psuhoffman

@Terpeast I wanted to illustrate my point regarding our exchange a few days ago.... yes the Aleutian ridge is the main problem...but my point is... how do we mitigate an Aleutian ridge to get snow in years where that is a permanent feature? We had a jet extension into the EPO domain with an extremely -AO/NAO twice this winter and both times it did absolutely nothing to mitigate the SER effect of the pacific patter. That used to be how we got snow when the pacific isn't in a favorable configuration so my question is...when we get a season where there is crap pacific like this year...how do we get snow? We can't afford to just chalk every season that features an Aleutian ridge off as a total and complete fail loss. An Aleutian ridge is a predominant permanent feature during a -PDO, and a -PDO cycle is a reality about half the time. People are acting like this -PDO we are in now means we just can't get snow...but my point is we've had -PDO cycles before and it did manage to snow. Yes slightly less than during +PDO cycles...but it was nothing like this last 7 years. The worst part is the previous -PDO cycles that had 7 year periods that were close to this bad there was a convergence of a -PDO and an extreme +AO. That is NOT the case now...yea we've had a hostile pacific but the high latitudes have actually been pretty favorable much of the time and yet its done us no good at all. Let me illustrate my point... this is the composite of 12 above normal snowfall seasons from 1949 to 1980. These made up actually the vast majority of our snowy seasons during that period. Look at the pacific! DC got above normal snow in all 12 of those seasons with the mean h5 above! So why are we acting like an Aleutian ridge means we have a SER from hell and no chance of snow? And here is my point...and why we can't afford to just accept that... if you remove those 12 seasons from that period, our snowfall mean for that whole period, 30 years, a whole climo period...becomes as dreadful as its been the last 7 years. We would only have had 6 above normal snowfall seasons in the whole 32 years if you remove all those seasons where it snowed a lot despite a bad pacific base state. I am not disagreeing with you that the reason for the SER is predominantly what is going on in the Pacific...but in the past there were ways to compensate and still give us snow even in that pattern. But lately nothing seems to work, when there is an Aleutian ridge we torch no matter what else is going on.

@Ji you’re right about what the biggest issue was but were talking about 17 years so it’s not a fluke. It’s hard to quantify this but it seems to me that we used to get a larger % of our snow from northern stream systems. Remember clippers lol.

Yes we got plenty of snow during that era but remember while we did "ok" during that period...our average actually was close to historical norms during the 2000-2016 period... the problem is we needed to do VERY GOOD because that was actually what should have been an extremely snowy period if you look at the predominant phases of the PDO and NAO during that time period. Look at the mean h5 northern hemisphere pattern. We had an extended period where the Pacific, high latitudes, and Atlantic patterns all were in a favorable phase at the same time! Yet all we did was average what was historically a normal amount of snow over that period. And places not far to our north did experience one of their snowiest periods, on par with the 1960s. Yet we did not. Unless you accept that there is a new normal and that Dulles averaging 23" (which they did from 2000-2016) is now extremely snowy for our area. Yet when I moved to northern VA in 1994 23" was what IAD's normal snowfall was. Since 2016 Dulles has averaged 10.9" of snow. Yes we are in a down cycle now, the high latitudes are still OK overall but the pacific has entered a long term hostile cycle. And guess what...we are also doing worse than past previous comparable periods where the pacific was equally hostile. My point is, in my opinion, we also were doing worse than we should have from 2000 to 2016 only it wasn't getting much attention because we were doing fine wrt snowfall...but the fact is we should have been doing way better than fine...that was the up period and all we got our of it was what should have been normal mid range snowfall. Now we are in a legit bad period and its really dreadfully awful even by bad cycle standards. So yes you are right many of those storms did produce a decent amount of snow. But we needed MORE than decent during that period if that was the "snowy" cycle to maintain what we used to consider "normal" climo here. We needed that storm in January 2011 to be 20" plus like it was to our north not 6-10" of slop. We needed some of those northern stream system to dig a little more. I can't quantify exactly which storms were caused by what...just saying that we had a 17 year period with an extremely favorable pattern in every way, and places to our north set record snowfall on par or even surpassing the 1960's period...and all we got out of it was what we considered "normal" snowfall. That seems like a problem to me.

Yes I meant Nina. I’m not strongly inclined to say the SER is a cause but I’m also not sure it’s wholly an enso effect. I’ve noticed a disconnect between the high latitude and mid latitude pattern lately. The mid latitude impacts could still be pac driven but it’s not just a typical Nina thing is all I’m saying.

Except a Nino does not = constant huge SER. Actually if you look at the mean of all ninos there is only a very minor SER signature. This isn’t as simple as just “Nino” imo.

You bring up a legit hypothesis and I can’t say for sure. But a counter point…it was a bit of both. There were some storms during that period where temps did limit snowfall. Several storms in 2001 that hit NYC did give DC appreciable precip but we’re too warm. Dec 2003, Feb 2006, Feb 2007, March 2007, Jan 2008, Jan 2011, Dec 2012, March 2013, all featured storms that would have been more significant in DC if it was a few degrees colder and that’s why NYC got way more snow. But yes there were a lot of NS systems that just tracked to our north in that period. But is that actually uncommon or did we used to simply hit on more NS systems back when the mean NS was further south decades ago? The “miller b” thing is overblown Imo. It’s not some weird thing. Or some travesty. We don’t get “jumped” it’s just that they track to our north and the snow west of us is upslope on the westerly flow hitting the 4500 ft mountains. A west flow here is downslope. But the actual synoptic precip from a pure NS wave simply goes north of us because the storm tracks too far north for our latitude 90% of the time. Pure NS waves were never the best here but when I was doing that case study if all warning events at BWI I noticed what seemed a lot more of them back in the 50s, 60s and 70s than recently. If we went from a 30% hit rate to a 15% that makes a huge difference. I don’t know though. That would be a headache to quantify.

@Heisy something I have been keeping an eye on, and it likely doesn't matter for snow now since its so late...but it would most definitely matter if this was still winter... over the last 2 weeks, and it happens again in a few days which is what kills that hail mary threat you were peeking at...even when the pac jet extends and gets the ridge into the EPO domain...even rolling it into western Canada at times...it can't do much to the SER. The energy just cuts off under it and dives into the SW anyways. At times the SER gets beat down as a system crashes over top if it, but it immediately reloads. That would NEVER work for us because its not the wave that beats down the SER that is a threat for us...it would be a wave AFTER. If nothing can squash it for more than a day or two there is no legit threat. Look at the evolution the next 7 days...even with the pac ridge rolling into Canada and a beautiful west NAO block...the SER can't be suppressed much. I was curious so I looked at the pattern analogs. And sure enough almost all of them have way less SER than the guidance shows now. Why would that be.... simple...because everything else about the pattern says there SHOULDNT BE A SER...so when the model looks for analogs the only way to get as strong SER would be to have things different in every other way and so it would be a way worse match overall than simply picking the analogs where everything else is similar but with less SER. I noted this a couple other times recently...where the analogs were also saying basically "why is there such a strong SER". I wish this would be more discussion...instead of simply chalking the SER up to the pac pattern...discuss why is the SER so much stronger than history says it should be at times...including the pac pattern into that equation.

Oh god this again. I wasted an hour of my life years ago proving that the results from one season had no statistically significant impact on the chances of snow the next winter. And it resulted in a bunch of “but that doesn’t feel right” replies. I gave up on that. Math is hard.

I remember playing this game back in 2020. You were sure it HAD to get better. You cited statistics like this. Then you got like 7” the next year, 10” last year and nothing this year. So…3 years later I ask. Has it REALLY gotten better?

It can't be worse

Funny…except this region struggles to get snow even in good years. It’s only the extremely rare 1-2 a decade years like 96/03/10/14 that snow comes easy. The rest, even ones you probably remember as great in your area, were a struggle with long frustrating periods and lots of fails mixed with a few victories. That was our climo to begin with, without accounting for any degradation.

Those means were already reduced. When I moved to northern VA in the 90s the IAD "avg" was 23". It wasn't long ago that BWI was close to 22". My baseline will always be set as those numbers. I know I am getting older but I am not a fossil or anything... it's not like we are talking about 50 or 100 years ago. But now we talk about "will BWI get BACK to 19" or will IAD get BACK to 20" but for me those numbers are already lower than what my baseline was. This has been going on for a while...so no its highly unlikely we get back to the climo numbers of the previous 30 year period...just like the most recent period didn't get back to the numbers of the one before and so on and so on...this trend has been happening for quite a while now. The real questions is...has it accelerated recently or is this just a down period following the 2016 super nino. I tend to lean down period...and that the snowfall will bounce back some. I'll feel a lot better when we see the actual evidence of that and its not just hope.

It’s going to be sunny and 60-65 Tuesday. 70s later this week. Seriously, life is harsh and unforgiving, filled with countless assholes you will have to deal with, death, pain, tragedy, unfairness, and misery. No one can afford to be so weak they can’t simply adult up and deal with a chilly day.

Given the pattern it won’t surprise me if at some point in the next 2-3 weeks we do get a storm that teases us with some snow in the area. It’s highly unlikely we get anything significant of course.

There is definitely a sweet spot where we can get the positive affects of a Nino without a significant permanent hemispheric climate impact. But now we’re talking about a really narrow range between too weak to appreciably alter the pacific (2019) and too strong. How narrow are our goalposts getting? This is speculative but there are tipping points. 66 and 83 maybe did contribute some permanent warming but the colder base state then was able to recover more. Warming is accelerating even absent a Nino. That might have an exponential impact. Like giving a little shove uphill v downhill. One of those has way more impact! I’ve seen this same speculation and even some preliminary studies that do suggest that the lessening gradient is somewhat responsible for much of this but also that an impact of the changed pac base state is increasing the frequency of Nina’s. It seems still too early to know how much though. Unfortunately for us I’ve seen so much speculation around numerous individual factors, some directly related to climate change some indirectly, and I have no idea how many are really impacting and to what degree, but the problem is it seems every single one of them disproportionately affects our location negatively wrt snow. Indo pac warm pool, reduced sulfur emissions, expanded pac Hadley cell, warmer gulf and Atlantic, altered trade wind patterns) it doesn’t even matter if ALL are having the speculated impacts because every single one has a negative impact on our snow and we didn’t exactly have a lot of room to spare with our snow climo before! Even if only 1-2 are actually having much impact it’s going to hurt us a lot.

Awesome write up. It seems we’re on the same page on much of this, including having some of the same questions and musings going forward. I think unfortunately when the majority of factors indicate a hostile longwave base state we just have to assume it’s going to be awful and not look for the kinds of intervening factors that could salvage a “decent” outcome in the past. Warm is just too warm anymore for the result to be anything other than bad. I share your musing (made a post to maestro speculating this) regarding a Nino. I do think it’s likely to increase our snowfall chances in the moment. But man what if it also ushers in a new even warmer base state like 1998 and 2016 did. Be careful what you what for.

The thing I see most is people playing in the ambiguity that exists here. Two things can be true. This year had a a horrible longwave pattern. That is attributable to factors “mostly” unrelated to any long term trend. But it’s also true that it’s very likely the reason things have been worse than past analogs to similarly hostile pattern periods is that it’s warmer now. Too many are playing one side of those two facts or the other as if they have to be mutually exclusive when they are not.

They did fine if you knew how to use them. Model output isn’t meant to be a plug and play forecast. They are possible permutations. You have to apply some intuition based on knowledge to the equations. Some of us were never fooled by the chaos induced colder long range looks. The ensembles never broke down the central pac ridge or pac NW trough that was driving the SER. The fact they kept losing the SER was just an error. But if you corrected for that error they did a good job.

You might need an intervention

Some will talk for days about a natural disaster but analyzing snow data is too much to bear. Lol. Im a very analytical person. Not everyone is. And that’s ok. I can’t produce beautiful works of art or hit a 3. Everyone has gifts. But I don’t shit all over art that I don’t understand or don’t like. Yet non analytical types will shit all over data analysis even when it’s clear they don’t really comprehend what it’s showing. That part annoys me. I don’t mind discussing weather even if it’s not what I want. But I don’t only analyze bad snow trends. Only a few years ago I posted a whole thread, literally like 20 posts, analyzing every warning event we’ve ever had and what trends and patterns lead to snow. No one minded that analysts. Oddly no one argued with that data. I enjoy analyzing weather. I would prefer that analysis was of snow. But since it’s now snowing the only analysis I can do is “why isn’t it snowing”.

I agree but it is the official recording station for DC. I can’t change that.

Y_S would you like to buy a vowel?

Some individual years have been more snowy. Mostly when we get a HECS. Those also seem inflated lately. But if you look at longer decadal periods no. Go back to my post this morning.

The most recent “snowy” cycles were not as snowy and the 1960s and other snowy periods prior to that.