Dec 16-17 obs/nowcast thread

[Amped]

13 minutes 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.

Also was pretty slow moving.  I do think there are comparable setups from 30+ years ago that didn't produce these kinds of totals. Warmer ocean temps could be assisting it.

[ScituateWX]

Some pretty good inundation of prone areas during todays high tide it seemed @CoastalWx.

[OceanStWx]

15 minutes ago, dryslot said:

I think i remember you yesterday scoffing at those numbers being to high on the expected snow map.............lol

I really didn’t think I was in line for a foot. More like 6-8”. I thought the fight with dry air and a deamplifying system was going to win out.

12 minutes 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. 

That’s pretty much where I’ve landed too. We must’ve maxed out the f-gen with the Arctic high and WCB. The high kind of locked the band in place and didn’t allow much movement north. If I had to guess, the upper air pattern probably  ended up more conducive for a parallel band than even a pivot.

[CT Rain]

Here's a NAM sounding over Brian's fanny from this morning. Don't get a better DGZ signal than this. 

[dryslot]

Just now, OceanStWx said:

I really didn’t think I was in line for a foot. More like 6-8”. I thought the fight with dry air and a deamplifying system was going to win out.

That’s pretty much where I’ve landed too. We must’ve maxed out the f-gen with the Arctic high and WCB. The high kind of locked the band in place and didn’t allow much movement north. If I had to guess, the upper air pattern probably  ended up more conducive for a parallel band than even a pivot.

Those bands hit a brick wall with that high in place and remained stationary before getting squeezed east under that block, The global models did not handle this event very well as they were just spitting out .20-.30" qpf here, Mesos were better last night at 00z handling the band placements where some of these higher totals fell.

[Arnold214]

6 minutes ago, CT Rain said:

Here's a NAM sounding over Brian's fanny from this morning. Don't get a better DGZ signal than this. 

Interesting wind profile if it verified. WAA in H7-H5 later with CAA above it would seem to keep lapse rates nice and steep in that omega zone.

[ScituateWX]

Weenie question.....What kept this storm from really deepening in terms of pressure?

[CT Rain]

Just now, Arnold214 said:

Interesting wind profile if it verified. WAA in H7-H5 later with CAA above it would seem to keep lapse rates nice and steep in that omega zone.

For sure. Pretty unusual to see that strong of a veering wind profile (WAA) that high up. Really maximized that omega plus the conditionally unstable layer above as you mentioned. 

[dryslot]

I think it was all southern stream driven.

[BombsAway1288]

That fronto band was pure ratio's and must have been awesome to be under.

Not every storm that you see the Kuchie clown maps underperform. They did start to pick up on the insanely high numbers but not really until nowcast time

An all-timer/epic storm up there. Congrats guys.

I'll take my 13"-14" though. Very pleasing storm all around, especially for mid-December!

[KoalaBeer]

Okemo reporting 44” storm total. Absolutely nuts.

EDIT: this would break Vermont’s 24 hour snowfall record of 42” at Jay Peak set in 1995.

https://mobile.twitter.com/OkemoConditions/status/1339740363632865280

[wxsniss]

1 hour ago, weatherwiz said:

what's the link to this?

I was hoping there would be an updated regional one like this on the right (it's a much more visually attractive map) but it is from 7 AM

 

https://www.weather.gov/source/crh/snowmap.html

[Wx4cast]

22 hours ago, 40/70 Benchmark said:

I'll bet its right. This area has a great shot at Subby City.

Kucera out performed ALL 10:1 snow maps....it tends to do well when you're dealing with a very cold artic airmass and column combined with the extreme FGEN.

 

[dendrite]

Just noticed I had more snow in 12 hours today than I had during the entire season of 2015-16.

[Wx4cast]

11 minutes ago, BombsAway1288 said:

That fronto band was pure ratio's and must have been awesome to be under.

Not every storm that you see the Kuchie clown maps underperform. They did start to pick up on the insanely high numbers but not really until nowcast time

An all-timer/epic storm up there. Congrats guys.

I'll take my 13"-14" though. Very pleasing storm all around, especially for mid-December!

Trust me it was. I measured at midnight 1.3 " wiped the board, measured again at 7am 21" wiped the board, measured at noon 11.5". 

[wxsniss]

Yeah it's a puzzle... looking back at soundings from Thurs 0z 3k NAM / 12k NAM (can't see HRRR that far back):

6z Thursday night, under the heaviest band near Binghamton... insane lift, but not an especially deep DGZ:

 

[Patfan1987]

This seemed to verify well. Thoughts?

[wxsniss]

0z Euro Thurs (event already underway) had a decent Kuchera map... QPF in the fronto band ranged from 1-1.7, so with ratios up to 20:1, you might see how you could get to 40":

(note... no Euro run before this had anything close to reality... models massively missed a historic weather event for PA-NY-VT-NH):

 

[wxmanmitch]

23.0" with 2.11" of liquid the final here. I was surprised there was that much liquid in the snow given how cold the storm was. Maybe I'll core it again tomorrow to confirm that liquid equivalency...

[OceanStWx]

26 minutes ago, wxsniss said:

0z Euro Thurs (event already underway) had a decent Kuchera map... QPF in the fronto band ranged from 1-1.7, so with ratios up to 20:1, you might see how you could get to 40":

(note... no Euro run before this had anything close to reality... models massively missed a historic weather event for PA-NY-VT-NH):

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.

[TalcottWx]

Wow. Snowing again here. Oes baby. Gonna be slick in spots out there tonight. 

[40/70 Benchmark]

1 hour ago, ScituateWX said:

Weenie question.....What kept this storm from really deepening in terms of pressure?

Shortwave attenuating due to crunch between trailing sw digging and running into block.

[TheSnowman]

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 

[HIPPYVALLEY]

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.  
 

[KoalaBeer]

Quick question on this storm for the certified  mets out there and especially BOX...I’m trying to search for it but someone posted the impact map for BOX yesterday for coastal zones...It can't find it but it showed extreme impacts for Cape Ann with significant loss of property and infrastructure almost as if a cat 3 hurricane was barreling up the coast. 

I want to know how that got posted as the minimum  pressure of this storm was always paltry compared to other historic nor’easters. Dynamics made up for this tremendously snowfall wise in interior NH but how the hell did extreme impacts get posted for the coast on that graphic!!?? I knew it was BS from the time it was posted. The much stronger coastal low from the week before was more impressive from a coastal flood viewpoint....

[NECT]

Definite snowhole IMBY with this storm. Slantstick gives me 6' in most parts of my yard.. Deepest drift is maybe 8" - maybe. Much higher reports all around me. I don't question any reports, I think I just got micro dryslotted if I'm allowed to make up new terms. 

[wxsniss]

2 hours ago, CT Rain said:

Here's a NAM sounding over Brian's fanny from this morning. Don't get a better DGZ signal than this. 

 

I pulled up soundings for that exact location and model... DGZ = 16091 - 2415 = 13676 feet !!!

Someone at Okemo could sneeze up and it would snow.

But still puzzled by soundings at Binghamton (I posted above)... DGZ throughout the event on multiple models was only ~ 3000 feet... not particularly deep. Either model soundings were not accurate (e.g., H85-H7 temps were much colder than progged), or combination of extreme lift + great ratios was enough.

[Jebman]

2 hours ago, dryslot said:

First storm with the 5.5" of cement, I had changed the belt on the JD tractor which is like 6' long and goes thru a v pulley and a flat pulley, Only have changed it twice in 30 yrs, I go to snow blow the driveway, And instead of the auger spinning clockwise and throwing the snow up the chute, Its going counterclockwise and throwing it out the front like a broom sweeper, Got that changed on Saturday, Tonight, Get half the drive way done, And a spring breaks that runs the idler pulleys to keep the belt tight to the hydrostatic drive so now i have no forward or reverse and had to push the tractor back into the car port, SMFH.

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

Just another routine winter day in SNE.

[CT Rain]

12 minutes ago, wxsniss said:

 

I pulled up soundings for that exact location and model... DGZ = 16091 - 2415 = 13676 feet !!!

Someone at Okemo could sneeze up and it would snow.

But still puzzled by soundings at Binghamton (I posted above)... DGZ throughout the event on multiple models was only ~ 3000 feet... not particularly deep. Either model soundings were not accurate (e.g., H85-H7 temps were much colder than progged), or combination of extreme lift + great ratios was enough.

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. 

[OceanStWx]

45 minutes ago, KoalaBeer said:

Quick question on this storm for the certified  mets out there and especially BOX...I’m trying to search for it but someone posted the impact map for BOX yesterday for coastal zones...It can't find it but it showed extreme impacts for Cape Ann with significant loss of property and infrastructure almost as if a cat 3 hurricane was barreling up the coast. 

I want to know how that got posted as the minimum  pressure of this storm was always paltry compared to other historic nor’easters. Dynamics made up for this tremendously snowfall wise in interior NH but how the hell did extreme impacts get posted for the coast on that graphic!!?? I knew it was BS from the time it was posted. The much stronger coastal low from the week before was more impressive from a coastal flood viewpoint....

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.