[EAS] 9-1-1 Outages From Derecho/Windstorm

[Mike McCarthy]

The understanding of mesocyclones in relation to meso-convective clusters
(MCS) is a more recently discovered phenomena with high precision
satellite and wind profilers able to detect the meso-level mid elevation
rotation. Mesocyclones tend to avoid longer squall lines given more linear
forcing associated with the long straight squall front doesn't lend to any
large scale spin-up.

That's not to say it won't happen in a long sqaull. They're simply not as
common as bow echo's which are directly related to high efficiency
downward wind production blowing  forward in a cell relative to others in
the line.

MCS's tend to form in otherwise non-linear locations where convective CAPE
is high, CINH (convective inhibition) reduced, and there is a gradient to
slide along for decaying cells to get spun swept into the jet stream and
come around again for another shot. MCS's also pulse cells which form
upstream along the periphery of the circulation ahead of the main body. 
Thereby propagating forward faster.

MM

> Mike,
>     This storm system started out somewhere west of Lake Ontario in
> Canada. The 1,000 islands are in the western end of this lake. The
> storm system proceeded across western New York, doing extensive damage
> in Rochester and Syracuse. The weather service called this event a
> derecho, and this was the first time I had ever heard that term used.
>     I did not know that there is mesocyclonic activity in a storm that is