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.

1. Assuming that thunderstorms were not predicted for the area, is my
concern unjustified?

2. Do most towering cumulus clouds not mature into thunderstorms?

3. Wouldn't large towering cumulus clouds have chartacteristics similar
to thunderstorms (severe turbulence, possible hail, heavy rain, icing)
even if they don't end up becoming an official thunderstorm (lightning
present).

Your advice and experiences would be most appreciated.

-Sami, N2057M Piper Turbo Arrow III

"O. Sami Saydjari" > wrote:

> 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.

You are wise to be concerned.

> 1. Assuming that thunderstorms were not predicted for the area, is my
> concern unjustified?

> 2. Do most towering cumulus clouds not mature into thunderstorms?

Whether a TCU turns into a CB depends on how unstable the atmosphere is and
how much moisture is available. Sometimes the weather guys get it right,
sometimes they don't, but I figure they've got a better chance of getting
it right than I do.

> 3. Wouldn't large towering cumulus clouds have chartacteristics similar
> to thunderstorms (severe turbulence, possible hail, heavy rain, icing)
> even if they don't end up becoming an official thunderstorm (lightning
> present).

You will certainly find turbulence in TCU, and if you're above the freezing
level, you'll find icing too. I only fly normally aspirated hardware, so I
can't climb high enough to reach the freezing level in the summer. You're
flying a turbo, however, so you might be able to.

Until it turns into a CB, there shouldn't be rain, hail, or lightning.
Flying into a CB is a really bad idea.

In general, I try to avoid flying into TCU. Even around busy airspace like
New York, I find controllers are usually quite accommodating about "request
20 degrees left for weather".

"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.
>
> 1. Assuming that thunderstorms were not predicted for the area, is my
> concern unjustified?
>
Whether or nor thunderstorms are predicted should not enter into your
thinking too much. Predictions made in the past are never as good as real
time looking out the window! There may be a change in the lapse rate at
some altitude above the current tops that will keep the TCUs from becoming
CBs or the forecast may be wrong. Only time will tell.

> 2. Do most towering cumulus clouds not mature into thunderstorms?
>

Statistically, I don't know but all thunderstorms matured from TCUs. Often
when a CU or TCU becomes dominant, the others around it tend to start
dissipating because the air around the big one is sinking. This is true
when you have airmass type CBs but may not hold for frontal CBs..

> 3. Wouldn't large towering cumulus clouds have chartacteristics similar to
> thunderstorms (severe turbulence, possible hail, heavy rain, icing) even
> if they don't end up becoming an official thunderstorm (lightning
> present).
>

TCU have, as you would expect, characteristics between CU and CB clouds.
All three can be thought as different stages of the same think, a cloud
pruduced by convection. Obviously three seconds before a TCU starts
producing lightning and becomes a CB, it is going to a lot like a
thunderstorm inside. Conversely, when a TCU is only slightly taller than a
CU, it is going to be more like a CU inside. There is a relationship
between the vertical height of a convective cloud and turbulence but it is
not absolute. I have never heard of large hail coming from anything other
than a big CB. It takes a rippin' updraft to produce large hail. Any CU,
TCU or CB is going to have icing below 0C and the stronger the updrafts, the
higher the icing is going to extend (it can go to -40C in a CB).

I suspect that you are considering flying into TCUs with tops below 20,000'
and if that is true, you will probably find them like CU clouds only more
so. If you are talking about TCUs over 25,000', you might want to fly
around....:-)


Naturally there is plenty of turbulence in clear air and there are plenty of
smooth rides in nasty looking clouds so YMMV.

Mike
MU-2

> -Sami, N2057M Piper Turbo Arrow III

When in doubt, don't! The CU's wouldn't be towering if they did not contain
strong updrafts...and don't forget the strong downdrafts on the outside of
the "tower." I can remember being rolled 60 degrees one day when I decided
to fly close to, but not into, such a cloud. Depending on penetration
altitude versus freezing level, they also contain what I call "splat icing,"
which can coat your airplane with a glossy load in a few seconds...look for
that (or please, don't look for that) in the top one-third of the cloud.

Bottom line: Stay away. Might not be anything in there, but I'm no one to
take chances.

Bob Gardner

"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.
>
> 1. Assuming that thunderstorms were not predicted for the area, is my
> concern unjustified?
>
> 2. Do most towering cumulus clouds not mature into thunderstorms?
>
> 3. Wouldn't large towering cumulus clouds have chartacteristics similar to
> thunderstorms (severe turbulence, possible hail, heavy rain, icing) even
> if they don't end up becoming an official thunderstorm (lightning
> present).
>
> Your advice and experiences would be most appreciated.
>
> -Sami, N2057M Piper Turbo Arrow III

O. Sami Saydjari wrote:

> 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.
>
> 1. Assuming that thunderstorms were not predicted for the area, is my
> concern unjustified?

No, one is always justified in being concerned about thunderstorms, or
more specifically, being concerned about avoiding them.


> 2. Do most towering cumulus clouds not mature into thunderstorms?

Yes, very few make it to a full-blown thunderstorm. Part of it depends
on your definition of towering. To me a 6,000 foot tall clouds is
towering, but if you mean 50,000 feet, then few probably get that high
without becoming a thunderstorm.


> 3. Wouldn't large towering cumulus clouds have chartacteristics similar
> to thunderstorms (severe turbulence, possible hail, heavy rain, icing)
> even if they don't end up becoming an official thunderstorm (lightning
> present).

I can't say for sure, but I don't think you'd have most of the agove
without also having thunder and lightning.


> Your advice and experiences would be most appreciated.

I've flown through many cumulus clouds that were 10-15,000 feet tall.
It is great fun, but can be a lot of work when IFR as it is hard to
maintain altitude and airspeed in some of the larger clouds. It isn't
unusual to gain or lose 500' while transiting a larger cloud.


Matt

"Matt Whiting" > wrote in message
...
> O. Sami Saydjari wrote:
>
>> 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.
>>
....snip...
>
>> 2. Do most towering cumulus clouds not mature into thunderstorms?
>
> Yes, very few make it to a full-blown thunderstorm. Part of it depends on
> your definition of towering. To me a 6,000 foot tall clouds is towering,
> but if you mean 50,000 feet, then few probably get that high without
> becoming a thunderstorm.

..... "...if you mean 50,000 feet....", then probably ALL will be a
thunderstorm. Few clouds-of-vertical-development will exceed 30,000 feet
ASL without characteristics of a "thunderstorm".

If a cu has penetrated the freezing level, that's enough to scare me. We get
some dandies over the Cascades, Siskiyous, and Rockies.

Bob Gardner

"Icebound" > wrote in message
...
>
> "Matt Whiting" > wrote in message
> ...
>> O. Sami Saydjari wrote:
>>
>>> 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.
>>>
> ...snip...
>>
>>> 2. Do most towering cumulus clouds not mature into thunderstorms?
>>
>> Yes, very few make it to a full-blown thunderstorm. Part of it depends
>> on your definition of towering. To me a 6,000 foot tall clouds is
>> towering, but if you mean 50,000 feet, then few probably get that high
>> without becoming a thunderstorm.
>
> .... "...if you mean 50,000 feet....", then probably ALL will be a
> thunderstorm. Few clouds-of-vertical-development will exceed 30,000 feet
> ASL without characteristics of a "thunderstorm".
>
>
>
>

"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.
>
> 1. Assuming that thunderstorms were not predicted for the area, is my
> concern unjustified?
>

It would help if, before you go, you try to get enough information about the
overall weather situation. You may be able to make a guess as to why the
forecast was what it was. Was there a serious area of thunderstorms
forecast to be to the south of you which may now have moved a little further
north than expected.... Or is there a high-pressure-system coming from the
west, and the forecasters thought it would suppress the serious development?

In the first situation, I would be extremely concerned that thunderstorms
were immenently probable. In the second, well... I would be more
comfortable with a wait-and-see... so the high-pressure-system hasn't
suppressed activity as much as they thought, but it is much less likely that
anything really serious is going to develop.


> 2. Do most towering cumulus clouds not mature into thunderstorms?
>

There are many factors that may encourage or suppress the vertical growth.
What is causing the lift, and is it strong and persistant, or weak and
temporary? Is the low-level atmosphere becoming hotter and more humid or
cooler and drier? Is the upper atmosphere under a cyclonic or anticyclonic
influence, etc... You defer to the judgement of the meteorologists, but in
some cases your own assessment of the *overall* weather situation may help
you confirm or question their judgement. In many cases obvious answers are
not available even to them.

> 3. Wouldn't large towering cumulus clouds have chartacteristics similar to
> thunderstorms (severe turbulence, possible hail, heavy rain, icing) even
> if they don't end up becoming an official thunderstorm (lightning
> present).
>

Towering Cumulus are but a stage on the way to development to thunderstorms.
Therefore you already have strong vertical currents, and large amounts of
condensed water. Most of it is still going upwards, but the result on the
windshield and engine-air-intake can be the same as a rainstorm. Some of it
could already be frozen... precursor to hail, only its not falling yet.
Turbulence, and (above the freezing level) icing.

> Your advice and experiences would be most appreciated.
>
> -Sami, N2057M Piper Turbo Arrow III

"Bob Gardner" > wrote in message
...
> If a cu has penetrated the freezing level, that's enough to scare me. We
> get some dandies over the Cascades, Siskiyous, and Rockies.
>

Generally a cloud that penetrates minus-10 Celsius will produce
precipitation. But in cold weather it may do that in 4000 feet and be a
rather benign shower. When the cloud develops vertically through 25, 35, or
especially 45 thousand feet, however.... that's when it gets exciting.

O. Sami Saydjari wrote:

> 1. Assuming that thunderstorms were not predicted for the area, is my
> concern unjustified?

I once flew into a towering cumulus in a C172 and had some interesting
things happen. I was on an IFR training flight and had been solid IMC
for about a half hour when we popped out to spot the most beautiful
towering white monster dead in our path that shot straight up to about
20k. It was clear blue all around except for the TC.

I asked my CFII if this was a problem and if I should ask for other
routing. He seemed unconcerned and so we proceeded directly into it.
I didn't question him because, after all, I was a lowly IFR student( an
attitude that I have thoroughly revamped ) and he had some 5000 hours of
flying on the logs.

The first thing that happened was a strong downdraft that pegged the
VSI, followed by small hail hitting us that sounded like the airplane
was being "sandpapered". We went through some wild oscillations of yaw
and 200-300 ft altitude excursions. The yoke required full right and
left deflection at times to keep upright and the seat belts cut into us
enough at times to be noticeable.

Then, I felt a static charge all over my arms ( the hairs actually rose
up!) that seemed to build followed by most of the instruments going TU.
The only instrument that seemed stable enough to be usable was my little
hand held GPS which allowed me to keep the aircraft level by watching
the GPS compass card.

We exited as suddenly as we entered into calm blue sky. The contrast was
actually kind of eerie!

> 3. Wouldn't large towering cumulus clouds have chartacteristics similar to thunderstorms
>(severe turbulence, possible hail, heavy rain, icing) even if they don't end up becoming an
>official thunderstorm (lightning present).

Yes, would be my answer.

Antonio

"Mike Rapoport" > wrote in message
nk.net...
>
> TCU have, as you would expect, characteristics between CU and CB clouds.
> All three can be thought as different stages of the same think, a cloud
> pruduced by convection. Obviously three seconds before a TCU starts
> producing lightning and becomes a CB, it is going to a lot like a
> thunderstorm inside.

A minor point: A TCU will not 'produce lightning to become a CB'. If
it produces lightning it *is* a CB, and has been for some time, but it is
not the production of lightning that makes it a CB.

It is not necessary that a CB produce lightning, nor hail, nor heavy
precipitation, nor Mammae, Funnel Clouds, Tornados or Waterspouts.
It can do none of these things and still be a CB. But if any of these
things happen it is necessarily a CB.

> Conversely, when a TCU is only slightly taller than a CU, it is going to
> be more like a CU inside. There is a relationship between the vertical
> height of a convective cloud and turbulence but it is not absolute. I
> have never heard of large hail coming from anything other than a big CB.

If it hails, it's a CB, by definition. A TCU can produce snow
pellets, however (and ice pellets, I think (it's been a while)),

"Ron McKinnon" > wrote in message
news:DcD8e.1052899$8l.772250@pd7tw1no...
>
> "Mike Rapoport" > wrote in message
> nk.net...
>>
>> TCU have, as you would expect, characteristics between CU and CB clouds.
>> All three can be thought as different stages of the same think, a cloud
>> pruduced by convection. Obviously three seconds before a TCU starts
>> producing lightning and becomes a CB, it is going to a lot like a
>> thunderstorm inside.
>
> A minor point: A TCU will not 'produce lightning to become a CB'. If
> it produces lightning it *is* a CB, and has been for some time, but it is
> not the production of lightning that makes it a CB.
>

That is what I said ( I think) A thunderstorm becomes a thunderstorm when
the thunder starts. Three seconds before the first lightning, it is still a
TCU.

> It is not necessary that a CB produce lightning, nor hail, nor heavy
> precipitation, nor Mammae, Funnel Clouds, Tornados or Waterspouts.
> It can do none of these things and still be a CB. But if any of these
> things happen it is necessarily a CB.
>
I am not sure what you are saying here, If it doesn't produce lightning it
isn't a thunderstorm (CB) so I would say that it is nessesary for a CB to
produce lightning.

>> Conversely, when a TCU is only slightly taller than a CU, it is going to
>> be more like a CU inside. There is a relationship between the vertical
>> height of a convective cloud and turbulence but it is not absolute. I
>> have never heard of large hail coming from anything other than a big CB.
>
> If it hails, it's a CB, by definition. A TCU can produce snow
> pellets, however (and ice pellets, I think (it's been a while)),
>

This is the first time that I have heard that hail defines a thunderstorm.
A thunderstorm is defined by lightning (and therefore thunder). Hail is
produced by updrafts in a cloud through the freezing level allowing frozen
precipitation to remain aloft and grow. I don't see why this couldn't
happen without lightning. I was hailed upon yesterday and there was no
thunder.

Mike
MU-2

"Mike Rapoport" > wrote in message
ink.net...
>
> "Ron McKinnon" > wrote in message
> news:DcD8e.1052899$8l.772250@pd7tw1no...
>>
>> "Mike Rapoport" > wrote in message
>> nk.net...
>>>
>>> TCU have, as you would expect, characteristics between CU and CB clouds.
>>> All three can be thought as different stages of the same think, a cloud
>>> pruduced by convection. Obviously three seconds before a TCU starts
>>> producing lightning and becomes a CB, it is going to a lot like a
>>> thunderstorm inside.
>>
>> A minor point: A TCU will not 'produce lightning to become a CB'. If
>> it produces lightning it *is* a CB, and has been for some time, but it
>> is
>> not the production of lightning that makes it a CB.
>>
>
> That is what I said ( I think) A thunderstorm becomes a thunderstorm when
> the thunder starts. Three seconds before the first lightning, it is still
> a TCU.

Well, no. A TCU becomes a cumulo-nimbus when the rounded califlower-like
shape of the TCU begins to top off with a wispy fibrous top, often
stretching downwind like an anvil. This is ice crystals forming at the very
top of the cloud.

That is the classic definition used by weather services. Observers will not
call it a CB if they continue to see the hard-edged form at the tops.... not
until they see the formation of the wispy fibrous top. However, once
lightning, or hail, or funnel-clouds are observed, the observer will almost
surely class it a CB, regardless.


>
>> It is not necessary that a CB produce lightning, nor hail, nor heavy
>> precipitation, nor Mammae, Funnel Clouds, Tornados or Waterspouts.
>> It can do none of these things and still be a CB. But if any of these
>> things happen it is necessarily a CB.
>>
> I am not sure what you are saying here, If it doesn't produce lightning it
> isn't a thunderstorm (CB) so I would say that it is nessesary for a CB to
> produce lightning.

The production of the ice-crystals at the top will normally be accompanied
by lightning, but ever if it is not, it would still be called a CB if the
fibrous ice-crystal anvil-shaped top exists.


>
>>> Conversely, when a TCU is only slightly taller than a CU, it is going to
>>> be more like a CU inside. There is a relationship between the vertical
>>> height of a convective cloud and turbulence but it is not absolute. I
>>> have never heard of large hail coming from anything other than a big CB.
>>
>> If it hails, it's a CB, by definition. A TCU can produce snow
>> pellets, however (and ice pellets, I think (it's been a while)),
>>
>
> This is the first time that I have heard that hail defines a thunderstorm.
> A thunderstorm is defined by lightning (and therefore thunder). Hail is
> produced by updrafts in a cloud through the freezing level allowing frozen
> precipitation to remain aloft and grow. I don't see why this couldn't
> happen without lightning. I was hailed upon yesterday and there was no
> thunder.
>

Hail (hard "real" hail, not the soft stuff in some cold-weather cumulus)
.... Hail does not define a thunderstorm, but because the conditions required
for it are typically exactly the same that produce lightning and the rest of
the CB symptoms, you will be hard pressed to find an observer who will not
call a hailing cloud a CB, just because he hasn't seen lightning or heard
thunder.

My general attitude toward TCU is if I could climb above it, then I'll
fly through it. In a 172SP, that means it has to be under about 14,000
feet tall. On long x-countries, I'll generally cruise at 9,000 or
10,000 feet, and have not really encountered anything beyond light to
moderate chop in a cumulus cloud. Generally I'll fly through the ones
that are at most 1,000 - 2,000 feet above me... anything taller, and
I'll request a deviation.

Things definitely get more "interesting" when trying to fly through a
maze of TCUs tho. Without onboard weather scope, I'd say it's safer to
land and wait it out (or if you've got an approach controller who's on
the ball, they may be able to lead you safely through the maze).

"Icebound" > wrote in message
...
>
> "Mike Rapoport" > wrote in message
> ink.net...
>>
>> "Ron McKinnon" > wrote in message
>> news:DcD8e.1052899$8l.772250@pd7tw1no...
>>>
>>> "Mike Rapoport" > wrote in message
>>> nk.net...
>>>>
>>>> TCU have, as you would expect, characteristics between CU and CB
>>>> clouds. All three can be thought as different stages of the same think,
>>>> a cloud pruduced by convection. Obviously three seconds before a TCU
>>>> starts producing lightning and becomes a CB, it is going to a lot like
>>>> a thunderstorm inside.
>>>
>>> A minor point: A TCU will not 'produce lightning to become a CB'. If
>>> it produces lightning it *is* a CB, and has been for some time, but it
>>> is
>>> not the production of lightning that makes it a CB.
>>>
>>
>> That is what I said ( I think) A thunderstorm becomes a thunderstorm
>> when the thunder starts. Three seconds before the first lightning, it is
>> still a TCU.
>
> Well, no. A TCU becomes a cumulo-nimbus when the rounded califlower-like
> shape of the TCU begins to top off with a wispy fibrous top, often
> stretching downwind like an anvil. This is ice crystals forming at the
> very top of the cloud.
>
> That is the classic definition used by weather services. Observers will
> not call it a CB if they continue to see the hard-edged form at the
> tops.... not until they see the formation of the wispy fibrous top.
> However, once lightning, or hail, or funnel-clouds are observed, the
> observer will almost surely class it a CB, regardless.
>

Do you have a source of this definition? I can't find one but while
looking, I found several sites with pictures of CBs that don't all have the
wispy tops

Here is one: http://www.chitambo.com/clouds/cloudshtml/calvus.html

>>
>>> It is not necessary that a CB produce lightning, nor hail, nor heavy
>>> precipitation, nor Mammae, Funnel Clouds, Tornados or Waterspouts.
>>> It can do none of these things and still be a CB. But if any of these
>>> things happen it is necessarily a CB.
>>>
>> I am not sure what you are saying here, If it doesn't produce lightning
>> it isn't a thunderstorm (CB) so I would say that it is nessesary for a CB
>> to produce lightning.
>
> The production of the ice-crystals at the top will normally be accompanied
> by lightning, but ever if it is not, it would still be called a CB if the
> fibrous ice-crystal anvil-shaped top exists.
>
>
>>
>>>> Conversely, when a TCU is only slightly taller than a CU, it is going
>>>> to be more like a CU inside. There is a relationship between the
>>>> vertical height of a convective cloud and turbulence but it is not
>>>> absolute. I have never heard of large hail coming from anything other
>>>> than a big CB.
>>>
>>> If it hails, it's a CB, by definition. A TCU can produce snow
>>> pellets, however (and ice pellets, I think (it's been a while)),
>>>
>>
>> This is the first time that I have heard that hail defines a
>> thunderstorm. A thunderstorm is defined by lightning (and therefore
>> thunder). Hail is produced by updrafts in a cloud through the freezing
>> level allowing frozen precipitation to remain aloft and grow. I don't
>> see why this couldn't happen without lightning. I was hailed upon
>> yesterday and there was no thunder.
>>
>
> Hail (hard "real" hail, not the soft stuff in some cold-weather cumulus)
> ... Hail does not define a thunderstorm, but because the conditions
> required for it are typically exactly the same that produce lightning and
> the rest of the CB symptoms, you will be hard pressed to find an observer
> who will not call a hailing cloud a CB, just because he hasn't seen
> lightning or heard thunder.
>


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.

Mike
MU-2

I've tried penetrating a few of these when they were not really high.
The experience was always turbulent.

"Mike Rapoport" > wrote in message
link.net...
>
> "Icebound" > wrote in message
> ...
>>
>> "Mike Rapoport" > wrote in message
>> ink.net...
>>>
>>> "Ron McKinnon" > wrote in message
>>> news:DcD8e.1052899$8l.772250@pd7tw1no...
>>>>
>>>> "Mike Rapoport" > wrote in message
>>>> nk.net...
>>>>>
>>>>> TCU have, as you would expect, characteristics between CU and CB
>>>>> clouds. All three can be thought as different stages of the same
>>>>> think, a cloud pruduced by convection. Obviously three seconds before
>>>>> a TCU starts producing lightning and becomes a CB, it is going to a
>>>>> lot like a thunderstorm inside.
>>>>
>>>> A minor point: A TCU will not 'produce lightning to become a CB'. If
>>>> it produces lightning it *is* a CB, and has been for some time, but it
>>>> is
>>>> not the production of lightning that makes it a CB.
>>>>
>>>
>>> That is what I said ( I think) A thunderstorm becomes a thunderstorm
>>> when the thunder starts. Three seconds before the first lightning, it
>>> is still a TCU.
>>
>> Well, no. A TCU becomes a cumulo-nimbus when the rounded califlower-like
>> shape of the TCU begins to top off with a wispy fibrous top, often
>> stretching downwind like an anvil. This is ice crystals forming at the
>> very top of the cloud.
>>
>> That is the classic definition used by weather services. Observers will
>> not call it a CB if they continue to see the hard-edged form at the
>> tops.... not until they see the formation of the wispy fibrous top.
>> However, once lightning, or hail, or funnel-clouds are observed, the
>> observer will almost surely class it a CB, regardless.
>>
>
> Do you have a source of this definition? I can't find one but while
> looking, I found several sites with pictures of CBs that don't all have
> the wispy tops
>
> Here is one: http://www.chitambo.com/clouds/cloudshtml/calvus.html
>

I chose the definition from the Canadian Manual of Observation which defines
CB:

DEFINITIONS OF CLOUDS
Cumulonimbus: Heavy and dense cloud with
aconsiderable vertical extent, in the form of
amountain or huge tower. At least part of its
upper portion is usually smooth, or fibrous or
striated, and nearly always flattened; this part
often spreads out in the shape of an anvil or vast
plume.

-----

But some more insight can be obtained from the World Met Organization
code-table:
http://badc.nerc.ac.uk/data/surface/code.html (Low cloud type)

Code 3 allows a CB to be defined without the "clearly fibrous" tops, but
which must "at least partially, lack sharp outlines", ....which shows the
the icing of the tops has begun.

Code 9 CB requires the "clearly fibrous" top.

The key is that to meet the classic definition of CB, the icing of the tops
(and hence the smoother fibrous shape)... has at the very least, begun to
form.



>>>
>>>> It is not necessary that a CB produce lightning, nor hail, nor heavy
>>>> precipitation, nor Mammae, Funnel Clouds, Tornados or Waterspouts.
>>>> It can do none of these things and still be a CB. But if any of these
>>>> things happen it is necessarily a CB.
>>>>
>>> I am not sure what you are saying here, If it doesn't produce lightning
>>> it isn't a thunderstorm (CB) so I would say that it is nessesary for a
>>> CB to produce lightning.
>>
>> The production of the ice-crystals at the top will normally be
>> accompanied by lightning, but ever if it is not, it would still be called
>> a CB if the fibrous ice-crystal anvil-shaped top exists.
>>
>>
>>>
>>>>> Conversely, when a TCU is only slightly taller than a CU, it is going
>>>>> to be more like a CU inside. There is a relationship between the
>>>>> vertical height of a convective cloud and turbulence but it is not
>>>>> absolute. I have never heard of large hail coming from anything other
>>>>> than a big CB.
>>>>
>>>> If it hails, it's a CB, by definition. A TCU can produce snow
>>>> pellets, however (and ice pellets, I think (it's been a while)),
>>>>
>>>
>>> This is the first time that I have heard that hail defines a
>>> thunderstorm. A thunderstorm is defined by lightning (and therefore
>>> thunder). Hail is produced by updrafts in a cloud through the freezing
>>> level allowing frozen precipitation to remain aloft and grow. I don't
>>> see why this couldn't happen without lightning. I was hailed upon
>>> yesterday and there was no thunder.
>>>
>>
>> Hail (hard "real" hail, not the soft stuff in some cold-weather cumulus)
>> ... Hail does not define a thunderstorm, but because the conditions
>> required for it are typically exactly the same that produce lightning and
>> the rest of the CB symptoms, you will be hard pressed to find an observer
>> who will not call a hailing cloud a CB, just because he hasn't seen
>> lightning or heard thunder.
>>
>
>
> 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.

"Icebound" > wrote in message
...
>
Snip

>
> I chose the definition from the Canadian Manual of Observation which
> defines CB:
>
> DEFINITIONS OF CLOUDS
> Cumulonimbus: Heavy and dense cloud with
> aconsiderable vertical extent, in the form of
> amountain or huge tower. At least part of its
> upper portion is usually smooth, or fibrous or
> striated, and nearly always flattened; this part
> often spreads out in the shape of an anvil or vast
> plume.
>
> -----
>
> But some more insight can be obtained from the World Met Organization
> code-table:
> http://badc.nerc.ac.uk/data/surface/code.html (Low cloud type)
>
> Code 3 allows a CB to be defined without the "clearly fibrous" tops, but
> which must "at least partially, lack sharp outlines", ....which shows the
> the icing of the tops has begun.
>
> Code 9 CB requires the "clearly fibrous" top.
>
> The key is that to meet the classic definition of CB, the icing of the
> tops (and hence the smoother fibrous shape)... has at the very least,
> begun to form.
>

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

>>
>> 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'.

Mike
MU-2

"Mike Rapoport" > wrote in message
ink.net...
>
> "Ron McKinnon" > wrote in message
> news:DcD8e.1052899$8l.772250@pd7tw1no...
>>
>> "Mike Rapoport" > wrote in message
>> nk.net...
>>>
>>> TCU have, as you would expect, characteristics between CU and CB clouds.
>>> All three can be thought as different stages of the same think, a cloud
>>> pruduced by convection. Obviously three seconds before a TCU starts
>>> producing lightning and becomes a CB, it is going to a lot like a
>>> thunderstorm inside.
>>
>> A minor point: A TCU will not 'produce lightning to become a CB'. If
>> it produces lightning it *is* a CB, and has been for some time, but it
>> is
>> not the production of lightning that makes it a CB.
>
> That is what I said ( I think) A thunderstorm becomes a thunderstorm when
> the thunder starts. Three seconds before the first lightning, it is still
> a TCU.

You are correct that a storm becomes a thunderstorm when thunder
starts (is heard). But a Thunderstorm is not a CB, and a CB is not a
thunderstorm.

A thunderstorm is a 'storm' produced *by* a CB, whereas a CB
is a Cloud. It is not necessary for a cloud to produce lightning/thunder,
in order to be a CB. But it is necessary for the cloud to be a CB
in order to produce lightning/thunder, and it is therefore necessary
for a CB to exist in order for a thunderstorm to exist.

CBs can grow quickly, but it does take time. It is unlikely that three
seconds before the first lightning the cloud was a TCU. It was
probably a CB for a longer-while before the lightning started.

>> It is not necessary that a CB produce lightning, nor hil, nor heavy
>> precipitation, nor Mammae, Funnel Clouds, Tornados or Waterspouts. It can
>> do none of these things and still be a CB. But if any of these
>> things happen it is necessarily a CB.
>>
> I am not sure what you are saying here, If it doesn't produce lightning it
> isn't a thunderstorm (CB) so I would say that it is nessesary for a CB to
> produce lightning.

If it doesn't produce lightning, there isn't a thunderstorm - this
is Correct.

But as noted above, a CB is a type of cloud, not a type of storm. The
cloud can exist without the storm, but the storm cannot occur without
the pre-existance of the cloud. Without thunder/lightning, it can still
be a CB.

>>> Conversely, when a TCU is only slightly taller than a CU, it is going to
>>> be more like a CU inside. There is a relationship between the vertical
>>> height of a convective cloud and turbulence but it is not absolute. I
>>> have never heard of large hail coming from anything other than a big CB.
>>
>> If it hails, it's a CB, by definition. A TCU can produce snow
>> pellets, however (and ice pellets, I think (it's been a while)),
>
> This is the first time that I have heard that hail defines a thunderstorm.
> A thunderstorm is defined by lightning (and therefore thunder). Hail is
> produced by updrafts in a cloud through the freezing level allowing frozen
> precipitation to remain aloft and grow. I don't see why this couldn't
> happen without lightning. I was hailed upon yesterday and there was no
> thunder.

I did not say that hail defines a thunderstorm. I said that the occurence
of hail proves the existance of a CB. This says nothing, about the
occurence of a thunderstorm.

But note that where I'm saying CB, you're thinking Thunderstorm.
They are not the same thing.

Hail does not define a thunderstorm. Thunder defines a thunderstorm.
An observing station will report the commencement of a thunderstorm
at that station when it hears thunder, and report it done when the thunder
hasn't been heard for fifteen minutes.

The presence or absence of thunder doesn't mean its not raining or
hailing or whatever anymore, nor that the cloud that is producing
these effects has gone away. As you note, hail can certainly occur
without thunder.

The type and nature of the precipitation is a function of the cloud (and
the conditions underlying the creation of that cloud). Though hail does
not define a thunderstorm, the occurrence of hail, by definition, implies
the presence of a CB. Hail comes from CBs, not from TCUs.

Regards

"Icebound" > wrote in message
...
>
> "Mike Rapoport" > wrote in message
> ink.net...
>>
>> "Ron McKinnon" > wrote in message
>> news:DcD8e.1052899$8l.772250@pd7tw1no...
>>>
>>> "Mike Rapoport" > wrote in message
>>> nk.net...
>>>>
>>>> TCU have, as you would expect, characteristics between CU and CB
>>>> clouds. All three can be thought as different stages of the same think,
>>>> a cloud pruduced by convection. Obviously three seconds before a TCU
>>>> starts producing lightning and becomes a CB, it is going to a lot like
>>>> a thunderstorm inside.
>>>
>>> A minor point: A TCU will not 'produce lightning to become a CB'. If
>>> it produces lightning it *is* a CB, and has been for some time, but it
>>> is
>>> not the production of lightning that makes it a CB.
>>
>> That is what I said ( I think) A thunderstorm becomes a thunderstorm
>> when the thunder starts. Three seconds before the first lightning, it is
>> still a TCU.
>
> Well, no. A TCU becomes a cumulo-nimbus when the rounded califlower-like
> shape of the TCU begins to top off with a wispy fibrous top, often
> stretching downwind like an anvil. This is ice crystals forming at the
> very top of the cloud.
>
> That is the classic definition used by weather services. Observers will
> not call it a CB if they continue to see the hard-edged form at the
> tops.... not until they see the formation of the wispy fibrous top.
> However, once lightning, or hail, or funnel-clouds are observed, the
> observer will almost surely class it a CB, regardless.
>>
>>> It is not necessary that a CB produce lightning, nor hail, nor heavy
>>> precipitation, nor Mammae, Funnel Clouds, Tornados or Waterspouts.
>>> It can do none of these things and still be a CB. But if any of these
>>> things happen it is necessarily a CB.
>>>
>> I am not sure what you are saying here, If it doesn't produce lightning
>> it isn't a thunderstorm (CB) so I would say that it is nessesary for a CB
>> to produce lightning.
>
> The production of the ice-crystals at the top will normally be accompanied
> by lightning, but ever if it is not, it would still be called a CB if the
> fibrous ice-crystal anvil-shaped top exists.
>
>>
>>>> Conversely, when a TCU is only slightly taller than a CU, it is going
>>>> to be more like a CU inside. There is a relationship between the
>>>> vertical height of a convective cloud and turbulence but it is not
>>>> absolute. I have never heard of large hail coming from anything other
>>>> than a big CB.
>>>
>>> If it hails, it's a CB, by definition. A TCU can produce snow
>>> pellets, however (and ice pellets, I think (it's been a while))
>>
>> This is the first time that I have heard that hail defines a
>> thunderstorm. A thunderstorm is defined by lightning (and therefore
>> thunder). Hail is produced by updrafts in a cloud through the freezing
>> level allowing frozen precipitation to remain aloft and grow. I don't
>> see why this couldn't happen without lightning. I was hailed upon
>> yesterday and there was no thunder.
>
> Hail (hard "real" hail, not the soft stuff in some cold-weather cumulus)

the 'soft stuff' -- you're probably talking about snow-pellets, which can
be produced by TCUs (as well as CBs)

> ... Hail does not define a thunderstorm, but because the conditions
> required for it are typically exactly the same that produce lightning and
> the rest of the CB symptoms, you will be hard pressed to find an observer
> who will not call a hailing cloud a CB, just because he hasn't seen
> lightning or heard thunder.

An observer will of course report a hailing cloud as a CB irrespective
of whether thunder or lightning has been observed. But this is because
thunder or lightning are not necessary phenomena for a CB, and it is
necessarily a CB if it produces hail.

Though reporting the clould as a CB, such observer would not report
a thunderstorm, unless he also hears thunder.

"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
news:oG%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
> news:oG%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.

"Doug" > wrote in message
oups.com...
> 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.

I have no idea about the depth or breadth of your weather
knowledge, nor your prowess as a pilot, except from what
you yourself stated, and what you yourself said that you did.

You stated that you were 'Pretty ignorant about weather',
and that you flew into a big, dark, TCU. I can only
infer from this that you were 'Pretty ignorant about weather',
and that you had no idea what to expect within a big, dark,
TCU.

My query was merely one of astonishment, and an expression
of a conundrum that one could indeed be 'pretty ignorant'
about weather' and have no idea what to expect within a big,
dark, TCU by the time they're an instrument rated pilot.

But in this there was no ridicule of you, nor impugning of
your intelligence, nor any intent to do so. I am sorry if
you took it that way. I stand corrected.

Ron,

No problem.

Doug

"Ron McKinnon" > wrote in message
news:Hfb9e.1074608$8l.983385@pd7tw1no...
>
> 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.
>

You would think so, wouldn't you.

I find it rather amazing that a certain number of IR pilots seem to look at
their rating as a wand that magically makes IMC something benign... to be
relished and welcomed.

IMC is to be treated like the plague. It contains icing, turbulence,
disorientation. It forces your dependence on electrical and mechanical
devices which, reliable as they may be, are never completely infallible.
The forecaster's ability to predict the precise conditions within the IMC is
way less than that for VMC situations, and especially so for the most
dangerous conditions.

With all that going for it, flight into IMC should always be initiated only
with the greatest of care. Part of that care, you would think, is a rather
complete knowledge of the processes that produce it and that suppress it.
And at least a passing knowledge as to how to recognize them on a weather
chart as part of pre-flight planning....

Fascinating discussion. Someone versed in learning theory could
probably put what seems obvious here - reading about it only imparts
some unverified, unvalidated knowledge. Poking your nose in it
completes the package.

Re-reading the entire post suggests to me that the original poster was
asking for some insight to all the stuff he has read to date. Despite
all the various opinions and guidelines - there is still no definitive
procedure for when one may safely penetrate a Cu and when one should
not. In the end, you have to start poking your nose in a few and
calibrate what you've read. Or you can simply *never* fly in one (at
least not knowingly - see embedded)and limit your flying to visual
reference or stratus-only (is there a rating for that?)

As one poster pointed out, training doesn't require any actual. Without
it, a lot of the weather training leaves one pretty ignorant about a lot
of weather.

Interestingly, this particular thread provides the so-called 'ignorant'
with perhaps more insight than can be gained from any training manual.

Def: "Weather Ignorant" he/she who has yet to poke one's probiscus in
weather that one's common sense had decided to avoid like plague in future.

Ron McKinnon wrote:
> "Doug" > wrote in message
> oups.com...
>
>>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.
>
>
> I have no idea about the depth or breadth of your weather
> knowledge, nor your prowess as a pilot, except from what
> you yourself stated, and what you yourself said that you did.
>
> You stated that you were 'Pretty ignorant about weather',
> and that you flew into a big, dark, TCU. I can only
> infer from this that you were 'Pretty ignorant about weather',
> and that you had no idea what to expect within a big, dark,
> TCU.
>
> My query was merely one of astonishment, and an expression
> of a conundrum that one could indeed be 'pretty ignorant'
> about weather' and have no idea what to expect within a big,
> dark, TCU by the time they're an instrument rated pilot.
>
> But in this there was no ridicule of you, nor impugning of
> your intelligence, nor any intent to do so. I am sorry if
> you took it that way. I stand corrected.
>
>
>

"Maule Driver" > wrote in message
. com...
> Fascinating discussion. Someone versed in learning theory could probably
> put what seems obvious here - reading about it only imparts some
> unverified, unvalidated knowledge. Poking your nose in it completes the
> package.
>
> Re-reading the entire post suggests to me that the original poster was
> asking for some insight to all the stuff he has read to date. Despite all
> the various opinions and guidelines - there is still no definitive
> procedure for when one may safely penetrate a Cu and when one should not.
> In the end, you have to start poking your nose in a few and calibrate what
> you've read. Or you can simply *never* fly in one (at least not
> knowingly - see embedded)and limit your flying to visual reference or
> stratus-only (is there a rating for that?)
>

Part of the issue is whether the pilot has been sufficiently trained in
weather to at least make some judgement calls on his own, as to whether THIS
situation is one in which it is probable the the TCU will rip his wings off,
or will have some mild turbulence and nothing more. In his preplanning,
does he simply read the forecast, (which maybe happened to say nothing about
TCU's or CBs), then when he actually encounters one, how can he judge?

Is it only: The forecaster's said nothing, so it can't be bad.... or does
he make some further mental preparation such as: They were forecasting
really serious CB with severe turbc to the south of here, maybe that area
has moved further north than expected and they are starting to pop and I
should be really careful? OR... This is the only one around and its pretty
small in horizontal dimension, so its probably not too severe in there and
I'll be through it in a hurry.... OR: It looks to be part of a line, so
maybe there is some kind of squall line with extra lift, or maybe that cold
front is moving faster than expected, and so probably its going to be more
severe.... etc.

"Poking your nose in" can be a dangerous thing to do, if you don't really
understand what is happening. "Weather knowledge" is NOT: its a TCU,
somebody told me those have turbulence, lets find out how bad... "Weather
knowledge" is making some educated guess as to the processes at work so that
you can make a reasonable judgement as to what severity to anticipate before
you go in.


Having said all that, if someone is looking for rules of thumb, my
preference would be always to avoid penetration of a cloud of vertical
development, and especially above the freezing level. Those that I would
try to be especially careful of are:
.... Dark, and/or of broad horizontal extent. The darkness indicated a huge
water content, and hence something (updrafts) is holding it up... and its
getting ready to come down!
.... Part of a line. Could be a weak front or squall line. Extra lift.
.... built up quickly and/or appears to be building rapidly. Indicates very
strong vertical currents.
.... broad horizontally. Shows strong convective power exists, (and it takes
longer to traverse).
.... in an area where severe thunderstorms were forecast. Self explanatory.


Those that I would be more tempted to traverse:
White throughout, not dark. Not much water.
Narrow. Not in them for long.
Been around for a while and not building. Currents probably weak.
Isolated, in an area where none were forecast. Convective power probably
weak.
Embedded in generally stable cloud. If the whole area is relatively stable,
less likely that smaller embedded areas would be *severely* unstable.

Remember that there is an exception to every rule... of thumb. :-)


....

This particular one was
Tall
Dark
No forecast of T storms
No lightning
Supposed below the freezing level (according to both the forecast and
my temp guage)
Isolated (they were cells, not really a line)
But the kicker for me is
It was easily circumnavigated
No icing airmet, no tstorm airmet

If I had to do it over again, I'd request a 90 degree turn to the right
and a decent. Then turn back to course when it looked better.
But I dunno, there is no black and white here. It is all about how much
risk you want to take. For some, if it's legal, you are good to go. But
for me, make the flight as safe as possible. If there is a reasonable,
safer alternative, take it. Minimize the time spent in the clouds. Go
above them, around them or below them if possible. Fly where the good
weather is. Yes, do a little IMC here and there, but don't push it.

Icebound wrote:

> "Poking your nose in" can be a dangerous thing to do, if you don't really
> understand what is happening. "Weather knowledge" is NOT: its a TCU,
> somebody told me those have turbulence, lets find out how bad... "Weather
> knowledge" is making some educated guess as to the processes at work so that
> you can make a reasonable judgement as to what severity to anticipate before
> you go in.
That's the basic weather knowledge some of us (now) take for granted but
that in fact, takes some training and experience to gain.
>
>
> Having said all that, if someone is looking for rules of thumb, my
> preference would be always to avoid penetration of a cloud of vertical
> development, and especially above the freezing level. Those that I would
> try to be especially careful of are:
> ... Dark, and/or of broad horizontal extent. The darkness indicated a huge
> water content, and hence something (updrafts) is holding it up... and its
> getting ready to come down!
> ... Part of a line. Could be a weak front or squall line. Extra lift.
> ... built up quickly and/or appears to be building rapidly. Indicates very
> strong vertical currents.
> ... broad horizontally. Shows strong convective power exists, (and it takes
> longer to traverse).
> ... in an area where severe thunderstorms were forecast. Self explanatory.
>
>
> Those that I would be more tempted to traverse:
> White throughout, not dark. Not much water.
> Narrow. Not in them for long.
> Been around for a while and not building. Currents probably weak.
> Isolated, in an area where none were forecast. Convective power probably
> weak.
> Embedded in generally stable cloud. If the whole area is relatively stable,
> less likely that smaller embedded areas would be *severely* unstable.
>
> Remember that there is an exception to every rule... of thumb. :-)
>
All very good stuff. The question is, "how do you get this information
and get it added to your knowledge bank?" Well, this thread is a good
place with experienced weather pilots giving their best. Reading every
issue of every flying magazine for xx years can help - I did it and it
did. But completing your IFR training I would submit, doesn't do it,
unless one has access to instructors and pilots that can somehow share
their knowledge. Everyone doesn't have that.

I spent over 10 years racing cross country in gliders. Every hour was
spend evaluating *every single cloud* in sight. After evaluating them,
I often flew under them and had a chance to validate what I saw. When I
screwed up, I often found myself on the ground. Along the way I was
rained on many times, landed out many times, sucked up into a TCU where
redline was required to get out, and hit by hail from below. I've
(stupidly) flown underneath a few thunderstorms, been in a microburst,
and landed in the middle of several storms, one notably with lightening
(if the finish line is under one and you made it that far, are you going
to quit and landout or finish? Landout is the answer but I was younger
then and foolish)

After all that, I found I still had a lot learn about actually flying
*in* those same clouds. I knew to stay out anything that looks or
smells like a TCU or thunderstorm. But I wasn't prepared for just how
violent those benign looking pure white Florida afternoon Cu's could be.
Or how terrifying embedded *light* convection can be when you can't
see where it is or really know how strong it might get. Or conversely,
just how comforting Stormscope, or radar, or ol' Cheap ******* can be on
a southern afternoon.

And I had no experience with ice - and though I've been dipped in it a
few times I'm fortunate in that there's so much good writing on the
subject that I've been able to avoid scaring myself so far.

It's hard to gain "weather knowledgeabe" status. And how many people
here are "knowledgeable" and yet not scared themselves in weather they
should have avoided? Or Icebound, how did you come up with that name?

"Maule Driver" > wrote in message
. com...

> ... Or Icebound, how did you come up with that name?

Hee-hee. I just looked at my life:

.... and realized that half the time I scrape it off my windshield, drive on
it, walk on it, even play on it. I used to forecast it, saw its effects on
the hulls of large ships, watched it snap every power pole in my village,
saw it destroy my father's crops.

My boat sits suspended above it for 6 months of the year, waiting for those
few short summer weeks when it can be truly called a "pleasure" craft.

I have flown as a passenger in it, (watching an hour of mysterious
pump-handle activity by the DC3 co-pilot, probably keeping the
leading-edge-boots working???). I have never flown in it as a pilot, (and
freely admit that my opinions come from meteorological, and not aviation,
experience).

Best of all, it cools my gin-and-tonic while I visit aviation newsgroups
where it is a topic of serious discussion.

Hee Hee!

Icebound wrote:

>>... Or Icebound, how did you come up with that name?
>
>
> Hee-hee. I just looked at my life:
>
> ... and realized that half the time I scrape it off my windshield, drive on
> it, walk on it, even play on it. I used to forecast it, saw its effects on
> the hulls of large ships, watched it snap every power pole in my village,
> saw it destroy my father's crops.
>
> My boat sits suspended above it for 6 months of the year, waiting for those
> few short summer weeks when it can be truly called a "pleasure" craft.
>
> I have flown as a passenger in it, (watching an hour of mysterious
> pump-handle activity by the DC3 co-pilot, probably keeping the
> leading-edge-boots working???). I have never flown in it as a pilot, (and
> freely admit that my opinions come from meteorological, and not aviation,
> experience).
>
> Best of all, it cools my gin-and-tonic while I visit aviation newsgroups
> where it is a topic of serious discussion.
>
>

"Icebound" wrote:
> > ... Or Icebound, how did you come up with that name?
>
> Hee-hee. I just looked at my life:
>
> ... and realized that half the time I scrape it off my windshield, drive on
> it, walk on it, even play on it. I used to forecast it, saw its effects on
> the hulls of large ships, watched it snap every power pole in my village,
> saw it destroy my father's crops.
>
> My boat sits suspended above it for 6 months of the year, waiting for those
> few short summer weeks when it can be truly called a "pleasure" craft.

8^)

Hmmm... Maybe I should call myself "Humiditybound."
--
Dan
C-172RG at BFM

I am still a new instrument pilot and do not have the experience of most
of the group. However, I am coming up with a rule of thumb that I would
like to see what you think. These towering cumulus clouds - to me if
they seem much taller than they are wide I try to stay away. If they
seem wider than they are tall, I seem to get through them with some
bouncing around. Each one is a judgement call. I was heading to one that
went way on up and had a anvil. I took a 30 mile trip around it. I
stayed out from under the anvil also.

What do you think of my rule of thumb?

Maule Driver wrote:

> Fascinating discussion. Someone versed in learning theory could
> probably put what seems obvious here - reading about it only imparts
> some unverified, unvalidated knowledge. Poking your nose in it
> completes the package.
>
> Re-reading the entire post suggests to me that the original poster was
> asking for some insight to all the stuff he has read to date. Despite
> all the various opinions and guidelines - there is still no definitive
> procedure for when one may safely penetrate a Cu and when one should
> not. In the end, you have to start poking your nose in a few and
> calibrate what you've read. Or you can simply *never* fly in one (at
> least not knowingly - see embedded)and limit your flying to visual
> reference or stratus-only (is there a rating for that?)
>
> As one poster pointed out, training doesn't require any actual. Without
> it, a lot of the weather training leaves one pretty ignorant about a lot
> of weather.
>
> Interestingly, this particular thread provides the so-called 'ignorant'
> with perhaps more insight than can be gained from any training manual.
>
> Def: "Weather Ignorant" he/she who has yet to poke one's probiscus in
> weather that one's common sense had decided to avoid like plague in future.
>
>snip


--
Regards, Ross
C-172F 180HP

It's a start - though I immediately think of the very thin, tall cu we
get on certain days here in NC. They seem be somewhat harmless but who
knows....

In my slow, lightly loaded and lightly equipped mount, I simply try to
avoid penetrating any convective clouds. And that is easier done than said.

In the Southeast, most conditions allow circumnavigation. If they are
too tall and dense for me to get up high enough to circumnavigate the
tops, they are unusually are unflyable. Don't feel like you have to fly
a straight course. Controllers in the SE will usually permit all the
deviations you may need. In FL you can count on it - along with a lot
of advisories to keep you out of the nasties.

Then what's left to penetrate are cumulus decks that may form under you
as the day matures but I find those are tolerable since by definition,
they haven't developed vertically. Also the occasional penetration of a
valley between taller clouds. But in general, you can avoid an awful
lot of cus.

The next step is airborne Nexrad. Being able to see what is happening
inside or on the other side of a cloud is worth it's weight -- and
cost. Now if I can just dig up the bucks.

Ross Richardson wrote:
> I am still a new instrument pilot and do not have the experience of most
> of the group. However, I am coming up with a rule of thumb that I would
> like to see what you think. These towering cumulus clouds - to me if
> they seem much taller than they are wide I try to stay away. If they
> seem wider than they are tall, I seem to get through them with some
> bouncing around. Each one is a judgement call. I was heading to one that
> went way on up and had a anvil. I took a 30 mile trip around it. I
> stayed out from under the anvil also.
>
> What do you think of my rule of thumb?
>

"Ross Richardson" > wrote in message
...
>I am still a new instrument pilot and do not have the experience of most of
>the group. However, I am coming up with a rule of thumb that I would like
>to see what you think. These towering cumulus clouds - to me if they seem
>much taller than they are wide I try to stay away. If they seem wider than
>they are tall, I seem to get through them with some bouncing around. Each
>one is a judgement call. I was heading to one that went way on up and had a
>anvil. I took a 30 mile trip around it. I stayed out from under the anvil
>also.
>
> What do you think of my rule of thumb?
>

The issue with the anvil is that it means the cloud has sufficient depth to
be producing hail (it is already a CB, no longer a TCU). CB's have been
known to "kick" the hail out in front of them, and it has been encountered
in the relatively clear-of-cloud area under the anvil. Also, in an area of
multiple CB cells, the clear areas between them can be very turbulent also,
so
giving them a wide 30 mile berth is wise.


As for the wider-than-it-is-tall issue, I can see merit to your reasoning if
you are looking at 2 or 3-to-1 width to height ratio, and they haven't
changed much in the last half-hour. But even so, if its an obvious cloud of
vertical development, and it's 5 miles across, I'd be concerned...
especially if it popped suddenly and may be growing quite quickly.

"Ron McKinnon" > wrote in
news:oG%8e.1066820$Xk.925695@pd7tw3no:

>
> "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....


I suspect that his level of "ignorance of weather" was that he was unable
to accurately predict the conditions inside that dark towering Cumulus
cloud he flew through.

I also suspect that most pilots, VFR or IFR, have been in the same boat at
some point after their IFR training, especially since it is not a pre-
requisite to receiving the instrument rating. We are mostly taught to
depend on forecasts and spend very little time during training on learning
to properly identify cloud formations from actual pictures or live
representations, and to understand what to expect within each type of
cloud.

During VFR training, you learn to just stay away from them. And during IFR
training, you get pounded about the extremes (CBs and Stratus clouds) but
there is really inadequate training of the stuff in the middle - probably
because the stuff in the middle varies so widely.

Can you accurately predict conditions inside of a towering CU unless you
get inside of it? There are different conditions even within the same cloud
that depend on many factors that include pressure, elapsed time, wind
speed, humidity levels, etc. So while one dark TCU may produce hail, rain,
and ice, the next dark TCU might be fairly uneventful and produce some
turbulence as you enter and exit and that's all.

I think most people are fairly ignorant of weather, even if we think we are
experts. Otherwise the meteorologists would never be wrong, and the rest of
us COULD just depend on the forecasts...

"Judah" > wrote in message
. ..
> "Ron McKinnon" > wrote in
> news:oG%8e.1066820$Xk.925695@pd7tw3no:
>
>>
>> "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....
>
>
> I suspect that his level of "ignorance of weather" was that he was unable
> to accurately predict the conditions inside that dark towering Cumulus
> cloud he flew through.

The level of ignorance implied by my post was the level of ignorance
stated by the original poster 'Pretty ignorant about weather", and the
stated actions of that poster
>
> I also suspect that most pilots, VFR or IFR, have been in the
> same boat at some point after their IFR training, especially
> since it is not a pre-requisite to receiving the instrument rating.
> We are mostly taught to depend on forecasts and spend very little
> time during training on learning to properly identify cloud formations
> from actual pictures or live representations, and to understand what
> to expect within each type of cloud.

How can you 'depend on forecasts' alone? They are a sketch of
what someone thinks is *likely* to happen. They are not cast in
concrete statements of what *will* happen everywhere in the given
area. And even if they're right-on, for the most part, they can still
miss very localized or short-term events. You can't rely on the
forecasts alone.

And, in any case, you need to know enough about weather to
understand the forecasts so that you know how they might impact
you. This implies a certain understanding of the characteristics
of things like clouds.

> During VFR training, you learn to just stay away from them.
> And during IFR training, you get pounded about the extremes
> (CBs and Stratus clouds) but there is really inadequate training
> of the stuff in the middle - probably because the stuff in
> the middle varies so widely.

If you know that you should stay the hell away from CBs, you
should know to stay away from "big, dark, TCUs" as well.
A big, dark, TCU, depending on how big and dark it is, for
your intents and purposes, should be considered the same
as a CB. A cloud doesn't just turn into a CB and becoume
dangerous because now it's a CB; it becomes dangerous the
bigger it gets. A big, dark TCU, should probably be considered
as dangerous as a new CB.

> Can you accurately predict conditions inside of a towering CU
> unless you get inside of it? There are different conditions even
> within the same cloud that depend on many factors tat include
> pressure, elapsed time, wind speed, humidity levels, etc. So
> while one dark TCU may produce hail, rain, and ice, the next
> dark TCU might be fairly uneventful and produce some
> turbulence as you enter and exit and that's all.

You don't need to know what a grizzly bear had for breakfast
to know not to poke him with a stick. Respect him just 'cause
he's a grizzly bear.

'Accuracy of predictions' is a red-herring, here. Accurate
predictions of conditions inside a TCU are not required.
Just know that if they're big and dark, they're probably nasty.
If you wouldn't penetrate or fly in the vicinity of a CB, you
should probably accord a 'big dark TCU' similar respect.

> I think most people are fairly ignorant of weather, even if we
> think we are experts. Otherwise the meteorologists would
> never be wrong, and the rest of us COULD just depend on the
> forecasts...

I suggest that meteorologists are not absolutely wrong as much
as you think. Or as much wrong as you think. But even so, this
does not speak to ignorance of weather, nor or weather processes,
but more to the difficulty in predicting very far into the future the
behaviour of a largely chaotic system such as the atmosphere.

Pilots do not need to be degreed meteorologists, but they do
need to know enough to understand what meteorologists are
telling them, and they do need to know the *basics* well enough
to expect that flying into a 'big, dark TCU' is very likely a
problem.

"Ron McKinnon" > wrote in
news:YL9be.1133064$8l.199556@pd7tw1no:

<snip>
>>> 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' ???
>>>
<snip>
> How can you 'depend on forecasts' alone? They are a sketch of
> what someone thinks is *likely* to happen. They are not cast in
> concrete statements of what *will* happen everywhere in the given
> area. And even if they're right-on, for the most part, they can still
> miss very localized or short-term events. You can't rely on the
> forecasts alone.
>
> And, in any case, you need to know enough about weather to
> understand the forecasts so that you know how they might impact
> you. This implies a certain understanding of the characteristics
> of things like clouds.
>
<snip>
> You don't need to know what a grizzly bear had for breakfast
> to know not to poke him with a stick. Respect him just 'cause
> he's a grizzly bear.
>
> 'Accuracy of predictions' is a red-herring, here. Accurate
> predictions of conditions inside a TCU are not required.
> Just know that if they're big and dark, they're probably nasty.
> If you wouldn't penetrate or fly in the vicinity of a CB, you
> should probably accord a 'big dark TCU' similar respect.
>
>> I think most people are fairly ignorant of weather, even if we
>> think we are experts. Otherwise the meteorologists would
>> never be wrong, and the rest of us COULD just depend on the
>> forecasts...
>
> I suggest that meteorologists are not absolutely wrong as much
> as you think. Or as much wrong as you think. But even so, this
> does not speak to ignorance of weather, nor or weather processes,
> but more to the difficulty in predicting very far into the future the
> behaviour of a largely chaotic system such as the atmosphere.
>
> Pilots do not need to be degreed meteorologists, but they do
> need to know enough to understand what meteorologists are
> telling them, and they do need to know the *basics* well enough
> to expect that flying into a 'big, dark TCU' is very likely a
> problem.

I don't disagree that pilots *should* not be ignorant of weather, and
*should* not depend on forecasts alone, and *should* be taught to
recognize CBs and TCUs and to stay away from them.

However, the IFR training syllabus fails to make this a prerequisite for
certification to fly a plane in IFR conditions, and as such many pilots
*are* ignorant of weather, and *do* depend on forecasts alone, and
*don't* recognize TCUs or CBs, because they have not flown near them
during their training.

A better example than your grizzly bear might be swimming and
snorkeling. When you learn to swim, you don't learn much about the fish
in the ocean - heck you may never even swim in the ocean during your
training.

So now you know how to swim, and you go snorkeling. Someone tells you
that it is OK to pet most fish because even the sharks don't bite if
they are not agitated. One day you find yourself petting a baracuda,
because no told you how to recognize it, or to stay away from it, and
just last week you pet a nurse shark without any problems and sharks are
much scarier, right?

I think too many IFR pilots are in that same boat - they don't even know
how to recognize a CB or TCU because they've never been shown one (the
instructor probably scrubbed the lesson because the forecast called for
them) and they passed through the clouds just fine last time...

What *is* and what *should* be are two very different things...

"Judah" > wrote in message
. ..>
> I don't disagree that pilots *should* not be ignorant of
> weather, and *should* not depend on forecasts alone, and
> *should* be taught to recognize CBs and TCUs and to stay
> away from them.
>
> However, the IFR training syllabus fails to make this a
> prerequisite for certification to fly a plane in IFR conditions,
> and as such many pilots *are* ignorant of weather, and *do*
> depend on forecasts alone, and *don't* recognize TCUs or CBs,
> because they have not flown near them during their training.
>
> A better example than your grizzly bear might be swimming and
> snorkeling. When you learn to swim, you don't learn much about
> the fish in the ocean - heck you may never even swim in the ocean
> during your training.
>
> So now you know how to swim, and you go snorkeling. Someone
> tells you that it is OK to pet most fish because even the sharks
> don't bite if they are not agitated. One day you find yourself
> petting a baracuda, because no told you how to recognize it,
> or to stay away from it, and just last week you pet a nurse shark
> without any problems and sharks are much scarier, right?
>
> I think too many IFR pilots are in that same boat - they don't
> even know how to recognize a CB or TCU because they've
> never been shown one (the instructor probably scrubbed the
> lesson because the forecast called for them) and they passed
> through the clouds just fine last time...
>
> What *is* and what *should* be are two very different things...

I've heard this plaintive refrain several times in this thread
- "No one taught me not to ", "It's not part of the training
syllabus", "its not required for certification" ...

It doesn't wash. It's a question of airmanship. Its a matter
of responsibility. It's the difference between being a Pilot,
or an airplane driver. The standards are minimums. The
standard curriculum is only a starting point.

And where your specific knowledge and training is not
sufficient, sufficient intelligence, and 'common' sense
should apply; you'll never be taught all the permutations
and combinations, but you should be able to reasonably
extrapolate from what you have already learned or
experienced.

(You should critically assess what you're told to do or
not do in any event, and see if it make sense. And even
then, if you've never seen a barracuda, or never been
told to avoid them, seeing an unfamiliar fish where a
quarter of its length consists of razor sharp teeth should
reasonably give you pause (you do know about razor sharp
teeth, don't you?). If you've been told not to fly into CBs,
you ought to recognize that a big, dark, TCU might be
just about as dangerous, and maybe you ought to avoid it, too.)

As pilot you are responsible for having all the information
reasonably available pertinent to your flight. This includes
*basic* knowledge of meteorology. Your life depends upon
it. The lives of your passengers depend upon it.

CBs are the sharks and barracudas of the sky. You might
get away with playing with them once or twice, but you
can't expect it. What you can expect is that they'll chew
you up and spit you out like so much bubble gum. A big,
dark, TCU may well be on the verge of being a CB; the
closer it gets to being a CB, the closer it gets to being as
dangerous as a CB, but even if it's not as dangerous as a
CB, it can still be dangerous.

None of us know it all, and All of us make mistakes.
We live (hopefully) and learn (hopefully). But in general
it is no argument nor excuse that "No one told me!" As
pilot , *you* are responsible.

Been following this thread and I'm unclear about something. Are
there *really* people out there who 1) have never seen a TCU/CB or
2) have never seen a tornado or 3) have never seen the films on
television about these things? I learned about clouds and how
they formed and about Tstorms in grade school science class.
In particular, hail from Tstorms and how damaging it can be.
And how fast the wind can whip a pencil thru 4inch lumber. Had
great demonstrations!

I've been on a number of commercial flights where the aircraft
deviates to avoid those big, white, fluffy, gorgeous clouds (do
love Ch9 on United. Just hate United).

Which leads me to wonder *WHY* would anyone even consider flying
thru CB or TCU? At least without a will and/or a deathwish.

Blanche > wrote in news:1115530461.148407
@irys.nyx.net:

> Been following this thread and I'm unclear about something. Are
> there *really* people out there who 1) have never seen a TCU/CB or
> 2) have never seen a tornado or 3) have never seen the films on
> television about these things? I learned about clouds and how
> they formed and about Tstorms in grade school science class.
> In particular, hail from Tstorms and how damaging it can be.
> And how fast the wind can whip a pencil thru 4inch lumber. Had
> great demonstrations!
>
> I've been on a number of commercial flights where the aircraft
> deviates to avoid those big, white, fluffy, gorgeous clouds (do
> love Ch9 on United. Just hate United).
>
> Which leads me to wonder *WHY* would anyone even consider flying
> thru CB or TCU? At least without a will and/or a deathwish.
>
>

You don't always see them.

If they don't have visible lightning, they don't necessarily show up at
night. Before getting our StrikeFinder, I got caught a few times. A
wild ride at times.

If you're in seemingly benign clouds, you may not know what lies ahead.
Lynda and I had a memorable encounter while enroute to Parents' Day for
our younger when he was in undergraduate school at Miami of Ohio. We had
been IMC for quite a while, with a smooth ride, when it all came loose
with no warning at all. The VSI was pegged in a vicious updraft. Slowed
to Va, extended gear, told ATC that a block altitude was required RIGHT
NOW. A Mooney in the vicinity was complaining about 2,000 ft per minute.
We had more, but I don't know how much more, as the VSI was off scale.

Ordered the StrikeFinder the next week. Have not had an encounter like
that since the device was installed -- it gives plenty of warning.

--L. R. Du Broff

"Blanche" > wrote in message
...
> Been following this thread and I'm unclear about something. Are
> there *really* people out there who 1) have never seen a TCU/CB or
> 2) have never seen a tornado or 3) have never seen the films on
> television about these things? I learned about clouds and how
> they formed and about Tstorms in grade school science class.
> In particular, hail from Tstorms and how damaging it can be.
> And how fast the wind can whip a pencil thru 4inch lumber. Had
> great demonstrations!

Theres a lot of weather short of big dark threatenly clouds with lighting
inside and funnels below, that light planes can benefit from avoiding.

Big puffy white Cu don't necessarily look threatening until you have
penetrated a few or otherwise experienced them - no matter what you've been
told. (I was fortunate enough to spend many hours in gliders among them -
with a full understanding of the processes involved, I've never had to poke
a big one to know what's in there)

Remember the word 'embedded'. There are conditions that are pretty benign
IMC that can transition to embedded cells. Without a strikefinder or nexrad
or onboard radar or attentive controllers (or Cheap*******) you're flying
among convective cells in the blind. Did that once, nothing was violently
over the top but 'embedded' became firmly embedded in this skull.

Study, research, hangar talk and whatever provide a lot of knowledge but it
has to be mixed with some experience in order for one to apply weather
knowledge effectively. The trick is dipping your toe without falling in -
or least being able to swim out and fly another day.
>
> I've been on a number of commercial flights where the aircraft
> deviates to avoid those big, white, fluffy, gorgeous clouds (do
> love Ch9 on United. Just hate United).
>
> Which leads me to wonder *WHY* would anyone even consider flying
> thru CB or TCU? At least without a will and/or a deathwish.

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