J.Spin

That’s some seriously sage advice – indeed it looks like that NVT vibe is a good fit for you. Of course, having one of those semi-private powder sessions in the local hills like you did yesterday can really help in that regard.

LOL, you’re killin’ us with the freak out episodes Phin – it must be the Mid-Atlantic weenie in you or something. I’m not sure what a “pattern flip” would actually mean for us up here, but my advice would be to not screw with what looks like a potentially great week or more ahead for resurfacing the slopes and/or building the base. If you’re looking for snow along the coast in the Mid-Atlantic, sure there might need to be some change in the pattern, but you have to change your mind set for your NNH place. A classic example I see discussed time and time again in the forum would be zonal flow. I’ve always found it weird how every subforum along the east coast seems to malign a typical zonal flow pattern, because it’s filled with “pacific puke” or whatever. Seriously, if a typical, average, zonal flow isn’t going to cut it for snow in your location, then it’s really the location, not the pattern. In places like that, looking for snow is going to mean constantly looking ten days out for that perfect pattern or storm to line up, because that’s really what it takes to get snow. For things to work out in the snow department in those sorts of locations you’d need a better than average, or in some cases a far better than average pattern that represents just a small percentage of a typical winter. Aside from when things do actually line up, it just seems like an exercise in medium to long-range model watching. It’s literally been snowing on your Randolph webcam this morning. I think you said you were down south for a bit now? Hopefully it’s not that environment getting to you!

It was just cloudy at observations time this morning, but snow has started back up here at our site. The next shortwave isn’t expected to be in the area until tonight, so it’s a bit tough to pinpoint where this snow is coming from, but one of the earlier BTV NWS AFD entries does give a bit of insight: Area Forecast Discussion National Weather Service Burlington VT 315 AM EST Wed Jan 13 2021 NEAR TERM /THROUGH THURSDAY/... As of 306 AM EST Wednesday...Very little change anticipated today from Tuesday acrs our fa. Water vapor shows several weak embedded 5h vorts in the west/northwest flow aloft, along with narrow ribbons of enhanced mid lvl moisture.

Event totals: 0.2” Snow/Trace” L.E. According to the BTV NWS AFD, last night’s snow was from the upper-level shortwave passing just southwest of forecast area. It looks like that system has moved on east of the region, and the next shortwave mentioned in the discussion is one approaching from north of the Great Lakes today. Details from the 6:00 A.M. Waterbury observations: New Snow: 0.2 inches New Liquid: Trace Temperature: 27.0 F Sky: Cloudy Snow at the stake: 6.5 inches

Event totals: 1.2” Snow/0.01” L.E. Details from the 6:00 P.M. Waterbury observations: New Snow: 0.3 inches New Liquid: Trace Temperature: 29.5 F Sky: Flurries Snow at the stake: 6.5 inches

For our typical small to medium bread and butter events, I find that very much the case. The BTV NWS does a fantastic job of accounting for our special microclimates here, but I think the extra upslope, long periods of snow globe flakes, and really high snow ratios we often get can easily screw with the ability to correctly forecast amounts. Even though we know it happens (this current system being a great example), the forecasters probably can’t go around assuming 40:1 or 50:1 ratios for snowfall when they’re putting together the forecasts. When I look at the point forecasts for our site for typical bread and butter events, the eventual snowfall total is often something closer to the higher end of the forecast range, or even above it. The liquid equivalent may actually be close to what the models and forecasters predicted, but the snow growth just ends up being so efficient that you get more inches out of it than the typical forecast would suggest.

Event totals: 0.9” Snow/0.01” L.E. After the snowfall started yesterday afternoon, we picked up 0.5” of snow through midnight, and then another 0.4” this morning by observations time. The details for those observations are below. We’d had another 0.3” before I headed off to Burlington today, so I think that’s where this event stands for now at our site. The snow has been falling in very calm air by us, allowing it to be exceedingly fluffy with ratios on the 1:40 or 1:50 range as people have noted. The 0.4” of snow from this morning actually contained <0.01” of L.E., so that’s way up there in terms of dryness. This new snow has increased the depth of the snowpack a bit, but not even to the point of adding a full 0.5” yet because it’s just so light and settles so easily. Details from the 12:00 A.M. Waterbury observations: New Snow: 0.5 inches New Liquid: 0.01 inches Snow/Water Ratio: 50.0 Snow Density: 10.0% H2O Temperature: 20.3 F Sky: Light Snow (5-10 mm flakes) Snow at the stake: 6.5 inches Details from the 6:00 A.M. Waterbury observations: New Snow: 0.4 inches New Liquid: Trace Temperature: 23.2 F Sky: Flurries Snow at the stake: 6.5 inches

There’s no color key on the map, but assuming that lavender magenta coloring is ~50”, that would definitely get most of the glades rolling. Actually, for a 14-day period, 1/3 of that amount would represent a below average snowfall pace for the local mountains; something in the range of ½ of those amounts would likely be about average. With how far they are behind average pace, the mountains around here are certainly due for some make-up snowfall though, so odds would argue that with their relatively low snowfall variance, they’ll run into an above average snowfall period at some point.

It looks like the atmosphere has moistened up enough with this latest push of echoes because I see we’ve got some snow reaching the valley here now.

Wow, I guess so. I wasn’t expecting to see things start to fire up until Tuesday, but it looks like chances begin to appear tomorrow: Area Forecast Discussion National Weather Service Burlington VT 646 PM EST Sun Jan 10 2021 .SYNOPSIS... More active weather is expected this week with several chances of light snow showers. Temperatures mainly in the 20s and 30s will become colder this weekend behind a more substantial low pressure system likely passing to our north. .NEAR TERM /THROUGH MONDAY/... As of 630 PM EST Sunday...The advertised mid-level clouds are beginning to filter into our forecast area. Froude numbers also remain quite low with evidence of more low-level clouds upstream. Thus, no change to the forecast. Although, looking into tomorrow for the TAFs, decided that between the upper shortwave, a jet streak to our south, and just enough moisture, that a few areas may be able to produce some light snow accumulations of a dusting to a few hundredths and swapped in light snow for flurries. Everything else remains in great shape. Have a great night! Tomorrow night, snow showers are favored ahead of a more vigorous upper-level trough across northern Vermont. The wave looks to move through rapidly so duration of accumulating snow looks short. Snow ratios should be roughly climatological in the 12 - 13:1 range. Favorable snow growth temperatures in the precipitating cloud layer will be counteracted by fairly warm conditions below that production zone and weak upward motion. The compact forcing will also make location tricky. While northernmost Green Mountains will likely see light snow accumulations, still could see snow showers a little further south than currently indicated into Stowe and into the central Vermont region. While a very minor snowfall of up to an inch, this area has been snow starved as of late, so it will be nice to see for many.

Ahh, yes, thank you. That’s the term I was looking for.

If we wanted to use it, I’m sure there’s a very pertinent audio reference that could be applied here.

Event totals: 0.1” Snow/0.01” L.E. I thought this would be the end of our current run of days with snowfall, but I was surprised to discover it snowing this morning at observations time. The snow continued after observations time as well, so it looks like we’ll have another couple of entries for this streak. There’s really no notable system around, and the main discussion in the BTV NWS AFD is about the inversion, so this snow is going to be attributed to the moisture associated with the current inversion event. Details from the 6:00 A.M. Waterbury observations: New Snow: 0.1 inches New Liquid: 0.01 inches Snow/Water Ratio: 10.0 Snow Density: 10.0% H2O Temperature: 23.4 F Sky: Light Snow (1 mm flakes) Snow at the stake: 6.5 inches

Yeah, that’s sort of the result of the first couple of salvos of snow that some of the models show for this coming week. If you look at the latest run of the GFS, you can basically see four snow events now, one each day starting on Tuesday, with each subsequent one becoming more substantial. It won’t necessarily play out exactly like that of course, but stepping through the GFS frames for this coming week has definitely got that sort of look… I can’t quite recall the term at the moment, but I know I’ve seen an image posted frequently here in the NNE thread to describe it. I’m sure the term will come to me at some point.

I was last out at the mountain on Sunday, and although we’ve only had a few additional inches of snow since then, it seemed like today was a good day to head on up for a tour and check out the conditions. I didn’t check out any of the manmade or lift-served terrain today, but I started my tour on the Bolton Valley Nordic and Backcountry Network and then connected over to the Wilderness area. The Colorado-esque weather regime over the past few days has definitely been outstanding with respect to snow preservation. In areas that haven’t been skied, all the recent snows are just sitting there in the form of midwinter powder, and I found depths of generally 6-12” at the 2,000’ elevation and 8-12” up around 2,700’, which was as high as I went on my tour. I’d say the main issue is still the base below that snow. It’s quite variable, and down at 2,000’ in the Village elevations there’s nothing at all below the powder in unprotected areas. In the higher elevations the base is a bit less variable, but there’s still nowhere near enough base for steep terrain. What I saw that impressed me most on today’s tour was the state of skier-packed natural terrain. Areas like Lower Turnpike, Telemark Practice Slope, Bryant Trail, and Nordic trails like World Cup (some of these may have been machine-packed) were in very good to excellent shape. Presumably, these areas of packed snow held up well against the warmth around Christmas, and now the additional snows of the past week or two have reinforced that base. Lower Turnpike had nearly perfect coverage, and all this packed terrain is going to make for some excellent powder skiing when the next storms come. All in all, though, you could definitely feel that winter has settled in for the mountains, even if the snowpack/base is on the low side. The water bards I encountered today were all sufficiently frozen, although most of them are still visible and require a bit of navigation. A few shots from today:

Yeah, can’t blame you for wanting to experience some of that cold NNE weather to get a feel for it in your new spot. But as PF has been showing, this is why when folks are pining for these patterns with dumps of super cold temperatures in the Northeast in midwinter, we’re not necessarily jumping for joy. For the most part, it’s not needed. Sure, it can freeze up bodies of water and the snow preservation is good, but it often means we get to sit in dry, frigid, arctic air and freeze our butts off on the slopes in subzero temperatures while the storm track is pushed southward out of the area. “Oh, you mean we get the privilege of having dangerous subzero temperatures in the mountains and no storms to refresh the ski surfaces? Wow, what a deal!” Obviously there are various degrees to which this happens, but you get the idea. Up here, getting moisture is the key in midwinter. Aside from being warm-sectored from a storm to our immediate west, or some highly anomalous pattern, the midwinter temperatures up here take care of themselves. The current stretch with these well above normal temperatures sort of testifies to that. Systems are still in the queue for next week though, with potential impulses on Tue/Wed, Thurs, and Friday, depending on which model you look at. It’s still a bit far out to start getting into amounts, but it looks like we’re talking northern stream stuff that is pretty reliable once we get within a few days. The thoughts from the BTV NWS seem right in line with what I’m seeing, with chances increasing as the week progresses: .LONG TERM /TUESDAY THROUGH FRIDAY/... As of 302 AM EST Saturday...Increasing chances for precipitation as we head through the week owing to a series of upper shortwaves that will cross the region. As is typical with these sort of scenarios, there`s a fair amount of disagreement in the specifics of these systems, not only model to model but also run to run. That being said, it still looks like the best chances for widespread precipitation will be late in the week with a weak clipper system moving in from Ontario, followed by the upper trough digging to our west. This latter feature will also result in a slight warming trend through the week; hence the precipitation would likely be a rain/snow mix in the valleys and snow in the mountains.

Those are my exact sentiments - these temperatures have been awesome. And it was around 20 F when I was out during the day yesterday and it definitely felt cold. It was a reasonable cold though, I didn't even contemplate putting on a layer over my pants, and it was still fine. I'm pretty sure a high temperature like that is below average though, even for around here in January.

I’m sure that here in VT, carpooling (with masks) has to be allowed to a certain degree because some people have no other means to get to work, get to the doctor, etc., but I don’t think the state regulations encourage being in an enclosed space (e.g. vehicle) with someone from outside your household, do they? I’m pretty sure you can’t eat meals with people from outside your household yet either here, but the rules could be different in different states.

I was just talking about that very topic with a colleague at work yesterday, and suspect those are the sentiments of a lot of folks around here. I actually expressed similar thoughts in my Bolton Valley report from Sunday: “…folks aren’t yet using all the acreage of tree skiing; the trees were generally untouched because people know that it’s still just a bit too thin in there for the skiing to be practical. I saw an occasional track of people who had headed into the trees, but you could tell they weren’t quite ready. If we get one more good snowstorm with an inch of liquid, then the low-angle trees will be in play.” “We still need a solid synoptic storm with an inch of liquid equivalent (or something similar from a series of smaller systems) to really get the base depths to more respectable levels, but Winter Storm John was a godsend to at least get a bit of base down and have some snow to see us through the next week.” Based on years of observations around here in the Northern Greens, I typically use the point of reaching 24” at the Mt. Mansfield Stake as a rough marker of when initial tree skiing starts in the local mountains. This would be for those lower-angle, well-manicured glades such as the Sunrise Glades and Birch Glades in the Mountain Chapel area at Stowe, or Wilderness Woods at Bolton Valley, etc. Obviously the depth at which tree skiing becomes practical can vary based on the density of the snow making up that 24” depth at the stake, and the snowpack depth will typically be a bit lower down at elevations of 2,000’ or 3,000’, but the 24” number seems to work pretty well, and it certainly works for a comparative benchmark. With the stake snowpack currently at 15”, we really are just about one large storm, or a few smaller ones, away from hitting that point. People may not remember it, but it’s interesting to note that last year was actually a relatively late start to getting the trees going based on the 24” assessment. Although we had a very early start to the continuous winter snowpack around here in the mountain valleys (November 8th), it wasn’t until January 2nd, that the Mt. Mansfield Stake finally hit that 24” mark. I’d certainly forgotten it was that late, and that’s actually more than 1 S.D. (actually 1.06 σ) behind the mean date of Dec 13th. Here’s the updated plot of the date for reaching the 24” depth using all the Mt. Mansfield stake date since 1954. You can see last season’s date of reaching 24” indicated by the red star, sitting just to the right of the 1 S.D. line in the plot. As PF has noted for this season, we are getting out into relatively rarefied territory with respect to the Mt. Mansfield snowpack depth at this point. If you look to the far right of the plot above, you’ll see that there are just a handful of seasons where the 24” depth has been achieved this late. Next week certainly has some potential for snow, but as of today, we’re already sitting at 1.37 σ) behind that mean date of Dec 13th, so we’re into the bottom 10% of seasons. It’s funny that both in terms of snowfall and snowpack depth, we’re really close to average here in the mountain valleys, but this has been one of those seasons thus far where the mountains are seeing much larger deviations, certainly when it comes to snowpack depth.

Event totals: 0.3” Snow/Trace L.E. Details from the 12:00 P.M. Waterbury observations: New Snow: 0.2 inches New Liquid: Trace Temperature: 23.5 F Sky: Light Snow (2-6 mm flakes) Snow at the stake: 7.0 inches

I’d been feeling like we’ve had quite a run of days with snow, but your comment made me check on my CoCoRaHS data. Indeed, the last day in which we didn’t have at least a trace of new snow at our site was all way back on Christmas, so that’s 14 days in a row. And today’s snow will actually add a 15th day to this run. Some of the least snowy periods around here are when we get under that cold, dry, arctic air with clear skies. The air is just so cold that it can’t hold much moisture at that point. You can still get accumulations from that arctic diamond dust during those periods, but that doesn’t produce the type of flakes we’re seeing today. This weekend it looks like it might actually clear out to a degree that would end the streak of snowy days, but the models suggest we’ll be back into some potential systems next week. Some models have snow signaled as early as Monday night/Tuesday, but most have something by midweek, and the chances just seem to increase as the week progresses. PF actually did a great job making the point about the models not catching all the potential snow in a post that he made back on (coincidentally) Christmas Day. The projected snow map showed a maximum of 1-6” of snow along the spine through the 16-day period ending on January 10th. Reinforcing the point, the top end of that snowfall projection was esentially surpassed the very next day. Now we’re almost at the end of that period, and we’ve had six distinct storms/events, three times the maximum projected snowfall down here in the valley, and I’m sure even more at elevation. The models just can’t catch all the multitude of systems that are going to affect these types of mountain climates, especially at those long lead times.

It sounds like you guys definitely got into the moisture up there. This snow certainly wasn’t expected around my area today, and we’ve got a much steadier light snow out there now. This type of snow is often something that doesn’t show up on the radar because it’s low level and not caught by the beam, but there is a visible pulse coming in from the NNW:

Thanks so much for these observations PF. I had already made my decision on the source of this snowfall for my storm records based on the BTV NWS AFD (although I had to make a best guess because they didn’t really mention it at all). Your observations from up high and down in the valley confirmed it though – today’s snow definitely comes from moisture under the inversion layer vs. persistent moisture from that system lingering in eastern Canada.