psuhoffman

The euro at 0z had the only way we get a big snow. Exact perfect timing between an amplified wave and a high. Look how they literally collide at the same time. That’s the only way to get a big snow from this setup. The 0z op euro showed its within the realm of possibilities but the full scope of guidance suggests it’s a low probability solution.

That's the wave I think has a decent chance to at least bring something to our area.

and you have no snow on January 26...what do you want?

Well yes won by 14-1 so here it is... but I will do everyone a solid. I am going to start with the positives and if you would rather stop reading there and sleep well tonight you can. I will warn you before I get into the negatives. Positives: For the first time since December there will be cold air around, that at least makes a good result possible. Everything else we've been tracking for a month just had no chance, it was DOA with nothing but +10 thermals all around. Even the last perfect track storm could barely manage some snow in the coldest highest NW fringes of this sub. And that was with EVERYTHING going perfectly right lol. This time if we get a perfect track it will snow. This is also how we have managed to get most of our snow over the last 7 years or so, with these progressive boundary waves, so there is precedence for this. I think we have 2 opportunities. The first is the wave as the cold is pressing. This has limited upside potential but I think it is actually the more likely to drop some snow somewhere in our region. The second threat would be with whatever energy gets left behind forming a wave that attacks the cold after the TPV slides by. This has higher upside but a lower probability. Together these 2 waves are likely our best chance at snow so far this winter. The negatives: Unfortunately the first wave is likely to be relatively weak, very progressive, and might have temperature issues. But the reason I actually think that is the bigger threat is the second wave has an even bigger problem. We are kind of stuck between a rock and a hard place with this setup. The reason the snow probabilities for 3" are only around 10-20" across our area despite what looks like fairly favorable precip/temp plots are the details. A good looking plot like that means nothing if it got there by 1/2 the members with a warm wet solution and 1/2 with a cold dry one. And that is what we have here. I know it's tempting to see some runs south and some runs cutting and thing...that puts us in a good place in between, but unfortunately the reason the vast majority of runs are one or the other with very few in between is because the in between solution is the least likely. Once again there seems to be 2 big problems, very little interaction between the streams and no mechanism for the cold to resist if a wave starts to amplify, other then for the short period where the TPV is directly overhead compressing the flow. The problem with that setup is...if the TPV is directly overhead compressing it will suppress the wave. But even in that scenario look at those runs...its not like there is some big area of snow to our south on most runs...there is actually almost no frozen precip on the northern edge of the storm on the southern solution members. Again, no interaction between the cold and moisture. IF the wave comes by before the TPV has exited and the flow relaxes it will simply slide south of us. If it waits until the flow relaxes and phases it will cut. There is a very very narrow timing window for the in between solution. There are barely any members on the EPS/GEFS/GEPS with that in between solution for a reason. The analogs to the day 8 ensembles are mostly bad results. There are a few dates we got a mixed event in our area from a wave that had significant snow to our north. There are no big hits in the analog set. This isn't a good look for a big snowstorm here. What I would want to see to feel more optimistic in future runs would be for there to be a healthy snowfall depiction on the north side of these waves at or south of our latitude, regardless of the exact track. I don't care if it misses south...but if it does miss south I want to see some big snow dump in NC not some wave that is mostly rain everywhere. What good does it do us if that trends north...because the thermals will trend north with it and we just get rain. I want to see some evidence that the STJ wave and the cold will have more interaction without phasing, because we won't survive a phase in this setup. With out that there is very little path to a win here.

just off the top of my head PD2 was north for a few runs around day 5. Then it went south then back north but not as far. I remember about a week out worrying about rain at Penn State. Late Feb 2007 there was a wave supposed to go through PA and ended up a DC area bullseye with 3-6”. March 2014 there were 2 storms that ended up south from where they were 4-5 days out The Feb 2015 4-8” to ice storm trended south A wave in Feb 2018 trended south from 4 days out Dec 2018 ugh even ended up missing most of us south after looking great 5 days out Even the storm last weekend trended southeast after looking like a cutter into a perfect track coastal it just didn’t matter, gave me 1.7” so celebration lol But your point is valid in that it’s more common the other way. I’d guess 75/25 But it can happen. I think the reason we don’t think about those as much is more often a south trend ends up a hit here so we don’t care about the bust. That’s simple geography. There is only so far south any mid lat amplified wave of significant can end up. We’re way closer to the southern envelope of possible tracks than the north. So a north trend is way more likely to screw us than a south one.

So...I've seen the overnight and morning guidance, I've looked at the points being made on both sides...and I've seen the data and indicators that I think are actually important here... who want's my honest assessment of the current threat window and who would rather just not know. I'll put it to a vote.... Hearts=YES Weenies=No ETA: voting closes at 1pm

@Terpeast just from an eyeball glance at an ACE yearly chart...the 60's were a little high overall but not enough to think that was the main cause here...they were no higher than the 50's and that decade stunk and they were lower than the last 20 years which have stunk by comparison. Obviously an eyeball glance isn't good enough, but I don't see anything eye opening there. What is eye opening is just looking at -PNA periods, we did manage to snow quite frequently with a -PNA during the last PDO cycle but its actually been trending the wrong way in that regards for quite a while...since the 1980s our snowfall during -PNA periods has been going down pretty drastically, its just been covered up because we have been in a +PNA dominant cycle so it wasn't that big of a deal.

I will try to look into ACE but my eyes are done after compiling all the NAO/PNA data for the last post. But I am very interested in the ACE theory and there could be something there. As for the enso...everyone is kinda assuming, or maybe just praying, that a nino will solve all this...but I am less sure because a lot of the nino's during the last -PDO still featured a predominant -PNA, but they also, as is true of most nino's still, featured more blocking which helped to mitigate the PNA. However, if lately blocking has not been doing that...what good would the nino do us? If we got the added pacific warmth but without suppressing the SER or PNA it might just make things worse. If that is even possible.

@Terpeast @WxUSAF @CAPE So I went through and tried to identify blocking periods that coincided with a hostile pacific and see what the trend is in snowfall at BWI. It wasn't easy, at first I tried to use pure monthly data but realized quickly, since I know what a lot of these snowy periods h5 looked like from that snowfall study I did years ago, that the monthly indexes were missing things. A 10 day -NAO can be hidden by a positive the other 20 days for instance. So I started breaking down months by 15 day chunks using the h5 composites to identify months that had a -NAO -PNA at some point then looked at snowfall. I know that gets messy and subjective but I couldn't find a simple better way. But the trends are pretty obvious. This is the scatter plot of BWI snowfall during -NAO/PNA months since 1950 with a moving average imposed. We have had some low periods before, its not unprecedented to get a short period where a -NAO is muted and doesn't result in prolific snowfall...but its suspicious we are in the longest such streak since 1950 right now. We are in the longest streak without a -NAO/PNA producing 7", 10" or 12" at BWI. Historically we averaged about 8" during a -NAO/PNA month from 1950 to 2000 but are only averaging about 3.5" during such periods since. Our failure to take advantage of a -NAO during a -PNA is a huge problem lately. The biggest problem is what has happened to December...there the trend is even more alarming This is the scatter plot with moving average for Dec -NAO/PNA periods since 1950 at BWI For whatever reason in the last 15 years or so the -NAO has lost its impact in December. We have gone from averaging about 7" from a Dec -NAO/PNA to less than 2" and the last 2 were 0. I know some say "December just isn't a snowy month" but that wasn't always true, and a -NAO december used to be snowy and now it isn't and that does account for a big part of this difference. When we only get 4 months that can realistically deliver snow we can't afford to just toss one and expect it not to take a huge bit out of our snow climo. But December does not account for the whole difference, the trend is down in other months also, just not as extreme as December...but January and February are not produce as significant snow results during a -NAO/PNA lately either. Luckily a -NAO+PNA has still be producing epic results however...if we are entering a -PDO where a -PNA will dominate the next 30-40 years this trend is ominous because during the last -PDO our snowfall during +NAO periods was atrocious. If the -NAO fails to deliver the way it did from 1945-1980 anymore...well the possible results would be catastrophic for our snowfall prospects.

no but that is an interesting theory and worth researching. I might try to get to that at some point.

the SER has a bit of a higher tendency to persist in a nina but that is not true of all Nina's so it's hard to say really. This year has kind of been a mix of patterns but the worst parts of each.

It's unheard of for a nina, the people saying "this is just a nina" are just plain flat wrong. Nina's have less variance than other winters. They are very rarely big snowfall years, but they are also rarely really awful ones either. This is unprecedentedly bad for a nina.

I ended up with slightly above 50% of average. But my main point is, and reason for my pessimism, that these patterns that have lead to some snow over the last 7 years, mainly progressive wave epo driven, are never going to lead to a sustainable truly snowy period. They just aren’t. They are patterns that are correlated to some snow but mostly fail. The issue is what’s supposed to be a good snowfall pattern, blocking, isn’t working lately. That’s a huge problem because that’s the only way historically we’ve sustained a ton of snow in a -pdo regime. Just because a -NAO has failed to work the last 4 times doesn’t mean these -epo patterns are going to be more successful. Yea once in a while we might luck into a wave this way. But unless we get blocking to resume it’s historical effect of neutralizing a -pdo and suppressing the SER, we will continue to be in a snow drought with only temporary sporadic waves to provide minor relief. I’m not hunting a single 4” snow. I’m trying to find a way out of this larger scale god awful cycle and into a snowier period on a larger scale. We are never getting there praying to get lucky with progressive waves in a -epo +NAO pattern.

The top analog is 1994. But remember that was mostly frustrating down here. We didn’t get that much snow that winter. It was below avg here! The snow was mostly north of us. And…that pattern persisted all winter. This looks like a 5 day window. So we’re talking 1-2 waves. How much snow did DC get from any 5 day period in 1994? Not much. So I could definitely see one of the waves early Feb acting like the plethora of 94 waves did but that would mean most likely the big snow ends up to our NW. But I’m just playing odds here. Maybe the unlikely outcome hits. The were due index is about to explode.

I posted the mid atl snowfall anomalies. 90% of the area finished below avg snowfall and by a lot. The only areas that did well were the immediate coast and a this strip that one wave hit. I pray to god that’s not the new bar for a “good” season.

It won't matter. If it makes everyone feel better to blame me fine. I can take it. But if me and the others who post objective analysis stop posting when it doesn't look good... when you log on each day if the only posts you see are day 15 clown maps and 3 posts a day by the posters that you know only post extra rosy optimistic takes, and there are no posts by anyone else...you will know by default it still looks like crap and will then be sad. The problem isn't the posts, its that its not snowing. You're just venting and finding things to take out your frustration on. But nothing is really going to make you feel better other than snow...and if it was snowing you wouldn't give a crap what I said.

I don't think holding the energy back necessarily ends better. The op GFS ended up an ice to rain storm. Unfortunately any cold shot will likely be short lived. IMO our only real chance at a win here, or higher probability chance, is to get a more strung out boundary with waves riding as the cold presses. That seems to be how that little snow signal to our SE shows up on the GEFS. I don't think a wave attacking established cold will work here, we don't have any mechanism for the cold to resist and so far the seasonal trend is for warm to rout in no time once the SER starts to pump behind any wave.

Thanks, FWIW I am not TRYING to be negative. My pattern analysis is simply my take on what I see. It's been so negative because our prospects for snow have actually been that bad. I don't feel like I am exaggerating it. Likewise, my climate analysis stuff is simply that...we have been struggling to snow lately and I am trying to analyze why and if its likely to change. I am not trying to come up with negative conclusions, but if the evidence leads me there I am also not trying to hide it. At some point things will get better and then my analysis will be more positive, and then you will know it's not just because I am trying to blow smoke up your ass but because I actually think we have a better chance at snow. Isn't that kinda "only analyze when its good" like I said.

Now I know why JB does what he does

So you're saying I shouldn't analyze the pattern unless its what you want to hear?

I don't think its dead. Ive said repeatedly its the best chance we've had. But that's a super low bar. My larger point is...That is unlikely to be a truly snowy period for the mid atlantic. Look at the GEFS snow probabilities... its still way below 50% for 3" across our area...even up here I am below 40%. That's actually below climo! So yes its above the level of recent threats which were near ZILCH...but still its a below climo period overall. But is it possible SOMEWHERE in our area might get a weak wave from this...sure. The GEFS has some hits, enough to cause that little increase in the mean to our SE. That could end up anywhere. But that looks like more of the same crap to me...kinda like last year... 2021-22 snowfall anomalies where one little area got lucky with one wave and if you lived in that small geographic area you felt like it was a decent winter...but in reality it was a god awful snowfall year for the mid atlantic and a crap pattern but the one little area that got lucky with one wave just happened to be right across some of our region. But it was never a pattern that was ever going to lead to a truly snowy year or period in a larger sense. Just one good enough to allow someone to maybe get lucky. So could this upcoming pattern produce that one lucky progressive wave, sure, and could that wave end up somewhere across our area, sure. But its going to be another thread the needle progressive wave, where the "win" zone is relatively small and the odds of any one location getting significant snow is very low and when its over 90% of the mid atlantic is probably still going to be looking at severe negative snowfall anomalies. So I am not getting excited by it. I remain more interested in seeing if the -NAO looks later in Feb are true. There are even hints on the extended GEFS, although the GEFS continues the raging SER even with the next blocking episode later Feb, but if we can time up a less hostile PNA with a -NAO later in Feb that is when maybe we could actually enter a period that I could feel more confident there is a larger percentage chance we actually make up some ground and put down some significant snowfall across a larger area of this region. I want that. If and when I see any hint of it I will be screaming halleluiah from the roof tops. I just don't see it yet.

This is like saying a .350 batter and a .150 batter are virtually the same because "they both fail most of the time"

it's not beating a dead horse its simply analyzing the reality honestly everyday. When things look good I say that too. Back in December I was optimistic. Go back and read my posts for a couple weeks in early to mid december. Because that look actually was good. We actually had a pattern close to ones that worked historically in a -PDO so I was optimistic and no one complained oddly enough even though I WAS DEAD WRONG and it didn't snow. Now in January I keep saying, this just isn't likely to work, these looks are not correlated to snow here in a -PDO, its gonna end up more hostile than it looks day 15 and I have been right over and over and everyone hates me for it lol. I get it people just want snow. But each day when I look at the guidance, analyze it, and decide it still isn't what I want to see to feel confident its gonna snow...I'm going to be honest about what I see and think. I like the analysis, and hopefully the pattern will look better so I can say something truly positive when I break down what I am seeing after a run of guidance.

so you want me to lie to you and make up BS analysis, ok It's a really good setup, despite a lack of blocking and a SE ridge its going to work, we're going to get wave after wave to take a perfect track and save our season. There. Have a good day.

I posted the 24 hour trend showing the degrading look on the gefs earlier. Cognitive dissonance. They really want snow. I get it. If this was 20 years ago I would be guilty of it too. But now I’d rather face reality head on then do what’s necessary for my sanity. For example I called off work so my daughter could play in the snow I got Monday. I wouldn’t have done that for 1.7” that melted by afternoon if I felt we were likely to have way more opportunities. I’m planning a trip in 9 days and already looking at where will probably have snow that weekend. I’m not simply kidding myself into the belief the snow will come to me. If it does great. Bonus. But I’m acting on the assumption it won’t.