ORH_wxman

The old Jefferson coops and the NORHC snow map archives showed a clear decrease of snowfall into Jefferson vs Randolph on the other side of Pilot/Pliny range.NE wind def downslopes them and they don't have the CAD capacity that further east does.

Probably the ugliest above average pack duration winter of all time up there. I wonder how many days it was a crusty 2 or 3”.

The only winter in the mid/late 1970s that came close where you were is prob 76-77 but even that winter had most of December with no pack after the late November snow was torched away by a cutter. Ditto ‘77-78 but even less close.

We actually have a pretty stout EPO ridge this week/weekend but we get a cutter with it (most likely). Shows the risk of EPO ridges at times. Theres probably a window behind the cutter to get something.

Yeah it should help at least keep some cold nearby. It’s going to be above average for that period but that look still gives a chance for something unlike the more classic Death Star pattern.

Looks a bit like the last 10 days of dec 2007 or so...there just enough WPO to push the lower heights further south into Canada and the western US. That was an above normal period for us but it did have some threats and a couple advisory events.

This crap was like slime and then froze overnight. Back in holliston we got about 4” of Italian ice. But the piles make it look like double that because of the water content.

If you want to hone in on a narrower range, I feel like the best period for us is probably like 12/16-12/19. That’s when there’s some cold established nearby (or hopefully over us) and could work with an imperfect synoptic setup.

They didn’t. Unless maybe you live in Norfolk.

Yeah you’re left with like these -5C needles falling into that deep 32-33F layer. Not a good combo for efficient accumulation is an understatement.

The lift was lowering throughout the event over E MA. There was prob more DGZ lift during the initial changeover than later on...maybe Chris or someone has easier access to the cross sections than I do at the moment, but I’m pretty sure i recall seeing the lift a bit deeper earlier in the event. Usually once you flip over to snow, keeping excellent DGZ isn’t a huge deal because your in the CCB and often advecting cold air into the system...but this was a unique system in which we were not so the issue ended up more glaring than it usually would be.

And the best zone that had decent lift in the DGZ was further west over ORH county into adjacent S NH...so they had the double advantage of better DGZ lift plus some elevation. It’s probably why you saw like 9-12 inches of snow there while Ray in Methuen was struggling to get 2”. You hardly ever see that type of gradient unless he was mostly raining which wasn’t the case.

Yeah this almost certainly a factor too. Even in warm spring storms, if you have a dry polar high sitting up there, it can be a nice source of drier dewpoints feeding into the storm to help cool the low levels even if temps were 55F the day before. There was probably a combo of factors that hurt further east. Less loft in the DGZ, lack of drier dewpoints up north to help advect in a source of lower level cooling.

Yeah I’m not sure. The temperature of the ice matters too. I’ll have to search for the paper I mentioned...I think I have it saved on my pc downstairs. It’s like my go-to source for this kind of stuff. It talks about everything including how you can get ice crystals in areas close to the ocean as low as -4C to -5C due to the salt nuclei being far more efficient at warmer temps.

Yeah if you’re throwing a bunch of marginal ice crystals at relatively warm temps (like around -5C as you said) into a layer at 32-33F, that sounds uglier than throwing a bunch of hooked dendrites at -10 to -14C into that same layer.

I have to go back and find that great paper about dendritic and ice crystal growth but I also remember from it that it talked about how the well-formed dendrites/ice crystals will latently cool more efficiently when they melt than marginal ice crystals. So kind of a double whammy there in a super marginal air mass. There was a ton of QPF that fell in the CCB...agreed on that. So it wasn’t like we got dried out over E MA. It just ended up basically being sleet ratios there.

Zwyts sent me a pretty sweet video of solid wind/snow combo. I told him I was glad in retrospect that you guys went with the more elevated zone vs lower down on skowhegan/Millinocket...being at 1200 feet ended up being a bigger deal than initially thought. Y’all hovered just below freezing which was huge.

I think the key is probably the DGZ lift. My guess is the best DGZ lift stayed near 495 and westward for most of the storm. It also coincided with the higher terrain so we saw a bigger elevation gradient than usual. But even a lot of 495 belt with modest elevation in the Littleton to Berlin to Hopkinton/Holliston zone saw 4-6”...it was kind of telling to me that once you got further east on 495 like over to Lowell and Lawrence that they really struggled and I’m wondering if the longitude there hurt with worse DGZ lift.

Phineas prob has 16-18? Could be more...Alex in the other side of the mountains looked like he did pretty well too though prob a bit less. Our N ORH county posters had 10-12...I measured just shy of 10” on winter hill on the north side of ORH. Back in Holliston we had about 4 inches of the densest/wettest snow I’ve seen. Randy/Zwyts chasing in eustis Maine prob had over a foot.

That was also a ridiculous cutter. It basically stalled up in Ontario. Pretty unique. When you have tropical dewpoints into northern Maine, there’s no escaping those cutters.

Yeah that is snowpack country there eastward into Maine because of the big CAD they get. The torches they get are usually brief, even in most cutters.

Yeah I was mostly commenting that the map got it right but prob not due to an exceptional skill there...it was wrong further southwest...even excluding elevated places like ORH (say, the 495 belt from maybe Berlin/Bolton down to Milford had solid advisory level snows 3-6” when the map was spitting out like an inch) But it was definitely far more accurate than the other clown maps which we knew would be too optimistic in this airmass. You're still going to defeat that map in the long run looking at soundings and analyzing the model.

Yeah I don’t think anyone would have forecasted 2” there based on the data we saw. Same reason I didn’t buy the 3-4” amounts it was spitting out for ORH. I figured at least 4-5” minimum for you (like what many got further south of you in the 495 belt). One of those weird events...I’m wondering if the longitude there hurt with the lift placement not being as much in the DGZ. Would be interesting to go back and look when this is over.

Ahh yes those piles were prob from the 3/4/19 storm. That was the best storm that winter. Dumped a widespread 8-16” for the eastern 2/3rds of SNE.

My guess is they had about 5 or 6 inches. Not too bad but I would’ve thought more of you asked me this morning when it was flipping pretty early.