psuhoffman

1996 lol There were also a couple Nina's early in the 1900s that judging by the statistics definitely did not behave like what we consider a "typical" nina today. NOT saying that is what is happening here....yet. Many have pointed out the enso north pacific sst combo is very unusual so maybe a canonical nina isn't in the works. Way too early to draw any conclusions though.

It's possible I missed some of that...once the big ugly pattern set it I kinda knew it was over and so I checked out pretty much. I would glance once in a while to see if there was any hope but there were days and days that would go bye without me taking more than a quick glance. But what I did see was more bad than good even out at range.

This look With that SW-NE ridge axis across Canada centered just north of Hudson Bay is actually a really good one that has lead to many moderate snow events in our region historically. I’m not getting into the “but will it happen debate”. But I am of the mine it’s better to look good than bad. Last year proved having the long range look awful all winter isn’t a good thing. Additionally seeing the pattern look nothing like a typical Nina (and that feature is not way out in fantasy land) is a positive development. The pattern analogs are littered with nino years right now. And even Nov 1995 in there. Sometimes we get lucky and the atmosphere just does something crazy. Not saying I feel optimistic yet...but there are positive signs.

Get the center of that ridge in western Canada a bit further NW and it’s a $ pattern.

Sorry I know you knew all that. My post was meant to add for some others who might be reading. I should be more clear about that when I post though.

depends how we get that numerical average. A neutral NAO with a crap pac doesn't really do us any good. But if the average is derived from a mix of positive and negative periods...that would be just fine as the negative periods would present windows of opportunity for us. Furthermore...there are times when the NAO can be negative but from an anomaly in a position that does us very little good...(extremely east based -NAO) and there are times we can get a bootleg block near the western edge of the NAO domain and the NAO numerical value is actually neutral yet the pattern is great for us. The devil is in the details.

Winter forecast. I used analogs and pattern recognition. Factors include ENSO, QBO, PDO, AMO, AAM, Atl SST, soil moisture, and trends. December I expect the predominant pattern to take on a configuration that resembles... January as the PV reaches its Max and the jet stream settles into its dominant winter configuration I could see things evolve to Finally in February as the same old regulars (we all know who) tell us everyday how awful it is as if we don’t know I think the pattern might transition to For anyone who makes it to March expect

I dunno about the luck but we do dumb pretty good

Where’s the blue???

And which of those is favorable right now?

First winter call

I’m not sure how much the former factor will help. There is often a lag effect between enso and pattern and even a weak to moderate Nina isn’t exactly great snow climo in our area. But I am very much in agreement on the latter. The pacific SST is really in contradiction between the enso regions and PDO regions. There aren’t very many good analogs to this configuration at all. I’m still being pessimistic but that’s probably just me not wanting to set myself up for a disappointment. I could see a scenario where this year does not behave like a typical Nina.

I think you should say this in a slightly different way a few times everyday.

I was thinking 65 which was a weak Nina. Why do you cite 67? That was an enso neutral winter during an extremely -NAO regime. Add in warming since and I doubt it’s a good comp to now. Hope I’m wrong.

Thanks for the info...love your work. But keep in mind all 4 of those years you cite were pretty sucky for snow here. 67 was ok but not really compared to the period it was in. The other 3 were all below normal and frustrating as we missed almost every storm just to our northeast. Nina’s are a lot less hostile in NYC than our area.

I see the similarities. And while 2000 was one of the best snowfall Nina’s in our area I also think expecting a repeat of that 2 week stretch in January is risky. We torched with no chance at snow the entire rest of that winter. What if that short period of blocking didn’t happen. Or what if we simply didn’t get lucky and nothing came of it. I tend to think of the outcome that season as more lucky than good. A repeat could end up a disaster. Please convince me otherwise though. I could use some optimism.

@Winter Wizard what sticks out for our area is when you look at each snowfall event you find that even the ones in a +AO/NAO Nina came during a period of blocking within the +AO. 2000 was a good example. All the snow came during a 10 day period with blocking. The rest of the winter was virtually snowless.

I posted a chart of the state of the major indices before all of the Baltimore/Washington areas warning snowfalls going back to 1948. Its in the snow climo study thread. As @CAPE said we need some HL help. An east based poleward EPO ridge can compensate for a bad NAO. The AO is tricky because there is overlap from both the EPO and NAO so you get some cross contamination when you simply use that index. But taken holistically it’s evident we need some help up top somewhere. We’re simply too far south if you get a contracted polar jet and zonal pattern. We need buckling somewhere. Specific to a La Niña the NAO becomes even more important. Baltimore rarely gets any snow of significance in a Nina without NAO help. I’ve not run the numbers but it’s likely similar for most of the region. It’s makes sense..in a Nina the pacific ridge is likely to be too far west to get er done all by itself. Add in a lack of STJ and fast NS jet and it makes sense that without the NAO buckling the flow in our favor we would be SOL.

It could make sense if there was a particular detail that caused the divergence in those years...and you know how and intend to tease out and compensate for that factor...to come up with a workable forecast. But putting together a pattern composite of those years as a forecast would be bad forecasting imo.

I don't agree with what he did. But I also don't agree with some of the analog composites being throw around (not by you) that throw together an amalgemom of vastly different Nina years to give an average that is skewed or some mix of opposite patterns that is equally unlikely to occur. With the exception of 1996 which was an extreme version of type 2, there seems to be 2 very clear distinct class of nina winters. When there is a flat central pac ridge we tend to get much more southeast ridge and +AO and those years are some of the worst complete crap non winters in the mid atlantic. In nina years with a more poleward pacific ridge we tend to get more trough into the northeast and also a higher probability of some blocking and while those years are still usually dry due to a suppressed STJ we at least get some respectable cold and closer to median snowfall. The problem I see with some of the analog sets being throw around is they use way too many factors and end up taking a small sample that includes years from both of those types and the average H5 pattern you get is simply an average of two opposite patterns and unlikely to be what the dominant winter pattern really looks like. One example I saw thrown around last month was particularly egregious. They were filtering for QBO and ENSO matches. Problem is there were only 3 years in that dataset. And one was 1996. 1996 was skewing the mean of the whole set to look like a -NAO was likely when both of the other two years had a positive NAO. That analog composite was completely misleading and useless. I think some people that don't really understand how correlations and analogs work are starting to have too much fun with maps.

The MC phases are more correlated to a +AO than the IO and Dateline phases. This is speculation but I think the relationship is an effect of the central pac ridge promoted by those phases tightening the pac jet and the gradient between the Hadley cell and the PV thus speeding up the flow around it and by effect promoting a stronger more pole centered symmetrical PV.

Almost every one of those factors is opposite what we want. That’s “average”? I guess lately...

Yea it’s hard to find good global sst matches anymore. 1942/3 is intriguing as it was one of the best Nina outcomes we’ve had. I would be VERY happy if it went down that way. But it’s dangerous using analogs from such a different time period.

Excellent write up. Only problem in application of those analogs is how drastically different they were for our area. 1971 and 2000 both featured at least one period of blocking which allowed us to cash in on a respectable snowy period. 2008 did not and so was a pretty awful non winter wall to wall. I think the general pattern is known but whether we can salvage some snow here in the mid Atlantic depends on how much if any blocking help and I see no reliable tells to tip that hat. Your area can work without it but Baltimore has never had a warning (5”) event during a moderate or strong Nina without blocking. Furthermore when I did a pattern analysis of every warning event back to 1948 Baltimore never even lucked into a warning snow in a Nina like central pac ridge pattern in a non Nina year without blocking. So imo for our area as the high latitudes go so goes our snow chances and I’ve yet to identify a strong indicator other than pure persistence.

One of those was a weak Nina (2018) and the other was actually cold neutral (2017). It was looking like a Nina in fall but ended up neutral but since it was kinda a Nina ish pattern and not so great winter most just think of it as a Nina. But there are lots of examples of weak cold enso seasons including some decent periods of cold and snow absent blocking. In a weak Nina the pac ridge can fluctuate and weaken enough at times. Unfortunately that isn’t true of strong cold enso. So if we’re heading for a strong Nina, and everything indicates such, we probably will need blocking or we’re unlikely to get much luck like those years you reference. That doesn’t mean I am canceling winter. Persistence is hard to ignore but the NAO can flip on a dime. We could get blocking help this year. But if we get a positive NAO all winter like last year...it’s probably going to be very similar. lastly, when I say very similar it doesn’t mean we all get the exact same results as last year. 2 points. First let’s say DC lucks it’s way to a 2” clipper in Dec and then some fluke lucky timed wave like last January is 20 miles further south and there get a 3” wet snow event in January. And that’s it. The rest of winter is 50+ degrees. DC gets 5” which puts it more in line with its common crap winters. But it wasn’t significantly different from last year. Just slightly luckier. And I have my doubts the people that get 5” vs 1” are really going to look back when it’s over and feel good about it! Lastly I am probably even more pessimistic because I didn’t get 1” I actually lucked my way to about 16” up here. And I got 7.5” over 2 days in January. And I knew that was likely “it” and so I enjoyed the crap out of it! But when I pull the analogs to strong Nina with a +NAO more are actually WORSE for me than last year!!! 2 of them are literally the worst 2 winters here in over 125 years of records and another is the 4th worst!!! Only 1 in the set is better. So actually statistically if we see a strong Nina with a + NAO I am likely to get less snow than I did last winter. As you said it’s and IMBY thing.