griteater

What have you seen? What are your thoughts? I think it is reasonable to have 'concerns' over the volcano having impacts on the behavior of the strat PV given the injection of high water vapor anomalies into the strat. Increased water vapor would favor a cooler stratosphere (as water vapor in the stratosphere radiates incoming infrared energy)

Yes, but they mention in the paper that the -NAO signal for solar max is not statistically significant - "We note that although the maximum phase has the largest negative mean NAO(−0.20±0.55), which is in agreement with the results depicted in Figure 4, it is not statistically different from the long-term mean." The biggest takeaway from that paper IMO is that the declining phase of solar cycles has a robust correlation with +NAO. The average in 12 of the 13 solar cycles (cycles 11 to 23 from 1867 to 2008) exhibited +NAO or +NAO temperature patterns. Interestingly enough, the NAO was positive as well in each of the 3 winters in the declining phase of solar cycle 24, those being the winters of 2014-2015, 2015-2016, and 2016-2017. Looking back at this year's solar cycle chart, it looks like this year would qualify as one of the solar "Maximum" years. Lastly, I thought this was a good summary in the first section of the paper ("Abstract"): "...Using 13 solar cycles (1869–2009), we study winter surface temperatures and North Atlantic oscillation (NAO) during four different phases of the sunspot cycle: minimum, ascending, maximum, and declining phase. We find significant differences in the temperature patterns between the four cycle phases, which indicates a solar cycle modulation of winter surface temperatures. However, the clearest pattern of the temperature anomalies is not found during sunspot maximum or minimum, but during the declining phase, when the temperature pattern closely resembles the pattern found during positive NAO. Moreover, we find the same pattern during the low sunspot activity cycles of 100 years ago, suggesting that the pattern is largely independent of the overall level of solar activity.

Last 4 days of the SOI have been lower than -20. One old rule of thumb I've seen is the 14/7 rule...when the 30 day SOI is -14 or lower and the 90 day SOI is -7 or lower, that's when Nino 3.4 warming kicks in. Not far off now

Yeah factoring in solar with the Strat PV and AO/NAO can get a bit tricky. The classic combo for a weak PV and -AO/-NAO is when the lower strat QBO is neg and we are in solar min with respect to both solar flux and geomag, which is typically right after the official solar minimum (years like 76-77, 86-87, 09-10). In lieu of that, I like this simple chart which shows how the strat PV tends to have early warming events during -QBO in both Solar Min and Solar Max conditions, with mid or late winter strat warmings favored during +QBO. "....In early winter (November–December), the most disturbed, and most variable, composites are the two QBO/E phase composites. In midwinter however (January–March), the two composites showing most disturbances in midwinter are the Smin /E and Smax /W composites. The disturbed nature of the Smax /W composite thus supports earlier evidence that the Holton Tan relationship is disrupted in Smax years." Source: Solar and QBO Influences on the Timing of Stratospheric Sudden Warmings in: Journal of the Atmospheric Sciences Volume 61 Issue 23 (2004) (ametsoc.org) Also, I like the chart in this paper where it shows that the Declining phase of the solar cycle is where the highest NAO values have typically occurred. This would be the time period of highest solar geomag just after solar sunspot / solar flux max (I suppose we are either in the Ascending or Maximum phases for this winter). "...Figure 7 verifies the unique nature of the declining phase, the only phase having a mean NAO index (0.46±0.36), which is statistically significantly different from the long-term mean. We note that although the maximum phase has the largest negative mean NAO(−0.20±0.55), which is in agreement with the results depicted in Figure 4, it is not statistically different from the long-term mean. Mean wintertime NAO values during the ascending and minimum phases are close to the long-term mean." Source: Spatial distribution of Northern Hemisphere winter temperatures during different phases of the solar cycle (wiley.com)

I don't have a strong opinion on it. It just seems like everything is lagging a bit with what the models continue to want to show vs. what ends up in reality (i.e. models showing the MJO more active that what really occurs / SST over the far W Pac remaining warm, etc.), but we'll see

In fairness, I don't think any of the variables are a slam dunk with correlations. But here are 4 El Nino winters with similar values in Nino 3.4 (all Moderate), and they show 4 different patterns for the most part. It's even more variable with weak El Ninos. Also, VP usage (with .2101 sigma) would only be accurate within the satellite era back to 1980, so the sample size is limited.

Here is a comparison for Jun 3 to Aug 3 in 2015 (Basin Wide Super Nino) vs. this year where you can see that the low frequency Walker Cell uplift region (-VP in blue and purple) has been slow to move east so far this year and is still reaching back into the Maritime Continent in spite of the El Nino SSTs being east-based. So, we'll have to see how that trends going thru the fall

I'm thinking this ends up as a Strong Nino instead of Super. Not buying the stronger models, but we'll see, I could be wrong. But yeah, if the low frequency Nino Walker Cell uplift is further west towards the Dateline, that would increase chances for a better Pac pattern and -AO/-NAO. By default though we are fighting multiple things that want to lean warm: 1) Affects from Hunga Tonga volcano 2) Affects from reduction of sulphur in shipping fuels - see thread (1) Leon Simons on Twitter: "For decades this area has been kept relatively cool by sulfur emissions from ships. But this changed in 2020. https://t.co/DFD39uyVJ3" / X / 3) Just general ongoing, background climate warming

Latest Euro Seasonal is in for Aug 1... 3.4 Plume is warmer this run -> and Super El Nino is forecasted Nino 1.2 is also warmer this run Nino SST footprint for Dec-Feb looks a lot like 2015-2016. Super Nino that is basin wide Precipitation for Dec-Feb has bulge at the Dateline / Gulf of Mexico / East Coast 500mb for Dec-Feb has +PNA / -AO / -NAO Surface for Dec-Feb has Aleutian Low / Low pressure along E Coast Indices show healthy +PNA / -NAO for Jan-Feb

I have posted some thoughts on the Hunga Tonga volcanic eruption and the QBO in Chuck's Winter thread - https://www.americanwx.com/bb/topic/59184-winter-2023-2024/?do=findComment&comment=6971703

Some thoughts on this... Pinatubo (Jun 1991) injected a heavy dose of aerosols into the stratosphere..."Strong explosive volcanic eruptions, like ones of the Mt. Pinatubo in Philippines in June 1991, inject millions of tons of sulfur dioxide gas at the altitudes of about 15 miles where it interacts with water vapor producing a volcanic aerosol layer that consists of tiny droplets of highly concentrated sulfuric acid." "...when aerosols get into the stratosphere, very rapid reactions that destroy ozone (especially in high latitudes) take place on the surfaces of aerosol particles. When ozone gets depleted, less UV radiation is absorbed in the stratosphere. This cools the polar stratosphere and increases the stratospheric equator-to-pole temperature difference, creating a positive phase of the Arctic Oscillation." Source: NASA - Top Story - THE 1991 MT. PINATUBO ERUPTION PROVIDES A NATURAL TEST FOR THE INFLUENCE OF ARCTIC CIRCULATION ON CLIMATE - Mar. 12, 2003 Hunga Tonga (Jan 2022) on the other hand ended up injecting a heavy dose of water vapor into the stratosphere..."With this data, Vömel and his colleagues gave a ‘conservative estimate’ that Hunga Tonga injected at least 50 million tonnes of water into the stratosphere. This represents an increase of 5% in the stratosphere’s total water content. The unprecedented water content of the Hunga Tonga plume has a number of implications. The first is that it could explain another observation made by scientists tracking the event: the seemingly low sulfur dioxide content. 'In the eruption column directly over the volcano, the entire stratosphere was probably saturated,’ says Vömel. ‘So you have a lot of ice particles in there and they can certainly wash out a lot of SO2. So there’s another very, very interesting research topic: what happened – was there not a lot of SO2 coming out of the volcano, or was there a lot and it was all washed out?’ Source: One year on from massive eruption in South Pacific, the atmosphere is still feeling the effects | News | Chemistry World Here is a loop I put together showing the increasing water vapor anomalies in the stratosphere from Dec 2021 to Jun 2023 following the Hunga Tonga eruption. Source: NOAA CSL: Chemistry & Climate Processes: SWOOSH. 1mb to 100mb on the left covers the upper to lower stratosphere, with latitude at the bottom (southern hemisphere to the left / northern hemisphere to the right) Looking at the individual image for June 2023, I've added a black box for the Northern Hemisphere polar cap (60 deg North to the North Pole). Here we can see enhanced water vapor anomalies extending thru much of the stratosphere, though weaker anomalies in the lower stratosphere. From what I've read, it's probably going to take a few <or> some years for this anomalous water vapor to subside. And from Dr. Jennifer Francis (Twitter): "Water vapor is a greenhouse gas, and like CO2, when it’s in the troposphere it warms the surface, but in the stratosphere, it radiates infrared energy to space."...i.e., this would favor cooling in the stratosphere in the coming winter. Does this mean a cold and strong stratospheric polar vortex and coupled +AO pattern? Possibly. However, here are a couple of things that may counter-balance... As mentioned before, -NAO is more common during Strong El Ninos than any other ENSO phase... Also, it's highly likely that we will be entrenched in a -QBO this winter... Here in this set of images we can see that the negative phase of the QBO is descending (i.e., moving from the upper and mid-stratosphere to the lower stratosphere), and has reached close to 40mb; and should continue its decent down thru the stratosphere over the next few months. And during El Ninos, Sudden Stratospheric Warmings (SSW) have occurred in 8/10 cases (80%) when the QBO was negative in winter (40mb on Jan 1). And in the 8 cases where an SSW occurred during Nino and -QBO, the combined AO/NAO index was negative 6/8 cases (75%). In contrast, when the QBO was positive in winter during El Ninos, SSWs have occurred in only 6/13 cases (46%). And in the 6 cases where an SSW occurred during El Nino and +QBO, the combined AO/NAO index was negative in only 2/6 cases (33%).

Latest update to El Nino SST Base chart (Best Match Years) with July data now in...

Yeah, I just don't see super with this one. It's got a heckuva long way to go to reach that level, and the zonal wind, SST anomaly layout, and subsurface behavior just isn't where it needs to be. Not buying the aggressive models, including the Euro. But hey, I've been wrong plenty of times before And when I say super nino, I mean at least 2 tri-monthlies with +2.0 or above (I like using the highest 3 tri-monthlies averaging out to +2.0 or higher)

Thanks man, no worries. I do not. Just the Twitter account

TAO subsurface loop in 10 day increments for Jul 13 > Jul 23 > Aug 2. Some slight weakening shown with the intensity of the pool of warm anomalies in the E Pac

Thanks. Keep in mind that the year shown on those charts is the winter ending / spring of the 2nd year. So, 1926 on the chart is for 1925-1926 (you were correct with 1957-1958 as 1958 is displayed on the chart).

In scanning thru some VP images, it seems like the VP that sets up in the Sep-Nov timeframe tends to throw out some clues in terms of how things will go in the winter. The El Nino years when the Sep-Nov -VP is either heavy in the E Pacific or extends from the E Pacific into S America, the resulting winter pattern has more of an east-based look with Aleutian Low pressure farther east and northern conus and S Canada ridging. See 91-92 and 94-95 (same ideas for 15-16, but image not shown) The El Nino years when the Sep-Nov -VP is weaker in the E Pacific and positive in S America, the resulting winter pattern has more of a west-based look with Aleutian Low pressure farther west and ridging into AK and W Canada. See 02-03 and 09-10 (same ideas for 14-15, but image not shown) Note that the VP pattern among the 4 years in the winter isn't as different as it is in the fall (2 camps seen in the fall)

Sharing some El Nino SST Base Charts that I've put together / updated. The charts are based on the E Pattern vs C Pattern from this paper from Takahashi et al. - ENSO regimes: Reinterpreting the canonical and Modoki El Nino Data for the charts comes from this link: Monthly E and C Indices First chart contains Super and Strong El Ninos since 1950: 2nd chart is for Super and Strong El Ninos prior to 1950: 3rd chart contains my view on the best matches to the current year solely with respect to El Nino SST strength and base: For reference, this chart contains all Moderate El Ninos since 1950: Lastly, here are the 2 most extreme values on opposite ends of the spectrum from the charts of Super / Strong / Moderate El Ninos:

The black box here is what the models have been missing out at range over the last few months. A push to +2.0 in Nino 3.4 would make some sense if the westerly anoms are persistent like this. Maybe things move in that direction as we work into Fall, but I'd be hesitant to count on this strong of a flip.

I’d say the sfc pressure pattern would imply neutral or negative PNA for Jan, +PNA for Feb & Mar

Yall posted the wrong tweet about the new CANSIPS

It’s kind of fun though to just beat it like a borrowed mule for its errors, but I see your point

Latest Euro MJO (*shakes head*)

This paper has been referenced in here, but these excerpts are from... The very strong coastal El Niño in 1925 in the far-eastern Pacific | SpringerLink "In contrast to the extreme 1982–1983 and 1997–1998 events, this very strong “coastal El Niño” in early 1925 was characterized by warm conditions in the FEP (Far East Pacific), but cool conditions elsewhere in the central Pacific. Hydrographic and tide-gauge data indicate that downwelling equatorial Kelvin waves had little role in its initiation. Instead, ship data indicate an abrupt onset of strong northerly winds across the equator and the strengthening/weakening of the intertropical convergence zones (ITCZ) south/north of the equator." "In the context of ENSO diversity, there have been several studies that have classified EN events according to their spatial pattern. But if we focus on those EN events that have very strong impacts on coastal Peru and Ecuador with very high SST and coastal rainfall, we can identify two major types: – Very strong warm ENSO events, e.g. 1982–83 and 1997–98, that are associated with the zonal dynamics in the equatorial Pacific and a nonlinear Bjerknes feedback that enhances their growth (Takahashi and Dewitte 2016), which are potentially predictable several months in advance – Very strong “coastal” El Nino, e.g. 1891 and 1925, with cold to neutral conditions in the rest of the equatorial Pacific (griteater comment - as they are developing) and associated with meridional dynamics in the FEP (Far East Pacific) involving the abrupt enhancement of the ITCZ and warming south of the equator and strong northerly winds. Based on our current knowledge, this type of event is not as predictable as the warm ENSO events."

Yeah that plunge you show there in 1.2 on the CFS is kind of what I would have expected in absence of westerly wind anomalies, but the eastern warmth has really anchored in there thus far and there are different opinions on what happens going forward. It feels like the first half of a wide open ballgame in terms of eventual outcome. We may think we know how this is going to play out, but we probably don't