Rich Freeman on 18 Jul 2017 08:19:43 -0700

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Re: [PLUG] Waaaaay Off Topic: Thunderstorm Movement

On Mon, Jul 17, 2017 at 10:21 PM, Lee H. Marzke <> wrote:
> Rich,  that is an excellent description and overview spoken like a real weather junky.

I'll take your word for that.  I know enough to be dangerous (granted,
I'd say the same of Linux).

> What caused you to have so much interest ?

Well, besides my interest in the physical sciences in general I have
an uncle who is a bit of a weather junky.  Plus, take enough
thermodynamics and kinetics in college and it almost starts to make

> I'm a commercial/instrument pilot and instructor in Airplanes and also a Glider instructor so weather conditions
> are of life/death importance to me and a hobby in Gliders.

Ah, another area where I have a lot of interest but know enough to be
dangerous.  I tend to stick to the simulators as the sense of panic I
tend to get when moving around in invisible air currents didn't really
go away despite giving it a pretty fair try.  At least in an airliner
I can just close my eyes and let somebody else land the plane if it
gets bumpy.  The reality is that something like a Cessna 172 is pretty
hard to lose control of, but I find that it doesn't feel that way...

> The weather service routinely launches rapidly rising balloons that have radiosonde packages
> that radio back the temperature and altitude readings as they rise.  This is plotted
> as the Actual lapse rate on a Skew-T Log-P diagram.   Glider pilots use these to
> predict expected max height of lift by taking the expected surface high temperature for the day
> and lifting a surface parcel of air at that temperature along the adiabatic lapse rate on the chart until it
> intersects the actual aloft temperatures reported from the morning soundings.

Interesting.  In retrospect it makes perfect sense, but I had no idea
that glider pilots bothered to use soundings.  I certainly haven't
seen them come up in powered aviation weather.

You seem to be describing the LCL though.  I'd expect moist air to
rise to that level, but wouldn't it continue rising until it condensed
out (cloud top, vs cloud base)?  Granted, you'd be inside the clouds
at that point which you'd probably want to avoid.  Also, I don't think
that cloud tops are so easily predicted from a sounding, unlike cloud
base (which is why the bottoms of clouds tend to be fairly flat and
uniform across an area compared to the tops).  So, maybe the LCL is
all you care about, and if you manage to get above that it is just

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