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Author Topic: Dec 10-11th Snow Event  (Read 16197 times)

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Offline snowdog

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Re: Dec 10-11th Snow Event
« Reply #210 on: December 11, 2019, 08:28:10 AM »
Some thoughts from OHX:

Some thoughts from Yoda:

Quote
Our column, unsaturated it was.

Offline BRUCE

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Re: Dec 10-11th Snow Event
« Reply #211 on: December 11, 2019, 08:40:57 AM »
They have have at least 4 or 5 events in the past decade of 3+ inches of snow in north alabama which is pathetic for the rest of us in middle tn to think about( excluding n/w sections )
agree... back in 70 s and winters 80s. That hardly ever happen ... Decatur Alabama got two inches
Come on severe wx season...

Offline Thundersnow

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Re: Dec 10-11th Snow Event
« Reply #212 on: December 11, 2019, 08:58:56 AM »
Some thoughts from OHX:

Quote
Our staff wisely ignored the models and kept forecast snow amounts low (0-1”) which ended up being quite close to reality

Just goes to show- we can criticize the forecast office of "playing it conservative" when a model is bullish, but more often than not, it works out for them. The short-term models that saw the dry air were indeed our sign.

Quote
This event was yet another reminder to not treat model output as gospel, as we unfortunately see people doing all the time on social media.

BOOM! I heard that.

Offline gcbama

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Re: Dec 10-11th Snow Event
« Reply #213 on: December 11, 2019, 09:02:06 AM »
that was the BIGGEST virga storm I have ever seen ….I mean EVER.

My area was in dark blue radar returns for 10 hours...normally that would have been 6-8 inches of snow.....and of course yet again not even a tenth of an inch, that is what is depressing. You know you are cursed when radar shows it and mother nature still decides to give you nothing lol

Offline Thundersnow

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Re: Dec 10-11th Snow Event
« Reply #214 on: December 11, 2019, 09:16:50 AM »
that was the BIGGEST virga storm I have ever seen ….I mean EVER.

My area was in dark blue radar returns for 10 hours...normally that would have been 6-8 inches of snow.....and of course yet again not even a tenth of an inch, that is what is depressing. You know you are cursed when radar shows it and mother nature still decides to give you nothing lol

The composite radar is really the problem when it comes to virga. I remember some impressive "virga storms" back in the early days of internet looking at the intellicast composite maps showing all the blue in the '90s.

Looking at the local radar though yesterday, at least on RadarScope on my phone, it didn't "lie" so much. The tell-tale sign was seeing the "hole" of no precip within 30 or so miles of the radar site. The outer range of the radar further out would show precip, like for example, over the Fort Campbell/Clarksville area from the Nashville radar site. But, when you went to the Fort Campbell radar, it showed a similar "hole" over that area, but precip falling over the Nashville area, oddly enough. That effect (for those who don't know) is because the radar beam naturally elevates up with distance. So, the further out from the radar site you go, the higher up in the atmosphere it's reading any precipitation. Basically, snow was falling high up, and distant radar sites see it. The closer radar sites, of course, don't see anything at the lower levels.

But, a composite radar basically combines overlapping radar coverage areas, which creates the illusion that it's snowing all over the place, when it's only falling high up, in reality.

I'm not sure how you effectively solve that with a composite radar.

Offline Curt

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Dec 10-11th Snow Event
« Reply #215 on: December 11, 2019, 09:58:17 AM »
smart move.. always ignore the gfs lol...

I haven’t had a chance to comment with being hectic busy.

Take every model into account. It might nail the next one. And as far wish-casting- lets give credit to just about everyone on this board that knows when they see  an outlier. I didn’t see anyone taking that to the bank. I was shocked that the GFS couldn’t pick up on what even other globals were seeing. As far as globals, the euro started picking up on the southward trend 2 days earlier. The 3k NAM picked up on the precip barely making it above 40 from Memphis to Nashville. It actually had snowfall totals overdone in the areas that saw some accumulation. The RGEM was overdone.

And now the post day griping. It happens and people will say “it snows more further south now than here”. I remember debunking that last year with some snowfall amounts from around the region. Almost every single time over the last decade, the further north one is will generally will do better on average. The only exception in the last decade I could find was Little Rock which has had really decent winters in the last 10 years.

Keeping in mind we live in the south,  this decade IMBY was better than the previous 10, and most certainly the 90’s.

Offline Crockett

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Re: Dec 10-11th Snow Event
« Reply #216 on: December 11, 2019, 10:35:05 AM »
The HRRR absolutely nailed this yesterday when it began to pick up on the secondary divergence, which really enhanced snowfall across a limited area of the northern plateau once darkness fell. The gradient was quite sharp, and I was on the wrong side of it; we only had a glorified dusting here at the house. But just about 20 minutes east, the state highway was closed due to multiple accidents after a period of moderate snowfall. They got around 3 inches in that area, and the HRRR nailed the gradient as well as amounts.

Offline Hank W

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Re: Dec 10-11th Snow Event
« Reply #217 on: December 11, 2019, 11:04:48 AM »
Quote
From what I’ve seen, models handled this event quite poorly with some like the GFS showing this dry layer well, yet still spitting out unreasonable 3-6” snow accumulations for the entire cwa. Our staff wisely ignored the models and kept forecast snow amounts low (0-1”) which ended up being quite close to reality - except the higher elevations of our Cumberland Plateau counties overachieved (as usual) with 2-3+”. This event was yet another reminder to not treat model output as gospel, as we unfortunately see people doing all the time on social media.
Great reminder of how much more NWS knows than we do. We have all learned to take the models with a grain of salt, but most of us can't help but start to buy in when the event is 36 hours out and every model, even NAM 3k, is showing large pockets of 3+ inches with some...cough RGEM, GFS...showing some insane numbers. Granted the 3k had the lowest totals, but it was the outlier. Obviously the ground temps had to be taken into account and we have all been burned enough times to know to cut down on those numbers, but even if you take 1/3 of what models were showing, it still would have been a decent December event. But give the credit to the NWS mets, they dug much deeper than the precip and accum maps and sniffed this one out from the start. And congrats to the folks who have snow on the ground!

Offline EastTNWX

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Re: Dec 10-11th Snow Event
« Reply #218 on: December 11, 2019, 11:31:48 AM »
Great reminder of how much more NWS knows than we do.

This goes both ways though, as the MRX office busted on the low end for both this storm and the November event.  They basically did the same thing as the Nash office did but were wrong.  At the end of the day they're just people that do the exact same thing that the uber hobbyists do on this and other forums.  They just happen to get paid for it.  The big takeaway from this to me is to emphasize that models are just a small part of the puzzle; climatology and local geographic features are larger pieces and instinct itself is the biggest piece. 

Post Merge: December 11, 2019, 11:32:38 AM
I ended up with a little over an inch here in Farragut for the event. 

Offline Crockett

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Re: Dec 10-11th Snow Event
« Reply #219 on: December 11, 2019, 11:42:00 AM »
At the end of the day they're just people that do the exact same thing that the uber hobbyists do on this and other forums.  They just happen to get paid for it. 

How many people do you think there are active on this forum who could stand in a room with anyone from the NWS and match wits on weather? I can think of one or two who might be able to hold their own.

Offline schneitzeit

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Re: Dec 10-11th Snow Event
« Reply #220 on: December 11, 2019, 01:03:25 PM »
At the end of the day they're just people that do the exact same thing that the uber hobbyists do on this and other forums.  They just happen to get paid for it.

I disagree entirely
.

Offline Coach B

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Re: Dec 10-11th Snow Event
« Reply #221 on: December 11, 2019, 01:31:27 PM »
Sat pic shows exactly who got the significant snow. Noticed the stripe of accumulation in Giles, Marshall, and Bedford counties.

https://ibb.co/wNq9B68

Well, I guess the best I can do is a link. Can't remember how to post a pic.
« Last Edit: December 11, 2019, 01:33:31 PM by Coach B »

Offline EastTNWX

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Re: Dec 10-11th Snow Event
« Reply #222 on: December 11, 2019, 03:35:50 PM »
How many people do you think there are active on this forum who could stand in a room with anyone from the NWS and match wits on weather? I can think of one or two who might be able to hold their own.

No offense intended. 

Offline Crockett

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Re: Dec 10-11th Snow Event
« Reply #223 on: December 11, 2019, 03:47:28 PM »
No offense intended.

I'm not offended...I'm not a meteorologist and I couldn't hold a candle to them either.  ;D

Offline EastTNWX

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Re: Dec 10-11th Snow Event
« Reply #224 on: December 11, 2019, 04:06:27 PM »
I'm not offended...I'm not a meteorologist and I couldn't hold a candle to them either.  ;D

I’m sure your local office Mets are great, what I said was not specific to them and wasn’t really the subject of my original comment anyway.  I worked closely with one of the MCO Mets and while he was a good guy I trust that more than a couple here would be capable replacements..and he worked a far more difficult region than the mid south.  That is apart from the point I made that models aren’t as important as local knowledge and experience anyway.

 

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