2018/19 Winter Banter and General Discussion - We winter of YORE

[toller65]

Sugarloaf ski resort reached 206" for the season on Sunday, may be some epic spring skiing

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[DavisStraight]

17 minutes ago, toller65 said:

Sugarloaf ski resort reached 206" for the season on Sunday, may be some epic spring skiing

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One of my favorite places, if only I could ski, spent last weekend in Vermont, wasn't bad up there either.

[OceanStWx]

The NWS decided to host an internal snowfall contest this season, similar to severe weather contests in the past couple of years. A good way for forecasters to stay sharp on skills that they may not always flex at their local WFOs. 

For those super interested we use a binormal probability density function, which in more simple terms means we pick an expected value and then adjust the tails (10th/90th percentiles) of the range based on our own confidence. This is a version of how we produce those snow probability maps on the website.

You're looking at a reliability diagram for >6 inches of snow for the NWS forecasters participating in said snowfall contest. What this tells us is how reliable a forecast is (no shit right?). A perfectly reliable forecast would follow the diagonal from the bottom left to the top right (i.e. if we forecast a 50% chance of something happening it should happen 50% of the time). Now we more or less do this through 30% chance. After 30% though we start to tail off to the right, this is an overforecast bias. You see this with a 90% forecast for >6" only verifying like 55% of the time. 

I can't say I'm shocked to see this either. Figuring out why would be interesting (bad model QPF?). This isn't that small a sample size either, 3 weeks in averaging between 20 and 50 forecasts a day has us approaching 1000 forecasts. 

It's also true across all snowfall amounts, EXCEPT 18" when we develop a bit of a dry bias. 

[HoarfrostHubb]

Some might say it is due to luck...

[HoarfrostHubb]

7F again

[Ginx snewx]

 9 degrees, big dogs having issues with partially frozen pack with break through.  9.0 depth

[weatherwiz]

8 hours ago, OceanStWx said:

That came up after the Joplin EF5, more specifically whether there should be a mandate for new construction to require a shelter. But people don't like governments (state or otherwise) telling them what to do, even if that is for their own safety.

Regardless, we're advancing tornado science quite a bit, but I don't think we're advancing the messaging/preparedness quite as fast.

Looks like perhaps AR or N LA as a hot spot? Quite the impressive overlap of parameters across those areas. I'm sure that will change, but for now the look is quite impressive. 

The messaging/preparedness aspect is very difficult, especially with regards to tornadoes. Even during the biggest outbreaks of the season when you have a large geographical area highlighted for severe thunderstorms and you have mention of tornadoes, it's still really only a small percentage of area affected by tornadoes and you sort of wonder if most people brush off the threat or just don't care to prepare until they're in a warning or they see conditions deteriorating rapidly...and by then it's too late. 

From my limited experience with work and communicating, the biggest challenge is people still want to go about their everyday lives (understandable) and even when you mention how bad the weather may be they'll still take risks. 

[dendrite]

2.8°

So over this crap. 

[Ginx snewx]

11 minutes ago, dendrite said:

2.8°

So over this crap. 

Have to figure this weeks cold will be the coldest from now on.

[powderfreak]

Face masks and hand warmers today on the slopes.  Wind chills currently -30s.

[OceanStWx]

22 minutes ago, dendrite said:

2.8°

So over this crap. 

Sorry KHVR is going to claim sick of this shit over KOOP.

[dendrite]

2 hours ago, OceanStWx said:

The NWS decided to host an internal snowfall contest this season, similar to severe weather contests in the past couple of years. A good way for forecasters to stay sharp on skills that they may not always flex at their local WFOs. 

For those super interested we use a binormal probability density function, which in more simple terms means we pick an expected value and then adjust the tails (10th/90th percentiles) of the range based on our own confidence. This is a version of how we produce those snow probability maps on the website.

You're looking at a reliability diagram for >6 inches of snow for the NWS forecasters participating in said snowfall contest. What this tells us is how reliable a forecast is (no shit right?). A perfectly reliable forecast would follow the diagonal from the bottom left to the top right (i.e. if we forecast a 50% chance of something happening it should happen 50% of the time). Now we more or less do this through 30% chance. After 30% though we start to tail off to the right, this is an overforecast bias. You see this with a 90% forecast for >6" only verifying like 55% of the time. 

I can't say I'm shocked to see this either. Figuring out why would be interesting (bad model QPF?). This isn't that small a sample size either, 3 weeks in averaging between 20 and 50 forecasts a day has us approaching 1000 forecasts. 

It's also true across all snowfall amounts, EXCEPT 18" when we develop a bit of a dry bias. 

Not sure which sites you’re forecasting for at which times, but I find a lot of my snow ratios seem to be skewed toward higher density snowfalls. This is unscientific, but it seems we have a peak around 9-10:1 for overrunning events and then it tails off toward 25:1. The few times I’ve checked the GYX ratio maps I usually see something that looks Kuchera-ish with 13:1 south and a gradient working up to 16:1 in the mtns...more or less hovering near climo. I’ll admit, I don’t check that product a lot so I may be off base on that. But maybe there’s an overestimate of ratios when forecasting for 6+? 

Some of these climo ratios for sites are probably a hair too high anyway given undercatch of the precip gauges. The AWPAGs are better now, but how were climo sites at BOS and CON getting their water equivs back in the day? Melted cores? Catching snow in the can and melting it down? Heated tippers like in the 90s? 

I think I tend to lean conservative. I’m more worried about what can go wrong than what could go right. But then again I grew up as a Red Sox fan pre-2004. 

[dendrite]

They can “havre” that shit. 

[weatherwiz]

I never noticed this, but on bufkit on the skew t there are these blue dashed lines for the -12C to -18C isotherms. 

[weatherwiz]

12 minutes ago, weatherwiz said:

I never noticed this, but on bufkit on the skew t there are these blue dashed lines for the -12C to -18C isotherms. 

It's actually pretty cute. Can turn off the snow growth overlay now on the skew-t. Get too many different colored lines going on the skew-t. 

[OceanStWx]

51 minutes ago, dendrite said:

Not sure which sites you’re forecasting for at which times, but I find a lot of my snow ratios seem to be skewed toward higher density snowfalls. This is unscientific, but it seems we have a peak around 9-10:1 for overrunning events and then it tails off toward 25:1. The few times I’ve checked the GYX ratio maps I usually see something that looks Kuchera-ish with 13:1 south and a gradient working up to 16:1 in the mtns...more or less hovering near climo. I’ll admit, I don’t check that product a lot so I may be off base on that. But maybe there’s an overestimate of ratios when forecasting for 6+? 

Some of these climo ratios for sites are probably a hair too high anyway given undercatch of the precip gauges. The AWPAGs are better now, but how were climo sites at BOS and CON getting their water equivs back in the day? Melted cores? Catching snow in the can and melting it down? Heated tippers like in the 90s? 

I think I tend to lean conservative. I’m more worried about what can go wrong than what could go right. But then again I grew up as a Red Sox fan pre-2004. 

We can forecast anywhere in CONUS for a 24 hour period ending 12z.

Snow ratios definitely skew high. My go-to was always: http://www.eas.slu.edu/CIPS/SLR/slrmap.htm, which uses coop SRG liquid and not automated data. Still issues but not as many with that type of measurement. This may actually have the opposite bias, where some coops estimate snow based off of liquid and skew things towards 10:1 (especially for small sample size WFOs).

Our SLR product is going to be hit and miss right now. If the forecaster edits those grids (like I do) they’ll be representative of the forecast. If they don’t, it defaults to the model blend which does skew high in the terrain.

[weatherwiz]

Looking at the pattern moving forward this could be one of the more active March's in terms of severe in a while. The past 10-years or so have been relatively quiet overall. I think even 2011 was on the quiet side? I know there were one or two years it was pretty active. Want to say like 2010 and 2012 or 2013?

[dendrite]

45 minutes ago, weatherwiz said:

It's actually pretty cute. Can turn off the snow growth overlay now on the skew-t. Get too many different colored lines going on the skew-t. 

Put this line in BUFKIT

[weatherwiz]

Just now, dendrite said:

Put this line in BUFKIT

I would probably get James-like output for snow totals 

[weatherwiz]

The model's structure of that high pressure in the SE tomorrow is pissing me off. 

[HoarfrostHubb]

2 hours ago, Ginx snewx said:

Have to figure this weeks cold will be the coldest from now on.

Yeah.  Fish was mentioning that today/tonight are probably the coldest for the remainder of the season.   I agree, but still some cold shots in store methinks

[weatherwiz]

2 minutes ago, HoarfrostHubb said:

Yeah.  Fish was mentioning that today/tonight are probably the coldest for the remainder of the season.   I agree, but still some cold shots in store methinks

Hopefully pretty soon our cool shots are like 50's and 60's...and then 70's once we get deeper into summer.

[weatherwiz]

Is there a way to find out if a particular location had frost? 

[Ginx snewx]

3 hours ago, OceanStWx said:

We can forecast anywhere in CONUS for a 24 hour period ending 12z.

Snow ratios definitely skew high. My go-to was always: http://www.eas.slu.edu/CIPS/SLR/slrmap.htm, which uses coop SRG liquid and not automated data. Still issues but not as many with that type of measurement. This may actually have the opposite bias, where some coops estimate snow based off of liquid and skew things towards 10:1 (especially for small sample size WFOs).

Our SLR product is going to be hit and miss right now. If the forecaster edits those grids (like I do) they’ll be representative of the forecast. If they don’t, it defaults to the model blend which does skew high in the terrain.

Tough to forecast here this year when my ratio so far this winter is this 

 

37.2 in. Snow 5.43 in w/e 6.8 ratio ouch

[tamarack]

7 hours ago, OceanStWx said:

Sorry KHVR is going to claim sick of this shit over KOOP.

That is impressive!  28°+ BN this year and 21° BN last.  I've seen departures approach 15° in the Northeast (2/1981, 12/1989, 2/2015) but no full-month departures have even sniffed at 20.  (AFAIK)

[Ginx snewx]

9 minutes ago, tamarack said:

That is impressive!  28°+ BN this year and 21° BN last.  I've seen departures approach 15° in the Northeast (2/1981, 12/1989, 2/2015) but no full-month departures have even sniffed at 20.  (AFAIK)

They are -43.2 this month

[powderfreak]

Doing a snow survey today at 1,500ft near the Stowe base area...the location is at the RT 108 winter closure gate on the southeast side of Smugglers Notch.  The snowpack is such that you just walk over the gate without even knowing it's there.

Most of the 1,500ft depths average 44-48" from what I saw.  The average was 46"...and it is pure glacier about a foot down.  Like it was very difficult to get the Adirondack Snow Sampler into this snowpack even with it's metal teeth.

With a 46" depth, there was an average of 15.0" of water in the snowpack, though some readings were as high as 16.5".

So well over a foot of water is sitting in the snowpack at the base elevations of the ski areas up this way...

 

The historic "Barnes Camp" location that was renovated a few years back near where the snow plot is...you go up stairs to get into this place yet the snow is still almost half-way up the first story.

 

 

[powderfreak]

Up at 3,700ft the NOAA/NWS camera stopped working so we are providing them with the COOP depth readings via photo on a daily basis or whenever we can get up there.

Here's today's... it's really hard to comprehend that you are 9 feet off the ground when walking around up there.  It's solid enough that you only sink in about 8" or so.

 

A picture of the NOAA/NWS camera up there...this thing is like 15 feet off the ground at it's top!

[wxeyeNH]

PF,  I don't know if you ever look at the Mammoth Mtn webcams.  They have a great webcam network.  Up at the top they have a webcam and I watch it from time to time.  At the summit is a totem pole type sign.  In the late summer when the ground finally becomes bare you can see the whole thing.  I don't know the actual height but I guess near the size of a telephone pole.  I took a look last week and only the top was visible.  Must have a depth up there of 15 or 20 feet.  Just incredible depths.  Here's the pic form a week or two.  Snowdepth has probably increased since then.  Just looked but its obscured in fog and snow.

[Ginx snewx]

4 minutes ago, wxeyeNH said:

PF,  I don't know if you ever look at the Mammoth Mtn webcams.  They have a great webcam network.  Up at the top they have a webcam and I watch it from time to time.  At the summit is a totem pole type sign.  In the late summer when the ground finally becomes bare you can see the whole thing.  I don't know the actual height but I guess near the size of a telephone pole.  I took a look last week and only the top was visible.  Must have a depth up there of 15 or 20 feet.  Just incredible depths.  Here's the pic form a week or two.  Snowdepth has probably increased since then.  Just looked but its obscured in fog and snow.

Don't forget that's groomed