OceanStWx

Scrawled across the desk journal of Ekster’s great great great great grandfather: “The snow, mark my words, doth ever arrive sooner than one might reckon, and the sleet likewise.”

I admittedly did not participate in the office run up to the storm, but from conversation I can say our post mortem caution flags should’ve been the dry air eating the northern edge versus the pretty simulated reflectivity and QPF maps presented, and falling for the NBM snow ratio trap. That second one shifted the heavy snow at least a row of counties north.

I'm not usually a pack retention kind of guy, but it's been impressive this season. I've had 6 days since 12/3 with a T or less on the ground. And I've been over 10 inches on the ground since 1/26. Chuck in a normal March snowfall and I'll be at the best snow season since 2018-2019.

Nah, it's under the "Lower Dynamics" section of most models (including the Euro!) but the FGEN is the last variable listed. Temp advection comes first so it's easy to miss. https://www.tropicaltidbits.com/analysis/models/?model=gfs&region=us&pkg=temp_adv_fgen_700&runtime=2025112912&fh=84

Can't tell whether Cantore had pants on or not because snow was over thy knickers.

Easy to spot the drift measurements in a storm like this up here.

Thank you for your service though, that 0.2" helps to define the edges of our snowfall map.

Part of me kind of misses the days of broad ranges with highlighted zones for "locally higher amounts" The problem these days is that you can try and forecast the band from PVD-GHG on this run. But then the next run it's ORH-BOS, so you increase the snow there. But you don't want to drop it from PVD-GHG just in case that was actually right. So the snow amounts are forever only going up until it's too late to recover from the messenger shuffle.

I wouldn't be surprised if post analysis counts it for Storm Data anyway. Some of it is a bit subjective, but if DAW, PSM, and PWM all hit blizzard up here how could I say coastal York wasn't also a blizzard.

In a typical developing (i.e. not peak intensity) storm your frontogenesis is going to be sloped towards the cold air. 850 is farther southeast than 700 mb, and so on. Lift tends to be maximized around 700 mb, hence congrats Dendrite. This storm bombed out a little farther south, so one of the first things I noticed was the position of the forecast 700 and 850 mb frontogenesis. While still sloped a bit, it's far more collocated/vertically stacked. That signaled to me that one major band would develop. And that look at 700 mb with a secondary band farther north suggested to me that it wasn't going to be a uniform precip shield. That a subsidence zone was possible between the two. I may have sent a text about toaster baths in the LWM area to @CoastalWx and @CT Rain Sunday. I made a little gif too, so you can see how the forcing is overlaid. I do think part of the problem with the secondary band was that it was advecting so much dry air into the storm. @dendrite posted somewhere along the line the map of RH, and 50% across central NH just wasn't going to get it done for that northern extent. It was like a dry wedge in the usually CAD spots.

One of the weirdest storms I’ve ever worked up here. Huge bust on snow totals - I have nothing on my snow board and snow depth went down a half inch today. I would guess I have around 2”. BUT PWM did verify a blizzard warning.

The reality is that outside of some real fluffy lake effect type stuff, measuring every 24 vs every 6 hours is only going to move your SLR from 12:1 to 14:1 not 12:1 to 20:1.

I think it's only required if they are paid observers. Either a volunteer near the airport or a FAA contracted observer at the airport.

Correct, last I saw officially you only need once in 24 hr measurement, but can clear up to every 6 hours.

At some point this year I would imagine, the evaluation period ended 12/1.

The NBM includes just about everything. In the extended it's primarily the ensembles members and then starts to bring in meso models in higher weights as you get inside 36 hours. There is dynamic weighting based on recent model performance (which is great when the pattern is stable, not so great when big changes occur). And some NBM fields are bias corrected on a grid by grid basis. Overall it's pretty good, but there are blind spots that humans can still improve on.

Unfortunately ASOS is king, and that liquid is what goes in for the climate. Even if the snow observer reports more (or less).

You can see from the study that only 1 in 4 obs is greater than 13:1 in SNE, maybe 1 in 10 greater than 20:1. Even factoring in people who measure once when the storm is done or the next morning with compaction, you're maybe moving the SLR 2 inches, not 5+.

We're still getting used to the forecast process now, and the NBM is good, but it still has some big holes. One is that it provides us with snow ratios, but it nearly always too high. It is too frequently in the 15-20:1 range. As an example for BOX's CWA, if you just had your extended forecast living in the 8-14:1 range you would be a lot less susceptible to these kinds of NBM busts.

@ORH_wxman Honestly he may have even done the work 20 years ago.

They are just like a coop, once daily measurement in the morning. But they will report to us on the 6 hours when they are in the office.

2 NNW is Pennichuck water. Their data is pretty meh overall, they do us a free service but there are occasional mistakes and they like their "round" numbers x.0 and x.5. The Hudson coop had 28.6" and is a former met, so pretty reliable obs there.

It won't necessarily get weaker, but you will see the band contract in size as the warm advection moves north and it becomes more driven purely by deformation.

Once a certain amount of time passes it is no longer a local WFO thing. Only NCEI can change it, so IIRC when Will pieced together the missing records it was too late for BOX to change things. And NCEI is notoriously unwilling to change data (with good reason, don't need ulterior motives driving data changes).