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I'm sort of wondering how bad it will be. The 2020 megagrinch was warm enough to melt 2-3' of snow off of NNE, but that was low-density snow and it was much warmer. Some SN/PL followed by 38˚ rain might and the cold might just create a glacier. But I also wouldn't be surprised if it wound up being a meltdown given the lack of base beneath. Good luck to the ski resorts.

If the next one shifts SE 700 miles we may be in business.

Congrats BDA.

The warmup in early Jan looks like the Grinch will just come right back after this weekend.

The ski slopes will turn to sheer ice, most likely, which is expected for New England.

2020 was a mega-grinch. To cherry-pick some 2020 stats: a station near Quebec City was >40 for 20 hours (may stay below 40 this entire storm). Middlebury Snow Bowl was >40 for 36 hours and >45 for 31 of those, peaking around 56. This time should be 6 above 40 and maybe 0 above 45 at the Snow Bowl. Once the CAD dam broke at BML, it spent 42 hours above 40 and then only slowly fell back to freezing. Of course, the models undersold that a few days out, but there was no arctic blast behind it. Of course the grinch to end all grinches may have been in 2015. RUT had one reading below 30 over the course of the week with a high of 70; friends celebrating Christmas south of there in Vermont said "normally we go skating on the pond but this year we went swimming." At least 2015 didn't melt 4' of snow which had fallen a year before. Given the density of the current pack, some rain at 40 degrees might just soak in and once it freezes, it will freeze real solid. So I guess it could be worse?

And if you enjoy 55˚ on Christmas get ready for 65˚ on New Years. ¯\_(ツ)_/¯

So I pulled data for KBOS at some point, did some unholy things with Excel and statistics, and it seems to show that the Grinch is real and a recent phenomenon. The data: 1936-2021 data for Boston (since obs were moved to Logan), and then for each day of the year I calculated the slope of the trend line for that day. So, for instance, January 1 is trending warmer by 0.019˚ per year (so 1˚ every 50 years), January 2 warmer by 0.005˚ per year, Jan 3 cooler by 0.025˚ per year. Obviously, any one day is going to be affected by outliers. But on average, temperatures have increased by 0.022˚ per year (so 1˚F every 45 years). That seems about right. But this is not evenly distributed across the year. For one thing, the winter and summer are warming by more than the spring and fall. May, October and November are only warming by about 1˚ every 100 years, February and September by 1˚ every 30ish and December 1˚ every 20! During a portion of late October and early November, if you average over a 21-day period, it's actually gotten slightly cooler. I assume this has something to do with sun angle and oceans, but I'm not about to explain it. And then there's the Grinch. The single highest day for warming, on a 21 day average, 0.079˚ per year (so something like 5˚ since 1936) is December 24, nearly 3.5 times the overall average. The only days over 0.Which squares with our experience. But here's the really bizarre thing. The 31-day average is long enough that it mostly smooths out these changes, but if you look at a weekly average, there are very obvious waves of warmth in the winter, following a pattern which does not exist in the summer. In the summer, the 7 and 31 day averages mostly track close, but in winter there are wild swings. The 7 days centered Nov 21 are cooling at a rate of 0.006˚ pear year, the 7 centered on Dec 1 are warming at 0.07˚, the 7 days centered on December 8 are -0.007. Then there's the grinch, late December all up 0.06-0.077 (December 23, naturally) before a 3-week wave pattern emerges: Jan 2: 0.005 Jan 11: 0.11 Jan 23: -0.012 Feb 1: 0.074 Feb 12: -0.007 Feb 23: 0.07 Mar 4: 0.007 Mar 11: 0.058 Mar 24: -0.008 I have no idea what is going on with this, but I wouldn't be surprised if there is some mechanism or oscillation or something somewhere which sort of pushes warmer and colder air and is based enough on solar changes that there is seasonality. Or something? I need a real hardcore climatologist to figure out wtf this is, or if I've just cooked the data somehow.

The GFS, on one of the busiest travel days of the year, would slam: ATL, CLT, IAD, DCA, BWI, PHL, EWR, JFK, LGA, BOS Probably shut down the NEC too, and driving? Ha. Good luck to anyone trying to get home for Christmas if it verifies. (the Canadian glances MSP and ORD, I guess?)

Yankee Mag has a webcam in Dublin at like 1500' and surprise, surprise it's SN there.

Last frame of the GFS is the Grinch coming a week late. Luckily off at 384h and before that … yum.

The same way they measure precip at KMWN. 6.66" for Irene IIRC, I was chatting with staff and they said "yeah that seemed like a pretty good guess." 29" on the North Shore and still coming down. A friend who works for NWS DLH has slept at the office the last couple of nights

Remembering Dec 17 2020 when the early models had the heavy snow band in southern Conn. and R.I. and it wound up 200 miles north. ofc a different setup, since that had SN all the way to the coast with more cold air. But a similar track.

In a lot of CNE/NNE IIRC the biggest storm was in late October. BOS had an inch of slop from that storm. CON 23".

What is this from? xmACIS shows 1936-7 at 9.0, 2011-2 at 9.3 for all-time lows.

We should probably start a glossary of terms used in this thread so n00bs can read a sentence like "it looked like a SWFE but then we got Leoned" and make some sense of it. (This might already exist.)

A few ticks south and it looks something like the mid-Dec 2020 storm that dropped 44" over some CNE folks. Of course, a week later was the mega-grinch …

So based on some Twitter threads I got to looking at how climate data at KBOS anyway (1936-2021) has not been changing over the years at the same rate at different times of year. After abusing Excel (as usual, I got to the point where I should have stuck this into R or py or something, but had too much invested) I came out with the attached chart. What this is showing is the change in temperature, per year, for each calendar day of the year (excluding February 29). There's some weird stuff going on that I can not begin to explain. Warming is not taking place at all evenly over the course of the year. It varies by quite a bit, but if you look at the orange line (21 day moving average; longer periods don't really change things) it's clear that there are several local minima and maxima to the rate of warming. Specifically: Late fall—from basically Columbus Day to Veterans Day—is not warming at all. Same for early May to Mid June, although there is a slight upward trend here (<1˚/100 years), and a period in late Morch Jul-Sep is warming at a rate of about 2˚/100 years, with late September slightly faster. Met winter is warming at a rate closer to 3˚/100 years, with lots of variability Late December is warming at a rate of 6˚ per 100 years, which is by far the fastest warming of the year. Looking at the variability, there seems to be a ~21-day period from late Nov to early Mar between rapidly warming cycles (7˚/100 years) and periods really without any perceptible warming. The cycles peak on 29-Nov, 22-Dec, 11-Jan, 1-Feb, 22-Feb, 9-Mar. The 7-day average's highest five days, warming at a rate of 7.5˚ per century, are December 20 to December 25. December 22 and 23 are two of the five highest days in the year. (The others: 12-Jan, 2-Feb and 1-Dec.) So basically the Grinch is very real and has been getting worse over time. The seasonal variation probably has something to do with the ocean+sun, given that the two minima are about 6 months apart when the sine curve of the sun flattens. But the local minima (3-ish week period) during the winter probably has to do with something else entirely? Anyway, IANAMeteorologist and IANAClimatologist and I may have buggered up these data completely. But if not, a) it's interesting and b) the Grinch is real!

I should have made the drive up to rip the GBA glades and the Sherbie. This should set up a nice base at least (finally).

Some interesting things going on with temps on Wundermap stations. 16˚ differentials over quite short distances, and the colder spots in the 36˚ range.

43 days in KBOS in 2015 was particularly impressive.

*spectacular

2015 redux, but without a Super Bowl parade. If this were to verify there would be very little melting and lord knows where the snow would go.

Yeah that would be a much better solution up on the hill!