Dec 16-17 obs/nowcast thread

[Henry's Weather]

55 minutes ago, TheSnowman said:

I just had a 1H 30M Weenie call with Paul Kocin.  Even HE can not explain this storm.  “The Set up was Excellent, but Nothing can explain widespread 30”-45” amounts.  Can’t wait to research it more.  Especially from a storm that was not only Not Depending, but losing power.”
 

Says it IS a KU!  And Louis Texted him while we were talking 

Holy shit, Kocin? That's pretty awesome.

[OceanStWx]

2 minutes ago, CT Rain said:

I mean it's possible the DGZ wasn't deep but there was sufficient lift there for it to puke dendrites. Obviously a deeper DGZ will help but it's not necessary. Also looks conditionally unstable above the DGZ in both which is definitely good. 

I mean BGM rates were good, ratio wasn’t necessarily extreme. I’d have to see their 6 hour break downs. If they were over 20:1 I’d say the DGZ was likely deeper, but 15:1 for the event could just been excellent dendrite formation.

[Jebman]

2 hours ago, ORH_wxman said:

I’m sure when this goes through some reanalysis and scrutiny, we’re going to find insane ML fronto numbers along with super deep DGZ column. 

We had a beast arctic high up there and this was slamming up right into it with extreme negative tilt aloft. So my guess is the models prob undersold the ML fronto...even though it was already really impressive on guidance. The super deep DGZ always helps too because you aren’t needing to be very precise with where the lift is to get the cross-hair sig. 

This, is definitely sig-worthy. Couldnt have stated it better myself.

[CT Rain]

13 minutes ago, OceanStWx said:

I mean BGM rates were good, ratio wasn’t necessarily extreme. I’d have to see their 6 hour break downs. If they were over 20:1 I’d say the DGZ was likely deeper, but 15:1 for the event could just been excellent dendrite formation.

Yeah I agree. They were putting up some huge ASOS precip numbers. They had 2.80" total liquid so a 14:1 ratio. Not like the fluff bomb in NH. 

KBGM 162353Z AUTO 09009KT 1/2SM SN FZFG VV007 M07/M09 A3004 RMK AO2 TWR VIS 3/4 SLP199 P0011 60028 T10721089 11056 21083 58023 RVRNO
 

KBGM 170553Z AUTO 1/4SM +SN FZFG VV002 M09/M11 A2985 RMK AO2 TWR VIS 3/4 SLP136 P0040 60120 T10891106 11072 21089 58023 RVRNO
 

KBGM 171153Z AUTO 02011KT 3/4SM BR VV013 M09/M11 A2990 RMK AO2 SFC VIS 1 SNEMM SLP153 P0007 60131 70279 T10891106 11089 21094 51008 PWINO FZRANO RVRNO $
 

[dryslot]

17 minutes ago, Jebman said:

No problem! Just grab the shovel, clear the rest.

Just another routine winter day in SNE.

Maybe if I lived in SNE, Or have you take a Jeb walk to Maine to lend a hand...

[KoalaBeer]

6 minutes ago, OceanStWx said:

The main graphic takes the max category of all the individual inputs. So an extreme flash freeze for instance would show up as extreme in the overall storm threat. 

Snowfall categories are based on climate of the area, so 12-18 is unlikely to trigger that.  In this case it looks like blowing snow triggered it. Probably due to the strength of the wind and visibility. 

Thanks for the response. Explanations from mets like you is why I’m on here! 

If im not mistaken that graphic is still in the experimental phase? Also is it computer generated or human? It’s not like coastal essex county hasn’t seen numerous blizzards before and this wasn’t even close to the worst they’ve seen. 

The wording needs a serious retooling in my opinion. Impossible travel conditions does not = property damage with extreme impacts to every day life. Even if you move the 40” of fluff out onto Cape Ann that wording is still absurd. Graphics like that get spread around with the general public like weenie maps do and causes a huge amount of misinformation...and then everyone telling you how you suck at your job and meteorologists are only right half the time

 

[OceanStWx]

4 minutes ago, KoalaBeer said:

Thanks for the response. Explanations from mets like you is why I’m on here! 

If im not mistaken that graphic is still in the experimental phase? Also is it computer generated or human? It’s not like coastal essex county hasn’t seen numerous blizzards before and this wasn’t even close to the worst they’ve seen. 

The wording needs a serious retooling in my opinion. Impossible travel conditions does not = property damage with extreme impacts to every day life. Even if you move the 40” of fluff out onto Cape Ann that wording is still absurd. Graphics like that get spread around with the general public like weenie maps do and causes a huge amount of misinformation...and then everyone telling you how you suck at your job and meteorologists are only right half the time

Auto-generated from the human forecast. It just takes our grids and produces the binned impact levels.

It’s still experimental because we’re trying to hammer down impacts. Like snow last year was one set of values across the whole country. But 2 ft here is not 2 ft in a place like RDU.

My guess is that blowing snow tripped to extreme due to combination of wind gust forecast and snow ratio.

 

[KoalaBeer]

11 minutes ago, OceanStWx said:

Auto-generated from the human forecast. It just takes our grids and produces the binned impact levels.

It’s still experimental because we’re trying to hammer down impacts. Like snow last year was one set of values across the whole country. But 2 ft here is not 2 ft in a place like RDU.

My guess is that blowing snow tripped to extreme due to combination of wind gust forecast and snow ratio.

 

Ya that makes more sense of receiving that output if it’s auto generated like that. Thanks again for the insight. I guess it’s just the wording I don’t like. I mean imagine that band rots 50-60 miles south instead...even 40” of snow in Gloucester is an extreme impact but no ones house is getting swallowed up by the Atlantic from this synoptic setup. 

This will certainly be a great storm to read up on once some post event analysis comes out. 

[MJO812]

Upstate NY driver trapped in car for hours after plow covers him in 4 feet of snow

 

https://nypost.com/2020/12/17/upstate-ny-driver-trapped-in-car-for-hours-after-plow-buries-him/

[Amped]

On 3/7/2018 at 9:10 PM, wxmanmitch said:

26" total when I measured about 30 minutes ago. Absolutely freaking nuts under this band with 18" in ~3 hours. Pure dendritic fluff! It's getting rather difficult to measure due to drifting. Snow still going strong, but flake size has decreased a little as the band appears to be pivoting east slightly. 

Anyone remember this event?  30-40 totals weren't as widespread, but it looks like rates were comparable over S VT and NW mass.

[Roger Smith]

I guess the long and the short of explaining the phenomenal amounts might be this -- the storm was weak enough to allow undisrupted banding, but strong enough to pump in mid-level moisture from a warmish Atlantic, with orographic uplift factors generally favorable to enhancement in the frontogenic band. 

Now that they have extended historical weather maps back into the mid-19th century, I've had an opportunity to check out postulated charts vs large storm events in the period when Caswell's Providence journal overlapped the first years of the Toronto observations (after 1840). Now obviously some of those maps are fairly tentative and based on insufficient data. But it struck me that some fairly heavy snowfall events looked relatively tame and I was reminded of that when this one came along.

Tame, but working with the colder air masses (inland especially) of that historical era, and a storm track that more frequently ran along the coast than in modern climate terms. That was quite a cold high for so early in the winter. 

20-20 hindsight of course, I was as surprised as anyone to hear the actual numbers from BGM, ALB and VT-NH. 

There's also an energy peak in the background, mark down Jan 1-3 and Jan 14-16, this peak will occur again, depending on the shape of the upper level flow steering patterns somebody may get a repeat performance (it may be in a different part of the country though). 

[Ginx snewx]

7 hours ago, HIPPYVALLEY said:

Due to intensity this one came close to a top 10 for me.
I was in awe from midnight to 2am.  
I would get arctic sand for a few minutes and then there would be a roaring gust overhead and instant flip to +SN whiteout. It went on and on like that.  

Heaviest snow I have seen since 2013. 

Great storm.  
 

Chris you have learned well from Jedi Master Dendy to downplay your expectations and then keep cashing them chips til the chickens come home. Eric Radarman and Pete were at Beast said 20 at top

[Ginx snewx]

6 hours ago, Henry's Weather said:

Holy shit, Kocin? That's pretty awesome.

Its been a great benefit of this forum membership to establish friendships with the great minds of American Meteorology. I was able to have breakfasts with K and U alongside the greatest WPC forecaster of all time Wes Junker multiple days. We have stayed in touch since. My star struck moment was meeting Kevin from Tolland, like meeting the Pope. I didn't wash my hand for a month.  Not because it would rub off but because it was absolutely burning raw from all the bottle cap flipping he taught me. 

Seriously though, you might not realize it but people like Paul Kocin might read your posts. Definitely a cool place.

[dendrite]

37 minutes ago, Ginx snewx said:

Chris you have learned well from Jedi Master Dendy to downplay your expectations and then keep cashing them chips til the chickens come home. Eric Radarman and Pete were at Beast said 20 at top

Heh. To be fair I was intrigued and had a lot of posts and interest in the thread. There was a part of me that thought it could get up here, but I didn’t have a lot of reliable model guidance to back me up. The euro was so paltry up here every run that it was hard to accept the NAM and canadian models. Everything ticked south at 18z and I figured I was done for. Before the 00z runs rolled out I noticed the trajectory of the band in PA/NY looked pretty good for mby so I waited the 00z runs out and that’s when everything came way north again and Ray started melting.

it’s probably worth giving the mesos more weight once inside 12-24hr when the synoptics are mostly ironed out. That was a draining cleanup though and I’m still not done. I’m already ready for a repeat though. I think even Lisa enjoyed it. 

[Ginx snewx]

3 minutes ago, dendrite said:

Heh. To be fair I was intrigued and had a lot of posts and interest in the thread. There was a part of me that thought it could get up here, but I didn’t have a lot of reliable mode guidance to back me up. The euro was so paltry up here every run that it was hard to accept the NAM and canadian models. Everything ticked south at 18z and I figured I was done for. Before the 00z runs rolled out Innoticed the trajectory of the band in PA/NY looked pretty good for mby so I waited the 00z runs out and that’s when everything came way north again and Ray started melting.

it’s probably worth giving the mesos more weight once inside 12-24hr when the synoptics are mostly ironed out. That was a draining cleanup though and I’m still not done. I’m already ready for a repeat though. I think even Lisa enjoyed it. 

In regards to your cleanup question from yesterday.  I clean up in 4 inch increments. May take more effort but also easier on mechanical and physical parts. Have to stay on top of it 

[klw]

10 hours ago, powderfreak said:

But it's the GGEM.  We all shovel a lot of GGEM snow. 

the SREF also did well about placing the heavy stuff through that area.

[klw]

8 hours ago, Patfan1987 said:

This seemed to verify well. Thoughts?

Yes but later runs of it really cut down on the totals in VT and NH and moved everything south.

[dendrite]

15 minutes ago, Ginx snewx said:

In regards to your cleanup question from yesterday.  I clean up in 4 inch increments. May take more effort but also easier on mechanical and physical parts. Have to stay on top of it 

I have this thing where there’s no way I can start cleaning up the snow until it’s over. I need to see the untouched aftermath or else I get ragey. It’s probably a Kevin OCD thing. 

[SouthCoastMA]

Had an inch overnight, wintry look this morning.

6" total

[powderfreak]

8 hours ago, OceanStWx said:

Kuchera is going to be a fine representation where ratios were extreme, but I view it as right for the wrong reason. It was right because the airmass was cold, not because it knew anything about the DGZ depth or lift within it.

As forecasters our job is really to sniff out these record events from model noise. I’m not sure there was a ton of signal in the noise until yesterday’s mesoscale runs started really getting beefy. This looks a lot like a good old fashioned model bust on the dynamics at play.

The liquid still boggles my mind... sure ratios were part of it but that band laid down a swath of 2-3” QPF at temps in the teens.  I’ve seen a lot of folks online just pin it on ratios but that band was extremely efficient at ripping moisture from the sky.

Both BGM and ALB cleared 2” water in like 12 hours in a snowstorm.  And those ASOS water numbers are insane.

ALB was even slightly SE of the band and ripped 0.93” water in 3 hours.  BGM’s 1.11” in 3 hours has to be one of the more incredible liquid numbers in a fronto band on the cold side of a nor’easter. That’s just choking snowfall.

Models printing that QPF get tossed on here prior to a storm because it’s just hard to fathom.

[dendrite]

Newbury NH cocorahs just came in with 43.9” and a 30” depth. That’s the same depth I had at peak yesterday. 

[Damage In Tolland]

32 minutes ago, dendrite said:

I have this thing where there’s no way I can start cleaning up the snow until it’s over. I need to see the untouched aftermath or else I get ragey. It’s probably a Kevin OCD thing. 

Yup. Never touch snow until the last flakes have fallen 

[CoastalWx]

20 minutes ago, dendrite said:

Newbury NH cocorahs just came in with 43.9” and a 30” depth. That’s the same depth I had at peak yesterday. 

Fake snow.

[dendrite]

1 minute ago, CoastalWx said:

Fake snow.

Kinda. But it looks really impressive for a couple of days. Thank god this wasn’t paste or else everything would have came down. I briefly lost power and had my cable wire come down in 3” a couple weeks ago, yet with this 34” not even a flicker. The bamboo is going to love it...nothing stuck to it and it has a nice insulation from the cold. 
 

Heavy, heavy migraine this morning. I think I got so amped up since the 00z models Wed night and then the following cleanup just wiped me out. 

[dendrite]

6 minutes ago, Damage In Tolland said:

Yup. Never touch snow until the last flakes have fallen 

I hate the pack being disturbed too. I do clear and orderly area of grass for my birds to free range on, but my neighbors make me go full tilt sometimes. Yeah, I know...they have kids having fun in it so I’m not really mad. But he will snowblow almost half of his backyard in a circle and blow all of the snow into the middle and make a mountain. The kids have a blast, but my OCD goes off the charts.

[CoastalWx]

6 minutes ago, dendrite said:

Kinda. But it looks really impressive for a couple of days. Thank god this wasn’t paste or else everything would have came down. I briefly lost power and had my cable wire come down in 3” a couple weeks ago, yet with this 34” not even a flicker. The bamboo is going to love it...nothing stuck to it and it has a nice insulation from the cold. 
 

Heavy, heavy migraine this morning. I think I got so amped up since the 00z models Wed night and then the following cleanup just wiped me out. 

That happens in a big one. Not much sleep, all that work and then you’re exhausted. 
Enjoy it. Finally got a biggy and for me...one that matters most. Rates. As I get older, I’m more impressed with impacts and how the storm happens vs what actually falls. 

[The 4 Seasons]

Going to work on a map now. Had to get this out of the way first. Scrolled through the last 25 pages to find all the CT reports, used PNS and NWS 72 hour snowfall maps. Reports earlier than 900AM were thrown out, as well as all the CoCoRahs stuff that ends exactly 7AM. BOX did a great job weeding out all those reports so that made it easier but OKX left a bunch of old garabge in that i had to sift through. ALY was good. Also threw out that 26" Litchfield county report from a drunken snow weenie measuring a snow plow pile.

If anyone has any additional reports id be happy to add them before i do the map, speak now or forever hold your peace.

 

[Damage In Tolland]

14 minutes ago, dendrite said:

I hate the pack being disturbed too. I do clear and orderly area of grass for my birds to free range on, but my neighbors make me go full tilt sometimes. Yeah, I know...they have kids having fun in it so I’m not really mad. But he will snowblow almost half of his backyard in a circle and blow all of the snow into the middle and make a mountain. The kids have a blast, but my OCD goes off the charts.

I would likely have to move if my neighbor did that. It would make me too angry . I’d lose it 

[Ginx snewx]

59 minutes ago, dendrite said:

I have this thing where there’s no way I can start cleaning up the snow until it’s over. I need to see the untouched aftermath or else I get ragey. It’s probably a Kevin OCD thing. 

I remember being that way then after 2011 I took pictures of undisturbed areas. 

[Whineminster]

15 hours ago, HoarfrostHubb said:

Yeah... a spotter there I know who I think over inflates only got 12.5 or something...

Why would he do that? That's not cool.