Stormchaserchuck1

NAM is north but it is the horrible NAM.

Block at 90N has only sustained though for more than a few days maybe 4-7 times since 1948 (I've gone through and looked at the data on daily - came up with 7 main index regions in the N. Hemisphere, and North Pole was not one of them). It's because of this a super strong low is now projected to form just south of Greenland. It's too bad it's not 5 degrees south, because that would have been an awesome 50/50 low. But the H5 change between projected time and day-of is not big, because the CPC calculates NAO error, and it has like a 90% chance in that graph of verifying positive. It's because of this slight displacement north of the 50/50 that we will now have a SE ridge! Unfortunate, but I'm saying there is a reason in this case for the -AO to link up with a SE ridge.. it's a little too far north. Now, 2017-2023, there were a lot of anomalous SE ridge's in that time (especially 22-23).

It's probably more about the Pacific pattern being good vs neutral/not.

I know you all like the Hrr at 48hr.. big storm

Before we get 1" of new snow! I would have actually favored more of a Weak Nina late season look, because I've correlated the ENSO subsurface with Pacific PNA pattern, and it actually came back with high forecasting predictability. But this season is different.. a good case study! A week ago, I wasn't thinking it would be as favorable as this.... I'm still real curious though to see if we can get solid cold in the 2nd half of Winter.. I do think that as the average temperature starts to increase, there is tendency of late to keep us warm.

I think for future reference, it's a good research to do where the block is. A lot of AO data overlaps with NAO, and a lot of times it's a Greenland block that is -AO.. but this time it's over the North Pole, so that's actually a little different. This is why I like to look at raw 500mb maps vs the actual index numbers, although you could probably look at AO vs NAO and get a good analog system from that.

Yeah I think it's a pretty legit shot at something good. Hopefully storm systems keep being as strong as modeled. If that Pacific pattern that is currently modeled holds, watch out... It's a good observation too that a 90N block correlates with cold at 45N, but further south at 40N there could be a tropical ridge tendency as the 3rd wave down. Today it has evolved to look like that because of south-based +NAO though.

I actually like that timeframe because there is a -EPO. It's a nice Polar connection of ridging from AO to EPO, and maybe even +PNA. If 500mb doesn't change, it should trend more wintry for the Mid Atlantic. But it's still 11 days away, but I really do especially like that -EPO modeled right now. That Day 7 storm though, is really +NAO. That low just south of Greenland gets up to -500dm. That's strong positive! It's a rare case of super -AO and super +NAO at the same time! Edit: I just saw for the Day 11 storm, models keep holding onto the south-based +NAO throughout their run. Just know that -EPO/+NAO is more ice, but +PNA/-EPO/+NAO is more snow.

See how the south-based +NAO aligns with a slight SE ridge? It's too bad the block isn't a little further south, or that N. Atlantic low would have been in the perfect 50/50 spot, and we have all this moisture/storm systems.. would have been a big one. We needed that Polar block at 80N, not 90N.

It's probably partly because the storm today is going way north.

Looks like a March storm

Huge storm. 1042mb High in SE Canada. Very interesting

I actually drove down from MD to FL this Summer, and was admiring how sensitive the climate and animals were, saying "it can snow here!". I couldn't believe places in GA never would see snow.. a stupid 12 hour drive south. Seems like every mile it's a different type of vegetation. I think it has actually snowed in the Florida keys before...

Maybe it really is about the PNA, and our chances of seeing +PNA again. The thing is.. the mid-latitude trough (+pna) has also not happened in the Atlantic, even with -NAO a lot of the time... so is there a bigger global pattern for warm mid latitudes, or can we connect to PNA cycle? This Winter is hopeful because despite a Fall PDO of -3.88, and Weak La Nina (even in the subsurface, which I've connected with the pattern), +PNA has prevailed. -PNA has actually happened none so far. I think since Nov 30, the lowest the CPC PNA index got to on the daily was -0.1, and it's back >+1.0 in the medium/long range again. But here's our cold, and real legit cold... with +PNA. I think that pattern could work.

By the way, this looks like snow to me

Something about the temperate base state isn't anomalous though.. there's something to it, driven by a factor I believe that is something specific vs global warming. Just look at a week ago, it was heavy dry/fluffy snow in Pensacola with a temp of 24F. There is something somewhere that is like a warm layer underneath.. that's what I was trying to connect to the 2nd half of Winter -PNA's, but that's not what it is.. I don't think it's AMO either, but we have seen glimpses of Winter. Last year in the Chiefs home playoff game, the windchill was -30F.

Pacific definitely has more pattern correlation in N. America, I think. Another thing is the orientation of the PNA. When it's a 40N, probably more hostile than 45-50N. 45N, it runs with waves that are more N/S, and can be broken by the time it's here. 40N ridges are pretty uniform.. it would probably be hard for us to get snow with a strong N. Pacific 40N ridge.

Maybe -EPO's are 2-4" inch events, because it's a Canadian cold pattern.. the cold air comes south from Canada, and the jet stream is essentially NW to SE, favoring clippers or storms moving W -> E, vs from the south.

Maybe it's common for a +EPO to progress into a GOA Low because they are almost the same thing? Big difference though in the downstream pattern, every degree of latitude difference there is huge! Edit: I don't know.. if you are cold a week before that's not very +epo. I just know that in the mid-latitudes over the Pacific and Atlantic, you have your strongest global anomalies for our snowstorm composite.

That's actually a pretty good -WPO surprisingly and also surprisingly because it correlates with Canada, neutral 500mb over and NE of Alaska. I'd like to see the +EPO snowstorm composite sometime if you ever see it, because a true +EPO, with the strongest anomaly in the Northern Hemisphere over Alaska... there is pretty much almost no chance of snow in that pattern.

PNA has a big precip correlation like the NAO. It's actually equal to temps. So if we are +0.5 in -PNA (75% chance of above average temps), we are also +0.5 precip (75% chance of above average precip). You can see how if other things are favorable, that could possibly align with more snow... but I would say in the 1960s we not only had some -NAO blocks, but there was a much stronger relative [underneath] mid level trough... maybe that was from -AMO -AMO ibb.co/bR3LvKW+AMO ibb.co/KctZCPm-AMO ibb.co/wKX4YCC+AMO ibb.co/sFSwm0j Thanks for your input about our discussions.. like I said before, you discuss these things and do research on it.. that's more than people can ask for. The thing I like about +PNA is it has lower pressure correlation on the coast, despite being 75/25 drier. So +PNA in the Winter can be more fun, because it's more associated with stronger low pressure and windstorms. -PNA's are just overrunning events.. I'm surprised you have 13 cases associated with +EPO. I think that's in part because of how it's calculated. A trough in the Gulf of Alaska is actually a BIG factor in East coast snowstorms.. that and a 50/50 low. 8"+ composite has like a -120dm anomaly in the Gulf of Alaska... that in some cases is called +EPO. I consider the EPO to be more a 500mb over Alaska and north of, and sometimes going NE Of Alaska into NW Canada and the Arctic circle. The CPC calculates the EPO much further south. Some blizzards may have technically had +EPO because of this, but when I think of +EPO, that pattern is shut the blinds, blowout, mid Winter 50s and 60s. I think the overlap between PNA/EPO is where the weakness in your snow data is. I see your clear cut correlation with NAO and AO in your data. Half of the NAO is calculated in the mid latitudes. Sometimes the mid latitude will be cold, and there will be none or a weak High pressure over top of it.. that's called a -NAO. We had a lot of that in the 1960s. We've had the opposite lately. NAO remember is North Atlantic sea level pressure differences between ~Iceland and ~The Azores. If there is neutral over the Azores, that's a 0 to half the NAO index. And of course, that mid-latitude trough extends to us.. so by default us having a trough is actually more of a -NAO pattern. See? If you separate out the high latitude High pressures it's probably a weaker correlation. We haven't had those mid latitude troughs lately, so the CPC has said 41/46 Winter months since 2013 have been +NAO (16/16 NAO cases monthly >1.11 in that time have all been positive!)!

Light rain has started here, not snow and sleet like models had the last few days.. started as rain.

Can you believe the Chiefs are favored? I have a rule, don't bet against Mahomes, but he didn't even make the Pro bowl this year..

I think the Eagles will win, as they have a much better team. Maybe even by 2 scores.

I think -EPO/+NAO would produce a 30" or 40" Winter, because NAO is strongly correlated to precip, and the positive phase has 3x more precip than negative phase (+0.50 correlation vs -0.50 correlation, is that 3x?)! EPO is neutral precip and the coldest pattern of all indexes.. so with the EPO having slightly more cold correlation than NAO, we would be below average temps with above average precip in that pattern! Only thing is EPO is loosely related to H5, so some of the cold precip could be ice. I also think it's just a general point - mid latitude cold, not necessarily related to upper latitude High pressure, is the snow pattern. So us losing mid latitude cold is the generality that is correlating with less snow. It doesn't always have to stack.