2016-2017 Great Tennessee Valley Winter Discussion

[tjgrogan]

Will East TN see any ice accumulation or snow accumulation?

[JayCee]

3 hours ago, John1122 said:

I live in the woods and in a very prone area to get icing due to cold getting trapped right over my area with the steep ridges on every side of me. Living in a bowl makes for interesting weather. It's most noticeable in icing events and clear calm mornings. I'm usually 5-8 degrees colder on most clear mornings than areas at 2500 feet or so. Sometimes 10 or more. I've went up 500 feet in elevation before and went from 25 degrees to 40 degrees.  The opposite happens in snow set ups. They are usually 2-3 degrees colder than me and that makes a lot of difference here in changeover times and amounts. It's crazy how small a distance north to south and an elevation difference of 4 or 500 feet make.

If I had my druthers, I'd live on the Plateau.  It does make for interesting weather.  I even looked at land there before I moved where I am now. 

I did live on the Cumberland Plateau in Kentucky, but there is a big difference in the topography of the Plateau between TN and KY.  It's mostly higher for one thing in TN, and southeast KY (east of London) is a deeply eroded form of what used to be a high tableland.  There are such deep and narrow "ruts" between ridges that the sun rises at 10 and sets at 2 in those deep "bowls."  As an example--Hazard, KY situated in Kentucky's Plateau region--is actually at a lower elevation than where I live in the Tennessee Valley.  I'm at 1,100 feet here east of Sevierville, while Hazard sits at a meager 928 feet.  Pikeville, to the east of Hazard, is even lower at 679 feet!  Many of the towns and livable places in eastern KY are in very deep, narrow river valleys situated between ridges (hollers), but most of those high ridges are only 1,200-1,500 feet, except for the higher Black and Cumberland Mountains near the KY-VA border. 

Anywho--sorry to digress into geography . 

 

 

[John1122]

3 minutes ago, JayCee said:

If I had my druthers, I'd live on the Plateau.  It does make for interesting weather.  I even looked at land there before I moved where I am now. 

I did live on the Cumberland Plateau in Kentucky, but there is a big difference in the topography of the Plateau between TN and KY.  It's mostly higher for one thing in TN, and southeast KY (east of London) is a deeply eroded form of what used to be a high tableland.  There are such deep and narrow "ruts" between ridges that the sun rises at 10 and sets at 2 in those deep "bowls."  As an example--Hazard, KY situated in Kentucky's Plateau region--is actually at a lower elevation than where I live in the Tennessee Valley.  I'm at 1,100 feet here east of Sevierville, while Hazard sits at a meager 928 feet.  Pikeville, to the east of Hazard, is even lower at 679 feet!  Many of the towns and livable places in eastern KY are in very deep, narrow river valleys situated between ridges (hollers), but most of those high ridges are only 1,200-1,500 feet, except for the higher Black and Cumberland Mountains near the KY-VA border. 

Anywho--sorry to digress into geography . 

 

 

The Campbell County plateau isn't true plateau land but is still considered part of it. Mostly the Plateau is 1500-2000 feet and reasonable flat. In Eastern Morgan, Eastern Scott and Campbell the plateau turns jagged and can go another 1000-1600 feet in elevation over the rest of it. Finding actual land for sale above 2500 feet is not easy, as most of it's WMA land.

[John1122]

22 minutes ago, tjgrogan said:

Will East TN see any ice accumulation or snow accumulation?

It's far enough out yet not to be sure, but right now I'd keep an eye on the forecast as it could easily ice up over a good portion of the area. It appears that the further west you are the better your shot due to the location of the coldest air. It almost always is further east and south than modeled. 

This is the current ice accumulation map from the 18Z GFS. Highly subject to change as all winter systems are in this part of the world.

 

[JayCee]

I have to insert a quick "props to Dolly Pardon" for the telethon she is holding tonight for her "My People" fund.  She seems to be a genuine, caring person and is doing all she can to help the fire victims.   A long time celebrity, but she never forgot where she came from.  Not too many super stars have that sort of humility and grace. 

[John1122]

The 0z has came in very similar to the previous 3 runs. Appears close to locking in on a major ice event from the Plateau westward. It's under 120 hours now. May be close to thread starting time. 

[John1122]

[John1122]

Para GFS is probably 30-40 miles east with where it sets the freezing line in this event. 

 

[John1122]

Para gets to here. 

[Mrwolf1972]

 CFS 0z

[Mrwolf1972]

06 z gfs

[whamby]

damn, 7 degrees in central Indiana and 45 in ATL... talk about a temperature gradient.. 

[weathertree4u]

14 minutes ago, Mrwolf1972 said:

06 z gfs

Folks at the NWS Nashville still think that most of the deepest moisture will be east of us when the real cold arrives; I have seen this type of situation bite them in the backside too many times, this has something written all over it, and I have a feeling it is going to be ice.

[dwagner88]

Don't get too excited in the valley for this one. Cold air chasing precip may work from the plateau westward from time to time, but it is notoriously difficult to scour out warm air from the valley in these situations. I can't recall one ever working in the southern valley. I recall an event from 2015 where the temp was 31 on walden's ridge and nearly 60 at my house in East Brainerd. Those locations are about 10 miles and 1200' in elevation apart.

[whamby]

25 minutes ago, dwagner88 said:

Don't get too excited in the valley for this one. Cold air chasing precip may work from the plateau westward from time to time, but it is notoriously difficult to scour out warm air from the valley in these situations. I can't recall one ever working in the southern valley. I recall an event from 2015 where the temp was 31 on walden's ridge and nearly 60 at my house in East Brainerd. Those locations are about 10 miles and 1200' in elevation apart.

But with this kind of arctic air mass to the north? 

[jaxjagman]

3 hours ago, weathertree4u said:

Folks at the NWS Nashville still think that most of the deepest moisture will be east of us when the real cold arrives; I have seen this type of situation bite them in the backside too many times, this has something written all over it, and I have a feeling it is going to be ice.

There is still so much spread between the Euro and GFS.Euro shows in our area better instability,showalter,KI,sbcapes around 200,should be some thunderstorms,GFS,not much.Then the GFS shows a shortwave/"Anafront" look with moisture ongoing well behind the frontal boundary,Euro dont show this.

[JayCee]

35 minutes ago, dwagner88 said:

Don't get too excited in the valley for this one. Cold air chasing precip may work from the plateau westward from time to time, but it is notoriously difficult to scour out warm air from the valley in these situations. I can't recall one ever working in the southern valley. I recall an event from 2015 where the temp was 31 on walden's ridge and nearly 60 at my house in East Brainerd. Those locations are about 10 miles and 1200' in elevation apart.

I've seen it myself countless times while living in London, KY, and after moving here--London sitting in the teens, while Knoxville is stuck in the 40's.  Cold, dense air has a very hard time making it over the Plateau in this type of situation where the front stalls out along the upper flow, and is not being pushed along.  The cold air slowly "oozes" its way in, and usually only after the parent low has moved to our east. 

[Mrwolf1972]

12z gfs shows a backside heavy snow on the 27th and stays below 32 till the 30th but gonna be 62 in Knoxville and 36 in Nashville  then drop 30 degrees in 6 hours.

[John1122]

12z lost the major back side ice, maybe a little in Middle Tn and some snow showers to close it out. 

[Mrwolf1972]

11 minutes ago, John1122 said:

12z lost the major back side ice, maybe a little in Middle Tn and some snow showers to close it out. 

I seen that but the 12z cmc still shows a blob of ice middle tn.

[Mrwolf1972]

[jaxjagman]

14 minutes ago, Mrwolf1972 said:

Mostly from the shortwave it still shows.GFS abandoned that idea this afternoon,Euro don't show it.

[Carvers Gap]

@BobChill from the MA mentioned that he EPS threw us a bone.  I agree and noticed the same thing.  The control, especially, wants to build a -EPO.  The mean hints at it.  Several operational runs of the GFS are not warm.  If it was cold that was being modeled, I would be nervous with the trends from the past couple of days.  In other words, this looks like seasonable warmth potentially followed by more cold.  We will see...

[John1122]

18z leaned back towards the prior 4 or 5 runs. Ice again from the Plateau west.  Good position on the LP that run. Wave developed down in Georgia. 

[Met1985]

1 hour ago, Carvers Gap said:

@BobChill from the MA mentioned that he EPS threw us a bone.  I agree and noticed the same thing.  The control, especially, wants to build a -EPO.  The mean hints at it.  Several operational runs of the GFS are not warm.  If it was cold that was being modeled, I would be nervous with the trends from the past couple of days.  In other wards, this looks like seasonable warmth potentially followed by more cold.  We will see...

This is a great post and completely agree. To me nothing out of the norm really.

[John1122]

Not much mention of ice potential by MRX though. Just rain or snow. 

[Carvers Gap]

28 minutes ago, Met1985 said:

This is a great post and completely agree. To me nothing out of the norm really.

Now, I promise I can spell "word."  The 18z GFS is a great example. It was interesting to see some LR storms along the coast.   Plenty of back-and-forth throughout the run.  I am not convinced this is a torch upcoming.  Additionally, it can also snow during a warm pattern as slightly above normal in January is still pretty cold.  One of the posters made this point, and maybe it is the one to debate...Was the cold a relaxation of the ongoing warmth or is the upcoming warmth a relaxation of the cold?  It is interesting to see the ensembles go wall-to-wall warm but the OPs do not after d10.   It is almost like when a few weeks ago the ensembles were wall-to-wall cold and that did not verify at the magnitude modeled.  The OPs revealed massive back-and-forth swings...and were correct.  In some cases well BN was modeled here for weeks on end.  I continue to think(and I may be wrong) that this winter is back and forth with big swings as Nina winters can have strong cold fronts(I think Jeff said that several months ago).  The GREAT news is that we are getting plenty of rain and will get more.

[Carvers Gap]

These fronts that are sagging across the area are interesting.  If one of those stalls across the GOM, that might be the ticket.  

[Met1985]

1 hour ago, Carvers Gap said:

Now, I promise I can spell "word."  The 18z GFS is a great example. It was interesting to see some LR storms along the coast.   Plenty of back-and-forth throughout the run.  I am not convinced this is a torch upcoming.  Additionally, it can also snow during a warm pattern as slightly above normal in January is still pretty cold.  One of the posters made this point, and maybe it is the one to debate...Was the cold a relaxation of the ongoing warmth or is the upcoming warmth a relaxation of the cold?  It is interesting to see the ensembles go wall-to-wall warm but the OPs do not after d10.   It is almost like when a few weeks ago the ensembles were wall-to-wall cold and that did not verify at the magnitude modeled.  The OPs revealed massive back-and-forth swings...and were correct.  In some cases well BN was modeled here for weeks on end.  I continue to think(and I may be wrong) that this winter is back and forth with big swings as Nina winters can have strong cold fronts(I think Jeff said that several months ago).  The GREAT news is that we are getting plenty of rain and will get more.

Carver well said. I do think we see a relaxation but the torch talk is a bit overrated in my opinion. I may be wrong but I only really see a day or two here and there of real warmth right before we go cold again. Another thing that is interesting with the dying Nina what will that do for the rest of the winter. I keep seeing this is behaving like a Nina which is true but I think there are stronger factors than a super weak Nina that are driving this pattern. These recent patterns have been anything but normal so why base them off of a normal variable when we have had some very early things happen with this pattern that has  kind of thrown things in a whirl wind.

[John1122]

0z dropped the ice accumulations for most but changed it over to heavy snow directly over my area and drops 2-4 inches right on Campbell County up into SE Ky.