantic above 123 ACE. 

Not worried about the SAL--that'll diminish near the peak. I do think stability in the eastern MDR could be a fly in the ointment, but I'd want to see what that looks like in mid-August. 

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11 hours ago, WxWatcher007 said:

Just looking at ACE, originally I would have been inclined to say that the -ENSO alone puts us in a place where average ACE is a floor, but that'd be lazy analysis. In fact, @GaWxrecently posted some great stats that show there tends to be a dramatic drop off in activity in a third-year Nina, though the sample size is on the smaller side. That gives a little pause, but I didn't expect hyperactive to begin with.  

That said, while I think it's tempting to look at a slightly cooler than normal MDR and the incredibly quiet Atlantic as a harbinger of things to come, I don't think it's going to get in the way of a very active peak that should bring us to at least average. I know you know this, but we still have approximately 90% of climo to go with regard to Atlantic activity, and there have been numerous examples this century of long quiet periods and less than favorable eastern MDR conditions that fail to get in the way of a season with a favorable background state becoming above active. 

I still think the combination of a Nina, lower than normal shear driven by the Nina, and importantly, warmer than normal temperatures and TCHP/OHC throughout the western Atlantic suggest a season that gets the Atlantic above 123 ACE. 

Not worried about the SAL--that'll diminish near the peak. I do think stability in the eastern MDR could be a fly in the ointment, but I'd want to see what that looks like in mid-August. 

I feel like this will be one of those relatively inactive seasons that will leave quite an impression, nonetheless....it only takes a storm or two, and the heat ridge ultimately retrogressing is going to leave the east coast vulnerable later August into September.

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10 hours ago, George001 said:

What are some possible wildcards to look for if looking for a big winter in eastern mass this year? 

La nina remaining weaker and or east-based for a higher likelihood of seeing intervals of poleward Aleutian ridging like last year.

Its early, but right now I am pretty confident that la nina will be more basin wide than last season, so it will need to remain relatively weak in order to provide us with the greatest likelihood of some Pacific variability (favorable interludes).

I think a "big winter" is pretty unlikely this year, but you def. want it to remain weak if it isn't going to be very east based in order to have a shot at that.

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Another thing to watch is kind of tied into it remaining weak, but if we see a rapid demise of la nina, it could lead to some increased variability late in the season. A couple of the triple-decker cool ENSO analogs had late season blocking, namely 1957 (cool neutral ENSO) and 2001 (weak modoki la nina). 1976 (strong and basin-wide) did not, possibly because it was a much stronger la nina.

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16 minutes ago, 40/70 Benchmark said:

Another thing to watch is kind of tied into it remaining weak, but if we see a rapid demise of la nina, it could lead to some increased variability late in the season. A couple of the triple-decker cool ENSO analogs had late season blocking, namely 1957 (cool neutral ENSO) and 2001 (weak modoki la nina). 1976 (strong and basin-wide) did not, possibly because it was a much stronger la nina.

2012-2013 is actually another example of a third year cool ENSO event...again, cool-neutral ENSO that continues the theme of weaker having a happy ending, so I will be watching for more sign of that later this fall.

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My early hunch is that the middle of portion of winter may be rather mild and lean, though not exotically warm on average...maybe another one of those nocturnally driven warmer periods that have become so prevalent in today's climate. I feel most confident in a favorable stretch in December and possibly another in March.

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It doesn’t look great right now but I’m not ready to write off a big winter just yet. I wasn’t on the board back then but going into the 2010-2011 winter I can’t imagine people were very optimistic. That year the La Niña was really strong and central based, and the MEI was extremely high which indicates la nina was coupled and dominating the pattern. Hopefully the polar vortex is weak this winter. This is a different pattern of course, but at least it’s not a moderate to strong nino.

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15 minutes ago, George001 said:

It doesn’t look great right now but I’m not ready to write off a big winter just yet. I wasn’t on the board back then but going into the 2010-2011 winter I can’t imagine people were very optimistic. That year the La Niña was really strong and central based, and the MEI was extremely high which indicates la nina was coupled and dominating the pattern. Hopefully the polar vortex is weak this winter. This is a different pattern of course, but at least it’s not a moderate to strong nino.

I wasn't doing outlooks back then, but if you read my stuff last fall then you would know that 2010-2011 was my top ENSO analog, which should tell you that it isn't a fluke that that winter wasn't a dud. It was central based, but it wasn't a modoki....it was actually biased a bit to the east end of the spectrum. I would forecast a decent winter given those same parameters today, as I did last season.

In hindsight, last season ended up even more east based, which saved us from a total train wreck because the sun ultimately porked us with respect to the poles.

Remember, a well coupled ENSO event is not necessarily bad if the forcing is in the right place, though often times well coupled ENSO events have hostile forcing because the most highly coupled events are usually east-based el nino events and modoki la nina.

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31 minutes ago, George001 said:

It doesn’t look great right now but I’m not ready to write off a big winter just yet. I wasn’t on the board back then but going into the 2010-2011 winter I can’t imagine people were very optimistic. That year the La Niña was really strong and central based, and the MEI was extremely high which indicates la nina was coupled and dominating the pattern. Hopefully the polar vortex is weak this winter. This is a different pattern of course, but at least it’s not a moderate to strong nino.

Steve and I called for a big winter and were laughed at.  Who’s laughing now?

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