"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