psuhoffman

I’ve pointed out another flaw in his opinion above in the past. DT has previously stated a Nina shifting towards neutral during the winter as a good thing and used it to justify a forecast for a snowier winter. But when I ran the numbers there is absolutely no evidence to support this. Actually, a week Nina transitioning to enso neutral produces our absolute worst snowfall results of every enso grouping. That said, the logic he has provided behind why the enso becoming more neutral SHOULD be good is sound. The problem is it hasn’t happened. There must be some lag effect. I’ve theorized that it’s bad because you tend to still get a lack of STJ following a Nina into neutral, but Nina’s can actually be colder and if you lose that you end up with a still dry but warmer pattern. We need an actual Nino with the associated amplified STJ for it to help us.

The PDO. We’ve been stuck in the most hostile PDO regime ever for like 6 years. We’ve set record low monthly values numerous times. Overall it’s been oscillating between moderately low and record low for the whole time. Until that changes and we break out of this current PDO cycle our snowfall luck won’t change much. We will continue to have god awful years with some meh kinda ok when we get lucky years but our baseline bar is going to be very low with this kind of PDO base state. We aren’t just in a -PDO. The longer term PDO cycles can last 15-30 years but within that are shorter term mini cycles and we are in an extreme -PDO cycle within the longer PDO. These are particularly hostile to snow. Yea we’ve had some previous similar cycles and those were also bad for snow. This cycle is similar WRT snowfall and what we would expect if you adjust snowfall downward for the 15-20% of snow climo we’ve lost. So this period is similar to say the extreme -pdo of the 70s and 50s but the snowfall results are about 20% worse because the whole snow climo has deteriorated about 20% regardless of the pdo. What’s troubling is this current extreme PDO is now extending past what is typical. These super negative periods don’t usually last beyond 5 or 6 years. So the were due index is through the roof. But I’ve also seen some speculation that the -PDO is being or at least enhanced by factors linked to longer term climate changes. So I guess the big question…is there another cyclical thing being added on top of the cycle we’re talking about. We should see snowfall improve once the PDO improves. But is the PDO taking on more of a negative base state in general?

This shit has to end eventually. But it feels like we’ve been saying that for a long time now.

We do not want anything that's happening right now! Snark aside, it's not a super strong correlation but in general yes. Same for snowfall, its a super small sample but winters following an October snowfall in our area tend to end badly. You misunderstand, a cold October means a warm winter. A warm October also means a warm winter.

That’s one of the reasons I’m less sure of a total dreg outcome right now than I was heading into our last cold neutral/weak Nina/ horrific PDO winters, but keep in mind 2014 was the most extreme outcome of all similar analogs. Even if we got another 2014 “type” winter it would be extremely unlikely to result in that much snow. That was an anomaly. Also, we’re not arriving at the warm pool through the same larger scale mechanism this time as @Bob Chill pointed out and that matters. SSTs can be just as much an effect as a cause.

He is giving me too much credit. It’s because people take one part of what someone says (if it confirms what they fear or want) and run with it. I did state in the fall leading into both those years that we had a very high chance at a total dead ratter winter. But it was based solely on the base state of the PDO and enso heading in and probabilities. I didn’t actually call TOD on those winters for sure until around Xmas.

I had a really bad feeling going into both 2019-20 and 2022-23 but things don’t look as hopeless right now. The JFM ONI was actually enso neutral those years and strongly -pdo enso neutral winters have been the WORST subset for us lately. Ninos have been slightly better mostly because they’ve been colder. Enso neutral have been warmer but still dry, at least when what little cold was around. That said we need the PDO to improve somewhat. It can be negative but not -3 to -4 that’s nuts. If winter ends up enso neutral AND the pdo is below -2 we provably get another 2020, 2023 dead ratter. But those two things aren’t written in stone…YET.

There are outliers to every subset but Nina’s in general are colder and drier than other enso states lately. That produces less variance across our region due to meso scale climate factors (elevation, slight changes in latitude). So in general that equates to better for places further SE in our region and worse for places NW wrt “normal”

Problem is some of the same large scale forcing that causes cold now can cause an opposite reaction mid winter. That’s why snowfall in October has no correlation with a snowy winter.

Phillys mean is a little higher than Baltimore. Baltimore is also in its least snowy 7 year period ever. Both are probably within a really small margin of each other wrt suckiest snow city in America recently.

I think it’s a combination of a result of a general pattern and bad luck making it worse. We have been in a Nina like pattern a lot and it’s more common in that type of pattern to occasionally get west to east snow events that don’t phase and instead are suppressed by the northern stream. On top of that the storms that were phased all tended to end up too far north for Baltimore to make up for the southern misses. March 2017, March 2018, March 2019, 5 storms in 2021, Jan and March 2022…all those features big snowstorms that the big snow missed just NW of Baltimore. The combo has created a gap zone around Baltimore that’s probably the greatest snowfall minimum WRT mean on the US over the last 10 years.

This applies to winter also

True. But keep in mind the heights in my plot are being skewed lower by some of the older years being measured against today’s means. The same pattern as say a 1958 or 1960 wouldn’t produce nearly as negative an anomaly today (by 1960s standards) and a might more positive anomaly over the high latitudes as well. Of course we could argue whether the same pattern would even produce similar snow now given the mean heights have increased significantly.

Well you remembered…

@Stormchaserchuck1 it’s not too surprising the mean anomaly you posted didn’t lead to snow most of the time. This look is decent but not really our snowy look this is the snowy season composite for BWI Note the negative in the TN valley. That’s the sweet spot. The pacific and high lat look is close but with the anomalies centered to our north it’s a cold dry look. We really want a negative anomaly centered to our SW on a winter mean to have a good chance of a snowy winter. Almost every decently big snowstorm has that. And it takes us multiple wasted good opportunities to score a hit most of the time. And we can’t get a snowy winter without hitting a couple times. So…it’s really hard to get a snowy winter without a negative on the seasonal means there. No mot impossible. It’s happened a few times. But betting on something that’s only happened a few times in 75 years isn’t a good bet. 90% of our snowy winters have a negative centered to our southwest for the season.

I believe it

I’m not an expert but it looks typical poleward EPO ridge Nina pattern imo. There are two typical canonical Nina long wave patterns and neither is “snowy” but the more poleward pacific ridge pattern is preferable and does shift whatever cold there is into the east more. Problem is both them to be dryer and lack the gulf storms we need to have a snowy winter. But a good example of the difference is for Baltimore a poleward ridge Nina has a median snowfall of about 14” and a flat ridge Nina median is 7”. One is bad and the other is awful so we take the bad option. I excluded 1996 from these numbers because it skews everything given the small sample size and extreme results Some extra observations: I keep hearing don’t worry about the warm everywhere look but over the last 10 years we’ve had a lot of warm everywhere results so…. Also yes the LW flow looks decent but recently a decent LW pattern absent a good STJ gets us simply bad snow results vs the god awful snowless results of some winters recently. So purely based on this I’d say it’s not indicating a total non winter like 2020 and 2023 but most definitely not hinting this is the year we break out of our funk either. It implies likely a typical Nina with likely snowfall in the 7-16” range in the 95 corridor.

A certain someone in Baltimore keeps weenying any post that’s pessimistic about snowfall. Yet Baltimore has had 9 straight below normal and below 20” seasons and has averaged 9.7” of snow in the last 9 years. Btw the previous longest streak of below 20” winters in Baltimore was 7. But ya, it’s just cyclical and everything is fine. we are due for a big year and I’m fairly sure sometime soon we will get both a big storm and season, but we would need to get like 5 straight 30”+ seasons to even get back close to what used to be normal for the post 2016 period.

The PDO has a crossover effect on this. Unless we get a 1996 type fluke (very unlikely in the current PDO) a snowy winter is off the table. It’s going to be hostile. But how hostile matters. One of the biggest factors determining between a god awful or just meh winter will be the PDO. If it’s closer to -1 for the winter like last year we have a shot. If it’s hanging out around -2 to -3 we’re in trouble. But it didn’t really start to improve until around thanksgiving last year so we won’t know for a while. But it’s not just the models. Red is crushing blue in areal coverage at our latitude overall lately. And no it doesn’t mean we can’t get a snowy winter. But it does make them less likely.

So much red

I’ll be watching the PDO. Its spike to only mildly hostile territory last fall foreshadowed the colder winter. The dryness and lack of big coastals was a typical cold enso issue here that was common even in snowier eras. If the PDO stays in record territory though I think a non winter is possible if not likely.

We will know more definitely in a few years because we’ve had a few recorded snow droughts similar (if adjusted slightly snowier to account for warming). But if this carries on for more than another 1-2 years without us getting a truly snowy 30”+ winter it becomes completely unprecedented and it’s time to consider a more extreme paradigm shift has happened. I still think it’s a combo of the continued steady degradation of our snowfall combined with a cyclical minimum due to an extremely hostile PDO period. We also got unlucky that the 2 winters heading into the hostile PDO were low snowfall years which made the following PDO indices period feel worse and longer. I do think our snowfall is clearly decreasing as well regardless of the recent cycles but I doubt we’ve suddenly shifted to where Baltimore averages 10” snow. However, if we go 3 more years without a real snowy winter I will be ready to entertain that possibility

No but one of my 4 “snowy” winters during their 14 years was probably westherbell’s second warmest “least snowy” winter forecast. 2020-21. I was just south of the normal line for snow and temps which implied below normal and it was one of my snowiest winters of the last 20 years. But to be fair that’s super picky so to be fair I included it as one of their “near normal” predictions. They are bad enough without having to exaggerate. Their one truly warm low snow winter forecast did end up being warm and not snowy. But that’s been 80% of the winters so that’s not really a win. If they had predicted warm and low snow every year (as opposed to the opposite) they’re have a great track record.