40/70 Benchmark

I included velocity potential along with the H5/temp and precip composites.

Well, I only use analogs back to 1950, so the 1951-2010 climo period is fine for me.

I'm sure the cut-off will be a couple of miles N of me.

Down to 44.1 this AM.

Well, I never said I'd forecast a big year down there. I will put numbers to everything in a couple of months. It's tough to discuss is too much right now because there is still a great deal of equivocating at this early juncture.

Thanks. I'll give that a shot. Like Summy said, the latest climo period does begin to wash out the anomalies, which defeats the purpose. That's why you need to use a larger climo period.

Its actually on Long island.

We need Forky to remind you that the snow stopped and the vis improved.

Without reading the article, I am going to take a wild guess and assume that this correlates to a +NAO/AO this winter and an enhanced PV.

Its no coincidence why this composite gives us the warmest look...its west-based.

What is important is how the sst anomalies at a given posotion manifest themselves into the weather pattern around the hemisphere, not an arbitrary longitude where you feel as though said manifestation should take place. Anyway, just my view....we are all different.

I guess we are just going to have to agree to disagree on this. The anomaly in this composite is centered at like 165-170W, which is pretty far to the west, and that is reflected in the resultant H5 and VP (forcing) composites.

I feel like you may not be coming up with a modoki composite because your criteria is too stringent and exclusive....ie, are you looking for seasons that did not have any la nina strength (-0.5C or cooler) at all over the central and east Pacific? If you look at the verbiage in my composites, that is a reflection of the criterion that peer reviewed, academic pieces use...like "small cooling" and "weak anomalies" over other sections. IOW, a west based event need not be entirely void of la nina caliber anomalies in regions further east, they just need to be very weak from around 150W points eastward, with the strong emphasis west of 150. It may help to look at the visual SST composites of my three groups for a more vidual representation.

You are referring to the intensity composites....yea, its because of the climo period. I used 1951-2010 for the temps, which will accentuate the positive anomalies due to the more expansive climo period encompassing a cooler overall global canvass several decades ago. However, the H5 composite would only allow me to utilize the 1981-2010 period, which attenuates the positive height anomalies because it excludes that same coolest stretch from several decades ago. I really wish the H5 composite would allow me to use 1951-2010...I said this to Will the other day.

Here is some relevant material with respect to the three structural designations from my work last fall, not including last year, which was east based and well behaved with poleward Aleutian ridge that drove the severe mid winter stretch centered on the blizzard....again, clear differences: East Pacific (EP) La Ninas East Pacific events are "characterized by the cooling SST anomaly center confined to the EP east of 150°W and relatively weak SST anomaly observed over the CP". They decay more quickly overall. These canonical la nina events are theorized to be relegated largely to the eastern Pacific due to the fact that they are a byproduct of the thermocline dynamics present in the Walker Cycle", which is explained in the ENSO & Tropical Background addendum. Here is a composite of cool ENSO events meeting this criteria: Note that the warmer anomalies near the dateline ensure that forcing remains over the central and western Pacific, similar to the weaker la nina composite. Sinking air that discourages convective forcing is focused well east of the dateline. Also evident is that the Aleutian ridge focuses more to the northwest relative to the modoki, cp event, which will be illustrated when that particular composite is reviewed. This often entails a protrusion of said ridge into the polar region at times, which likely contributes to the lower heights over the mid latitudes: Note again the similarities to the weak la nina H5 composite that was comprised in the intensity segment of the discussion. Obviously that is because all of these events were weak, however, there are some stronger basin wide events that were still decidedly biased east. Two such events there were referenced earlier are the strong la nina events of 1955-1956 and 2010-2011, which were both fairly cold across the eastern US and featured a great deal of blocking. Both of these have been designated as mixed-type "hybrid" events. Mixed Type La Nina Explains Why Some Stronger La Nina Events Behave Differently When the large cooling anomaly occupies both the eastern Pacific and the central Pacific during the mature phase of development, we have what is referred to as a mixed type of la nina. These events usually mature on average a bit later in January, as opposed to December for EP and CP events, which coincides with the forecast NDJ tri monthly peak of this event. During the maturing stage, the cooling anomaly shifts rapidly from the east pacific to the central Pacific. This is precisely how this current event had been evolving throughout the month of September, when region 1.2 dramatically warmed and region 4 cooled. However, this trend has since ceased and even reversed, ensuring that it will remain of the mixed variety and not transition into a modoki. Zhang cites 3 events as meeting this criteria, which are the la ninas of 1970-71, 2007-2008 and 1999-2000. However, Eastern Mass Weather has modified this composite to also include other events deemed to be of the basin wide, "mixed type" variety, which includes the strong 1955-1956 and 2010-2011 events. Note that the location of the composite maximum anomaly at roughly 130-180* longitude is slightly west of the current placement, between about 120 and 140* longitude, which is consistent with some of the more eastward leaning basin-wide events, such as 1955-1956 and especially 2010-2011. Here is the 2010-2011 season, which is perhaps the best fit to the current season structurally speaking, though it was significantly stronger.: The 1955-1956 strong la nina event had the area of maximum anomalies biased even slightly more to the east end of the mixed composite spectrum. Where as a basin wide season such as 2007-2008 had the max anomalies more evenly distributed east and west of 150 degrees longitude, and if anything biased slightly to the west. This season had a notable absence of high latitude blocking and a rather flat Aleutian ridge more redolent of the modoki and strong la nina composite: Since the majority of the hybrid seasons in this grouping are more like 2007-2008 and not as biased to the east as 2010-2011 and 1955-1956 respectively, the resultant forcing of the mixed-basin wide composite is fairly dissimilar to the EP composite, which makes sense since the western ENSO flank does have significant negative anomalies. Here is here is the resultant H5 composite for the mixed la nina data set: There is notably less high latitude ridging and a flatter Aleutian high than noted in the eastern pacific counterpart. Let see how this compares to the modoki composite. Central Pacific (CP) La Nina (Modoki) "The SST anomaly center associated with the CP La Niña is shifted westward into the CP west of 150°W and small cooling SST anomaly is found over the EP". In contrast to the canonical EP event, which advances somewhat westward to as much as 150* longitude and decays faster, the CP event decays more slowly and remains in place, while propagating only a small amount in either direction". These differences in zonal location of SST anomaly and their evolutions suggest the possibility of different underlying dynamics, which is indeed the case. Modoki la nina are largely the product of a local air-sea interaction that develops and decays in place over the central Pacific. The reduced cooling over the east may also be further attenuated by a modified Walker cycle, according to Zhang, which features a displacement to the west of the easterly trades responsible for upwelling. In the modoki la nina, the EP trades are replaced with an anticyclone, as a direct result of the cool SST anomalies being shifted west to the CP. As was the case with respect to the first two composites, Eastern Mass Weather has added some seasons to the Zhang et al CP composite. Most notably, the 2011-2012 la nina, which is a prime example of how modoki characteristics can cause a moderate la nina composite to be more reminiscent of a stronger event. If anything, the very mild 2011-2012 (-1.1 peak ONI) season is biased even further west than the above modoki composite, which partially explains why it was even milder than many strong la nina seasons across the eastern US. Note that the sinking air over the center of the negative SST anomaly in the CP is inimical to forcing in this area when considering the modoki composite. The EP and WP forcing associated with the "modoki" la nina generally features an inverse pattern from that of a modoki el nino across North America. This resultant N. American pattern is more akin to an east-based, canonical el nino. however, we obviously have the prominent Aleutian high as opposed to the Aleutian low during el nino due to opposite anomalies over the tropical Pacific. The Aleutian high in this composite is appreciably flatter and displaced to the southeast in relation to its canonical counterpart, as alluded to. Note that this composite is completely void of the trace of high latitude blocking evident in the basin wide composite. It should be clear that the primary distinction between the different structural ENSO types is how they interact with and modulate the polar domain, which obviously has a profound impact on the resultant N. American weather pattern during boreal winter. However, before more closely considering the differences with respect to the polar domain, it is important to review the structural differences with respect to ENSO in order to ensure an adequate foundational understanding. Summary of ENSO Types -The simplest way to conceptualize ENSO and its impact over North America is that canonical el nino and la nina events are east-based and a product of the thermocline dynamics associated with the Walker circulation cycle. - Canonical la nina events are inverse to canonical el nino events, which are usually stronger and favor higher heights over the eastern US during boreal winter. Canonical, east-based la nina events are usually more moderate in intensity due to a faster rate of decay and favor lower heights over the eastern US during winter. -Modoki are different, as the Japanese term suggests, in that these ENSO events are born of local in-situ thermocline dynamics. Modoki El ninos are usually more moderate in intensity and favor lower heights over the eastern US during boreal winter. This is in contrast to modoki CP la nina, which are usually stronger events due to a slower rate of decay and favor higher winter heights across the eastern US. -Its also important to remember that there are exceptions within each distinction. -There are weak modoki seasons such as 2000-2001 and 2008-2009, the latter of which was a second year la nina, that were cold in the eastern US and featured blocking. -There was weak EP seasons such as 2005-2006 that were still mild. -There were strong events such as 2010-2011 and 1955-1956 that were cold because they were biased slightly east, while 2011-2012 was exceptionally mild due to its modoki nature, despite being of modest intensity. CP Modoki: In the above Modoki composite, vertical motion is weak over the W Pac and more pronounced over the E PAC. Descent is very evident over dateline, which discourages convective forcing. Hybrid: While descent is still present over the dateline in our hybrid composite, it is MUCH weaker and vertical motion is more focused west. This is the favored regime this season, with milder intrusions more frequent south of roughly I-80. Canonical: East Pacific Based: Descent is displaced east of dateline in the EP composite, which focuses more convection and vertical ascent there. The placement of this vertical ascent favors convective forcing in MJO phases 5-8 more often than not, which teleconnects to colder weather in the east. Finally, since the significant cool anomalies of the mixed type la nina encompass both the EP and CP, Zhang postulates that the resultant pattern across North America may mix signals of the EP an CP la Nina in terms of the extratropical atmospheric response. This can be inferred from above referenced basin-wide composite given the relatively unremarkable upper air features, which include a modified se ridge and a neutral to subtle negative NAO signature that is presumably the result of muted CP and EP forcing. This can make correctly diagnosing the crucial polar fields, which Zhang identifies as the "dominant climate variability mode", over North America in a season such as this one most challenging.

Here is intensity, save for last season, which I have designated as moderate due to the MEI. There are definitely differences apparent: Cool Neutral: Weak La Nina: Moderate La Nina: Strong La Nina:

I'll show you the years I had for modoki tomorrow.

I totally expect to get porked for one more season, but I'll leave the board if '23-'24 sucks, too.

I loved the winter of '92-'93.

Been saying that all summer.

Not too sure about Mongolia, but over here I would say -AO/-EPO would be a good start.

I defined the ones with very little cold east of about 150W as being west based. I link my groupings later. There is subjectivity, which is what I was mentioning last night in my initial ramblings...the data is objective, but the interpretation, synthesis and application is all at least somewhat subjective.

Yea, this is why I suggest grouping basin wide and central together, which is how I do it.