"dave" nospam wrote in message
...
| Sorry if I sound like a buffoon to you meteorologists. I'm simply a
layman
| that knows nothing about this but wants to learn. I did some searching
and
| it is said that warm rising air keeps clouds up. Is it possible the
static
| charge in the clouds could also have an effect? Something like
anti-gravity
| on a small scale? Thanks.
|

You seem to have drawn some interesting replies to your question, including
a number who seem to be doing it the hard way.

Anti-gravity or electrostatic effects are not necessary. Cloud droplets when
first formed are very small and therefore fall very slowly. Clouds also
evolve with time - either they dissipate by evaporation into the air around
or continuing uplift causes more condensation and more cloud droplets to
form. The time it would take for the small droplets to fall out of the
cloud is similar to or greater than the time scales on which these processes
operate, so you would either see the cloud evaporate or continue to grow,
rather than see the cloud droplets fall out.

If the cloud continues to grow, other processes take over. The cloud
droplets will eventually grow by collision with each other, but surface
tension forces and the tendency of the layer of air around each drop to
deflect other approaching drops makes this a slow and inefficient process.
Prolonged uplift or condensation will eventually result in cloud droplets
growing large enough to fall out and typically this produces the fine
drizzle you get on windward coasts and hills during cloudy, humid weather
with no heavy rain about.

Under favourable circumstances it is possible to get heavier rain this way,
and this can happen in shallow shower clouds in the tropics. Most of our
rain, however, is formed in clouds which extend above the freezing level.
Once ice crystals have formed (which is actually hard to do because small
water drops can remain liquid down to -40F unless special freezing nuclei
are present to help the ice structure to form), then the ice crystals will
grow rapidly at the expense of the water drops (by evaporation of the water
drops and condensation onto the ice crystals), producing snow crystals which
fall out, melting to rain on the way down if they encounter air above
freezing. This is the main fall-out mechanism.

Vigorous convective clouds with strong up and down currents in them can
produce other exciting things such as hail and torrential downpours, but
that is another story...
--
- Yokel -
oo oo
OOO OOO
OO 0 OO
) ( I ) (
) ( /\ ) (

"Yokel" now posts via a spam-trap account.
Replace my alias with stevejudd to reply.

On Aug 6, 10:58 pm, "Yokel" wrote:
"dave" nospam wrote in message

...
| Sorry if I sound like a buffoon to you meteorologists. I'm simply a
layman
| that knows nothing about this but wants to learn. I did some searching
and
| it is said that warm rising air keeps clouds up. Is it possible the
static
| charge in the clouds could also have an effect? Something like
anti-gravity
| on a small scale? Thanks.
|

You seem to have drawn some interesting replies to your question, including
a number who seem to be doing it the hard way.

Anti-gravity or electrostatic effects are not necessary. Cloud droplets when
first formed are very small and therefore fall very slowly. Clouds also
evolve with time - either they dissipate by evaporation into the air around
or continuing uplift causes more condensation and more cloud droplets to
form. The time it would take for the small droplets to fall out of the
cloud is similar to or greater than the time scales on which these processes
operate, so you would either see the cloud evaporate or continue to grow,
rather than see the cloud droplets fall out.

If the cloud continues to grow, other processes take over. The cloud
droplets will eventually grow by collision with each other, but surface
tension forces and the tendency of the layer of air around each drop to
deflect other approaching drops makes this a slow and inefficient process.
Prolonged uplift or condensation will eventually result in cloud droplets
growing large enough to fall out and typically this produces the fine
drizzle you get on windward coasts and hills during cloudy, humid weather
with no heavy rain about.

Under favourable circumstances it is possible to get heavier rain this way,
and this can happen in shallow shower clouds in the tropics. Most of our
rain, however, is formed in clouds which extend above the freezing level.
Once ice crystals have formed (which is actually hard to do because small
water drops can remain liquid down to -40F unless special freezing nuclei
are present to help the ice structure to form), then the ice crystals will
grow rapidly at the expense of the water drops (by evaporation of the water
drops and condensation onto the ice crystals), producing snow crystals which
fall out, melting to rain on the way down if they encounter air above
freezing. This is the main fall-out mechanism.

Vigorous convective clouds with strong up and down currents in them can
produce other exciting things such as hail and torrential downpours, but
that is another story...

I wonder if the difference between high and low pressure areas might
in some strange way be dependent on the fact that rising air takes up
moisture while diffusing it away from impurities and falling air can't
really reverse that process having a superabundance of ice and dirt.

But anyway, whilst looking for info on the production of electricity
with ice formation (in the manner of that stuff they get very low
temperatures with) I found out this disseratation on the various
structurews. Not really an answer but interesting:
Page
1.Introduction857
1.1.Iceasacasestudy857
1.2.Naturalsnowcrystals858
1.3.Themorphologydiagram858
1.4.Complexityandsymmetry861
1.5.Thephysicsofsnowcrystals862
2.Prismgrowthfromvapour-theory862
2.1.Basicterminology863
2.2.Diffusion-limitedgrowth864
2.3.Diffusionmodellingofprismgrowth868
2.4.Facetgrowthwithdiffusion869
2.5.Attachmentkinetics870
2.6.Surfacestructureandcrystalgrowth871
2.7.Chemicallyenhancedgrowth874
3.Prismgrowthfromvapour-observations875
3.1.Experimentaltechniques875
3.2.Conclusionsfromgrowthmeasurements878
3.3.Summaryofsnowcrystalprismgrowth881
4.Dendriticgrowth882
4.1.Thetransitionfromfacetingtobranching882
4.2.Dendritetheoryandsnowcrystalgrowth884
4.3.Fullmodellingofdendritegrowth887
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv vvvvv
4.4.Electricallyandchemicallymodi?edicedendritegro wth888
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^

http://www.its.caltech.edu/~atomic/p...rpp5_4_R03.pdf

"Yokel" wrote
...
"dave" nospam wrote in message
...
| Sorry if I sound like a buffoon to you meteorologists. I'm simply a
layman
| that knows nothing about this but wants to learn. I did some searching
and
| it is said that warm rising air keeps clouds up. Is it possible the
static
| charge in the clouds could also have an effect? Something like
anti-gravity
| on a small scale? Thanks.
|

You seem to have drawn some interesting replies to your question,
including
a number who seem to be doing it the hard way.

Anti-gravity or electrostatic effects are not necessary.

But I see small problem. The hot smoke. In the sunny days it goes straight
up but under clouds do not..

Cloud droplets when
first formed are very small and therefore fall very slowly. Clouds also
evolve with time - either they dissipate by evaporation into the air
around
or continuing uplift causes more condensation and more cloud droplets to
form. The time it would take for the small droplets to fall out of the
cloud is similar to or greater than the time scales on which these
processes
operate, so you would either see the cloud evaporate or continue to grow,
rather than see the cloud droplets fall out.

If the cloud continues to grow, other processes take over. The cloud
droplets will eventually grow by collision with each other, but surface
tension

Here also could have an effect the voltage which is raising when droplets
grow.

forces and the tendency of the layer of air around each drop to
deflect other approaching drops makes this a slow and inefficient process.
Prolonged uplift or condensation will eventually result in cloud droplets
growing large enough to fall out and typically this produces the fine
drizzle you get on windward coasts and hills during cloudy, humid weather
with no heavy rain about.

Under favourable circumstances it is possible to get heavier rain

After lightning rain is heavier.

this way,
and this can happen in shallow shower clouds in the tropics. Most of our
rain, however, is formed in clouds which extend above the freezing level.
Once ice crystals have formed (which is actually hard to do because small
water drops can remain liquid down to -40F unless special freezing nuclei
are present to help the ice structure to form), then the ice crystals will
grow rapidly at the expense of the water drops (by evaporation of the
water
drops and condensation onto the ice crystals), producing snow crystals
which
fall out, melting to rain on the way down if they encounter air above
freezing. This is the main fall-out mechanism.

Vigorous convective clouds with strong up and down currents in them can
produce other exciting things such as hail and torrential downpours, but
that is another story...

Here also the charge in the clouds could have an effect. Air currents and
electric currents work together.
S*

"Rodney Blackall" wrote
...
In article , Szczepan Bia³ek
wrote:
SNIP
You seem to have drawn some interesting replies to your question,
including a number who seem to be doing it the hard way.

Anti-gravity or electrostatic effects are not necessary.

But I see small problem. The hot smoke. In the sunny days it goes
straight up but under clouds do not..

In convective conditions warm smoke will rise; Cloudy conditions are often
stable and smoke plume would have to be very warm and large (e.g. from
power
station) to rise far.

But the smoke from small house chimney is much easy to examine.

[Snip]

If the cloud continues to grow, other processes take over. The cloud
droplets will eventually grow by collision with each other, but surface
tension

Here also could have an effect the voltage which is raising when
droplets grow.

Why? Does it?

I wrote about it:
" I remember reading an article about electrical charge dispersal in the
open atmosphere.ruling out that it can build up in clouds to the
extent that it causes lightning.

You must recognise the charge from the voltage. The charge cannot build up.
But when the droplets join together the voltage is raising (capacitance of
sphere) and it can cause lightning."

Capacitance of the sphere is proportional to the radius of a sphere - the
volume to r^3.


[Snip]

Under favourable circumstances it is possible to get heavier rain

After lightning rain is heavier.

But only sometimes. Lightning may discharge voltage through 10 km of
cloud;
it takes a LONG time for even a large raindrop to fall 1 km.

Anyway cloud must discharge the voltage before fall down as rain.

[Snip]


Vigorous convective clouds with strong up and down currents in them can
produce other exciting things such as hail and torrential downpours,
but that is another story...

Here also the charge in the clouds could have an effect. Air currents
and electric currents work together.

No. Strong air currents are needed to generate the electric field.

To generate the electric field the charge are needed.

On the question:
"I did some searching and it is said that warm rising air keeps clouds up.
Is it possible the static
charge in the clouds could also have an effect?"
Your answer was:
"There is a semi-permanent "fair weather field" of several hundred volts per
metre near ground level that does not seem to have much effect on anything."
How much - this is a question.
S*

Szczepan Bialek schrieb:
Anyway cloud must discharge the voltage before fall down as rain.

Really? One can regularly observe rain, both convective or stratiform,
falling down without any previous lightning.
Anyway, since cloud and ground are oppositely charged (otherwise you
would not get discharges in the form of C-G lightning), the
electrostatic force would *attract* cloud droplets towards the ground,
so they would fall faster *before* the discharge. However, this force is
several orders of magnitude weaker than the force exercised by
gravitation and air currents.

Falk

"Falk Tannhäuser" 3rote
...
Szczepan Bialek schrieb:
Anyway cloud must discharge the voltage before fall down as rain.

Really? One can regularly observe rain, both convective or stratiform,
falling down without any previous lightning.

The discharge phenomenon occurs not always with sparks. In the wet air it is
wery fast without the sparks. Nature use sparks (lightning) in the extremal
conditions only.

Anyway, since cloud and ground are oppositely charged (otherwise you would
not get discharges in the form of C-G lightning),

The ground and clouds are both negatively charged (exces of electrons).
Different is the voltage.

the electrostatic force would *attract* cloud droplets towards the
ground, so they would fall faster *before* the discharge.

The electrostatic force repulse cloud droplets towards the sky.

However, this force is several orders of magnitude weaker than the force
exercised by gravitation and air currents.

It depends from the chrge and the altitude
S*

U¿ytkownik "Rodney Blackall" napisa³ w
wiadomo¶ci ...
In article , Szczepan Bialek
wrote:
Anyway, since cloud and ground are oppositely charged (otherwise you
would not get discharges in the form of C-G lightning),

and C-C lightning shows charge varies within and between clouds

Before C-C lightning the voltage is different within and between clouds.
After lightning charge varies and the voltages become equal (for a moment)

The ground and clouds are both negatively charged (exces of electrons).
Different is the voltage.

So where are the positive charges?

We must distinguish the charges from the charged bodies. Droplets are
bodies. In electrostatics the positive meens defficiency of electrons and
negative the exces of electrons.in a body. Droplets when hang in the air
have exces of electrons. If they loss them have to fall down (Millican).

All what I am talking about was explained in XIX century. In that time
Armstrong made the vapour generator (of high voltage) and Kelvin the drop
generator. The all was described by J. Frenkel in words: ".. Clouds are
electrogravitational generators in in continual run. In place of the
friction and the induction (as it take place in normal generators) are the
condensation and thedroplets grow."
But the most important is to remember that the surface of the Earth has
ALWAYS excess of electrons. They are ewerywhere and in sunny days migrate
up. It is obvious that they must come back.
S*

Rodney Blackall schrieb:
In article , Szczepan Bialek
wrote:
Anyway, since cloud and ground are oppositely charged (otherwise you
would not get discharges in the form of C-G lightning),
and C-C lightning shows charge varies within and between clouds

Right, the lower part of the cloud is negatively charged, while the
(usually anvil-shaped) summit carries positive charge. A small zone of
positive charge is also often observed at the cloud base where the rain
falls out.

The ground and clouds are both negatively charged (exces of electrons).
Different is the voltage.
So where are the positive charges?

Due to electrostatic induction, the area on the ground lying directly
below the negatively-charged cloud gets positively charged, leading to a
reversal of the usual fair-weather field. Hence the negative C-G
lightning actually increases the net negative charge of the earth.
Thunderstorms effectively act as generators - without them, fair-weather
current would soon make disappear the difference of potential between
ground and atmosphere.
Note that positive C-G lightning also occurs, but is considerably rarer
than negative one. Typically it originates from the cloud's anvil and
strikes a place on the ground that is peripheral to the thunderstorm
(and thus negatively charged). It is more often found during dissipating
storms (where the lower cloud parts often disappear first) or in winter
thunderstorms (when the cloud summits are lower).
Typical field strengths are on the order of magnitude of E = 10 kV/m
between ground and cloud, and 100 kV/m within the cloud. For comparison,
fair-weather field strength is about 0.15 kV/m near to ground level.

Concerning gravitational and electrostatic forces:
Consider a spheric rain droplet of a mass of m = 1 mg.
(It has a volume of V = 1 mm^3 and hence a diameter of 1.24 mm, since V
= 4/3*pi*r^3 - not an unreasonable size).
Its weight (force exercised by gravitation) is m*g = 9.81*10^-6 N
(with g = 9.81 m/s^2).
The electrostatic force equals q*E where q is the charge of the droplet.
If electrostatic force is supposed to prevent our droplet from falling
down, it has to compensate the gravitational force. Then we can
calculate the charge needed for this. If we set E = 100 kV/m = 100 kN/C,
we obtain that our droplet has to have a charge of 9.81*10^-11 C.
This would mean 1.02*10^10 such droplets (corresponding to 10.2 m^3 of
water) would carry an aggregate charge of 1 Coulomb.
Now we let's consider that we may find about 100000 m^3 of water in a
small thunderstorm cloud (just to get an idea of the order of magnitude
- this would correspond to 10 mm of precipitation over 10 km^2, note
however that only a part of the water in the cloud finally makes it to
the earth as precipitation). The aggregate charge of this mass of water
would then equal to 10000 C - a value that seems much to high to me!
Average lightnings transport a charge of less than 10 C - furthermore, a
punctual charge of Q = 10000 C would produce a field of about
E = 10 MV/m at a distance of d = 3 km
(E = Q / (d^2 * 4*pi*eps_0)
eps_0 being the vacuum permittivity of 8.8541878176*10^-12 F/m)
- which is stronger by a factor of 100 than the values actually observed
in thunderstorm clouds.

As a conclusion, I believe that electrostatic force can be neglected
when compared to gravity, and even more the vertical winds in a
cumulonimbus, where updrafts commonly reach 30 m/s and more.

Falk

"Falk Tannhäuser" wrote
...
Rodney Blackall schrieb:
In article , Szczepan Bialek
wrote:
Anyway, since cloud and ground are oppositely charged (otherwise you
would not get discharges in the form of C-G lightning),
and C-C lightning shows charge varies within and between clouds

Right, the lower part of the cloud is negatively charged, while the
(usually anvil-shaped) summit carries positive charge. A small zone of
positive charge is also often observed at the cloud base where the rain
falls out.

The ground and clouds are both negatively charged (exces of electrons).
Different is the voltage.
So where are the positive charges?

Due to electrostatic induction, the area on the ground lying directly
below the negatively-charged cloud gets positively charged, leading to a
reversal of the usual fair-weather field.

Are you sure? It would mean that the technical grounding is not zero under a
cloud. When electrons are in clouds the field is reversal.

Hence the negative C-G lightning actually increases the net negative
charge of the earth. Thunderstorms effectively act as generators - without
them, fair-weather current would soon make disappear the difference of
potential between ground and atmosphere.
Note that positive C-G lightning also occurs, but is considerably rarer
than negative one.

I have read that they start from place where the normal lightning has stroke
(in the same moment) . So they are C-C.

Typically it originates from the cloud's anvil and strikes a place on the
ground that is peripheral to the thunderstorm (and thus negatively
charged). It is more often found during dissipating storms (where the lower
cloud parts often disappear first) or in winter thunderstorms (when the
cloud summits are lower).
Typical field strengths are on the order of magnitude of E = 10 kV/m
between ground and cloud, and 100 kV/m within the cloud. For comparison,
fair-weather field strength is about 0.15 kV/m near to ground level.

Concerning gravitational and electrostatic forces:
Consider a spheric rain droplet of a mass of m = 1 mg.
(It has a volume of V = 1 mm^3 and hence a diameter of 1.24 mm, since V =
4/3*pi*r^3 - not an unreasonable size).
Its weight (force exercised by gravitation) is m*g = 9.81*10^-6 N
(with g = 9.81 m/s^2).
The electrostatic force equals q*E where q is the charge of the droplet.
If electrostatic force is supposed to prevent our droplet from falling
down, it has to compensate the gravitational force. Then we can calculate
the charge needed for this. If we set E = 100 kV/m = 100 kN/C,
we obtain that our droplet has to have a charge of 9.81*10^-11 C.
This would mean 1.02*10^10 such droplets (corresponding to 10.2 m^3 of
water) would carry an aggregate charge of 1 Coulomb.
Now we let's consider that we may find about 100000 m^3 of water in a
small thunderstorm cloud (just to get an idea of the order of magnitude -
this would correspond to 10 mm of precipitation over 10 km^2, note however
that only a part of the water in the cloud finally makes it to the earth
as precipitation). The aggregate charge of this mass of water would then
equal to 10000 C - a value that seems much to high to me! Average
lightnings transport a charge of less than 10 C - furthermore, a punctual
charge of Q = 10000 C would produce a field of about
E = 10 MV/m at a distance of d = 3 km
(E = Q / (d^2 * 4*pi*eps_0)
eps_0 being the vacuum permittivity of 8.8541878176*10^-12 F/m)
- which is stronger by a factor of 100 than the values actually observed
in thunderstorm clouds.

Excelent job. Calculate now how many of the water particles (H2O) can one
electron lift when E = 0.15 kV/m. It will be something as cross-examining.
Not the all electrons fall down in form of lightnings. The most as the
normal electric current.

As a conclusion, I believe that electrostatic force can be neglected when
compared to gravity, and even more the vertical winds in a cumulonimbus,
where updrafts commonly reach 30 m/s and more.

Here is not place for "believe". The calculations should be done.
S*





Falk

Szczepan Bialek schrieb:
"Falk Tannhäuser" wrote
...
Due to electrostatic induction, the area on the ground lying directly
below the negatively-charged cloud gets positively charged, leading to a
reversal of the usual fair-weather field.

Are you sure? It would mean that the technical grounding is not zero under a
cloud. When electrons are in clouds the field is reversal.

Yep - that's http://en.wikipedia.org/wiki/Electrostatic_induction. It
occurs because the Earth is quite a good conductor.

I found some interesting web sites about thunderstorm charge distribution:
http://www.britannica.com/eb/art-19731/Electrical-charge-distribution-in-a-thunderstorm-When-the-electrical-charge
or http://minilien.fr/a0khcv (one can see that ground charge is
negative under the small centre of positive charge at the rain cloud
base and positive under the (negatively charged) remaining part of the
cloud base - the negative ground charge in fair-weather conditions is
not depicted.
http://scf-cfs.rncan-nrcan.gc.ca/index/lightning-faq/3 shows a similar
picture and even gives examples of observed electrical charges:
__________________________________________________ ______________________
"The three centres of accumulated charge are commonly labeled p, N, and
P. The upper positive centre, P, occupies the top half of the cloud. The
negative charge region, N, is located in the middle of the cloud. The
lowest centre, p, is a weak, positively charged center at the cloud
base. The N and the P regions have approximately the same charge,
creating the positive dipole. Malan (1963) documented charges and
altitudes above ground level for the p, N, and P regions of a typical
South African thundercloud (1.8 km above sea level) as +10 coulombs (C)
at 2 km, -40 C at 5 km, and +40 C at 10 km. These are representative of
values that can vary considerably with geography and from cloud to cloud."
__________________________________________________ ______________________

Hence the negative C-G lightning actually increases the net negative
charge of the earth. Thunderstorms effectively act as generators - without
them, fair-weather current would soon make disappear the difference of
potential between ground and atmosphere.
Note that positive C-G lightning also occurs, but is considerably rarer
than negative one.

I have read that they start from place where the normal lightning has stroke
(in the same moment) . So they are C-C.

C-C between the positive anvil and negative cloud centre as well as the
negative cloud centre and the positive rain base do happen, of course.
However, positive C-G can occur independently.

Typically it originates from the cloud's anvil and strikes a place on the
ground that is peripheral to the thunderstorm (and thus negatively
charged). It is more often found during dissipating storms (where the lower
cloud parts often disappear first) or in winter thunderstorms (when the
cloud summits are lower).
Typical field strengths are on the order of magnitude of E = 10 kV/m
between ground and cloud, and 100 kV/m within the cloud. For comparison,
fair-weather field strength is about 0.15 kV/m near to ground level.

Concerning gravitational and electrostatic forces:
Consider a spheric rain droplet of a mass of m = 1 mg.
(It has a volume of V = 1 mm^3 and hence a diameter of 1.24 mm, since V =
4/3*pi*r^3 - not an unreasonable size).
Its weight (force exercised by gravitation) is m*g = 9.81*10^-6 N
(with g = 9.81 m/s^2).
The electrostatic force equals q*E where q is the charge of the droplet.
If electrostatic force is supposed to prevent our droplet from falling
down, it has to compensate the gravitational force. Then we can calculate
the charge needed for this. If we set E = 100 kV/m = 100 kN/C,
we obtain that our droplet has to have a charge of 9.81*10^-11 C.
This would mean 1.02*10^10 such droplets (corresponding to 10.2 m^3 of
water) would carry an aggregate charge of 1 Coulomb.
Now we let's consider that we may find about 100000 m^3 of water in a
small thunderstorm cloud (just to get an idea of the order of magnitude -
this would correspond to 10 mm of precipitation over 10 km^2, note however
that only a part of the water in the cloud finally makes it to the earth
as precipitation). The aggregate charge of this mass of water would then
equal to 10000 C - a value that seems much to high to me! Average
lightnings transport a charge of less than 10 C - furthermore, a punctual
charge of Q = 10000 C would produce a field of about
E = 10 MV/m at a distance of d = 3 km
(E = Q / (d^2 * 4*pi*eps_0)
eps_0 being the vacuum permittivity of 8.8541878176*10^-12 F/m)
- which is stronger by a factor of 100 than the values actually observed
in thunderstorm clouds.

Excelent job. Calculate now how many of the water particles (H2O) can one
electron lift when E = 0.15 kV/m. It will be something as cross-examining.
Not the all electrons fall down in form of lightnings. The most as the
normal electric current.

Water has a molar mass of 18 g/mol and with the Avogadro constant of
6.022*10^23/mol we obtain the molecule's mass of 2.99*10^-26 kg and a
weight of 2.93*10^-25 N.
OTOH an electron has a charge of 1.602*10^-19 C and experiences an
electrostatic force of 2.403*10^-17 N in a field of 150 V/m. That's the
weight of 82 million water molecules!

However, 100 C gives only 6.24*10^20 electrons while in 100000 m^3 of
water there are 3.34*10^33 molecules - a ratio of 5.35*10^12

As a conclusion, I believe that electrostatic force can be neglected when
compared to gravity, and even more the vertical winds in a cumulonimbus,
where updrafts commonly reach 30 m/s and more.

Here is not place for "believe". The calculations should be done.

Well, when I wrote "believe", it was because I based myself on
simplifying assumptions (punctual charge at a distance of 3 km, instead
of charge continuously distributed within the cloud as in reality) and
guesstimating (quantity of water in the cloud). And of course, all
clouds are different! A better model for charge distribution between the
negative cloud centre and the positive anvil would perhaps have been a
plate capacitor. However, as the text form the website I cited above
shows, my estimation was not that far from the truth - typical charges
in a cumulonimbus are of an order of magnitude closer to 100 C rather
than 10000 C. Split this charge among droplets (or calculate the ratio
of water molecules per electron), and you'll see that resulting
electrostatic force is pretty weak compared to gravity.