J.Spin

I’d noted your comment about the net gain for the snowpack, and indeed it looks like this system should be another net gain even down here in the valley. I had time to core the snowpack this morning here at our site to get an idea of where it stands, and found that it currently contains 1.69” of liquid. I checked on the NOHRSC modeling for our site, and the modeling’s done quite well over the past 12 days since I last did a snowpack core. Their modeled value for snowpack SWE at our site today was ~1.63” of liquid before I put in my data this morning, which is just a few % difference from the actual analysis and I’m sure easily within the variability in my sampling. We’ve had over 18 inches of snowfall and 1.26” of liquid during that intervening period, and the modeling really incorporated that into the snowpack well. I just refreshed the NOHRSC snow depth/SWE/snow density modeling plot for our site, and I’ve added it below. I was surprised to see that they’ve already incorporated (or at least plotted) my data from this morning (the most recent SWE and snow depth points), so that was quick. The modeling indicates that the snowpack is expected to go up to ~2” SWE, then drop back down a bit to the 1.8” to 1.9” range. The modeling doesn’t yet go out to incorporate any backside snows, so we’ll see how that plays out. If it turns out to be the typical backside type of snow it will potentially add a bit of SWE to the snowpack, but it’s usually more notable for adding snow depth.

I got an alert yesterday from the BTV NWS that we’re under a Winter Weather Advisory in association with this next storm. The advisory is for mixed precipitation, and presumably in place for any potential ice because snow accumulations are expected to be fairly minimal. There is some additional snow expected on the back side of this system, but the current projected accumulations map only covers through 7:00 P.M. tomorrow, so it doesn’t include those potential accumulations.

LOL, just have them recruit students from chemical/biomedical graduate programs. We literally train for decades to make meticulous observations, manipulate small samples, and measure them with accuracy and precision. I guess all you have to do is somehow get them interested in snow.

I’m passing along a conditions update and a few shots from this weekend’s skiing at Bolton. We were out on the backcountry network on Saturday, and then we went for lift-served skiing on Sunday. Despite the fact that that the Mt. Mansfield Stake has hit 40” (a common threshold for most standard off piste skiing to be ready around here) and is getting close to average depth for this time of year, Bolton is lagging behind that benchmark a bit. I think it’s because the thaw cycling hit them pretty hard in areas below 2,500’ or so – the base coverage down at those elevations seems like it was patchy after that last warm storm system. The Timberline area covering the 1,500 – 2,500’ elevation band is only marginally open, and even Cobrass (which faces south in some key spots) off the summit wasn’t open. We actually had some fantastic runs in the trees on Sunday, because some areas we encountered (like the Preacher Woods and Cobrass Woods) were in nice shape, but it’s still very inconsistent. Areas that already had great base coverage offered fantastic turns this weekend thanks to the new snow, and areas that were borderline were pushed to that next level. So the dense snow from Winter Storm Jacob was obviously a huge help, but I’d say they still need another inch or two of liquid equivalent to really get close to 100% open.

It was a solid week here at the house as well; we had 18.1” snow/1.20” L.E. between the four storms. That was definitely the best week of the month in terms of snowfall. This next week doesn’t look as productive though; it looks quieter than average for the midweek. Our CoCoRaHS numbers for the month thus far are 33.5” snow/3.20” L.E., so it’s certainly not last January where we’d hit 50” at this point, but at least it’s moving along decently with the final third to go.

Final totals at our site for this storm were 6.0” Snow/0.43” L.E.

Event totals: 6.0” Snow/0.43” L.E. Details from the 6:00 A.M. Waterbury observations: New Snow: 0.2 inches New Liquid: Trace Temperature: 5.4 F Sky: Mostly Clear Snow at the stake: 11.0 inches We’ve mostly cleared out now, so the totals above should represent the final numbers for Winter Storm Jacob here at our site. With 6.0” of snow accumulation we just barely hit the bottom of the 6-12” range that was in out point forecast, but that’s sometimes the way it goes with these SWFE-type events. Indeed, roughly 2/3 of the liquid from this storm came with a fairly dense 8.6 to 1 snow to water ratio.

Event totals: 5.8” Snow/0.43” L.E. Details from the 9:00 P.M. Waterbury observations: New Snow: 0.7 inches New Liquid: 0.01 inches Snow/Water Ratio: 70.0 Snow Density: 1.4% H2O Temperature: 13.6 F Sky: Light Snow (1 to 4 mm flakes) Snow at the stake: 11.0 inches

Event totals: 5.1” Snow/0.42” L.E. Details from the 12:00 P.M. Waterbury observations: New Snow: 1.2 inches New Liquid: 0.05 inches Snow/Water Ratio: 24.0 Snow Density: 4.2% H2O Temperature: 21.4 F Sky: Light Snow (2 to 7 mm flakes) Snow at the stake: 11.5 inches

Event totals: 3.9” Snow/0.37” L.E. Details from the 6:00 A.M. Waterbury observations: New Snow: 1.4 inches New Liquid: 0.08 inches Snow/Water Ratio: 17.5 Snow Density: 5.7% H2O Temperature: 19.6 F Sky: Light Snow (4 to 10 mm flakes) Snow at the stake: 11.0 inches

Event totals: 2.5” Snow/0.29” L.E. Details from the 10:00 P.M. Waterbury observations: New Snow: 2.5 inches New Liquid: 0.29 inches Snow/Water Ratio: 8.6 Snow Density: 11.6% H2O Temperature: 13.5 F Sky: Light Snow (1 to 5 mm flakes) Snow at the stake: 10.0 inches

I actually took another look at the BTV NWS website around midday and saw that they’ve updated the projected accumulations map from the one I saw this morning – I guess the old one was from last night. This new one seems more in line with what I’m seeing in the point forecasts, with much more 8-12” coverage and some of that 12-18” shading along the spine near Mansfield. The point forecast there does suggest roughly 12-20” through tomorrow night, so that matches up reasonably. That’s more aggressive than the numbers that are mentioned in the BTV NWS forecast discussion, but they really just mentioning the front end numbers there and note that there will be more in the higher terrain. If there’s only a half inch of liquid equivalent in total then that would be tough to reach, but if it’s 0.75” or 1.00” of liquid, combined with upslope snow ratios, getting a foot of snow at elevation would be no problem. Some of the mesoscale models do get up into that range of liquid through Monday, but we’ll just have to see as we get a bit closer. I suspect the BTV NWS will have an update on their upslope thoughts with their afternoon discussion, so we’ll get their thoughts at that point. Updated map is below:

I quoted PF’s thoughts along with yours – I’d say the BTV NWS maps I posted above include the upslope component of the storm in the totals, since they go through 7:00 P.M. tomorrow. From what I’ve seen, that’s why those areas of 8-12” are shown in the Northern Greens vs. the Central Greens. .NEAR TERM /THROUGH TONIGHT/... As of 624 AM EST Saturday...Winter Weather Advisories remain in effect for the entire forecast area, valid from 1 PM this afternoon to 4 PM Sunday. The center of the low will ride up the Saint Lawrence Valley early Sunday morning, allowing strong southerly flow to veer to the west. At this point, expecting snow to become more tied to terrain, with downsloping hole emerging the Champlain Valley and continued upslope snow over the northwestern Adirondacks and the northern Greens. This pattern will continue through the day Sunday, with little additional accumulations expected in valley locations but another few inches over higher terrain during the day.

Does BTV make those ratio maps as well? I looked around a bit on their site but didn’t see them - it would be great to monitor what they suggest vs. what analyses reveal.

I’ve got the latest maps from the BTV NWS for upcoming Winter Storm Jacob. The point forecast here has seen a bit of a bump with the latest update, suggesting 6-12” through tomorrow night. We’re in the 6-8” shading on the projected accumulations map, although there is some 8-12” shading nearby as well that covers the higher elevations around here.

It looks like this storm is complete at our site, so 11.8” Snow/0.65” L.E. should be the final totals. This was the 30th accumulating storm of the season, and so far the largest with respect to snowfall.

Event totals: 11.8” Snow/0.65” L.E. Details from the 6:00 A.M. Waterbury observations: New Snow: 0.6 inches New Liquid: 0.04 inches Snow/Water Ratio: 15.0 Snow Density: 6.7% H2O Temperature: 1.2 F Sky: Mostly Cloudy Snow at the stake: 11.0 inches

Event totals: 11.2” Snow/0.61” L.E. Details from the 10:00 P.M. Waterbury observations: New Snow: 4.2 inches New Liquid: 0.11 inches Snow/Water Ratio: 38.2 Snow Density: 2.6% H2O Temperature: 16.9 F Sky: Snow (3 to 15 mm flakes) Snow at the stake: 11.5 inches

We were at a school meeting tonight and I got a text alert of an updated Winter Weather Advisory for our area. The BTV NWS talks about it in their discussion: .NEAR TERM /THROUGH FRIDAY NIGHT/... As of 649 PM EST Thursday...Have issued winter wx advisory for the western slopes and mountains of central/northern VT, including the NEK thru 05z as crnt headline was expiring at 7 PM. Thinking the combination of additional snowfall of 2 to 4 inches and very strong/gusty winds will produce areas of blowing/drifting of snow, along with continued poor traveling conditions. Have received several reports of near white conditions across north/central VT this evening, so advisory looks reasonable.

We’re just passing 11” now, so that’s certainly a possibility. My next analysis is at 10:00 P.M. so we’ll see where we are at that point. With the snow on the back side of this storm it’s actually become that largest we’ve seen here this season, moving ahead of the 8.4” storm back on December 6th.

Event totals: 7.0” Snow/0.50” L.E. Details from the 4:00 P.M. Waterbury observations: New Snow: 4.2 inches New Liquid: 0.28 inches Snow/Water Ratio: 15.0 Snow Density: 6.7% H2O Temperature: 27.5 F Sky: Snow (5 to 10 mm flakes) Snow at the stake: 8.0 inches The roads in Burlington were really in good shape when I left today, they were just wet and no snow was falling. That was the situation all the way through to Richmond, but changed as got onto Route 2. Clear tire tracks of pavement were available for a while, and then snow started picking up as I got to Bolton. By the time I got up to the house, snowfall had intensified to the point that visibility was down to about ¼ mile. The snowfall has been coming in pulses and bands as the radar shows:

Seeing this, I just did a quick check outside my lab here at UVM and measured 5.5 inches of snow. As PF mentioned, it’s quite picturesque because the snow is sticking to everything and wind hasn’t really been an issue yet. It looks like we’ve picked up right around 6 inches at the house in Waterbury.

Event totals: 2.8” Snow/0.22” L.E. Details from the 6:00 A.M. Waterbury observations: New Snow: 2.8 inches New Liquid: 0.22 inches Snow/Water Ratio: 12.7 Snow Density: 7.9% H2O Temperature: 31.3 F Sky: Snow (3 to 15 mm flakes) Snow at the stake: 5.0 inches Snowfall started up at the house last night sometime after 10:00 P.M., and I found 2.8” on the boards this morning at observations time amidst fairly vigorous snowfall. I see from our webcam that we’ve had at least another couple of inches since then.

That’s great to hear – these first couple of systems were expected to be the smaller ones, so getting a dense accumulation like that is kind of a bonus, and perfect to have below whatever comes from these next events.

The latest maps from the BTV NWS for the storm in the area tomorrow are below. There are Winter Storm Warnings along the spine of the Northern Greens and parts of the Adirondacks, with Winter Weather Advisories elsewhere. The projected accumulations look similar to last night’s map, and have our area along the edge of the 6-8” and 8-12” zones. The point forecast here indicates roughly 6-10” of snow through Thursday evening, which seems in good agreement with the map.