psuhoffman

I didn’t say it wasn’t worth watching. But the current h5 mean favors an OTS solution imo. Trough/Ridge alignment out west is too far east. And the trough is amplifying at our longitude when we want to see that happen around TN. Remember we need a much earlier and further west development here than NYC. We’ve missed just about every single coastal storm that’s crushed NYC the last 6 years because they’ve tracked to east or developed too late. For DC to get a big snow we need a low that’s already mature tucked in just off VA beach tracking NNE. This (at least on that mean) looks similar to all the recent misses. It’s close enough to watch. But it’s not a great look right there for us.

That indicates fish storm.

@Maestrobjwa no you can’t have that list and no you don’t want it.

I see nothing overly interesting. There are some long shot scenarios I suppose but I feel like they are being elevated in interest simply because it’s all we got. I could see one work out, but if I had to wager I’d bet DC gets to Jan 20 with no measurable snow.

Extreme northeast Carroll, near me, has done significantly better than further south in the area the last 5 years or so 2020

Depends what the expectations are whether it’s worth it. The worst season I’ve had here in 18 years was 14”. Most seasons at least break 20. Median is about 35” and mean is 40. My snow climo is closer to coastal southern New England or NW NJ. That’s enough for some.

Yesterday I noted across guidance there were several mid latitude waves in the next 2 weeks with no appreciable frozen precip associated with them anywhere. Maybe some rain/snow mix on the NW periphery. Another thing logged into the journal. I’ve noted this before a lot lately. It seems we need arctic air to get frozen precip south of 40* lately. Problem is that was always rare. Getting snow at 32* in a blah airmass from a good track was always the more common way we snowed.

My daughters name is Nora Lynn

The pattern continues to look more Nino than Nina. But unfortunately not all ninos are good. Remember we like modoki ninos. Some east based ones can be ok. But the more east centered the Nino the more chance the north pacific low ends up too Far East and floods N America with mild air. Unfortunately that’s the kind of Nino pattern we’re in. The top analogs right now do include 4 ninos. But they are the 4 worst ninos lol. 1983, 1992, 1995 and 1998. 83 was saved by one big storm but was a torch otherwise. The rest were simply torches straight through.

We’ve reached the bargaining stage

Before some jump down my throat I will clearly state again that this is definitely a bad unlucky cyclical period (at least we better pray it is). But I really do believe that. Better times are ahead. The issue is how much better. I’ve seen several troubling things over the last 5 years. Like when a sub 1000mb low took a perfect track in late January without it even being a particularly hostile airmass and produced nothing but 38 degree rain. Or when several high latitude blocks linked with mid latitude ridging. DC getting single digit snow in a season I had 50”. That’s unprecedented. Usually in the past if my area does that well DC is closer to 20”. Struggling to even get below freezing at night for very long stretches. I’ve noted that the southern mid Atlantic has decoupled with locations they used to have more correlation wrt snowfall. The bad years have been awful but years that should have been good weren’t that good. Frankly the last really “snowy” cycle was the early 2000s but it failed to produce the same level of above normal anomalies in DC as further north or higher in elevation except for 2003 and 2010. Each time I say hmm and log them away. The log is getting longer then I am comfortable with. But it will snow again, very likely this season at least some. And eventually we will get another 2003/2010/2014 type season. Don’t take my frustration to mean I don’t think it can snow anymore. But I do think years in between the unicorn snowy seasons are becoming increasingly a struggle.

So we’re posting hour 600 control runs now. Ya….that’s how it’s going.

You don’t get it…or you don’t want to “get it”?

I don’t think they put much effort into those maps once outside the DC metro area and immediate surrounding area. This has been more common than actually getting a “typical” blocking response the last few years. It seems blocking the first half of the season has lost its mid latitude impact recently.

Unfortunately what he did was kinda smart. I think many wanted to be optimistic (myself included) and sided with a forecast of a closer to median snowfall winter. But the analogs and stats said there was pretty close to a 45% chance of a god awful single digits season, 45% of a closer to median bad but not horrible season and like 10% or less of a truly snowy season. So why not do what he did and stick out there. Even if we get closer to the better outcome we’re very likely to end below avg so he won’t bust too bad. And if this goes the way of some of the awful analogs he gets to crow and look like a genius. Smart play.

Our disaster scenario would be if we had a Nino ish pattern earlier (not good because it’s hard to overcome the pac puke you get) and then the SSTs couple mid winter and the typical Nina dreg Feb pattern takes over with a central pac ridge of death pumping a SE ridge to Quebec.

I have no idea. Sometimes the SSTs fail to produce the typical effect on the atmosphere. FailIng to couple is the catch phrase lately I think. Obviously it’s more common when the SST anomalies are less pronounced but other then that it’s difficult to predict.

@Jimade a good point yesterday. The reason the stats are so awful regarding Nina’s that start bad like this is that there are two archetypes of Nina and the colder type typically produced some snow by now. The warmer type tends to be a torch straight through. But this year hasn’t been the warmer type so far we just didn’t get snow. So maybe this is an anomaly that won’t fit the past comps. Also, we’ve been in a Nino type north pac pattern a lot. Quite often the best analogs have been ninos. And ninos do tend to flip mid winter and end snowier. The data is the data but perhaps there are reasons to have hope this year doesn’t fit the typical patterns.

Adding to my last thought, I’d also like to see us snow from a domestic airmass with no epo help. Below is the composite of our 6 biggest snowstorms of the last 50 years. One problem we’ve had repeatedly recently is we only get cold enough to sustain snow with epo help. Some have started to excuse our fails with “of course it failed look at the epo, or no cross polar flow” but that ignores the fact that historically 90% of our snow did not occur in an arctic airmass with cross polar flow. That’s actually not a good longwave pattern to get storms to amplify into the box we want. Fact is a lot of our big snows happened in a look many would say is a “hostile” pacific (look above) because that’s actually the best longwave pattern to get a system to dig and amplify along the east coast. That’s why often a big snow was followed by a big warmup. Cold isn’t sustainable in that look. Conversely a lot of our really long truly cold periods didn’t include a big snowstorm or if they did it came at the end. A very negative epo has 2 problems. If it’s west based anything that amplified will cut. If it’s more east it can overwhelm the CONUS and just squash everything to the south. The TLDR version: we’ve been too quick to just dismiss things with “pac puke” when a lot of our past snow came in a pac puke pattern. It’s just pac puke didn’t used to be sooooo warm that it was automatically a shut the blinds pattern.

@CAPE you mentioned our next modoki Nino will be a good test case indicator. This setup coming up could be also. A western Hudson Bay high used to be a classic way to create a bootleg setup to get a snow absent a good setup with the NAO/AO/EPO/PNA. They weren’t typically huge storms. Temps were always an issue and they are mostly progressive but there were a lot of 4-8” type snows from this kind of setup in the “study” I did of all 4”+ events. A western Husdon high in an otherwise crap longwave pattern was actually the second most likely look to snow up behind the classic +pna -NAO for a long time, 1940 through 90s. Then they kinda went extinct. Over the last 5 years after I did the study I’ve noticed several of these setups and I’ve noted they did often produce a storm that took a good track, but each time it was simply too warm and DC got a 35-40* rainstorm. That is anecdotal though. I didn’t scour through every rainstorm of the 40s to 90s to confirm how common a perfect track rain in this setup was. But what’s not anecdotal is we used to get a snow from this kind of look fairly regularly until recently when suddenly we haven’t. I would feel a lot better if one of these Hudson high setups in an otherwise crap longwave pattern worked out to some degree. Just to prove we can in fact still get snow this way.

It was fairly cold leading into 2016, we had a very minor cold snow a couple days before. But your point is true. DC often has had very warm temps just a couple days either side a significant snow. Upper 50s and 60s for sure. 70s also but they usually were reserved for late Feb and March storms but perhaps that will become more common in January too.

past results do not always predict future outcomes... but lets be honest its not how we want the season to start.

@WesternFringe I replied in the "snowfall futility" thread. Lets move our discussion there so as to not further clutter up this thread. Others have been discussing this general topic there also so I agree with terp that this belongs there.

Moving this here so as not to clutter up the main thread any further. Counter points... 1) Using grades might not be the best example since my district enforces a minimum grade of 50 so as not to skew students grades with 0s lol. But lets not get into that please. Thought I would start with some levity. 2) The claim that outliers don't skew the mean is predicated on the mean of the whole dataset. But we are comparing the change in mean over time. To do that you have to chunk the mean into smaller portions. Climo uses a 30 year mean. If we remove just 4 years out of those 30 the current mean for DCA is only 9". Those 4 years are most definitely skewing the mean of the current 30 year period...and by doing that is also skewing the slope of the trendline. 3) This depends what you are trying to tease out of the data. The mean tells you over a period of time how much total snowfall is likely to fall proportional to each year. But it does not tell you how much snow is most likely to fall in any given year. The truth is over the last 30 years that 9" number (what you get if you remove the 4 super outliers) is way closer to what you should expect going into any given year than the 14" mean number with which was only reached 26% of the time. In any given season there was a 74% chance you were getting less snow than that. If you are trying to calculate how much snow you should expect in any given season, the mean is not the best tool. 4) Maybe we are trying to get at different things. What I am getting at are in any given season the odds of getting a specific amount of snow are dropping. The odds of getting 8", 10", 12", 15" and so on...going into any season are going down. And going down a LOT. The odds of getting a 4", 6", 8" storm are all dropping. That is what I am focused on. That going into any specific season the chances of it being crap are going up. The mean does not capture that fact as well. 5) You keep focusing on what the change is per year. Over time very small changes add up to be significant. 6) In a vacuum its correct to say 99% is attributed to random chance because the math you are using doesn't know any corroborating evidence. But we do know some additional facts. The fact that it is getting warmer for instance. If you apply logic to the fact that at the same time the slope of snowfall is decreasing correlates to an increase in temperature the amount we should attribute to "random chance" goes down. 7) Lastly I am not making this about human caused climate change. Maybe this is cyclical. Maybe its not human caused. Maybe at some unknown point in the future the trend reverses. Those are all true. But that is not what I am getting at. I am not living at some random unknown point in the future. I don't care what the chances of snow will be is 2323 I care what the chances of snow are right now in 2022. For the sake of this argument I don't care if the warming is man made or natural it is still impacting my snowfall right now just the same. And since we don't know when or if the trend will reverse I don't even care about that. What my analysis was showing is that our chances of snow in any given season right now are significantly lower than they were during recent recorded history. It's not even a predictive thing. I am not making a statement about what snow probabilities will be 50 years from now. I have no idea. I am making a statement on what they are RIGHT NOW. Your analysis isn't wrong. Everything you say is 100% true. But you are focusing on different metrics that me and teasing different things out of the data. You seem to be more focused on predictive measures of snowfall over any long period of time with statistical certainty. That is a very different concept than trying to calculate what the probability of a given amount of snow in one specific season is right now and how that probability has changed over the last 100 years. We are looking at very very different things.

I left El Niño’s out when I posted the stats because they more commonly start warm then flip snowy. I posted all neutral and Nina years. La Nina’s are more often front loaded so when they start bad it can get really bad. However, we’ve had a bit of a Nino ish pattern so…if this year doesn’t behave like a typical Nina it leaves the door open more. Also as Ji pointed out most of the past Ninas that were snowless were warm early. Nina’s that start very warm tend to stay warm. But it was kinda cold just no snow. There are good reasons to cling to hope. But I wouldn’t use El Niño years since they are notorious for flipping in January.