Here's the scenario...

[Scott Dennstaedt, PhD]

It's the middle of February at 4 a.m. with the winds out of the northeast and the surface temps are a chilly 39°F.  What are the chances of being woken up by a raging thunderstorm with intense lightning and war zone-sounding thunder, intense rain and 40 knot wind gusts? Well, that happened to me last night just south of Charlotte.  

The real interesting thing about this convective event is that it erupted so fast in this area.  Below is the lightning picture as of 0840Z.  No strikes just south of Charlotte.

Then, within 5 minutes at 0845Z, all of those white strikes just south of Charlotte appeared as this line of embedded convection erupted.  

This was a line of elevated thunderstorms that developed despite a very intense surface-based inversion as shown in the model analysis sounding below.  The inversion was nearly a depth of 7,000 feet.  However, the instability occurs aloft as cold, dense air is locked in at the surface due to what is referred to as a cold-air damming event.  You can see in the sounding below that low-level winds are out of the northeast providing the cold and low-level moisture.  However, the winds above the inversion shift around to the south which is a warm flow that rides UP and over the cold, dense air creating a dynamic lifting source for that air.  You can see that the most unstable CAPE here is 440 J/kg.  All of that vertical development is occurring above 10,000 feet creating elevated convection.

  

The enhancement to the sound of the thunder is due to the surface-based inversion that ducts the sound and it reverberates across a much greater area for a longer period of time (think about the sound echoing in a canyon).  Also, due to the stable conditions near the surface when air doesn't mix, thunder can be heard from a much greater distance.  

Edited February 21, 2023 by Scott Dennstaedt, PhD

[GeeBee]

Sometimes see the same thing in north GA as the mountains aid the cold air damming and you get snow along with thunderstorms. You get an inversion, with cold air at the surface, fast moving cumulus overcast with tops about 4000' and inversion above. Whenever I see that in winter descending into ATL, I know it is about to get wild. I never thought about the sound amplification of the sound. That makes sense. Thanks.

[carusoam]

Inviting @201er to see the weather he was flying around….

Thank you Scott!

Best regards,

-a-

[201er]

To avoid passing through this system coming back to NJ from Fort Lauderdale, made a layup to Louisville the previous day. 
 

Flew through a bunch of light to moderate, occasionally heavy, rain to get out. Cleared up when I reached the Smokies. Interestingly the mountains continued to block the weather like a wall for the next 24 hours. Came back to Linden today.

Chose Louisville because it was the best place to make a brief visit and then get a VMC straight shot back Sunday.

 

[Jim Peace]

I guess I timed it right. Flying from NJ to Daytona tomorrow. 

[Hank]

Yep. These two systems are why the Mooney stayed in the hangar and we took the Nissan from Sweet Home to Big Easy on Thursday morning and back Saturday afternoon. Lots of wind, ceilings down into treetops and rain, sometimes quite hard as yellow bands blew through. 

But good times and light to no rain while there!

So yes, the Mooney is great for traveling, but there are times and places it is not the best choice.