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1/23/26-1/25/26 Winter Storm Thread

AMZ8990

By AMZ8990,
in Tennessee Valley

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fountainguy97

fountainguy97

Posted
Posted
2 minutes ago, Carvers Gap said:

So mountain waves are not really seeking corridors like gaps.  @Math/Met - bat signal for an explanation.  My understanding has always been that these are places where the winds out of the SE hit the mountains almost at a 90 degree angle, are forced to compress on the ridges which speeds them up at the top - like a wave coming into the beach.  There probably is a component where they are hitting the lower points on high ridges.  Basically works like a compressor.  The ridge has to be the right slope for this to work on both sides of the mountain in order to allow the winds to come across smoothly and race down the other side.  If the beach is too steep...not great waves.  Needs to move from deep to shallow water at a certain rate(sharp but smooth) in order to create big waves.  The only thing with this...the wave rushes down the other side of a mountain.  Just a few places in the world which can do what Camp Creek does.

And camp creek and roan mountain I guess are almost creating a vacuum pulling that cold air through the valleys which is why the cold air is cold and not warm like the actual downsloping region.

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Holston_River_Rambler
Holston_River_Rambler

My current take: The players:   The setting: the game: All in motion on the Euro       Comparison:   Euro trend:

Reb
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John1122
John1122

I feel like this is a trap. I'm having 2017 ptsd from when the Euro showed 30 inches imby 48 hours out, and I ended up with two inches. 

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Carvers Gap

Carvers Gap

Posted
Posted
3 minutes ago, Holston_River_Rambler said:

This is what we've come to for this system lol, it's like an inverse Bays Mountain band situation:

kP6o6qK.png

Purple arrows are wind trajectory modeled and blue lines are the approximate flow of the two rivers. Black circles are where the rivers come out of the mountains. 

The bottom purple arrow is almost exactly where Camp Creek is....almost perfectly.  And that may have been your intention.

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Holston_River_Rambler

Holston_River_Rambler

Posted
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4 minutes ago, Carvers Gap said:

So mountain waves are not really seeking corridors like gaps.  @Math/Met - bat signal for an explanation.  My understanding has always been that these are places where the winds out of the SE hit the mountains almost at a 90 degree angle, are forced to compress on the ridges which speeds them up at the top - like a wave coming into the beach.

That's what I'm trying to say. The trajectory of the winds isn't through the gaps where the rives cut, it's directly over ridges in locations that are often affected by mountain wave events, so I don't think its that, or cold air leaking through the river gaps. 

I'm wondering if there is some physical process where the relative warming can be coupled with a relative cooling OR somehow the trajectory of the winds transports air that is so relatively cold that that even with relative adiabatic warming it still cools valley areas. 

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tnweathernut

tnweathernut

Posted
Posted

You guys are making my head hurt, not to mention I’m on my phone instead of desktop.  Are you saying the same downslope component that warms certain areas (i.e. camp creek) actually works to pull cold air through valleys in the mountain chain from NC to TN in other places?

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Reb

Reb

Posted
Posted
Just now, Holston_River_Rambler said:

I am going to shut up about this stuff (at least for a while) now because I think other posters might be over it. 

I will be watching for this now. I love microclimate stuff. 

I’m here for it!!!

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fountainguy97

fountainguy97

Posted
Posted
2 minutes ago, tnweathernut said:

You guys are making my head hurt, not to mention I’m on my phone instead of desktop.  Are you saying the same downslope component that warms certain areas (i.e. camp creek) actually works to pull cold air through valleys in the mountain chain from NC to TN in other places?

Last post lol. The way I see it is the fast downsloping winds are creating friction with the surrounding air and  pulling the cold air through the valleys.

IMG_0041.jpeg

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Carvers Gap

Carvers Gap

Posted
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2 minutes ago, fountainguy97 said:

And camp creek and roan mountain I guess are almost creating a vacuum pulling that cold nail through the valleys

I honestly don't know where the other "streamer" is coming from".   It may well be catching the Indian Creek drainage from near Sams Gap.  You really want to look at the mountain on the NC side.  It has to sit perpendicular to the SE winds.  Could be Unaka.  As much downslope as Johson City gets(and I am on the terminus of that I26 streamers). But yeah, that almost has to be Roan Mountain causing that other warming area - sits perfectly upstream for that warming to happen.  That Roan Mtn warming comes right around the end of Buffalo(could be using Buffalo as well).  And honestly, JC could be catching the Indian Creek funnel which connects to the Roan stream.  Crazy physics in the mountains.  Just another great example of why it is so difficult to forecast here.  And the win can howl on Roan Mountain.  

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fountainguy97

fountainguy97

Posted
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5 minutes ago, Carvers Gap said:

I honestly don't know where the other "streamer" is coming from".   It may well be catching the Indian Creek drainage from near Sams Gap.  You really want to look at the mountain on the NC side.  It has to sit perpendicular to the SE winds.  Could be Unaka.  As much downslope as Johson City gets(and I am on the terminus of that I26 streamers). But yeah, that almost has to be Roan Mountain causing that other warming area - sits perfectly upstream for that warming to happen.  That Roan Mtn warming comes right around the end of Buffalo(could be using Buffalo as well).  And honestly, JC could be catching the Indian Creek funnel which connects to the Roan stream.  Crazy physics in the mountains.  Just another great example of why it is so difficult to forecast here.  And the win can howl on Roan Mountain.  

So verbatim I'm sitting in a cold stream of air with 20-30mph winds with zr falling for 12+ hours. Nice

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tnweathernut

tnweathernut

Posted
Posted
12 minutes ago, Holston_River_Rambler said:

I am going to shut up about this stuff (at least for a while) now because I think other posters might be over it. 

I will be watching for this now. I love microclimate stuff. 

Everyone should keep in mind, this is all some of us have to be concerned/curious about for pretty much the duration of this storm.................  lol

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BNAwx

BNAwx

Posted
Posted
7 minutes ago, Scottie16 said:

OH BOY! (So far)


 

Dang!  Pretty big shift.  I’ve felt a shift back south on modeling might occur but it was probably 50% from experience watching these types of storms and 50% wishcasting.

It is the GFS so who knows….

 

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Carvers Gap

Carvers Gap

Posted
Posted
3 minutes ago, Scottie16 said:


Honestly try asking Google AI lol


.

@Math/Metis the legit expert on mountain wave events.  Any time I read MRX talking about mountain waves...I am like, I recognize this verbiage!  Something to think about.  Not saying those dots connect.  Not saying they don't.  I think he is from that area as well.  Guru on this and interesting.

The wind can be howling in Camp Creek...and barely a breeze here.  That weather station there was built to collect mountain wave data.  One year, the wave was so strong...it knocked over the tower anemometer.  They get like 80mph gusts with high end stuff.  @Holston_River_Rambleryou are correct that the river valleys are a component of this...but I couldn't explain it in 5 pages.  @Rebback to our normally scheduled programming of ice, heartbreak, and 8-9 day storm discussions.  Haha!

Here are some sources.  If one of you all wants to start a thread on it, I would be more than happy to participate.  It pretty fun to track.  One day, I am going up there to see the MWE for myself.  Interestingly, this weekend's setup is ideal for mountain wave events - cold air damming on the east slopes, slp cutting from MS through TN.  

https://www.weather.gov/mrx/arealextent

Also, weaker cold-air damming on the eastern side of the southern Appalachian Mountains appeared to allow warning-level winds at the Coker Creek and Shady Valley sites, with the weakest cold-air damming observed during the warning-level wind dates at Shady Valley.

https://www.weather.gov/mrx/mtnwavewinds

The composite maps of surface isobars (Figure 19) revealed a low pressure system over the mid-Mississippi River Valley (northwest of the southern Appalachian Mountains) with an area of high pressure centered off the mid-Atlantic coast during both warning-level and advisory-level wind events. A deeper low pressure area was observed with the warning-level wind events (compared to the advisory-level events), which resulted in a stronger pressure gradient across the southern Appalachian Mountains. In both the warning-level and advisory-level composite maps, the surface temperatures revealed that cold air damming was occurring across the eastern side of the Appalachian Mountains. This cold air damming was a little stronger with the advisory-level events (compared to the warning-level events), while warmer temperatures were further north on the western side of the southern Appalachian Mountains with the warning-level events. The combination of a weaker low pressure system over the mid-Mississippi River Valley and stronger cold air damming (a blocked boundary layer) on the eastern side (upwind) of the southern Appalachian Mountains likely caused the wind flow below 700 hPa to be weaker during the advisory-level events.

 

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