J.Spin

Yeah, definitely some steady snow and great flake size here at the house – we were outside doing holiday pictures and the scene was great. We’ll see how much we get with the continued push of moisture, but we’ve had about a half inch thus far:

Event totals: 0.3” Snow/0.01” L.E. I found 0.3” of unanticipated snow on the boards this morning, and since there was no mention of it in the BTV NWS forecast discussion, I’m just putting it down as diamond dust from the cold air. Details from the 6:00 A.M. Waterbury observations: New Snow: 0.3 inches New Liquid: 0.01 inches Snow/Water Ratio: 30.0 Snow Density: 3.3% H2O Temperature: 10.1 F Sky: Mostly Clear Snow at the stake: 7.0 inches

Event totals: 2.2” Snow/0.07” L.E. Smaller flakes in this second part of the storm here have definitely made for denser snow accumulation – the evening snowfall density was twice that of the afternoon snow. Details from the 10:00 P.M. Waterbury observations: New Snow: 0.6 inches New Liquid: 0.03 inches Snow/Water Ratio: 20.0 Snow Density: 5.0% H2O Temperature: 22.1 F Sky: Light Snow (1 mm flakes) Snow at the stake: 7.5 inches

I can give you some quick numbers that pretty much back up your impressions, using my data as a proxy for the local higher elevations since we typically run in synch. There’s no question about November, it was really strong and put us well ahead on snowfall. The peak of the surplus, depending on whether you want to look at it in percent or inches, was somewhere in the range of Nov 16th (502.3% of average) to Dec 7th (27.7” ahead of average). The current season held its record pace (at least in the context of my data set) until Dec 15th at 51.1” of snow. On Dec 16th, it fell behind ‘07-‘08, which was at 62.5” on that date. As of today, this season has fallen to 3rd place behind ‘07-‘08 and ‘08-‘09, which were running nearly neck-and-neck on Dec 24th at 72.4” and 74.3” respectively. Indeed as you surmised, December snowfall has been a bit behind average pace according to my data. The average December snowfall as of December 24th here is 26.8”, and including the couple of inches so far from today’s event, we’re at 21.6”, so 5.2” behind/80.6% of average for the month.

Event totals: 1.6” Snow/0.04” L.E. Details from the 4:00 P.M. Waterbury observations: New Snow: 1.6 inches New Liquid: 0.06 inches Snow/Water Ratio: 40.0 Snow Density: 2.5% H2O Temperature: 29.5 F Sky: Light Snow (1 - 5 mm flakes) Snow at the stake: 7.5 inches

I saw that the near term in the BTV NWS forecast discussion was updated around 3 PM to discuss the latest observations and trends: .NEAR TERM /THROUGH TUESDAY NIGHT/... As of 302 PM EST Monday...Interesting day across the North Country as synoptic and mesoscale features have resulted in an over- achieving snowfall for portions of the North Country. 12z data, especially the HRRR/RAP trended north with axis of steadier snow and associated qpf with potent shortwave energy. This resulted in a 1 to 3 inch snowfall from mss to slk to btv areas, while limited precip occurred north or south of this line. Web cams show 3 to 4 inches near the Tupper Lake area. Locally here in BTV, strong blocked flow with froude numbers between 0.30 to 0.50 helped to enhance low level convergence and produce localized enhanced snowfall, along upstream of the Green Mtns. NWS employee reported 2 inches a couple miles north of the City of Burlington and 1.3 here at the airport thru 20z. The final element which has helped to produce a white christmas here in the BTV area is good deep layer moisture thru the favorable snow growth region, producing snow ratios of 20/30 to 1. Water vapor continues to show shortwave and best mid level moisture moving across the northern Dacks attm, which will pivot over the central CPV, before lifting across eastern New England overnight. So anticipate another few hours of light snow thru this evening, especially cpv and points east. Areas of slippery travel likely this evening, especially on untreated road surfaces.

Although the snow start to fall here a bit before noon, it wasn’t until about 1:00 P.M. or so that it really started to get going substantially with respect to accumulation. The intensity hasn’t been outrageous, but with big flakes at times, we’d picked up about an inch here as of 2:00 P.M. Looking at some of the short term models, it seemed like the snow was going to fire up a bit later this afternoon, but that may be from the potential inverted trough. I’ll make some observations at some point this afternoon to see where things stand. The BTV NWS did update their discussion on the current shortwave to note accumulations pushing a bit northward, and there is also a Special Weather Statement in effect for parts of the area to address the snowfall: .NEAR TERM /THROUGH TUESDAY/... As of 1246 PM EST Monday...NWS employee reports 1.0 a couple miles north of Burlington and 0.5 here at the airport. Have updated to increase snowfall amounts here locally to better match what has already fallen. Otherwise, likely to cat pops look reasonable with accumulation of 1 to 2 inches possible, with localized amounts up to 3 inches possible. Outside of the axis of snowfall, only a dusting of snow is anticipated. Always a positive when you have to expand likely pops and increase snow accumulations further north, especially a day before Christmas. Radar/obs show light snow with embedded pockets of moderate snow is occurring from MSS to PBG to BTV to MPV line. Have increased pops to likely/cat in this area with snowfall of a dusting to 2 inches possible. Based on web cams around Tupper Lake already showing a couple inches, would not be surprised a few locations in the western dacks/southern St Lawrence county get 3 or 4 inches by later this evening. Water vapor shows potent short wave energy with embedded ribbon of mid level moisture approaching the SLV. Have noted in soundings good rh in the snow growth region, even as further north as BTV, so anticipate a 3 to 5 hour window of light snow with periods of sfc vis down to 1 sm, with a an inch or so accumulation possible. Otherwise, lift/moisture quickly exits our cwa by 00z this evening, with precip ending.

Light snow has started up here in Waterbury – radar shows it coming in from the west.

Event totals: 0.3” Snow/2.42” L.E. We picked up 0.3” of snow as the back side of this recent system came through. With the snowfall tapering off to flurries and the temperature dropping, I decided to clear/swap out the snowboards and take observations before everything tightened up and made that task more challenging. I also cored the pack for a post-storm analysis, and the current snowpack liquid is 1.72” compared to the 2.67” it held prior to the event. So with this storm, the snowpack depth went down by about 3 inches or so and the liquid content in the snowpack dropped by roughly an inch. Interestingly, the overall density of the snowpack is essentially unchanged – it was 26.7% H2O before the storm, and now it’s at 26.5% H2O. There’s really not much on radar that I can see in the immediate area, aside from some echoes off to the north, but the intensity of the snowfall has picked up in the last several minutes, so I’ll see if there’s any additional accumulation to report later. Details from the 1:00 P.M. Waterbury observations: New Snow: 0.3 inches New Liquid: 0.06 inches Snow/Water Ratio: 20.0 Snow Density: 5.0% H2O Temperature: 33.3 F Sky: Flurries Snow at the stake: 6.5 inches

Precipitation has changed over to snow here at the house as of ~10:00 A.M.

As I often do ahead of these warmer storms, I cored the pack this morning as part of my CoCoRaHS observations to get a sense for how much liquid is in there and hopefully pass along the best info to the relevant agencies for flood analysis. The core revealed 2.67” of liquid in the snowpack, with the NOHRSC modeling for our site at around 2 inches: I guess if the snowpack at a location is very meager/unconsolidated snow or there’s going to be multiple inches of rain and 60 F+ temperatures, the snow could totally disappear, but with each one of these storms passing to the west, there always seems to be a lot of unnecessary fretting about the issue. Expecting a dense snowpack containing multiple inches of liquid to disappear overnight is sort of unrealistic.

It’s actually just as NoPoles noted (not sure where that very pertinent post went, but it was here right in the thread earlier, just a bit after Gene’s inquiry). My text is often used in multiple places (posts here, posts to my personal web page, incorporation into my winter weather summaries, posts in other forums, etc.) so I never create anything in the forum editor. I write, and save, all my text offline (typically in Microsoft Word unless there’s a specific reason to use another application) and then paste it in where it’s needed, with modifications as required for the specific environment. I’m surprised more people don’t go that route, because if there’s one thing I’ve learned after years of posting in various online environments, it’s that you can’t trust any of it. The online text editors can fail on you at any moment, or the entire website can simply be taken offline forever, and all that data is gone. For example, most people around here know how easy it is to get things off the EasternUSwx.com forums now. The biggest issue is definitely writing in the online text editors though, it probably took me about one experience of writing up some substantial text only to have it disappear into the ether to know that I was never doing that again. It’s interesting, because Gene has brought this up a number of times and we’ve discussed it, and I thought the general consensus was that it was an issue specific to Gene’s display? The problem is that the forum software seems to change every few months with upgrades, and the text editor and display sometimes change with it. I use only the default settings in the forum, so each time things change, I specifically adjust my input text to make it come out the same size as the other text I’m seeing. For example, right now my input text is 10 ½-point Arial, which I specifically chose because the output I see in the forum has text roughly the same size as what I see from other people. If I go up to even 11-point font (at least as of my last test) the text becomes awkwardly large. I go with what shows up on my end because I use the default settings and assume that would be the most common for everyone else. The only thing I see differently on my end is that my text isn’t multi-spaced (I prefer that because the excessive spacing really takes up a lot of space in longer posts). Here are some examples of what I see. The first one is what I see for my most common environment (my laptop in Internet Explorer, with me signed into the forum). The second is what I see signed in on my phone, and the third is another look I took where I’m not signed in and viewing on laptop via Chrome browser. All the text is basically the same size on my end via multiple platforms and browsers, so I haven’t wanted to fiddle with the format yet, but I guess others can provide input as well.

I headed up to Bolton Valley this morning for some turns, so I’ll pass along some snow info and images. I was sort of surprised to see the mountain only reporting 4 inches of new snow this morning, especially since we’d already picked up about 5 inches down at the house. Granted, the resort is probably measuring one settled morning total, and I was catching six-hour increments, but generally they still report substantially more (typically double) compared to what I record at our place down in the bottom of the Winooski Valley. I figured that they might have missed out on some of the snow because the Froude number was suggesting it was blowing downwind of the spine, but after touring around at the resort today, I can say that definitely wasn’t the case. I was actually planing to earn some turns and ski tour a bit before the lifts opened at 9:00 A.M., but I was up there later than I’d hoped and it was right around opening time. That didn’t matter too much though, because winds were fierce and the Vista Quad wasn’t even running, so I just headed off to Wilderness for a tour as I’d initially planned. With those harsh winds, you’d be hard pressed to know that much snow fell at all from just looking around the base area parking lots. The accumulations were really patchy on a lot of snowbanks because the new snow had been ripped away and sent elsewhere. Once I got onto the skin track on Lower Turnpike and out of the wind though, the actual snow accumulations became apparent. Indeed I’d say that the 4 inches reported was a safe way to go in terms of being conservative, but aside from scoured areas, that definitely represented the low end of accumulations I encountered. Omitting the extremes of drifts and scoured areas, my depth checks revealed settled snow depths of 4 to 10 inches throughout my tour. That wasn’t really elevation dependent, it seemed to just be a factor of how the snow sifted down in various areas. Drifts I found up around the 3,000’ elevation were generally in the 2 to 3-foot range, though there were some bigger ones as well of course – I got a shot of one neat example in my images below. Anyway, the skiing was obviously much different than what you would get from just four inches of fluff. With a number like that I’d be expecting to get good turns on only low angle terrain, but bottomless turns were pretty standard all the way up to about single black diamond pitch as long as the subsurface was smooth. I was on my 115 mm boards, but one could certainly still float on a lot less. I’d say the storm must have put down a half inch of liquid or so on the mountain based on what I was skiing. Accumulations really tapered off as I headed west out of the mountains, with just a bit of accumulation in the Richmond Village area and it seems like just a trace to nil in the Burlington area. A few images from today:

Indeed, it was a nice refresher, both on the slopes and in the valley. The snowfall had slowed down and flakes were small at the house at observations time this morning, but there was a resurgence after that with some nice big flakes. I was up at Bolton for some turns this morning, so I’ll pass along my observations from there as soon as I get a chance to write that up.

Here’s what I’ve seen reported for 48-hour totals from the Vermont ski areas, which includes the initial as well as backside snow for this latest storm. North to south listing is below: Jay Peak: 12” Burke: 6” Smuggler’s Notch: 5” Stowe: 6” Bolton Valley: 4” Mad River Glen: 4” Sugarbush: 2” Middlebury: 0” Suicide Six: 1” Pico: 3” Killington: 3” Okemo: 2” Bromley: 2” Magic Mountain: 4” Stratton: 3” Mount Snow: 1”

Event totals: 4.8” Snow/0.23” L.E. Details from the 6:00 A.M. Waterbury observations: New Snow: 1.3 inches New Liquid: 0.04 inches Snow/Water Ratio: 32.5 Snow Density: 3.1% H2O Temperature: 18.1 F Sky: Light Snow (1-2 mm flakes) Snow at the stake: 11.0 inches

Event totals: 3.5” Snow/0.19” L.E. Temperatures have come down and flake size has definitely come up this evening so we’ve got a much fluffier consistency of snow falling now. Details from the 12:00 A.M. Waterbury observations: New Snow: 2.2 inches New Liquid: 0.08 inches Snow/Water Ratio: 27.5 Snow Density: 3.6% H2O Temperature: 21.7 F Sky: Snow (2-15 mm flakes) Snow at the stake: 11.0 inches

Event totals: 1.3” Snow/0.11” L.E. Details from the 6:00 P.M. Waterbury observations: New Snow: 1.2 inches New Liquid: 0.11 inches Snow/Water Ratio: 10.9 Snow Density: 9.2% H2O Temperature: 33.8 F Sky: Light Snow (2-6 mm flakes) Snow at the stake: 9.0 inches

On the trip home from Burlington, accumulations of new snow began to appear right around Jonesville, and the snowfall intensity just kept ramping up as I headed deeper into and through the spine. When I first got to Waterbury around 4:30 PM there was a steady light snowfall, but within a few minutes it had really intensified up to what I’d call moderate intensity. Here at the house I’d say the snowfall is light to moderate with about an inch on the boards.

Snowfall is still on and off here in BTV, but it’s generally been picking up, and I can see that we’ve got snowfall and a couple tenths of additional accumulation at the house via our webcam.

There’s snow expected in the Northern Greens heading into tomorrow – PF made a quick update in the NNE thread, there are some additional posts there now as well, and PF has a detailed discussion of the upslope potential at Braatencast.

Event totals: 0.1” Snow/Trace L.E. I found 0.1” of snow on the boards at observations time this morning from the current system. The next part of this storm is expected to affect the area later today, with our point forecast suggesting additional snow in the 2-4” range, and higher amounts at elevation. AREA FORECAST DISCUSSION National Weather Service Burlington VT 636 AM EST Mon Dec 17 2018 .NEAR TERM /THROUGH TUESDAY/... As of 341 AM EST Monday...Shortwave energy rounding the base of the approaching trough begins to shift into northern New York after the noon hour and then into Vermont around the evening commute with winds increasing from the northwest. This is when we`ll see upslope snow shower activity increase in coverage across the higher terrain of the Adirondacks and northern Vermont which will blossom during the overnight hours. Based on forecast froude numbers, the low level flow will be largely unblocked so the highest accumulations are expected to be along and downwind of the mountain spines where a general 1-3" is expected above 1000 feet, and up to 6" above 2500 feet by sunrise Tuesday. Details from the 6:00 A.M. Waterbury observations: New Snow: 0.1 inches New Liquid: Trace Temperature: 32.9 F Sky: Cloudy Snow at the stake: 8.0 inches

Checking on the BTV NWS point forecasts in this area, all told I’m seeing something in the range of 3-6” down here at our site, and then more of a 4-8” range for the high elevations through Tuesday. Those ranges seem pretty reasonable – in the BTV NWS forecast discussion, they mention a couple of inches through Monday in the near term and then they have 6 inches noted in the short term: .NEAR TERM /THROUGH MONDAY/... Due to marginal boundary layer temperatures, snow accumulations will be light with only a dusting expected in the valleys and perhaps 1-2" across the higher terrain. The event continues into Monday night with additional accumulations expected, and we touch more on that below. .SHORT TERM /MONDAY NIGHT THROUGH TUESDAY/... As of 339 AM EST Sunday...Light upslope snow on Tuesday should come to an end during the afternoon hours. Expecting the northern Adirondacks of New York and the northern half of Vermont to see anywhere from 1 to 4 inches of snow starting Monday afternoon, but continuing Monday night into early Tuesday. The highest portions of the northern Green Mountains in Vermont could see as much as 6 inches of new snow.

It’s been a couple of days now since the last snow, but the BTV NWS forecast discussion suggests a couple of chances are coming up soon. They may sort of blend together, but there’s some potential from a northward push of moisture on Sunday night, and the possible upslope on Monday night into Tuesday: .SHORT TERM /SUNDAY NIGHT THROUGH MONDAY/... As of 323 AM EST Saturday...Surface low passes well south of the area Sunday night...but there will be a northward push of some light precipitation up across the area. Precipitation will mainly be in the form of light snow...but any accumulations will be less than an inch. This precipitation will move east of the region early Monday morning and there should be a little break in the precipitation before shortwave trough drops down from Canada Monday afternoon. This will increase dynamic support over the region and we should start to see an increase in areal coverage of precipitation from northwest to southeast across the area. With highs in the 30s there may be some rain or snow in the larger valleys with mountain locations remaining all snow. Any snow amounts will be less than an inch. .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... As of 323 AM EST Saturday...The best chance for accumulating snow will come Monday night as upslope flow develops over the area and enhances precipitation over the northern Adirondacks...the west slopes of the Green Mountains...and north central and northeast Vermont. Not a lot of moisture given the shortwave trough exiting the area came from Canada...but can see 1 to 4 inches of snow over the higher terrain. Cold air advection continues Monday night into Tuesday and thus high temperatures on Tuesday should only be a few degrees warmer than the lows Monday night. Looking at highs on Tuesday in the upper teens to mid 20s. Any lingering snow showers on Tuesday should be confined to the higher terrain of northern Vermont.

I saw your post PF, so I looked through the snow output on a few recent runs. I got a kick out of this one from the FV3 that I’m guessing you also must have tinkered with in your basement. It sure makes you think that the FV3 gets the concept of upslope in the Northern Greens: