J.Spin

Some discussion of the upcoming snow from the BTV NWS – I haven’t heard PF mention it yet, but guess there’s some upslope potential: Area Forecast Discussion National Weather Service Burlington VT 648 PM EST Wed Nov 27 2019 NEAR TERM /THROUGH THURSDAY NIGHT/... As of 541 PM EST Wednesday... Expect rain to change to snow across the summit by 06z as 850mb temps drop below 0c and a mix of rain/snow in the valley by 09z Thurs, with some light snow accumulation possible on the eastern side of the CPV by 12z Thurs. Best snow accumulations of 2 to 6 inches will be western Slopes from mansfield to jay peak above 2000 feet late tonight into Thursday, as favorable moisture, upslope flow, and caa will produce accumulating snowfall. Noticed high resolution btv 4km has qpf of 1.0 to 1.25 in the form of snow thru 18z Friday, but issue will be lack of moisture in the favorable snow growth zone after 18z Thursday, which will limit qpf/snowfall.

Event totals: 1.0” Snow/0.10” L.E. Details from the 6:00 A.M. Waterbury observations: New Snow: 0.1 inches New Liquid: Trace Temperature: 33.1 F Sky: Cloudy Snow at the stake: 3.0 inches

Event totals: 0.9” Snow/0.10” L.E. Details from the 4:00 P.M. Waterbury observations: New Snow: 0.9 inches New Liquid: 0.10 inches Snow/Water Ratio: 9.0 Snow Density: 11.1% H2O Temperature: 33.3 F Sky: Light Snow (1 to 2 mm flakes) Snow at the stake: 3.0 inches

I hadn’t passed along the BTV NWS map updates from earlier today, so I’ve got those pasted in below. Since 11:00 A.M. when the snow started up, it’s been just sort rolling along at a light pace of ~¼”/hr. It’s definitely whitening up the old snow nicely and covering up any grassy spots that started to appear. In general it’s just a quiet, snowy day thus far.

Hehe, yeah, you can definitely do that a lot more up here. Folks just need to remember that it’s a perk when it’s happening in May and June as well. I find that for some reason there can be less embracing of the cool temperatures by the public at that time of year.

Well, if those bands down in Addison County want to continue pushing up this way, I don’t think anyone would complain (unless they’re some sort of mixed precipitation or something):

Indeed, your comment didn’t come off in a sensationalist way at all – you were addressing a bit of a deficiency in modeling that is something poorly addressed, and we’ve seen it play out that way a number of times.

I didn’t see traces of any precipitation overnight, but the first flakes of this event are just starting to fall here in Waterbury.

Right, but you even pointed out that you were thinking out of the box and wouldn’t necessarily have gone that route if you were actually responsible for the forecast. I think that disparity speaks to what does on for some of the “weenies” in the forum – if they have zero responsibility related to their predictions, they’re sort of free to go wild and say whatever they want, then you meteorologists have to reign them in. I get it that this sort of a “hobby” for many people, but from my perspective, the grandiose snowfall predictions always come off as sort of “weenie-ish?” (I guess that’s a term) I assume it’s all part of the drama.

The whole original comment is meant to simply be a troll though. Forum members have routinely been pointing out the reality of SNE November snowfall averages, so the statement is akin to saying, “May through October really went out with a whimper for snow lovers”.

Agreed, normal November snowfall through the 23rd of the month here is 8.1”, and we’re at roughly double that amount with another potential storm on the doorstep. This is far from a whimpering November – sure we’re behind where we were last year at this time on snowfall, but it’s actually been quite good.

I just got a text alert that we’re under a Winter Weather Advisory.

Here’s the midday projected snow accumulations map from the BTV NWS.

That certainly seems possible based on some guidance. I really like that the BTV NWS typically seems to take their snow forecasting step by step and only slowly ramps it up as needed. We don’t have massive population centers that lead to huge traffic pileups and the folks around here are well acclimated to the snowy climate, so I think they have a bit more leeway to take a conservative approach. That’s the way it feels to me at least, even if it’s not official policy.

The forecast around here has changed fairly dramatically from even yesterday evening, where there wasn’t much precipitation expected with this next system, but now a Winter Storm Watch is in place: Area Forecast Discussion National Weather Service Burlington VT 413 AM EST Sat Nov 23 2019 .NEAR TERM /THROUGH SUNDAY/... As of 334 AM EST Saturday... We`ve seen a rather dramatic shift northward shift with the 00Z NWP guidance suite with the track and evolution of strong low pressure affecting our region for Sunday. The 00Z NAM, GFS and ECMWF all indicated the northward shift, with 00Z NAM and ECMWF indicating sfc low track across RI and sern MA (984mb low in operational 00Z ECMWF soln). Likewise, system development occurs early enough that models indicate a closed 700mb low to our south across sern NY/Long Island around 18Z Sunday. These trends are favorable for a period of moderate to heavy precipitation across central/ern portions of our forecast area, especially Sunday afternoon.

Event totals: 0.1” Snow/0.08 L.E. The most recent storm has cleared out, so the above snow and liquid values are the final totals here. Details from the 6:00 A.M. Waterbury observations: New Snow: 0.1 inches New Liquid: Trace Temperature: 21.7 F Sky: Mostly Clear Snow at the stake: 2.0 inches

Looks good now – I just made a new event for what we’ve got going on this evening and everything seemed to work. Thanks for the quick fix!

Hi Kevin, it looks like there might be some sort of issue with the “season” field? No options come up in the pull down menu for that field, and I can't seem to make a new entry without something entered there?

The incoming snow just hit here in BTV – ramped right up from nothing to some brisk snowfall/graupel.

Event totals: 0.9” Snow/0.07 L.E. Details from the 6:00 A.M. Waterbury observations: New Snow: 0.5 inches New Liquid: 0.02 inches Snow/Water Ratio: 25.0 Snow Density: 4.0% H2O Temperature: 27.7 F Sky: Mostly Clear Snow at the stake: 3.5 inches

Event totals: 0.4” Snow/0.05 L.E. Details from the 6:00 P.M. Waterbury observations: New Snow: 0.2 inches New Liquid: 0.05 inches Snow/Water Ratio: 4.0 Snow Density: 25.0% H2O Temperature: 32.7 F Sky: Light Snow (1 to 2 mm flakes) Snow at the stake: 3.5 inches

Event totals: 0.2” Snow/Trace L.E. The BTV NWS indicates that today’s snowfall is due to an upper-level shortwave trough, and at the house we’ve seen some accumulation of very dry snow. Details from the 6:00 A.M. Waterbury observations: New Snow: 0.2 inches New Liquid: Trace Temperature: 31.6 F Sky: Light Snow (2 to 5 mm flakes) Snow at the stake: 3.0 inches

Event totals: 0.2” Snow/0.29” L.E. This afternoon’s snow didn’t really accumulate much at the house, just a slushy coating of 0.1”. I think Burlington accumulated a bit more than that, but based on what I saw on our webcam we didn’t get the big aggregates that I saw there this afternoon. Details from the 2:00 P.M. Waterbury observations: New Snow: 0.1 inches New Liquid: 0.03 inches Snow/Water Ratio: 3.3 Snow Density: 30.0% H2O Temperature: 36.7 F Sky: Light Snow (1 mm flakes) Snow at the stake: 3.0 inches

Although not pulling off the 3 x 24” in one season, while looking through the data I did find another related occurrence to go along with the 6 x 12” from 2010-2011. In 2008-2009, there were 12 storms of 6” or more, which is the only season in my data set hitting that number. The 6” mark is another threshold for significant storms since it’s around that base Winter Storm Warning level (from what I understand, our criteria here are 6” in 9 hours or 9” in 24 hours?). As PF will point out though, with the extended nature of storm cycles up here, there are probably a number of 6” storms that won’t warrant a Winter Storm Warning.

I’m trying to think of the best way to check on that with respect to using my data, but smaller storms are just more frequent than larger storms in general, so one would really have to compare distributions of storm sizes among different sites. From my data set, the whole number averages for occurrence of storms per season based on some common accumulation thresholds of 3” or more are as follows: 3”+: 15 4”+: 12 6”+: 7 8”+: 5 10”+: 4 12”+: 3 15”+: 2 20”+: 1 24”+: 0.5 I went with whole numbers for simplicity, but all the mean values are actually within a tenth or two of these numbers. I had to round to the nearest 0.5 for the 24”+ storms because they are relatively infrequent. I can certainly get analysis for percentages in certain storm size ranges if there are specific ranges that people want to compare to.