Pentrating Towering Cumulus Clouds

"O. Sami Saydjari" wrote in message
...
Thunderstorm season is up us. I get a little concerned when I see
towering cumulus clouds forming in my flight path because I know that
towering cumulus clouds can turn into thunderstorms.


I get concerned too. So I stay away from them and out of them. My choice
is to not take the chance and get beat around inside. If it's towering it's
likely got
some fair updrafts in there. It's about personal minimums and sticking to
them.

"Mike Rapoport" wrote in message
ink.net...

"Icebound" wrote in message
...


Thanks! I have been using "CB" and "thunderstrom" interchangably, perhaps
this is not strictly true.


Ron has correctly described the difference. CB is a cloud, thunderstorm is
a condition reported only when thunder is heard or lightning seen. Being
the "thunderstorm cloud", the terms CB and thunderstorm are often used
interchangeably in generic descriptions, but we can and should be more
precise.


I agree that most observers would call a hailing cloud a CB but the hail
that fell on me yesterday was pea sized and mostly clear yet fell from a
cloud that had a top of perhaps 15,000' and was not producing thunder.


Where, geographically? And did it fall on you on the ground, or did you
encounter it in flight? And how was the cloud top determined.



North Idaho. I was on the ground (bicycling in hail of all things) The
tops I estimate at 10-12k based on my experience flying in the area (I am
confident that I could easily top them VFR). I gave 15,000' as a very
conservative estimate, I have a high degree of confidence that they were
lower. The highest terrain around is 6200' and this was sticking to the
bottom of the cloud so the vertical height was about 6000'.


I don't pretend to be an expert in mountain meteorology. But because the
direction of the wind plays such an overwhelming part in the lift equation,
it would be my guess that a TCU was developing, the vertical currents were
there, the coalescence of water was occurring and freezing. But in a
typical flatland TCU/CB this build-up keeps going for perhaps up to couple
of hours and great height, here I would guess that a wind change killed the
vertical currents rather quickly... and the precipitation, no longer
supported, simply fell out.

My guess, don't know.

"Ron McKinnon" wrote in message
news:J0U8e.1064452$Xk.40112@pd7tw3no...

Thanks. You are right, I have been incorrectly using CB as shorthand for
thunderstorm.

Mike
MU-2
Learning something every day

I was in one once. A towering Cumulus. A big dark one. Weather said
just rain, no thunderstorms. It started raining. Then I lost some
altitude. Looked up and my airplane was coated with ice! Clear, but
ragged ice, about 1/2" thick on all forward facing surfaces.
Fortunately I had warm VMC under me, so I descended and shed the ice. I
don't fly into dark Cumulus clouds anymore. Only reason I did that time
is I was pretty ignorant of weather. I was just happy to have a
clearance and be able to fly in actual. I was in and out of IMC. Here
comes a big dark one. In I went. Coulda been worse, coulda been hail....

"Doug" wrote in message
oups.com...
I was in one once. A towering Cumulus. A big dark one. Weather said
just rain, no thunderstorms. It started raining. Then I lost some
altitude. Looked up and my airplane was coated with ice! Clear, but
ragged ice, about 1/2" thick on all forward facing surfaces.
Fortunately I had warm VMC under me, so I descended and shed the ice. I
don't fly into dark Cumulus clouds anymore. Only reason I did that time
is I was pretty ignorant of weather.

How on earth could you be an Instrument rated Pilot, or even a
non-instrument rated pilot for that matter, and be 'pretty ignorant
of weather' ???

I was just happy to have a
clearance and be able to fly in actual. I was in and out of IMC. Here
comes a big dark one. In I went. Coulda been worse, coulda been hail....

"Ron McKinnon" wrote in message
newsG%8e.1066820$Xk.925695@pd7tw3no...

How on earth could you be an Instrument rated Pilot, or even a
non-instrument rated pilot for that matter, and be 'pretty ignorant
of weather' ???


Why on earth would you criticize someone for admitting that their
weather knowledge was less than they'd like? You can get an IR
without ever flying in a cloud. The knowledge needed for the
written certainly doesn't require that high of a level of understanding.

Real weather is something you learn by flying in it. By gradually
changing your personal minimums as you learn.

"Ron McKinnon" wrote:
How on earth could you be an Instrument rated Pilot, or even a
non-instrument rated pilot for that matter, and be 'pretty ignorant
of weather' ???

Most people get very little exposure to making real weather-related
decisions during training. Most of the time in training, you depend on
your instructor to make decisions for you, and just go with the flow.

I don't do any primary training; mostly club checkouts and BFRs and high
performance upgrades, things like that. Presumably these are people who
have already received training in weather. I try really hard to impress on
my students that I want them to make the go-no/go decision, and then defend
it. I'm often amazed at just how ill-equipped many of them are to do that.

I had one guy not long ago, recent instrument rating, working on his
complex transition. We had a lesson scheduled one day where it was IFR,
with freezing levels around 3-4000. He wanted to go flying. He says he
got a FSS briefing and it sounded OK (I can't imagine what the briefer told
him). I had to drag him step by step through DUATS, and show him how to
read the FD reports (he had never seen one before). He had no idea what I
was talking about when I mentioned "airmet zulu", nor how to read one.

By mid-morning, the system had a half-dozen pireps of moderate icing at the
altitudes we would have been at.

"OtisWinslow" wrote in message
...

"Ron McKinnon" wrote in message
newsG%8e.1066820$Xk.925695@pd7tw3no...

How on earth could you be an Instrument rated Pilot, or even a
non-instrument rated pilot for that matter, and be 'pretty ignorant
of weather' ???

Why on earth would you criticize someone for admitting that their
weather knowledge was less than they'd like? You can get an IR
without ever flying in a cloud. The knowledge needed for the
written certainly doesn't require that high of a level of understanding.

In point of fact it would be a criticism regarding the fact of their
lack of knowledge, not for their admission of it.

But it was in any case not a criticism. It was an expression of a
query; A conundrum. (Some degree of weather knowledge is
in most places a requirement for the Private licence/certificate,
and, considering what's at stake, I'd think a pilot'd would have
acquired more than the bare minimum knowledge by the time
they've got an IR. Apparently not.)

I believe the way you learn about weather is by flying in it. By relating
what
you see with what was on the forecasts. Over a period of time that helps
us put the big picture together. Certainly the ideal situation is being
able to fly with a highly experienced CFI when we're getting our rating,
and spend a bunch of time in the clouds. Unfortunately many CFIs are
not that experienced at weather flying.



"Roy Smith" wrote in message
...
"Ron McKinnon" wrote:
How on earth could you be an Instrument rated Pilot, or even a
non-instrument rated pilot for that matter, and be 'pretty ignorant
of weather' ???

Most people get very little exposure to making real weather-related
decisions during training. Most of the time in training, you depend on
your instructor to make decisions for you, and just go with the flow.

I don't do any primary training; mostly club checkouts and BFRs and high
performance upgrades, things like that. Presumably these are people who
have already received training in weather. I try really hard to impress
on
my students that I want them to make the go-no/go decision, and then
defend
it. I'm often amazed at just how ill-equipped many of them are to do
that.

I had one guy not long ago, recent instrument rating, working on his
complex transition. We had a lesson scheduled one day where it was IFR,
with freezing levels around 3-4000. He wanted to go flying. He says he
got a FSS briefing and it sounded OK (I can't imagine what the briefer
told
him). I had to drag him step by step through DUATS, and show him how to
read the FD reports (he had never seen one before). He had no idea what I
was talking about when I mentioned "airmet zulu", nor how to read one.

By mid-morning, the system had a half-dozen pireps of moderate icing at
the
altitudes we would have been at.

Well, I had received a preflight briefing. No mention of T Storms or
ice. I was below the freezing level. Now you see, if I had KNOWN what
was going to happen to me BEFORE I went into that cloud, I would not
have done it. But I didn't KNOW ahead of time that I would get ice. I
thought it would just be rain and maybe a little bumpy.

Also, I was on my flight plan. My route took me through the cloud.
Flying through clouds is what IFR flying is all about. I didn't see any
lightning. It was a towering cumulus. I'd never had one of those in my
path before. The preflight briefer said it was "just rain".

If I encountered one of those now, assuming I could see it ahead of
time, I'd request a diversion around it. That decision is based on
experience. My experience made me wiser than I was previous to this
event.

It is possible to be ignorant even though one is intellegent, by the
way. Ignorance means one just does not know, is not informed on the
subject on hand. Not that one is stupid or unable to understand the
subject. And the fact that I was ignorant on this subject does not mean
I was ignorant of the entire subject of weather. I was never told not
to fly into towering cumulus clouds. I was told not to fly into
thunderstorms. I believed and still believe there is a difference.

The whole reason I posted was to share my experience with others. Not
to set myself up for ridicule because of my ignorance. I am sorry you
took it that way.