December 8-10 Storm Discussion

[TellicoWx]

Difference 1° made in the 850 line over East TN on startup of Euro

[John1122]

Here are the actual 850 temps. Even the Euro is way too warm in places.

[Reb]

1 minute ago, TellicoWx said:

Difference 1° made in the 850 line over East TN on startup of Euro

That’s a pretty big deal if verifies. Getting my ice buckets prepped to spread over the yard as I type...gotta have those ground temps ready! 

[TellicoWx]

18 minutes ago, TellicoWx said:

Areas in the valley below Loudon/Blount would have had a greater increase in snowfall, but the Euro warms the 925's during the day tomorrow (850's below 0 across the entire valley)

Lol, just noticed the 925 map looks like the Euro is pointing at NE TN as if to say I'm coming for you.

[John1122]

1 minute ago, Reb said:

That’s a pretty big deal if verifies. Getting my ice buckets prepped to spread over the yard as I type...gotta have those ground temps ready! 

Hah!  I remember being a kid and putting ice on the ground to help snow start laying. It actually seemed to work.

[John1122]

I live close to the 925 and my cousins live above it just a short trip away. Their extra 700 feet makes a tremendous difference in snow over the course of a season. One is moving and I'm tempted to buy his house.

[Holston_River_Rambler]

Looks like a rain/ snow line is trying to show up on MRX NEXRAD correlation coefficient.  Also, a bright band down toward Maryville.  

[Holston_River_Rambler]

Actually, I have a little sleet here near downtown Knoxville. we'll see how long it lasts

[John1122]

2 minutes ago, Holston_River_Rambler said:

Actually, I have a little sleet here near downtown Knoxville. we'll see how long it lasts

The 925 is close to 0 in your area, and the 850s are below, so you may have it for a bit.

[1234snow]

Have we seen a bigger close for our area than that 12z suite?

To quote Darrell Waltrip: “Have you ever?”. Lol

I don’t believe I have seen consistent 12”+ modeled on virtually every model for our immediate area in NETN. NAM and GFS tried to lose the storm and shove it South a few days ago but the trend reversed back to the copious amounts of QPF.

I’m still trying to figure out how Lucy will pull the football from us this time. My biggest concern would be a slower changeover to snow Sunday morning. If we waste a few hours switching over then we will lose probably around .5 of QPF or more.

I’m curious to see if we start all snow to begin with. If that happens it is game on.

[TellicoWx]

19 minutes ago, John1122 said:

850s have dropped further south at the top of the hour update. The 0 degree line is now S of Nashville I believe and it's touching the Hamilton County line. -1 over the Northern Plateau and Valley. Also notable if Arkansas is seeing snow. the 850 line is barely into northern Arkansas.

The changeover reports and pics in AR was happening halfway between the state line and Jonesboro.

[Holston_River_Rambler]

Just now, John1122 said:

The 925 is close to 0 in your area, and the 850s are below, so you may have it for a bit.

Went outside to double check and it isn't sleet, it is just super melted wet snow plopping down. 

[John1122]

1 minute ago, Holston_River_Rambler said:

Went outside to double check and it isn't sleet, it is just super melted wet snow plopping down. 

What is the elevation there? 900 feet maybe? The 925 I think is 2300 feet. So the flakes are surviving 1400 feet or so without melting if that's the case.

[Math/Met]

Euro text shows KTRI with 13.6 inches. That’s based on ratios that are around 8:1 for the majority of the storm and end around 10:1. The actual ratios would probably be a little lower than that, but I don’t have soundings to analyze.  It also has the high temperature for today at 43, so we can see how that verifies this afternoon. 

[realdeal2414]

Just had a question as I live here in western Sullivan county and noticed the precipitation shield moving closer and closer but with temps being around 40..is dynamic cooling going to be the factor on this snow and as the precip moves in will cool the atmosphere as precip falls. I’m not weather smart but love following this site. Thanks to all.

[Holston_River_Rambler]

@John1122 yeah I'm just around 900 feet or so. I can see more up on the towers, but it is just super wet snow, with nothing but an ice crystal core left as far as I can tell 

[realdeal2414]

3 minutes ago, Math/Met said:

Euro text shows KTRI with 13.6 inches. That’s based on ratios that are around 8:1 for the majority of the storm and end around 10:1. The actual ratios would probably be a little lower than that, but I don’t have soundings to analyze.  It also has the high temperature for today at 43, so we can see how that verifies this afternoon. 

Could you explain the ratios..let say 8:1, 5:1 or 10:1. What is the meaning between the 3. Thanks

[Carvers Gap]

1 minute ago, realdeal2414 said:

Just had a question as I live here in western Sullivan county and noticed the precipitation shield moving closer and closer but with temps being around 40..is dynamic cooling going to be the factor on this snow and as the precip moves in will cool the atmosphere as precip falls. I’m not weather smart but love following this site. Thanks to all.

The great thing about this event is that it will happen tonight.  With no sun and strong precip rates, the air column will cool.  I suspect we don't see much until the sun sets.  Most models are showing a very brief start w light rain to mix to snow.  As 1234 stated above, if the switch is quick...game one.  We want really strong precip rates.

[Blue Ridge]

Euro text shows KTRI with 13.6 inches. That’s based on ratios that are around 8:1 for the majority of the storm and end around 10:1. The actual ratios would probably be a little lower than that, but I don’t have soundings to analyze.  It also has the high temperature for today at 43, so we can see how that verifies this afternoon. 

43 at KTRI as of 1345.

Much of Johnson City was within a range of 39-41 as of 1200. Currently visiting family in Erwin, where it’s 42.

[John1122]

1 minute ago, realdeal2414 said:

Could you explain the ratios..let say 8:1, 5:1 or 10:1. What is the meaning between the 3. Thanks

Ratios are simply how much liquid it takes to make an inch of snow. Snow at 30-32 is 10:1, if it gets above that they start changing. Other factors go into it as well. If it's 18 and snowing you might see 25:1 ratios. This will be a wet snow with 5:1 to 8:1 ratios across the areas it falls the way it looks now.

[1234snow]

Euro text shows KTRI with 13.6 inches. That’s based on ratios that are around 8:1 for the majority of the storm and end around 10:1. The actual ratios would probably be a little lower than that, but I don’t have soundings to analyze.  It also has the high temperature for today at 43, so we can see how that verifies this afternoon. 

Are you concerned about winds aiding in downed trees and power outages? Especially in the mountains? That’s part of the storm that I haven’t even considered yet. Winds are probably around 5-10mph here right now.

Close to a foot of this snow would probably yield around 1.5” of QPF. I could see this being a problem for some in the higher terrain.

[John1122]

38/31dp here. 850 around -1, 925 at -1.

[Blue Ridge]

Could you explain the ratios..let say 8:1, 5:1 or 10:1. What is the meaning between the 3. Thanks

Good to see a new face!

 

I’m not math/met, but I can help. This is the ratio of snow to liquid. In a 10:1 ratio, 1 inch of liquid equals 10 inches of snow. A 5:1 ratio is 5 inches of snow per inch of liquid.

 

In a vacuum, a higher ratio with a fixed amount of liquid would equal higher snow totals. A 5:1 or 8:1 ratio (what we are likely to face with this system) is going to be the heavy, wet cement snow that sticks to everything and can cause power outages.

[TellicoWx]

Just saw a video from just NW Jonesboro, AR...they have changed over to moderate snow sticking to the grass and side streets.

[Holston_River_Rambler]

Don't think I've ever seen a warm nose run up the mts. This is at 925mb, 850 0 line is still way down near Chatt. 

 

[tnweathernut]

3 minutes ago, realdeal2414 said:

Could you explain the ratios..let say 8:1, 5:1 or 10:1. What is the meaning between the 3. Thanks

The higher the ratio the more fluffy (easy to shovel) snow is.  Average rates are around 10:1.  15 or 20:1 is possible when all layers of the atmosphere are very cold.  The lower the ratio the heavier the snow.  5:1 to 8:1 is extremely heavy and much harder to shovel having a higher water content.  Anything with these ratios where more than 5 to 6 inches falls and there will likely be a lot of downed limbs and power lines.  I suspect electric companies will likely be busy with this storm in northeast TN if the forecast pans out.

[John1122]

1 minute ago, Holston_River_Rambler said:

Don't think I've ever seen a warm nose run up the mts. This is at 925mb, 850 0 line is still way down near Chatt. 

 

The winds are blowing east over the mountains. I suspect that's downslope warming.

[PowellVolz]

[mention=499]John1122[/mention] yeah I'm just around 900 feet or so. I can see more up on the towers, but it is just super wet snow, with nothing but an ice crystal core left as far as I can tell 

I’m a little north of Halls at 1100 feet


.

[John1122]

5 minutes ago, PowellVolz said:

I’m a little north of Halls at 1100 feet


.

I'm trying to see how far below the 0 degree 925 that frozen makes it to the ground. So hopefully you start seeing precip soon. It's going to creep north very slowly today.

[Angry Smokey]

Mostly lurk, but enjoy following your guys talk and trying to learn, What does that warm nose mean for the totals for Washington and lower Carter county?