Stormchaserchuck1

I've just noticed -PNA/+EPO has a higher tendency to break it consistently, and it's usually by a lot. We've actually been doing this "busting through model forecasts" a lot over the last several years after the low yearly min temp happens on Jan 27, after that in February and March we have been going higher quite often.

When the Pacific is in -PNA/+EPO, we blow past forecasts. When +PNA/-EPO, not so much (although this pattern has been more rare in the last 8 years). NAO is in a 3-sigma block right now and it's 70 degrees... that has gone in an opposite correlation since about 2007 or 2013.. Pacific is just as unfavorable for cold, if not moreso, when the NAO is negative a lot lately.. Pacific trumps.

It wasn't the same pattern as the last few Winters because the Southeast got several snowstorms. They were shut out the last few years. You act like because New York City had the same amount of snowfall as the last few Winter's that the pattern wasn't different, but it wasn't the same, at least through December and January. It was just drier. That drier pattern started last Summer when the cap wasn't breaking for anything, despite hot temperatures and high humidity in the Northeast. This "drought" pattern really only started in 2024.

Scandinavia loading pattern at the very end of 12z GEFS, March 24th. That is aligned with Stratosphere warming for possibly -NAO last few days of the month into early April.

The time it should connect with -NAO is last week of March, into early April. I'm not sure that's in the range of modeling yet.

+EPO/+WPO/-PNA really hit hard there. I think the Pacific has more effect.. we have started to cool down -NAO's/-AO's in the last 2 Winters though.. although we have this 70s day coming up with a 3 sigma -NAO block around March 10-11. I think the majority of the time, the NAO state is correct as a cold/warm signal.. those correlation maps I posted input all data, so it has 1,000 data points going back to 1948, everything included.

Yeah, but the NAO is a North Atlantic pressure difference index. Between the Azores and ~Iceland. So a lot of these "west-based -NAO blocks" over the Davis Strait and Baffin Island really have nothing to do with the North Atlantic ocean. But I said earlier, sometimes when these blocks are too far north, because we are south of 45N, there can be unfavorable troughs that form underneath of them at even a higher latitude than ours.. that is what happened when the -5 AO storm cut inland.. The -300dm at 45-50N in the N. Atlantic Ocean favored that inland track, and that was the closer and more anomalous (volatility/latitude) pattern to us. I agree that I have no idea what the CPC is seeing in their index states some of the time... this Winter was not #1 +PNA non-El Nino in 75 years lol. We would have been colder in the east.

Yeah, and if you go back, Feb-March 2018-2024 had a most +H5 on record by almost 200% #2 in the historical dataset for a 7-year consecutive period covering 2 months, over the N. Pacific ocean -PNA region.. That is a warm pattern for the east. So many of the indices have been unfavorable for some time now. We also had 5/6 +WPO Winter's before this one, and the 1 was Neutral.. so 6 in a row of neutral or positive... switch those things around and it's not nearly as bleak a picture as these more recent climate stats are making it out to be.

I'm just saying, higher frequency of -NAO's has kept it more moderate.. no anomalously unknown SE ridge here

-EPO still works here. Dec '22 and March '23 the only real exceptions. +PNA still works here. Those patterns have though also been more rare since 1998, and especially 2016. So the 3 favorable for cold are hitting less often, these are either + or -. Actually I think this January was one of the rare -NAO/-EPO/+PNA Hopefully the start of them hitting again.. although I disagree that Jan 15-Feb 10 was +PNA. High pressure prevailed in the N. Pacific then. So since the NAO has only been negative 8 Winter months since Dec 2011, the 3 have probably lined up never.

I mean, yeah the globe is warming, it gets warmer every year. But the specific phenomena are easily explained by global patterns. In this case, indices have not always been favorable for cold everywhere. We have done "moderate" for cold in the midst of a warming globe lol. +NAO has highest correlation on the East coast.. that is probably why it's hitting the Midwest harder, that and a more favorable Pacific pattern for there (-EPO, -PNA). If we start getting some sustained -NAO's, I bet the east coast will be cold. -32F in Nebraska and 8" of snow in Florida.. not some bad Winter maxes this year.

Because the NAO has been mostly positive.

Maybe in February and March something is happening. The last 2 January's have been pretty cold when -AO/-NAO. We've only had 6 -NAO months in the 2020s so far.. 3 of them higher than -0.30.. 4 of them higher than -0.52.

March 2023 was a rare pattern, December 2022 was too. I think for March '23 we had -EPO too. Anomalies happen, but most of the time it's true that the +NAO is flexing the SE ridge.

I do too. I don't know if you even have the right email. Can someone help?

Nino 1+2 is currently +1.6c. A warm Nino 1+2 in March actually has a pretty good correlation with warm Atlantic SSTs during peak season (Aug-Sept-Oct)

It's why the SE ridge is linking up though. Over Greenland and the Davis Strait you have a -AO, but further south over the N. Atlantic the NAO is usually positive.. we saw this, this year when the AO was -5. That +NAO is actually closer to us than the AO is, and it's making it easier for a mid latitude ridge to happen over the East Coast. 9 Winter months of negative NAO since Dec 2011, 14 years, is not a lot. And 16/16 months of >+1.11 NAO. It's not because of global warming that we are seeing more SE ridge, it's the Atlantic SLP pattern, not always aligned with the AO. Summer is interesting because it has not been significantly hotter in the East. Until last year the differences in max highs were not that great. Good to see the NAO correlating there.

Before this year, we had 44/52 Winter NAO months (DJFM) positive since Dec 2011. 16/16 of NAO >1.11 in a month during that time were all positive! No NAO less than -1.11 since Dec 2011, including this year. Could be the reason.. I don't see why warmer Atlantic SSTs in general would favor +NAO. I have seen studies where there's a big sea-level height difference in the Atlantic 2011-2022. With Winter 24-25, it's now 46/55 months +NAO. That's your answer.

Yeah, but those maps are based on 1991-2020 averages. So if you're using only + analogs and going back way before, it's going to skew your mean colder. I'm just talking about the pattern, and what it typically produces, although I think you may be saying the warming trend is relevant too. I don't think it's a big part to do with Atlantic SSTs, although this AMO correlation is interesting: -AMO ibb.co/bR3LvKW+AMO ibb.co/KctZCPm-AMO ibb.co/wKX4YCC+AMO ibb.co/sFSwm0j Edit: I see you're talking about AO/PNA. The orientation of the PNA makes a big difference. No Alaska trough and a Pacific ridge extending north is a colder pattern. A flatter 45N ridge is a warmer pattern. 1960s didn't have lot of +EPO's, but yeah the SE ridge does seem stronger now.

That's fair.. here are the 20 most recent analogs I came up with (max for composite) The reason there is so strong of a Pacific -PNA on the hand picked Atlantic analogs, is they are both part of a AAM pattern - neg Atlantic/pos Pacific is -AAM, and visa-versa. The Pacific part makes there be a cold signal in the Midwest, but you can see a very slight SE ridge happening, and when our average temps are low 40s, that near neutral anomaly is a good part of a storm track up to SE Canada (during the -5 AO).

Nice -NAO block here correlating with SE ridge I should get into the 70s on this day. The Pacific has gained significant as a direct factor recently vs the AO.. this actually started back in 13-14 and 14-15 when the strong +NAO of those Winters actually extended a trough down the east coast.. still the last coldest Winter to this day (13-14) was a +3.48 DJFM NAO (/4), positive every month.

Glad to see my Summer N. Atlantic SST indicator work out for the NAO, despite it being a cold Winter. I was afraid that would happen, saying that -epo/+pna has been correlating with +NAO, and there were 9 troughs over Greenland earlier in the year for the first time 2020-2023... sign of maybe a colder time.. but I couldn't pull the trigger in my Winter forecast, just going with the boring indicators and default +NAO temp correlation.

Well none of your analogs had more positive than a near 0 Winter NAO. The average NAO for your analogs was -0.5/month. I'm just saying a -AO block near the north pole was so far north, that a strong low pressure formed under it in the N. Atlantic, and "downstream" from this 45-50N trough, was a SE ridge, sending that mysterious -5 AO storm north.. that atlantic trough though was the closer pattern to us than the AO, and the relative magnitude was actually slightly higher (average volatility/latitude difference). I understand that it is hooking up with SE ridge more often now, some of that is because of a stuck -PNA/+EPO pattern, which has been correlating with the NAO at 0.40 since 2019, and 0.30 since 2013. Overall, it's hard to argue against total warming, but the reason for specific events is more pattern based.

Yeah, but the NAO difference is big. Look at Europe. DJF came in +2.29 total for NAO, so +0.76/month.

This +NOI is a La Nina pattern Part of a progressive flow.. here is what ENSO really is (a lot of misconception being around its main influence is the PNA)