Major Wind Damage/Possible Gravity Wave This Morning

[HAltschule]

The winter storm discussion over the Northeast now has a new variable to it. Apparently, Rutland, Vermont experienced a major wind damage event as a result of a gravity wave or entrance into the warm sector where 50kt + winds mixed down. The entire city is without power and numerous trees and power lines are down as well as some roofs and siding of some houses. See Discussion on this thread below.

http://www.stormtrack.org/forum/showthread.php?p=131738#post131738

PS: Hopefully MOD's are OK with this link.

 

[cdcollura]

Good day,

I have seen this happen.

This is where the strong winds aloft, at the top of the boundary layer are mixed and momentum reaches the surface (example: low level jet).

This is called a NON-CONVECTIVE DAMAGING WIND event.

It occurs either from sinking air and / or mixing in the boundary layer where there is a lot of friction before the mixing occurs. This is why during a nor ' easter, there are 40-50 MPH winds at the coast, and almost no wind inland (the wind is higher up, a couple of hunderd feet or so).

Mix these winds down to the surface, especially in an elevated terrain, and you have winds at the speeds (or near) the low-level jet at the surface = wind damage!

 

[rdale]

A gravity wave is not related to the low-level jet...

http://www.auf.asn.au/meteorology/section7.html

 

[cdcollura]

Good morning,

A gravity wave is not related to the low-level jet...

That is correct, a gravity wave is more or less like an ocean wave, forming on pressure / temperature (aka density) "surfaces" which are different in the atmosphere.

These waves can, however ... Especially if the gravity wave is within the boundary layer ... Allow a strong wind aloft to become closer to, or even reach, the ground.

 

[B Ozanne]

I was under the impression that this was a downslope windstorm and the mountains were a major contributing factor.

The wind damage was isolated in a corridor along US-7 between Rutland and Brandon, an area that runs close to the western slopes of the Green Mountains.

Local news coverage here: http://rutlandherald.com/