"Jim Burns" wrote in message
...
Sami, you've hit upon the answer to your question, and one thing to keep
in
mind is that radar don't know squat about whether the rain is from a
thunderstorm or not, all it sees is the "reflection" of the precip, the
higher the number, the higher the bounce back. Granted, a thunderstorm
that
is full of rain and hail will definately produce a higher return.
Additional information about the current conditions vs. forecast
conditions
combined with front locations, movement, direction, sigmets, and airmets
should provide you with a more complete picture of what your Data Link is
showing you.

Over the past couple weeks, we've had two totally different low pressure
systems move through Wisconsin. The first contained a leading edge of
thunderstorms, high winds and heavy rain. The last contained high winds,
heavy rain, but no thunderstorms. The echoes for both storms were level
2's
and 3's. The difference between the two storms was the amount of lifting
action available. The first storm occurred during a period of relatively
hot and unstable conditions. The second occurred during cool and more
stable conditions, it was much less violent but the radar returns were the
same.

Jim Burns

Yes, the real issue is that it takes vertical motion to get the droplets to
coalesce together to procduce larger drops with higher reflectivity. If you
have little moisture, it takes more vertical motion to get the same radar
echo, hence the rule of thumb that the storm intensity for a given
reflectivity goes up with decreasing availible moisture. Radar is about
probablilities-a particular echo intensity has a particular probablility of
producing a given level of turbulence, hail ect.

Mike
MU-2