Welcome to American Weather
Sign in to follow this  
Followers 0
powderfreak

NNE Fall Thread

865 posts in this topic

2 minutes ago, alex said:

I wish our snow depth were anywhere near that. :huh:

Really coming down though, nice surprise!

 

Mountains? A lot East was from the failed rainer when it had snow east

Share this post


Link to post
Share on other sites
40 minutes ago, powderfreak said:

Everyone is caught pants down.  I hear 89 is a ****show.

This is legit.

Pants down and :weenie:'s out

1 person likes this

Share this post


Link to post
Share on other sites
14 minutes ago, powderfreak said:

True true.  It's either it happens or it doesn't.  

When the model spits out 20% POP after 12z this morning...we'll we got the 20% chance it goes to town.  Say 8 out of 10 other times nothing happens but some Mtn flurries.

 And given where that short wave came from, it could have not been sampled properly either. A few things just added up and it turn nothing into something. That's the fun of weather.  Nice to see you fellas enjoying this. Funny, I may have to eat my own words because our busts usually involve  fake snow too,  LOL. 

Share this post


Link to post
Share on other sites
5 minutes ago, CoastalWx said:

 And given where that short wave came from, it could have not been sampled properly either. A few things just added up and it turn nothing into something. That's the fun of weather.  Nice to see you fellas enjoying this. Funny, I may have to eat my own words because our busts usually involve  fake snow too,  LOL. 

You're right about the snow growth though... 

Say 1.5-6.0" depending on location, and I'm guessing this is easily 25:1 and higher...JSpin in his calm/quiet spot but under the max orographic lift location probably squeaks out 40:1.    

So if you look at a "surprise" 1.5-6" that means the models missed what?  0.05"-0.15"?  That's such a small almost noise level QPF.  It's not like they missed a half inch of QPF.  

Funny how all that comes together and still produces a higher impact 3-hour crush job with no plows out while kids get out of school and hits the roads with inches before rush hour.

Share this post


Link to post
Share on other sites
8 minutes ago, powderfreak said:

You're right about the snow growth though... 

Say 1.5-6.0" depending on location, and I'm guessing this is easily 25:1 and higher...JSpin in his calm/quiet spot but under the max orographic lift location probably squeaks out 40:1.    

So if you look at a "surprise" 1.5-6" that means the models missed what?  0.05"-0.15"?  That's such a small almost noise level QPF.  It's not like they missed a half inch of QPF.  

Funny how all that comes together and still produces a higher impact 3-hour crush job with no plows out while kids get out of school and hits the roads with inches before rush hour.

Yes exactly re QPF. Just some slight underestimates can turn the forecast into one big bag of crap. 

Share this post


Link to post
Share on other sites
2 minutes ago, CoastalWx said:

Yes exactly re QPF. Just some slight underestimates can turn the forecast into one big bag of crap. 

This sorta happened on Friday up here. We had a great great set-up for powder snow but the temps didn't get to the snow growth level as predicted and we ended up with rods instead of dendrites....4" of rods is nice but at today's ratio's that would have been 10"

 

Share this post


Link to post
Share on other sites
6 minutes ago, eyewall said:

Looks like 5" on the JSpin webcam.

 

Yeah, that’s what I’m seeing; I’ll run liquid when I get home (not exactly sure when that will be based on the roads) and we’ll see what sort of ratios this event produced around here.

Share this post


Link to post
Share on other sites

Congrats to all that saw heavy squalls today.  About an inch here early this morning.  Just about all sublimated away today.  Town salted the roads to death which drives me nuts as I knew it would be gone in a couple of hours. Well if I can't see a white landscape at least we will have white salted roads!

Share this post


Link to post
Share on other sites

The gradient from Taft Corners to Winooski is pretty abrupt. From a few tenths to over 2 inches in Williston. It will be interesting to see what BTV reports.

Sent from my VS995 using Tapatalk

Share this post


Link to post
Share on other sites
1 hour ago, J.Spin said:

 

Yeah, that’s what I’m seeing; I’ll run liquid when I get home (not exactly sure when that will be based on the roads) and we’ll see what sort of ratios this event produced around here.

Yeah your area is ground zero for where people live, as usual.

Ski Patrol reporting a half a foot on Mansfield at 4pm.

Fun stuff.

Some parking lot shots from 2:30pm when there was around 3".

When it snows this hard at 1,500ft you can imagine what's going on 2,000 feet higher.

lQfuM37.jpg

9BLJgUy.jpg

 

2 people like this

Share this post


Link to post
Share on other sites
4 minutes ago, eyewall said:

The gradient from Taft Corners to Winooski is pretty abrupt. From a few tenths to over 2 inches in Williston. It will be interesting to see what BTV reports.

Sent from my VS995 using Tapatalk
 

Very sharp over here too.

I found like 2" at home but there's 4-5" a few miles west closer to the Spine.  J.Spin's got the sweet spot of the orographic lift.

Share this post


Link to post
Share on other sites

Definitely a lake enhanced band all the way from Huron/Georgian Bay area.  You take that narrow axis of moisture and then push it into the Greens and it snows.

Its tapered off up here and pushed just south of Mansfield/Stowe but still spraying right down the I-89/Winooski Valley area into J.Spin's area.  Definitely much lower snow rates but with fluffy snow it could still be quarter inch to half inch per hour in the most concentrated areas. 

The striations under the band are fairly interesting. 

VS4dkwG.gif

Share this post


Link to post
Share on other sites

Event totals: 5.6” Snow/0.10” L.E.

 

Details from the 5:00 P.M. Waterbury observations:

 

New Snow: 5.6 inches

New Liquid: 0.10 inches

Snow/Water Ratio: 56.0

Snow Density: 1.8% H2O

Temperature: 24.3 F

Sky: Snow (2-12 mm flakes)

Snow at the stake: 6.5 inches

 

The trip home from Burlington to Waterbury today was one of those typical journeys where you head into snowfall of ever-increasing intensity as you get deeper into the mountains.  The snow had really shut off in Burlington proper, but snowfall was quickly back in the air by Williston, and cranking right along by Richmond.  The driving conditions on I-89 weren’t bad, now that they’ve had plenty of time to work on it.

 

The snow is extremely dry, as upslope/lake-effect snow usually is, but I could certainly feel some resistance to it as I headed up the driveway.  With that said, I found 5.6 inches on the snowboard and only a tenth of an inch of liquid, so there’s no doubt that this stuff is comfortably in the realm of Champlain Powder™.

 

It’s still snowing pretty steadily out there, so there will be at least a bit more to add to the storm total.

Share this post


Link to post
Share on other sites

That's pretty awesome all kidding aside. I can't believe how calm the winds are with you Jspin. I'd have 4' at times if I had those conditions...lol. Just fluffies falling lightly. Classic good snow growth.

1 person likes this

Share this post


Link to post
Share on other sites
1 hour ago, backedgeapproaching said:

56-1, pretty efficient use of moisture..lol

JSpin--do you have data on highest ratios you have seen at your spot?

 

Yes, although there are some things to think about with respect to determining and reporting snow ratios.

 

I’ve recorded snow to liquid ratios up around 100 to 1 on numerous occasions, but that’s generally for stack depths <1”.  Getting really high ratios is much easier to when you’re talking sub-inch amounts of snow that are being measured, because the overall mass of snow in the stack is fairly small and less likely to crush the dendrites on the bottom.  Therefore, the deeper the stack/more mass there is in the stack, the harder it generally becomes to maintain very high ratios.  For a 5.6-inch stack of snow, today’s 56 to 1 is quite respectable, but in the context of looking for highest ratios that I’ve recorded, we’d want to set some sort of threshold, or thresholds for stack height.

 

Taking a quick look at last year’s data, a few notable snowfall ratios that I see are:

 

41 to 1 on a 7.7-inch stack (1:00 A.M., Mar 16th)

54 to 1 on a 4.9-inch stack (6:00 P.M., Feb 16th)

65 to 1 on a 1.3-inch stack (6:00 A.M., Feb 14th)

70 to 1 on a 0.7-inch stack (6:00 A.M., Dec 11th)

80 to 1 on a 1.6-inch stack (8:00 P.M., Feb 13th)

90 to 1 on a 0.9-inch stack (6:00 A.M., Feb 17th)

100 to 1 on a 1.0-inch stack (10:00 P.M., Dec 28th)

120 to 1 on a 1.2-inch stack (7:00 A.M., Jan 15th)

 

So you can see, the most extraordinary ratios are generally reserved for those samples with stack heights down in the ±1 inch range.  But with just a quick look at the list, you can tell that this afternoon’s 56 to 1 on a 5.6-inch stack is pretty darned respectable for the mass of snow that’s there.

 

Also note, there may be substantial rounding in the ratios when one gets down to those ±1 inch stacks, especially where the liquid is at 0.01”.  While my system for measuring the liquid, in which I use 1 mL through 25 mL serologic pipets, can easily get me down to resolutions of 0.001” with respect to the liquid I’m measuring, I end up rounding to the nearest hundredth of an inch because that’s the lowest resolution that we report for liquid to CoCoRaHS etc.  I have my Excel spreadsheet calculating the ratios after rounding to the nearest 0.01” of liquid because if you don’t, then there appears to be a discrepancy between the ratio calculated from the actual numbers you are displaying for liquid (measured to hundredths of an inch) and the snow depth (measured to tenths of an inch).  So, when I have a 0.01” of liquid in the data I report, it could actually be anything from 0.005” to 0.015”.  With respect to the amount of liquid, this rounding “should” basically average out in the aggregate, but you’d want to take any of those ratio calculations with 0.01” of liquid as “rough”.  Pay close attention to the last five examples in the list of ratios I gave above – you’ll note that in every case, the ratio is simply 100X (or in one case 50X) the depth of the stack.  That’s because all those liquid samples are rounded to 0.01” (or in that one case 0.02") of liquid, and the ratios are calculated off that rounded number.

 

In the sense of things “averaging out”, so to speak, I can give the ratios that would come from some of those samples without rounding:

 

That 120 to 1 ratio sample wasn’t actually 0.01” of liquid from 1.2” of snow, it was 0.015” of liquid from 1.2” of snow, which would be a ratio of 66.7 to 1.

 

That 100 to 1 ratio sample wasn’t actually 0.01” of liquid from 1.0” of snow, it was 0.005” of liquid from 1.0” of snow, which would be a ratio of 200 to 1 (probably not realistic, so who knows if a bit of liquid was lost, etc.)

 

Anyway, hopefully you get the idea – some of those 0.01”-based ratios that I report are going to be high, some are going to be low.

 

Stacking multiple cores (which I always do for those samples with low liquid amounts) helps to reduce the effects of rounding, and even just going to 0.02” of liquid in the calculation drops the rounding issue substantially.

 

To build on that point, the beautiful thing is, the larger the volume of liquid you’re measuring, the less that rounding to the nearest 0.01” matters, so this afternoon’s ratio calculation should be pretty robust because it was based on 0.10” of liquid (more actually, because I stacked two cores in this case).  Barring the aspects of experimental error, which I haven’t addressed here, the “rounding-induced error” associated with the calculation on that 56 to 1 ratio using 0.10” of liquid is only ±5%.  So that ratio from today is actually pretty accurate and representative.

1 person likes this

Share this post


Link to post
Share on other sites

Ended up with 1.75”-2”  As you can see, I’m practically as meticulous about measuring as JSpin. :lol:  Anyway, it was enough for me to take one of the snowmobiles out of the shed and burn around the yard a couple of times. I figured with the studs on it I was basically just aerating the lawn anyway lol. 

1 person likes this

Share this post


Link to post
Share on other sites
5 hours ago, powderfreak said:

Yeah your area is ground zero for where people live, as usual.

Ski Patrol reporting a half a foot on Mansfield at 4pm.

Fun stuff.

Some parking lot shots from 2:30pm when there was around 3".

When it snows this hard at 1,500ft you can imagine what's going on 2,000 feet higher.

lQfuM37.jpg

9BLJgUy.jpg

 

 

Those are some great shots of the snowfall – trying to catch images of snowfall and do it justice is one of my favorite photography challenges.

 

It looks like 6.1” is the final for the snowfall here, barring anything else falling tonight.  We were following a fairly average snowfall progression for the month, but this event had definitely pushed us several inches ahead of average pace.  We’re still not to the point of guaranteeing an above average month, but we’ll see how things go over the next 10 days.

Share this post


Link to post
Share on other sites
5 hours ago, J.Spin said:

Event totals: 5.6” Snow/0.10” L.E.

 

Details from the 5:00 P.M. Waterbury observations:

 

New Snow: 5.6 inches

New Liquid: 0.10 inches

Snow/Water Ratio: 56.0

Snow Density: 1.8% H2O

Temperature: 24.3 F

Sky: Snow (2-12 mm flakes)

Snow at the stake: 6.5 inches

 

The trip home from Burlington to Waterbury today was one of those typical journeys where you head into snowfall of ever-increasing intensity as you get deeper into the mountains.  The snow had really shut off in Burlington proper, but snowfall was quickly back in the air by Williston, and cranking right along by Richmond.  The driving conditions on I-89 weren’t bad, now that they’ve had plenty of time to work on it.

 

The snow is extremely dry, as upslope/lake-effect snow usually is, but I could certainly feel some resistance to it as I headed up the driveway.  With that said, I found 5.6 inches on the snowboard and only a tenth of an inch of liquid, so there’s no doubt that this stuff is comfortably in the realm of Champlain Powder™.

 

It’s still snowing pretty steadily out there, so there will be at least a bit more to add to the storm total.

Wow at those ratios!  That's pretty cool. I was thinking 40:1.  The atmospheric conditions that have to come together for that... though its basically a cold airmass and some moisture being pushed over the mountains.  You get that solid orographic lift coupled with prime dendritic snow growth zone and it snows.  It may be high-ratio but its a fun afternoon of weather.

Share this post


Link to post
Share on other sites
9 hours ago, J.Spin said:

 

Yeah Will, I saw your post about the shortwave in the other thread.  The BTV NWS actually had it mentioned in their discussion, but they’re now starting to update the discussion and are pointing out that the setup has been more potent than guidance suggested:

 

.NEAR TERM /THROUGH TUESDAY NIGHT/...

As of 1247 PM EST Monday...well, still trying to play some catchup with the combo Lakes Superior/Huron snow band that has moved across northern NY and now into northern VT. The snowfall intensity and coverage has ended up being more than even the hi-res models indicated, at least here locally in the Champlain Valley and along the western slopes. Given that it`s snow, radar doesn`t detect it very well, so it wasn`t until it started snowing here in the Champlain Valley that we could "see" it on radar. Appears that there was some blocked flow that developed as well. That said, it appears that using the GOES-16 IR channel has been working well by using the -25C cloud top temperatures to show where the best snows are occurring. Over the last hour, the overall trend has been for cloud tops to start to warm. Although the hi-res models were doing fairly well earlier this morning, they have totally missed the snow here in the Champlain Valley and across the Green Mountains. Have tried to enhance coverage of the snow above what the models give, but even then, I`m still too low.

 

Will probably continue to forecast chase the snow band over the next few hours. However, by this evening, wind flow will turn more southwest and be disruptive to the bands that are out there. So as we go on toward midnight, we will only be left with clouds and a few flurries, especially across northern NY.

They do some pretty solid work. It'll be nice when we absorb some of their forecasters when the consolidation starts. :devilsmiley:

This was a good example of the shortwaves Will always talks about, where the flow is zipping along and the models don't see it until it is 00 hour. This wave happened to be a little more amplified than forecast. Hi-res models did whiff completely on it though. I took a look at the forecast soundings for HIE though, and saw saturated to near-saturated low levels and the DGZ was nearly to the surface. I don't care if 700 mb isn't saturated, that will produce snow showers every time with westerly flow over the terrain. Chuck in some lake enhancement, and you have a recipe for an overperformer. 

I think this settles it though, we're going to add Pittsburg as a verification point for snowfall. We're going to make snow forecasts great again.

Share this post


Link to post
Share on other sites
11 minutes ago, J.Spin said:

 

Those are some great shots of the snowfall – trying to catch images of snowfall and do it justice is one of my favorite photography challenges.

 

It looks like 6.1” is the final for the snowfall here, barring anything else falling tonight.  We were following a fairly average snowfall progression for the month, but this event had definitely pushed us several inches ahead of average pace.  We’re still not to the point of guaranteeing an above average month, but we’ll see how things go over the next 10 days.

Sunday looks pretty decent there...obviously a ways out still and something as nuanced as upslope can change a lot, but most guidance has the ULL with decent synoptic moisture on NW flow. Some even try to give an inverted trough look.

Share this post


Link to post
Share on other sites
13 minutes ago, powderfreak said:

Wow at those ratios!  That's pretty cool. I was thinking 40:1.  The atmospheric conditions that have to come together for that... though its basically a cold airmass and some moisture being pushed over the mountains.  You get that solid orographic lift coupled with prime dendritic snow growth zone and it snows.  It may be high-ratio but its a fun afternoon of weather.

The DGZ just stayed right in the mid to upper slope levels through most of the day, so your max low level terrain forced lift was in a perfect spot.

Share this post


Link to post
Share on other sites

Event totals: 6.1” Snow/0.11” L.E.

 

Details from the 6:00 A.M. Waterbury observations:

 

New Snow: 0.5 inches

New Liquid: 0.01 inches

Snow/Water Ratio: 50.0

Snow Density: 2.0% H2O

Temperature: 19.8 F

Sky: Mostly Clear

Snow at the stake: 5.0 inches

Share this post


Link to post
Share on other sites
3 hours ago, J.Spin said:

Event totals: 6.1” Snow/0.11” L.E.

 

Details from the 6:00 A.M. Waterbury observations:

 

New Snow: 0.5 inches

New Liquid: 0.01 inches

Snow/Water Ratio: 50.0

Snow Density: 2.0% H2O

Temperature: 19.8 F

Sky: Mostly Clear

Snow at the stake: 5.0 inches

Didn't settle too much overnight... I'm actually a bit impressed that after 6" of 56:1 (!) there's 5" on the ground today.  Still crazy at how high that ratio is for a stack that big.

Of course today's warmth is taking care of the snow in my yard rather quickly but I only had 2".  

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0

  • Recently Browsing   0 members

    No registered users viewing this page.