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

[Matthew70]

Curious could not the LP not create its own colder air kinda like a cut off low does sometimes in springs? So whoever is under that LP would have better chances of having snow instead of FZ.

[fountainguy97]

Anyone want to try to guess what these fingers of freezing temps are on the GRAF?

just random model physics?

 

 

 

 

[Carvers Gap]

1 minute ago, Holston_River_Rambler said:

Ideal for MBY

I think when the first piece of energy isn't stronger...that second waves digs a bit more into Texas, and pops those heights in front just a bit.  The fact that modeling is correcting colder earlier in these runs might also mean that modeling was too warm w/ earlier runs, and is possibly correcting.  I noticed at lunch that the eastern Plains really cooled off.  Though, I do think the second wave is contributing.  The ice was substantially worse with that run for MBY.  TRI is catching a bullseye today for ice...not a fan of that.

[Carvers Gap]

2 minutes ago, fountainguy97 said:

Anyone want to try to guess what these fingers of freezing temps are on the GRAF?

just random model physics?

 

 

 

 

Mountain wave coming from the southeast.  The second to last green streak is likely Camp Creek.  The other one is Unicoi.

[fountainguy97]

Seems like the nam has them too. Maybe just downslopjng the warm areas?

[Holston_River_Rambler]

3 minutes ago, Carvers Gap said:

TRI is catching a bullseye today for ice...not a fan of that.

Can't argue with that. Maybe there will be the illusive Bays Mt lake valley CAD? 

[fountainguy97]

The rrfs takes forever to erode the CAD between those downsloping hotspots. Over an inch of zr for my backyard.

[Holston_River_Rambler]

5 minutes ago, Carvers Gap said:

Mountain wave coming from the southeast.  The second to last green streak is likely Camp Creek.  The other one is Unicoi.

You also have two river valleys that cut through the mountains that the model is seeing and trying to leak some of North Carolina's CAD, French Broad and Nolichucky.  

Or at least I think that's a possibility

[Carvers Gap]

1 minute ago, fountainguy97 said:

Seems like the nam has them too. Maybe just downslopjng the warm areas?

Then, that is very likely that is the mountain wave event.  I looked pretty closely earlier today.  Wicked downslope.  Saw some gusts as high at 65mph on earlier models. That last "streak" usually works its way right up I26.  I usually get a text from someone in Gray who says their house is 45 while I am in the upper 20s and low 30s.  Bout thirty minutes later...it starts raining at my house.  Hahah.  Let's hope there isn't ice on those trees as @Holston_River_Ramblernoted earlier today....high winds and ice are a bad combo.

[fountainguy97]

1 minute ago, Carvers Gap said:

Then, that is very likely that is the mountain wave event.  I looked pretty closely earlier today.  Wicked downslope.  Saw some gusts as high at 65mph on earlier models. That last "streak" usually works its way right up I26.  I usually get a text from someone in Gray who says their house is 45 while I am in the upper 20s and low 30s.  Bout thirty minutes later...it starts raining at my house.  Hahah.  Let's hope there isn't ice on those trees as @Holston_River_Ramblernoted earlier today....high winds and ice are a bad combo.

Very cool to see the micro climates showing. Also hoping I don't end up in a pocket of zr the entire event haha

[Carvers Gap]

1 minute ago, Holston_River_Rambler said:

You also have two river valleys that cut through the mountains that the model is seeing and trying to leak some of North Carolina's CAD, French Broad and Nolichucky.  

For sure...but likely wind.  I looked this AM when I saw those warmer temps streaking across Tenn.  The general correlate to winds I think.  

[fountainguy97]

So I wonder if the downsloping is actually aiding in transporting the CAD over into Erwin keep those tongues of cold temps. Crazy

[Matthew70]

6 minutes ago, fountainguy97 said:

The rrfs takes forever to erode the CAD between those downsloping hotspots. Over an inch of zr for my backyard.

Ouch 

[bearman]

4 minutes ago, fountainguy97 said:

The rrfs takes forever to erode the CAD between those downsloping hotspots. Over an inch of zr for my backyard.

Knoxville wins the lottery with that one, keeps us completely clean.

[Holston_River_Rambler]

But in this case wouldn't it be colder air coming across @Carvers Gap since the map @fountainguy97 showed shows fingers of freezing rain?

 

The 3km NAM shows a little bit of this, but strangely enough it does appear to be cutting across the mountains to me and not in the valleys:

[John1122]

The high res models try very very hard to account for terrain. Probably too hard at times. It's because their resolution is so small they see every hill and valley. Are those fingers deep valley areas?

[Holston_River_Rambler]

1 minute ago, fountainguy97 said:

So I wonder if the downsloping is actually aiding in transporting the CAD over into Erwin keep those tongues of cold temps. Crazy

After looking at the NAM temps above, that was my first thought. The air is warming as it moves away from the foothills and into the valley of the 81 corridor so that makes some sense. 

You know how they do those air parcel tests to see where airmasses come from? It'd be really interesting to see where the air that is moved by the mountain wave events originates and what happens to it as it accelerates over the mountains and descends into the East TN valley. 

This seems like a very unusual situation. Usually when we have mountain wave events it seems like we have a strong cutter heading west and there isn't really any concern for cold air except on the backside of the system. 

[fountainguy97]

WeatherFront app is amazing btw.

 

Yeah it's coming over the mountains I believe. Crazy to see. This wind is siding the cold transport.

[Scottie16]

Icon is just the icon.


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[Carvers Gap]

I would say 95% chance it is the mountain wave event.  You can see the winds and direction on the second image.  

 

 

[fountainguy97]

1 minute ago, Holston_River_Rambler said:

After looking at the NAM temps above, that was my first thought. The air is warming as it moves away from the foothills and into the valley of the 81 corridor so that makes some sense. 

You know how they do those air parcel tests to see where airmasses come from? It'd be really interesting to see where the air that is moved by the mountain wave events originates and what happens to it as it accelerates over the mountains and descends into the East TN valley. 

This seems like a very unusual situation. Usually when we have mountain wave events it seems like we have a strong cutter heading west and there isn't really any concern for cold air except on the backside of the system. 

Very true. I've never thought about the temperature of mountain wave winds lol.  But yes I think that's the conclusion I've come too.. and it's a scary one for myself. My house is quite literally in the coldest streak coming over Erwin. 

[Carvers Gap]

2 minutes ago, fountainguy97 said:

WeatherFront app is amazing btw.

 

Yeah it's coming over the mountains I believe. Crazy to see. This wind is siding the cold transport.

I think technically the warm areas are actually the mountain wave downslope.   The colder places in between are areas not hit by the downslope.  But I can't say that for sure.  

[Scottie16]

After looking at the NAM temps above, that was my first thought. The air is warming as it moves away from the foothills and into the valley of the 81 corridor so that makes some sense. 
You know how they do those air parcel tests to see where airmasses come from? It'd be really interesting to see where the air that is moved by the mountain wave events originates and what happens to it as it accelerates over the mountains and descends into the East TN valley. 
This seems like a very unusual situation. Usually when we have mountain wave events it seems like we have a strong cutter heading west and there isn't really any concern for cold air except on the backside of the system. 

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[Scottie16]

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Did not mean to post that.


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[John1122]

The graphic MRX released has my general area snowing for 12 hours Saturday, 6 light and 6 moderate snow. Then wintry mix of sleet for 6 hours, then 3 hours of freezing rain, 6 hours of rain, back to 3 hours of mix and 6 hours of moderate snow to finish. 

[Holston_River_Rambler]

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

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. 

[fountainguy97]

1 minute ago, Carvers Gap said:

I would say 95% chance it is the mountain wave event.  You can see the winds and direction on the second image.  

 

 

If we see Morristown talk about this we will know they are watching us haha.

 

2 minutes ago, Carvers Gap said:

I think technically the warm areas are actually the mountain wave downslope.   The colder places in between are areas not hit by the downslope.  But I can't say that for sure.  

I was typing this out. The cold streaks seem to line up with the valleys. So I'm assuming the reason for the cold air is the wind is pulling the CAD could air over. 

[Holston_River_Rambler]

I think Carver's is right about it being related to the mountain wave. That trajectory is too spot on. Is there some physical process where by air can cool near to a relatively warming downslope flow? 

[Carvers Gap]

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.

[fountainguy97]

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:

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. 

Can clear,y see the two valleys here.