Stormchaserchuck1

The SOI never went strong during the 23-24 Strong Nino. Here's the monthly data: 2023 4 -1.20 2023 5 -15.26 2023 6 -3.19 2023 7 -3.32 2023 8 -10.85 2023 9 -13.87 2023 10 -6.63 2023 11 -8.38 2023 12 -3.78 2024 1 3.96 2024 2 -15.55 2024 3 -0.35 From 2020-early 2023 we had 34-straight months of +SOI.... so this decade there has been a severe +SOI tendency compared to other ENSO variables. Oct 2025 is likely going to make the 15th straight month of +SOI, although none of those months have gone over +10.. it's been consistently weak Nina/negative-Neutral for 2 years now... and La Nina-like SOI for 5+ years, with a little blip to slightly negative during the 23-24 Nino.

I'm always kind of surprised at you saying the WPO was very positive last Winter, are you referring to an actual index number? The 500mb looks neutral to slightly negative WPO.. Japan had a cold Winter

I think the only difference between this year and last year is 2nd year La Nina's have a little more Winter -PNA than the first year, and 2nd year -PDO's, when they don't correlate the first year, correlate the 2nd year at +1.24x. But La Nina is struggling right now.. it's starting to look like at the surface it won't make the 5 consecutive ONI month criteria. Subsurface is also weak right now.. barely -1 to -2 subsurface anomalies, and the SOI is weakly hanging around +5. Border line weak-Nina/negative-Neutral. Also last Summer we had a strong 4-corners High pressure.. that rolled forward to a pretty cold composite for the eastern 2/3 of the US for December and January (+PNA).. the SW, US High pressure wasn't as strong this Summer. However, 9 of the last 14 months have been +PNA [CPC], despite negative-ENSO. The Aleutian ridge hasn't yet gone back to levels it was before the 23-24 Strong Nino fwiw. It would surprise me if we saw a strong/persistent Aleutian ridge this cold season. It seems like it would have to kind of come out of nowhere.

They still play the Steelers 2x and Bengals 2x. If the defense gets better like last year (last week was a good performance, only giving up 17pts to the Rams with 3 offensive turnovers), we have a chance at the division. It's about as attainable as it gets for being 1-5. Vegas still has pretty high super bowl odds for the ravens (1/20).

Long range models continue to show a -AO to start November

March has a high -PNA/-NAO and +PNA/+NAO correlation.. wedges the SE ridge to near neutral. This is definitely a pattern though.. the lack of benchmark storms is because 80% of our Winter months have been -PNA since 2018 But there is a strong, strong correlation with US Temps and the SOI pre-1948. I suggest you check it out. I was only calling what I saw as SE ridge/NW trough -PNA, without looking at the North Pacific H5 (no data before 1948). It is possible the total composite of the 1948-2020 dataset is not big enough, if that is possible. Late 1800s - 1950, the SOI indicating a La Nina/El Nino was strongly correlated to Winter US Temperatures.

PNA is a big deal in January The biggest thing with PNA is its high sea-level pressure correlation on the coast, about +0.5. That's our benchmark storm or not. But yeah, in some other Winter months especially December and March the PNA correlation nears 0. EPO is by far the greatest pattern for temps in the NE 1/2 of the US. I was looking at SOI matches to SE ridge/NW trough before 1948, since that's when the global climate maps started, and it's a strong SE ridge/NW trough correlation with SOI pre-1948.

I don't know if I trust the validity of that graph to be honest.. it looks like the greatest bunch is weighted toward +NAO/+AO and DC is 39N latitude.. counter-intuitive. +NAO's are wetter. There is more precip, but I think a place so sensitive to the freezing point would be heavily weighted toward -NAO/-AO periods.. I know during my lifetime it hasn't snowed a lot when the NAO and AO have been positive. Pacific overwhelms the Atlantic though. Anomaly-wise W->E is actually greater than N->S. I've found the New Foundland warm/cold pool has a strong correlation with the Winter NAO in the preceding May-Sept, but not so much the day of. Maybe it has something to do with subsurface currents.

Going back to the 1800s, the SOI has a strong correlation with Winter PNA state https://data.longpaddock.qld.gov.au/SeasonalClimateOutlook/SouthernOscillationIndex/SOIDataFiles/MonthlySOIPhase1887-1989Base.txt

On the surface the La Nina has really struggled to get going lately.. we probably won't hit 5 straight months <-0.5 in the ONI. Of course, because of global warming there would now be 60% el nino's and 40% la nina's, so because the focus is on the Hadley/Mid-latitude Cell meeting point, the RONI is good at better gauging this Hadley Cell expansion/contraction.. The RONI is solidly Weak Nina. I found that for Winter PNA pattern the following is true: Weak Nina: +50dm -PNA Moderate Nina: +80dm -PNA Strong Nina: +100dm -PNA Weak Nino: +40dm +PNA Moderate Nino: +70dm +PNA Strong Nino: +120dm +PNA So there is difference in the PNA correlation depending on how strong the event gets.. and it looks like this will comfortably not go above Weak. Here's the SOI.. despite 14 straight +SOI months, the SOI hasn't had a +10 monthly reading since early 2023 Subsurface is also not impressive.. barely holding Weak Nina ground More chance for variation in the Winter N. Pacific pattern with Weaker negative ENSO

+correlation. Dec and March are about 60% probability of the same NAO state as November, January is 50% and February is 52%.

It seems like whenever we get a -NAO episode in the Fall, someone goes on with strong correlations about how the Winter is going to be cold. The fact is, the data since 1948 shows that October is the only month of the year that has an opposite correlation between the monthly and Winter (DJFM) NAO state. Now, over 200 years, not 76, that might not be true.. It makes sense that the same pattern would run forward, but as it stands now an Oct -NAO is not a big sign for a cold Winter.. I'd look more to see if the Pacific is in -EPO/+PNA in October.

There was actually a big +PDO in the Fall of 1995. A +PDO/east-based Nina is actually a very cold Winter composite in the Northeast. I've also found that the ENSO subsurface is more important than surface SSTs (Kelvin/Rossby waves, and their impact on the N. Hemisphere pattern)... ENSO subsurface was Neutral in 95-96, not La Nina, so there was more space for a Winter +PNA to develop and persist.

Uh oh. raindance's post got the most likes in this thread. Be on alert for the opposite to happen.

Looks like Halloween is going to be cool/cold this year. In the 2000s, we've had some very warm Halloweens

Have to love this +PNA/-NAO.. it's a colder pattern if it were later in the year. And a corresponding trough in the Mid Atlantic a few days later.. the ensemble mean is nothing like the OP

They use the last month as the year. So Dec-Jan 2001 would be 00-01. US Climate division data uses the year for the first month, and those monthly climate maps use the last month.

This pattern for the end of October doesn't look bad, with +PNA and west-based -NAO developing.

This pattern for the end of October doesn't look bad, with +PNA and west-based -NAO developing. This year has been nothing like 2020-2023 where there was strong -PNA all the time. -PNA periods have been in short periods, and sometimes transition to neutral, or in this case a potential +pna

Our most recent good Winters Classic 3-wave cold N. Hemispheric pattern (vs 1 warm-AO) setting up in the Fall.

360hr 12z EPS.. this is not what you want to see in the Pacific/Alaska, but these correlations are like 54-55% going into the Winter, If anything it I think it just cancels out the wall-to-wall blowout good Winters like 02-03, but doesn't do so much for the Winters in between.

That's really about as close of a match as you ever are going to get, the only place in the world that was really different was south of South America.. I think after the Solar Flares in May 2024, the Earth went into a pattern. A lot of this is described as +AO, but that pattern continues now going into the cold season I think. The 4-corners High pressure wasn't as strong this Summer as last, and that did show tendency to become +PNA last Winter, so maybe not so much +PNA this Winter, but 24-25 is a good analog going forward.

I personally think a cold October is better for a cold/wet Winter, just by common sense. I kept a weather journal starting in Sept 2002, and I was surprised looking back at it that it snowed 4 times in October 2002. The data though, going back to 1948, Oct -EPO/+PNA is good for snow at about a +0.2 correlation, and +EPO/-PNA is bad for snow at a -0.2 correlation. The Atlantic has an opposite correlation though (-NAO Oct usually begets +NAO Winter, and +NAO Oct usually begets -NAO Winter), so that's where the confusion comes from.. but I bet over 200 years, not 76 years, there would be no inverse NAO correlation.

^Pretty strong on us getting to Weak El Nino by April-May next year. If you count last year as Weak Nina, this is going to be 5/6 consecutive La Nina years, and 7/10 consecutive La Nina years! Data going back to 1948 shows that such a strong streak is likely the reverse in the next 2-3 years.

10mb events are usually uniform.. you'll usually get a smooth + or - mean. That's a pretty good one though, I know in the N. Hemisphere the monthly mean never really exceeds +1800m (and that one's +1100) I will have to go through and manually make 10mb analogs.. I was incorrect in saying it's AAO. AAO is actually a 500mb anomaly, not 10mb. There isn't a known index that calculates S. Hemisphere monthly 10mb anomaly... so the roll forwards indicating "random" is not really a correct response to anomalous 10mb September.