"Corky Scott" wrote in message
...
On Tue, 8 Feb 2005 12:25:34 -0500, "Icebound"
wrote:

If we had a real good understanding of all aspects of meteorology, we
could
recognize the situations in which forecasting should be relatively "easy",
and the situation is which it is more "difficult".... therefore the
situation in which we can take the TAF as gospel, and the situation in
which
it is likely to be suspect.

Can you give me a realistic example of how knowing exactly what the
definition of lapse rate is would help a pilot flying from point A to
point B?

....


If a pilot does not know the definition of lapse rate, then it is pretty
difficult for him to recognize the conditions which lead to atmospheric
buoyancy or to atmospheric stability.

I get to the airport on a clear summer morning. 7 AM. Sun is up. Not a
cloud in the sky. Temperature is 20C, dewpoint is 15. TAF for my airport
for later is PROB30 TSRA. TAF For airport 40 mi south for a similar time
period is TEMPO TSRA. Okay, only a risk of thunderstorms for me, more
definite for the guy down south.

As a pilot, I am interest in the possibilities of the TAF being "wrong". I
take off, fly up through the early-morning inversion and find the
temperature starts to fall off at about 4000 feet, peaking there at, say,
about 20 to 22 C.

*If I know* (maybe get a PIREP) that the 10,000 foot temperature in my area
is rather warm, say 14-15... that's maybe 1.5 degrees per 1000, pretty
stable in that mid layer and I'm pretty confident that even with good summer
heating only a few are likely to pop and I pretty much trust the TAF. I
know that it is "pretty stable" because I understand the concept of
adiabatic lapse rates and therefore know more-or-less how much colder a
rising air parcel will be than its environment.... and hence not buoyant.

But if I find out that the 10,000 foot temperature is closer to, say 6 or 8,
that's becoming 2.5 per 1000, and I am starting to consider the possibility
that my airmass maybe just as unstable as the guy down south and
Thunderstorms are a distinct possibility and something more than a "risk".

Am I likely to do exactly that kind of calculation in flight?

Maybe, maybe not..... If I did, would it affect my go-nogo decision? Maybe,
maybe not. But if I *did* go, I know what I would be looking out for, and I
would treat the first appearance of a Towering Cumulus quite differently in
those two situations. In the first case, I'm not panicking until I see a
few more.... in the second, I'm thinking seriously about heading for an
airport.

My rant was about knowledge of meteorological concepts in general, not lapse
rates in particular. Lapse rates were an easy target example because of the
obvious misunderstanding of adiabatic lapse rates in that particular post.
I agree that in a great many cases, knowing the actual lapse rate may not
help you much. You might not have the information, or it may be a situation
where it is not important. (And FAA or TC exams that test "knowledge" are a
whole other issue :-) )

But knowing the complete concept... how adiabatic lapse rates affect the
temperature of rising parcels... how that relates to the difference in
temperature between the environment and a rising air bubble... how that
difference in temperature affects buoyancy... how the degree of buoyancy
affects convection....

Knowledge of these concepts may just help you to understand the TAF, your
own observations, and how to reconcile a busted forecast.