40/70 Benchmark

Yes, that is how I use it. I don't understand why they don't fix the December data...absolutely drives me insane....do that with a month no one cares about, like September or April.

I don't this event is having much impact at all.

Raindance is the best, agreed...but nobody is perfect. He did miss the NAO last season, but no one noticed because the record -PDO was so overwhelming that the blocking was negated and had little sensible impact. A similar miss this season with respect to the polar domain will likely have much larger ramifications than it did last year.

Great work. I wish I had your math skills....really allows you create some wonderful tools.

Yes...pretty much echoes what I said. Most of what was released into the atmosphere was water vapor, not S02, and thus not very impactful on the NH PV...what impact there was should have already been observed last winter. And the impact of these events is over simplified..it depends on location and global circulation patterns as to how they impact the poles, if at all. Have you read about how some eruptions back in the 1960s and in 2009 even augmented a -AO/NAO response? I am not implying that will happen this year....just drawing it to your attention because its interesting.

My point is more that ascending is favorable than it is that max is favorable...there really wasn't a strong signal for max. I'm also not trying to claim that exotic blocking should necessarily be expected this winter. But I do think that your focus on overall sunspot activity as a predictor for the NAO is misguided, as the research that I reviewed revealed that it's more about the trend (ascending vs descending) than min vs max. This is why we have years like 1994 and 2006 that were descending near the min with very positive NAO.

I say 160 because that is where 2016 was, but whatever...in that area.

Yea, I know it varies, but I'm def no expert on the solar stuff...just used the min/max dates listed on the wiki page.

If this el nino ends up with an ONI near 2.0 and the forcing makes it as far back east as about 160W, then none of this is likely to matter because we are cooked. Canonical el nino forcing that powerful would be the main driver.

Like the solar relationship, the impact of volcanic eruptions on the polar domain is also over simplified and poorly understood. There are a multitude of factors such as location of the eruption and global wind circulation patterns that dictate how it impacts the poles, if at all. Some have no impact...some produce negative AO/NAO.

2009-2010 also near solar min, but on the other side...ascending....the rest is history. Solar isn't the only factor and there are some exceptions, but this ascending vs descending dichotomy checks out most of the time looking back. 1957-1958 was ascending near solar max with a strong el nino, like This year....big blocking. I'm not trying to say slam-dunk -AO/NAO....I just think it's a bit more up for debate than some of us think.

1994 and 2006 are two perfect examples...right mear solar min, yet two very strong PV seasons....why? Descending sun.

I went into this season believing that a +NAO was favored due to nearing solar max, but that doesn't look to be the case. I guess we'll find out in a few months.

Looks to me that ascending vs descending is more important than minimum vs maximum. Influences of the Solar Cycle on the Polar Fields The impact of the solar cycle and the stratosphere on the earth's atmosphere continues to be a work in progress and much like seasonal forecasting in general, it is still very much a frontier science. Traditionally, research correlated high levels of solar activity near solar max to a stronger polar vortex and thus milder winters for much of North America and Europe. There are a multitude of theories as to why this is the case, however, most of these theories cite drivers such as UV radiation and total solar radiation (TSI), which closely mirror sunspot activity, as responsible for increasing ozone levels and temperature in the equatorial stratosphere. This warmer tropical stratosphere then results in a stronger latitudinal gradient and a cooler polar stratosphere (stronger polar vortex) via a modulated Brewer-Dobson cycle. The issue with these theories is that the peak levels of the aforementioned potential drivers of the solar-stratosphere connection coincide with solar max. And most recent research cite stronger drivers that do not coincide with solar max, such as geomagnetic energy and solar winds, which peak during solar flux or, about one year after solar max in terms of peak UV and TSI . (Maliniemi et al, 2014). Malimiemi et al theorize that geomagnetic energy makes its way into the polar region via the process of energetic particle precipitation, which then produces nitrogen oxides in the the upper atmosphere that have a protracted period of time to descend downward and increase ozone during the polar winter in the absence of any sunlight, which cools the stratosphere and strengthens the PV. This more closely corroborates both with other recent research, which cites drivers that do not peak at solar max as defined by UV and TSI (geomagnetic energy peaks approximately one year after solar max), as well as the research of Malimiemi et al (2014), which found that the declining phase of the sunspot cycle remarkably consistently produces the spacial pattern of surface temperature anomalies related to the positive NAO during the last 13 solar cycles" (Maliniemi et al, 2014). This makes sense since the geomagnetic energy peak that Maliniemi et al cite as the main driver behind the connection between the solar cycle and polar domain lags solar max as defined by UV, TSI and sunspots by approximately one year, which is during the declining phase that so strongly correlates with the +NAO response in their research. This is also consistent with other recent studies of seal level pressure patterns that revealed a +NAO pattern lagging solar max by approximately 2-4 years. The work of Maliniemi et al also showed that this relationship is not at all dependent on overall sunspot activity due to intra-cycle variability. Mean winter NAO index values for the four cycle phases, averaged over cycles 11 to 23. The red line represents the overall mean value of wintertime NAO (0.05). Bars represent the 95% confidence intervals. Perhaps more germane within the context of the coming winter is that the study found that both the solar max and the ascending portion of the solar cycle are weakly correlated to a colder pattern redolent of the -NAO, although this is more dependent on intra-cycle variability of activity. There is no clear correlation between the solar minimum and the NAO, but perhaps modest one that perhaps a modest negative correlation. These relationships between solar behavior and the NAO are evident in the graph above, with reds, denoting +NAO, very evident in the declining phase of the last several solar cycles. And Blue, indicative of -NAO, prevalent in the ascending portion of the cycles. Winter 2023-2024 will be in the ascending phase with the peak of solar cycle 25 anticipated within the next couple of years, thus an exceedingly strong PV is unlikely in the mean during the coming boreal winter season. Now we can view the aforementioned EMI analogs through this solar lens in an effort to gain clarity into why the polar domain behaved in the manner that is did in each respective case. In the case of the 1986-1987 winter season, given that solar minimum occurred during prior fall in September of 1986, that particular season occurred near the solar minimum at the onset of the ascending phase. This is consistent with the research marginally favoring a negative NAO. The 1994-1995 cold season coincided with the descending phase of solar cycle 22 given that the minimum was observed in August of 1996, which also corroborates the research of Meliniemi et al that favors a +NAO during this portion of the solar cycle. Finally, the 2006-2007 winter season also took place during the descending phase of solar cycle 23, as the minimum was in December 2008. This season featured both a +NAO and exorbitantly potent PV in the seasonal mean.

Depends which research you read.

Pretty clear pattern among every analog set...including Raindance's....the ones with blocking were good out this way.

I haven't made any predictions yet, but there is certainly some evidence for at least a modestly disturbed polar domain.

I am willing to bet that you can find one or two duds in EVERY ENSO state. Often? Jan 2016 is the only super el nino HECS I know of that missed south...and it was a brush, not a whiff.

NVM the fact that the initial impacts in the SH were the powerful PV a year ago...plenty to time for SH to feel the impact another 6 months later, last winter.

Nice try....a year is long enough regardless of where it takes place.

Me neither. Preliminary Analysis of the Polar Landscape for Boreal Winter 2023-2024 | Eastern Mass Weather

According to research, the max impact is during the first DJF period following the eruption....and it takes about 3-6 months to work into the atmosphere. Any compelling reason why it will have a greater impact 24 months removed from the January 2022 eruption than it did 12 months removed? S02 was never much of a factor in this eruption, but it has also peaked.

If you want to make it even simpler, guess which is the only one of those seasons with a disturbed polar region? There are reasons why the others all featured a strong PV.

Not a big deal IMO...the event had to move westward if el nino were to flourish, as 3.4 is the main indicator.

Right...I didn't know any better as a 15yo in 1996. You would think the pros would have-