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Old June 12th 06, 08:18 AM posted to rec.aviation.ifr
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Default Garmin 396 Weather avoidance..

On 9 Jun 2006 17:04:28 -0700, "Robert M. Gary"
wrote:

I wish I had an easy answer for you. However, wx is a non-trivial
subject. There are two ways you can make use of your 396 in wx. First,
you can fly with a CFI who is experienced in flying cross country.
Second you can start out very, very conservative and learn as you go
how the wx on your 396 affects your flight.

My take on this and I've been storm chasing longer than we've had
Loran, let alone down linked RADAR. I've seen 5 tornados and one
really big water spout. I even managed to get caught outdoors along
with two of my neighbors, in a little F-1 and that can certainly raise
your sense of awareness.

The 396 has some advantages and disadvantages when compared to
airborne RADAR. Starting with the good, it does not have the blind
spots you will find from time to time in airborne RADAR caused by
absorption in heavy precipitation which can hide some nasty stuff.
OTOH if you keep in mind that the display is probably 5 minutes old or
a tad more AND you have been following it you can pick your course.

However I agree with Robert. Take a conservative approach and learn to
interpret what you are seeing on the display, how to track, and how to
predict. Learn to follow both cell and frontal movement. They are
rarely the same. Usually the cells are traveling at right angles to
the front, but NOT ALWAYS. Learn to identify upper level winds by the
rain blown off creating plumes that may or may not go in the direction
of the front or cells. You normally want to stay away from those
plumes as they may contain hail and that can be as much as 5 to 10
miles ahead of the storm at altitude. Speaking of hail and altitude,
you really don't want to run into hail in front of a cell at altitude.
It is a *lot* larger than what we see at ground level.

BTW when on the ground and in front of an approaching storm. If the
wind is blowing toward the storm that is "inflow" and a sign of a
storm with very strong convective activity.

Once you learn to determine cell movement, remember that cells can
"pop up" behind the ones you are watching. Has the storm shown a
tendency for cells to pop up along, ahead of, or behind the front. Are
the cells associated with frontal movement or a general wide spread
instability?

Knowing the storm and front movement, speed and direction along with
the knowledge the information you are seeing is at least 5 minutes old
would certainly tell me I would want to give a lot of space when
flying in front of the front or cells. OTOH Cells growing up along a
line may start to pop up on the "up wind" side of current activity.
Some times the growth of this line can be a real surprise and it can
contain some really nasty stuff.

As was said earlier. Get all the information available about the
activity and area through which you will be flying. Then use that
information along with what the RADAR is showing. A storm scope can
be really helpful in extending your "real time" knowledge of what is
going on and should be a good indicator of where those RADAR images
are headed as well as what to expect from them.

Just remember that conservative approach.

-Robert, CFI


Dan wrote:
For those of you with a Garmin 396, how do you avoid dangerous weather,
avoid yellow and steer clear of the lightning strike indications? I am


Yellow and even red may not indicate anything other than heavy rain if
it's not associated with convective activity. You learn what you are
seeing, where it is compared to the display, and where it is going.
Then stay out of its way. All this takes practice and liberal use of
FSS can help.

Good Luck,


Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com


considering the purchase of one and am wondering how to use the info
safely, but yet with the maximum utility.

Dan