Stormchaserchuck1

Very cool. Nice pictures. Your trip to the UP of Michigan was probably my favorite. They had one heck of a LES season.

I'll have to do a write up in the next few days, now that US climate division data has updated.. I actually did good on methodology, but it didn't translate at the surface to -PNA (SE ridge), so that was my flaw. Natural Gas though jumped 60% this Winter, so if you went with the CPC's cooler forecast, you could have made money.

I think we had 3 record breaking storms last year, for how strong they got east of 40W at that time of the year. It's no surprise SSTs have cooled off this year, after a La Nina.

Here is how Dec - March 24-25 compares with 13-14 It was relatively the 2nd coldest Dec - Feb in the eastern 1/2 of the CONUS since 13-14 though. I do get that "cool analog" correlation

90-day SOI is near +9.. here's how that rolls forward to following years ENSO Pretty good North Pacific High (+NOI) correlation

Weak

Well I got barely any rain out of this nor'easter. It was suppose to last for 4 days, and it was only 2 days. It seems like the overall dry pattern is still in effect, where the best chance at good rains comes from a SE ridge and low pressure coming in from the west and thunderstorms.

I don't disagree that that SE ridge has been stronger than usual.. it was really bad 3 Winter's ago, but the last 2 years when Greenland blocking happened, it has actually happened with a cooler pattern. The one big anomaly being this February, but there was a really strong low pressure in the Atlantic at 50N (the -AO was too far north, over the North Pole). However, I do think if the CPC NAO goes the direction it has in the Spring/Summer/Fall in the coming Winter's than we will see more benchmark storms and snow. A general warming is definitely occurring, but I'm not ready to connect it to SE ridge, since SE ridge is in play with a number of factors, where something like a Southwest, US High pressure is more independent.. I think a globe warming should be warming the west coast the most.

Another really high correlation is state of the AO and benchmark storms. I will give this one to bluewave.. that lately this one has not been hitting, although you can see it's kind of mutable, where NAO is right on the coast.

10mb warming still going strong on April 10th... making it 32 straight days! (1st day was March 10th)

One of the biggest anomalies is how the Southeast, US (north of Florida) has stayed shielded from landfalling tropical systems, since year 2000, when the Atlantic activity has been well above average during that time. Until last year, that was because of a trough pattern over the East in the late Summer.. then last year a heat ridge developed for the first time in a long time and stayed there for 2 months.. finally in September the pattern broke down, and it got cooler in the east, when tropical activity started heating up, peaking in October. It will be interesting to see if we see some semblance of last Summer this year, and if it may time better with Atlantic tropical activity.

I guess you have it stuck in your head, the 12/20 times it didn't happen vs the 500/784 that I'm pointing out it did. My point is that the NAO is strongly correlated with benchmark low pressure systems. And that we've had 14 straight +NAO Winters in a row. That's all.

Your issue is with the CPC and how they measure the NAO. I've been impressed though over the last few Winters - their methodology has correlated with X conditions over the east coast more than what happens over Greenland and the Davis Strait. Many times in the last few years we had a SE ridge with Greenland block, but their index says it's positive during that time. You might say there is something wrong with that, but the methodology has nothing to do with the east coast. In other words, Greenland block is correlating -0.4, but their methodology has been at -0.6 to -0.7, for something independent. Like I said, it's a specific measure of sea-level pressure over the North Atlantic ocean, which is not always completely connected to Polar blocking.

It's not about using climate indices from another climate era. That's a wrong/bad point. They are calculated by specific methods, and that methodology is not different in a cooler or warmer planet. It's actually a very strong correlation, benchmark low pressures and the state of the NAO and PNA. I will argue this one. Here's the PNA: The PNA is very negative in the 2018-2025 example you posted. Such an extreme state really tightens up on these correlation numbers. (The map above is default positive, but includes both states of the index). The NAO is not a Greenland High pressure.. Greenland isn't part of the Atlantic Ocean. It's a calculated sea level pressure between ~The Azores, and ~Iceland. That's a SLP anomaly. One region has positive readings vs the 2nd region negative readings and visa-versa. It's not a function of climate change, because that's 50/50. The lower part (~Azores) is where the mid-latitude and Hadley Cells meet, and more often than not extends west to have similar conditions as the east coast, US. The example I'm posted represent a total of 784 months. So +NAO has benchmark tracks 200/784, and -NAO has benchmark tracks 584/784. Then the PNA is also correlated (not related to the 1st set of numbers). The correlations of these Pacific and Atlantic representative indices are actually really high for something so specific as as coastal pressure systems. It's large scale phenomena that has not been favorable lately. The -NAO was more favorable for benchmark tracks in the early 2000s. -PNA and +NAO together have benchmark tracks something like 35/384. +PNA and -NAO together has benchmark tracks 349/384. There is nothing post-2012 that has happened differently from the 1949-2012 period. It's calculated the same, and is having the same effects. The PNA has been negative, and the NAO has been positive. A small time period (with somewhat +pna conditions your map shows) does not negate the total dataset. Remember too the correlation composites include both sides of the index, so +NAO and -NAO are included in the same correlation map. Over the last 10 Winters or whatever, the +NAO correlation with lack of benchmark low pressure has been really strong. This matches the historical data.

The 90-day SOI is now about as high as it ever got during the La Nina last year 12 Apr 2025 1013.34 1008.55 17.30 10.65 8.13 11 Apr 2025 1013.52 1007.55 25.81 10.49 7.70 It led the lack of strong Nina last year.. while the subsurface and surface were showing signs of a jump negative, the SOI never budged and the event ended up being barely greater than Neutral. Also, since 2020, we've had 82% of the months with +SOI over the 5-year period.. Nina long term state is being somewhat reflected in the SOI It's been positive the last 48/50 days..

Cold water in the subsurface is trying to get squeezed out.. but this negative pool in the central-subsurface should at the very least keep us away from El Nino in the next few months.

We actually have a little bit of an Atlantic tripole right now. I did research on this last year, when the SSTA configuration was close to opposite: Since 1995, Positive analogs: 2016, 2011, 2010, 2007, 2002, 1998 Since 1995, Negative analogs: 2018, 2015, 2014, 2012, 2009, 1999 Positive analogs: 15.5 NS/yr, 7.7 Hurr/yr, 3.3 MH/yr Negative analogs: 12.3 NS/yr, 6.5 Hurr/yr, 2.5 MH/yr. (12 analogs encompasses 41% of total timeframe (95-23))

Central Atlantic, Gulf of Mexico, and Caribbean has decent +SSTA's. There is still some cold water off of Africa

Historic snowfall only happened a short time ago. I remember in the early 2000s, when every low would hug the coast, that it must be a gravity of -NAO. What we are in is definitely a "pattern". SE ridge amplified from +NAO/-PNA. The NAO decadal is about as positive as it will ever be, although we once in a while get Greenland blocks (more -AO). It's the mid-latitudes where the Hadley Cell and Mid Latitude Cell in the Atlantic interact that is our problem.. there is always High pressure there in recent Winters. That area usually extends to the east coast. Combined, -NAO and +PNA have benchmark SLP correlation at -0.85! That is 9/10 vs average. I think we've had that combo 3 Winter months since 2016 (when the normal frequency should be 1/4).

They aren't outdated, the same things are carrying. It's 65 years of data to 2012, but since 2012 we have had +NAO every Winter, and the correlation of benchmark SLP is still +0.6. +0.6=+0.6. The same thing has happened as the historical data. It ends at 2012, then you are saying it's a mystery why there are no benchmark storms post-2018 and I'm pointing out that the NAO has been very positive in that time. 1 or 2 or 3 examples isn't going to change anything. I had my best Winter month in January this year since 2016, but yeah it was a little dry. -NAO has also started going colder the last 2 Winter's. The data's too overwhelming to dismiss it.

Final NAO this Winter was +0.65/month.. 3/4 months positive, and the lowest being January -0.52. @40/70 Benchmark My Atlantic SST method hit within the estimated 0.54 standard deviation this Winter. (+0.52 forecast vs +0.65 final) https://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/norm.nao.monthly.b5001.current.ascii.table

The correlation composite takes into account over 1,000 data points. A 0.6 correlation on SLP on the benchmark means it happens 2/10 times, x100. You can get good snows in +NAO Winter's, especially because -NAO's tend to be dry.. so +nao when phased with a good Pacific can give you more moisture during a colder pattern. But I think if we had -NAO this Winter, there would have been benchmark storms. Something to look for going forward.. it's also an index so can be traced to certain climate phenomena, so not really all that connected to climate change. +PNA also has a huge correlation with benchmark low pressure, and -PNA not.. as you are pointing out. +NAO/-PNA isn't necessarily climate change.

Everyone fits everything that's happening with everything that's happening. I don't see the correlation between CC and +NAO, because the NAO is sea-level pressure difference between two areas. One negative, one positive. 50/50. It's not an index that is always measuring warming vs cooling. The problem is that the south part of the NAO has run warm over the last 14 Winter's. I think it's been split 50% negative and 50% positive events in the Summer during that time.

You aren't going to see benchmark storm tracks with the NAO so positive in the Wintertime.. It's been positive 14 Winter's in a row (and negative in other seasons). It's no mystery. This is actually a really high correlation.

More cool April, per the after effects of March 10 - Apr 10 Stratosphere warming The cold season correlation is about -0.2 in the East +time