Carvers Gap

@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.

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.

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

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.

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

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.

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.

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

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.

The 18z NAM rolls w/ two waves of precip. The first wave absolutely hammers the eastern valley. Precip w/ that wave is south of the first wave on the 12z. It makes me think the model is adjusting the earlier hours. I bet that might happen w/ that second wave as well. Makes sense as the big high is impacting the early part of the run.

The 18z NAM had less of a warm nose in middle Tennessee. It is also for sure south w/ its precip shield(first wave...edit).

Evaporational cooling.

The 18z NAM is hammering TRI. Tucker, I see CAD on WxBell.

I still have my 14-15 snow shovel.

A big error with models is they don't "see" the cold right at the surface. I have been forecast for snow in NE TN...only to have it verify in north Alabama before. Why? Lots of reasons. One....sometimes the cold is undermodeld. These could just be ebbs and flows on modeling, but trends have to be watched. The GEM-para shift is noticeable.

@Matthew70, I am reminded that you consistently said not to cancel winter. Just a little thank you card from me.

Real feel Euro for next Thursday. @Matthew70, this is what we don't want, right? -40 real feels in the Apps. -10s to -20s in the valleys.

I haven't checked Steve's friend's (hurricant hunter source) update for today...but more should be gathered today. I definitely thought of that. My guess is that Arctic air mass is finally out of the information void above the Arctic Circle.

Ah. Sure did. What is interesting about that is that means the model will likely have to correct downstream as it approaches. It is a decent sign modeling is behind the curve after about 36 hours or so.

The 12z GEM-para moved southward.

Which model did it cave to? Looks like Hoth to me!

I have to think modeling is FINALLY feeling the effects of those big highs. Cold air is just pouring down the west flank of the Apps. I looked at the wind on this morning's runs(after reading MRX's write up about mountain waves being possible), and you can see the cold just running parallel to the Apps and making a beeline southward.

Haha. I always tell my friends...you will know I am not AI, because I have too many typos in what I write. Between self correct and typing fast, I make all kinds of errors. I generally go back and proof one more time after I post - I just shake my head. If I ever start posting stuff that doesn't have typos...you know the singularity got me! Even better, I am very prone to getting model names and model run times (0z,6z,12z,etc) mixed up. For once, my typos are a good thing!

LOL. Where did you find that?