Mountain Waves over the Appalachian Mountains

[Bartman]

We had a great 4 days with friends on Amelia Island FL. Today we returned with 50 kt winds out of the northwest and our path would have taken us over Mount Mitchell.  Climbing to 8K to 10K and then 12K we could see the standing waves so we deviated from Greer to the northeast before getting back on course. Despite that we experienced rhythmic fluctuations in airspeed from 78kts up to about 135kts due to mountain wave effects.  I noticed wave effect as far as 100 nautical miles downstream.  Those below us were very uncomfortable and even a 737 reported loss of altitude in a PIREP. 

Here’s what it looked like from above. 

[ArtVandelay]

Yep, winds at 14,000’

 

[GeeBee]

There are not a lot of things that cause me to start inhaling a seat cushion, but mountain wave gets my attention. I've like that 737 been in stuff so bad, I've had to give the airplane its "head" and just ride it out. The worst mountain wave in the world is believe it or not over northern Iran. 

The biggest worry about wave IMHO is sooner or later there is a rotor somewhere, and you need to avoid it if you want to keep the wings on.

 

[eman1200]

I flew from Charlotte to KY this past Friday, same thing....50-60kt winds and some insane turbulence. So much wrong with this picture....

[Scott Dennstaedt, PhD]

These are called trapped lee waves and are very common over the Appalachians.  It has a very classical signature on the Skew-T diagram.

 

[Bartman]

I had the same experience with airspeed @eman1200with my lowest ground speed of 78 knots in level flight and I think this is when this image was taken.  However there was zero turbulence at 12,000 and I willingly sacrificed airspeed for the smooth ride. Those behind and below me were asking for higher. 

I chose not to do this flight yesterday for multiple reasons, including icing. 
 

 

[Bartman]

  On 5/9/2021 at 12:48 AM, Scott Dennstaedt, PhD said:

These are called trapped lee waves and are very common over the Appalachians.  It has a very classical signature on the Skew-T diagram.

 

 

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Thank you. I see these a lot on satellite images and I have usually found these bands of clouds to be usually benign, but never knew what they were called. When I approached KGSP and Mount Mitchell in our path ahead we could see what looked like multiple lenticular looking clouds and turned northeast. Basically flew between two of the downstream trapped lee waves in smooth clear air until we were north of the highest peaks and then back on course. 

However, I have encountered rotor clouds in otherwise clear air over Mount Mitchell at 9,000 and know better than to fly there on days like today. That was not a pleasant experience. 

[icurnmedic]

When flying west, I always fly north of Mt Mitchell . There is a gap in the mountains that is typically a much smoother section. Even at 10k The turbulence at Mitchell can seemingly come out of nowhere and sometimes scares the daylights out of me. 

[Philip S]

This is a little after passing Mt. Mitchell. I’ve been able to find smooth air between 10 and 12k. But have definitely hit my head while finding it. 78 knots near the nose really puts your speed in perspective (and makes me wish for longer range tanks). I usually pass south of the mountains but maybe a northerly route would be preferable as icurnmedic suggests. 

[ZuluZulu]

I wanna play!  This was from a flight in February.

[Hank]

My worst turbulence has been downwind of Mt. Mitchell. Headed home from SnF to WV, I got bounced around over SC enough that I climbed to 10,000 hoping for a smoother ride. My buddy said that last half hour to just past AVL was the worst turbulence he'd ever experienced.

Another time going home from the inlaws at KFAY, the winds were stupid and there was icing in southern WV, so I went the long way:  west across NC at 4000msl and almost 100 knots; climbed to 9000 between GSP and TYS, the tired of dodging cloud tops below freezing at twilight asked for 10,000 and ground speed fell to 68 knots while indicating 140mph. As soon as we cleared terrain, ATC let me descend to 6000 and groundspeed rose to about 100 again as I headed for LEX. Wish I could remember what it was when I turned east for KHTS . . . . At least the ride was smooth most of the way.

There's a reason for the callout on the sectional beside Mt. Mitchell, the highest point in North America east of the Mississippi.