psuhoffman

Just want to make it clear my points have nothing to do with who or what is causing the warming. I have my own opinions but this is not the place. I am simply making observations on our changing snow climo, regardless of what the cause or fault of those changes are!

Our snow mean and median were dropping before this recent period. I do think its likely we are in a periodic minimum and the pattern will get more snowy at some point. God I pray that is right at least! But even if that is true...it doesn't invalidate my point that we are losing some snow along the margins. I do not know and cant quantify exactly which events are affected and by exactly how much. That's a debatable thing...but the fact its snowing less is not.

The boundary is being affected most, especially with UHI effects...but the warming is affecting all levels to some degree. I think just from anecdotal observation the events being hurt the most are boundary layer issue events...where its just cold enough at mid and upper levels but we need the surface to cool...and its just not. But its affecting other events too...if the 850's end up 1 degree too warm! And what we can't measure are how many events where the whole boundary is sensitive to minor changes and so the whole storm ends up 100 miles further north than it would have been 50 years ago! That's really hard to quantify. But its easier IMO to see an event where the surface took a perfect track, the mid and upper levels were just cold enough...and the surface simply ended up 3 degrees too warm, and in that case to say...yea this probably would have worked out 50 years ago.

Not trying to sound an alarm. I don’t even think what I’m saying is some profound revelation. I’m not saying we can’t get snowstorms. Not saying we can’t get a big year. Just saying we are getting less. We’re losing some snow on the margins. Is that controversial? If we know it’s 2-4 degrees warmer isn’t that just “duh”?

This is exactly what I was talking about. Everytime I bring up a marginal event that went the wrong way someone brings up the reasons it wasn’t colder because every factor wasn’t perfect. We’ve snowed in a -NAO but flawed pac pattern before. The airmass wasn’t putrid in early Feb. There had been an injection of some attic air from brief cross polar flow in late January. It wasn’t a fresh arctic airmass by then but that setup has worked plenty of times. It worked in Feb 2010!!! Im not sure exactly what you’re point is. Are you denying it’s several degrees warmer now than it was? Are you denying the fact that being warmer means some storms that would have worked and been a 32/33 degree snow before is rain now? That seems a pretty simple and obvious conclusion. Our falling snow means bear it out. What’s more troubling is our median is dropping like a rock. The mean is being propped up some by an uptick (until recently) of big storms and big years. But the % of single digit snow years is way higher now than any past periods in records. Everytine I bring up a synoptic event that I feel should have been snow based on historical norms someone basically says “but it didn’t snow because it was too warm for this or that reason”. Well ya! My point is but if it’s 3 degrees warmer now and it was a 36 degree rain event…well do the math! Maybe instead of it being slightly too warm because of whatever imperfections you being up 50 years ago it was just cold enough to overcome it. The vast majority of past snow events in Baltimore were flawed and we had to overcome something not right about the pattern. We won’t snow often if we need a perfect setup.

Except that is actually how it used to work up here! And it still does more than on the coastal plain. I hope people don’t think I’m complaining about MBY. Ya this year sucked but last year I was a regional max for snow! I have no right to complain. I do fine in the longer run. But there have been more and more of these “marginal” events that break wrong even up here lately. I’m not saying they all should have worked out. But I log them in my mind and I do think even up here marginal events are bleeding the wrong way some. That super bowl Sunday storm last winter for example. Imo that should have been a 3-6” snow in DC and 6-10 up here. The track was perfect and the storm was a trailing wave right behind a cold front in early February. There was no excuse for the boundary layer to be torched like that. Yea people point out the surface temps were just too warm but my point is based on the pattern it shouldn’t have been. But it was 38 degree white rain in DC and 5” of 34 degree wet slop up here.

We know that snowfall is decreasing in DC and Baltimore. What’s harder to quantify is exactly what impact warming is having on specific events. It’s impossible to calculate because temps don’t act in isolation. Change the global thermal profile and the whole pattern changes and the storm isn’t even there at all anymore. But common sense would reason that it’s hurting us with marginal events most of all. I would bet your stats will show snow is being hurt most along that fringes of where its typically cold enough to snow. Like here! Get far enough north and averages might even go up as warming causes more precip and it’s still cold enough.

I don’t have the ability to quantify this accurately. I’d be very interested if someone found a way to model this and went back and tried to use old saved data to project how some historical events would be different in todays temps. Of course maybe we could do that simply for the UHI effects but it’s not really likely to work on a full scale since the temp changes affect the global patterns so the truth is none of those storms would have even existed at all and completely different storms would if we changed the whole temp equation. You can’t just change just the temps but keep everything else the same. It doesn’t work that way. But to simplify I think everything’s bleeding the wrong way to some marginal degree. Ignoring the fact they wouldn’t be the same events I think in general storms that would have been a 30* 8” snow would be a 32* 6” wet paste bomb now. Some 6” paste bomb might be a 2-4” slush slop fest now. And what I was a slop fest is now white rain. You get the idea.

This is another event I log into my "this is concerning" mental file. Maybe not for DC and Baltimore as marginal events in mid March were always problematic for them, but up here this was troubling imo. We had a low off the Delmarva with a reasonable airmass profile across the CONUS to work with, at least by recent standards, and the lower levels didnt work out even for our area with 1000 ft of elevation. Even when it was pounding snow it was 34/35 degrees at my house! There have been numerous little things that bug me every time I see them. Like how there are frequently storms in mid winter without any appreciable frozen precipitation shield on the NW side at our latitude! Like how there are more and more examples of storms where there is no ice transition zone because the boundary temps are so warm well into the "cold sector" of the storm that it just goes right from rain to snow. We saw a troubling thing today that I have noted recently a lot...typically there are two zones of higher snowfall. One just NW of the rain/snow line where there is heavy precip associated with the frontal/baroclinic forcing and one further NW associated with higher ratios and better mid and upper level forcing. But lately the former zone is often rain...and the only snow zone is the latter because the rain snow line is much further NW then it should be given the track of the system and where the baroclinic boundary is! The retort I get every time I bring these things up is for people to focus on the imperfections. "Well this or that wasn't exactly perfect". Yea. That's true. I am not saying it can't snow anymore. But its not going to snow very much if we need EVERY DAMN THING to be exactly perfect. It used to snow frequently in very flawed scenarios. I know...I did a deep examination of every warning snowfall event for both our area and Baltimore! Not even the majority were perfect classic everything was right setups. All of the 20" plus storms were...and I would say most of the 10" plus ones in the cities are also...but up here we bootlegged our way to 10" storms quite a bit with really funky looking patterns and synoptic looks in the past. Recently it seems to get a snow of any significance we need everything to be almost freaking perfect and that is annoying and has be pretty disillusioned because perfect doesn't come along very often. We need to be able to win with decent but flawed looks more often then we are lately imo or our winters are going to be...well like they have been most of the last 7 years. And yes I am including 2016 in there because while we did get the HECS...that was a PERFECT setup so that doesn't count towards my gripe here...and there were 2 other marginal but pretty good im0 setups that year that failed. One managed a decent event up here but was another example of a mid winter perfect track 36 degree rain event in the cities!

This…I obviously don’t have the ability to prove anything with statistical significance but deductive reasoning paints the picture. Just putting some facts together. 1. Temps have warmed in the metro areas most. 2.Boundary temps are affected the most of all levels. 3. I was struck by how many of the snow events in dc and Balt happened with temps right near 32! What bothers me most is the amount of times recently we’ve seen synoptic setups that SHOULD support snow, good tracks, decent thicknesses, and it’s a 36 degree rain event. I do think 30 years ago those were snow and it’s why our avg is dropping.

Of course we finally get a juiced up wave to take a decent track a week too late for it to work.

Hopefully the midweek system hangs around on guidance and we can do a zoom early this week. Sorry I haven’t been around much lately. I’ve been dealing with some stuff.

This is a matter of degrees type discussion. I agree with help up top AND the pac we had it would have been better. I don’t doubt it’s still possible to get cold. But we used to get arctic shots from an epo pattern without Atlantic help. Snow was harder to come by in those. But some of our coldest shots were in pac driven years without a lot of seasonal snow to snow for it. It just seems we need more and more of the dominoes to fall in our favor now.

I’m not surprised given the NAO in our struggles to max out snow potential this year. But what’s more concerning imo is the cold was kinda weak sauce for the most part too. We discussed this before the pac pattern set in. It was perfect for arctic shots yet we really only ever got typical cold. It seems really difficult to get a true arctic cold shot here lately even when the pattern is aligned right for it.

No one should demean anyone over cultural differences. Humans need to get over our ingrained tribalism. I also wish EVERY culture, especually my own, could be more introspective about both the positives and negatives. Every culture has things worth defending but also things that are inexcusable.

I had snow cover for like 5 days from that lol

it was 3-10-76. A year with very little snow before that. According to coop data it was a general 8-12” across our area. Some specific totals I found. 8.1” in Westminster, 12.5 in Unionville. 12” in Hanover. 9” in Emmitsburg, 10.5 in Parkton

I think I had 14” from that.

Mid March is kind of a hot spot for snows in Nina years also for some reason. Even some really awful ones like 1976 managed a mid March fluke.

Go explain it to him. Have a nice conversation.

?

It snows more further north. Got it. Don’t know what we would do without you. Thanks.

What a full and rewarding life you must have.

I generally agree but the AO flipping negative could change the equation slightly. I’m skeptical but willing to be open minded. But a epo/pna driven pattern with a raging positive AO is just as flawed and difficult to score in as a -AO with a hostile pac. Right now, as I said to Cape in his storm thread, we are in a double bind. We need waves to gain amplitude to overcome the progressive flow and not get suppressed. But with a raging +AO anything that does amplify likely tracks to our northwest. We’re left needing to thread a needle. If the AO does flip negative we could have more luck we there could be some resistance to a more amplified wave not just cutting. We are running out of time but could get a window before it’s over if the changes up top on guidance are real.

Once it became apparent we wouldn’t get the tpv displacement we wanted and thus was just another iteration of the same pattern I didn’t give it much chance. We had some luck early during the transition when the AO was still beat neutral. But ever since this became a pure pac driven pattern with a +++AO it’s been mostly fail city. We had a similar problem early in 2015 before the tpv became displaced into Quebec in Feb. The amplitude waves need to overcome the progressive flow will usually mean they also lift too far north because of the lack of blocking. We’re left walking a tightrope. I have slightly more interest with guidance suggesting the AO is about to flip. It’s too far out but that could change the equation in our favor. Of course we’re in March by then so…