Honestly don't know whether it was Center or terminal, but I suspect that it
was Center. The whole discussion was about delays. In precipitation mode,
the image is updated every 4 to 6 minutes. This link gives the NWS
explanation of NEXRAD.
http://weather.noaa.gov/radar/radinfo/radinfo.html. The WARP (Weather and
Radar Processor) system, which is the weather display at Center consoles,
suggests further delays as the radar information is processed (duh). I have
been beating the drums, writing letters to the editor, etc, to try to
eliminate the phrase "real-time weather" from articles and advertisements.
NO ONE gets real-time weather, not even the folks at the NWS radar sites.

Because the presentation was by the Air Safety Foundation, you might find
more info on their web site.

Bob


"Ronnie" wrote in message
. com...
Bob,

Was this a center or approach control facility and more
specifically, was the weather info display primary or
NEXRAD? If NEXRAD, did they discuss the amount
of delay in the weather info on the controller's display? I'm
wondering if it is significantly shorter? I know the satellite
broadcast distribution adds some additional delay, but as I
undersrand it, NEXRAD radar systems take a few minutes
to build the composite view from several sweeps. Point is,
the controller's display may be a few minutes old as well.

Also, as you point out, the weather chances quickly and
the radar is only showing precip. Thus, it is not showing
the radid air currents of a developing storm. Until you have
experienced being sucked up into a radily developing convective
storm by flying through an area that your StrikeFinder and ATC
agreed was the best path, you don't fully appreciate how danerous
this type of weather can be.

I second your recommendation to stay well clear of this type of
weather.

Ronnie


"Bob Gardner" wrote in message
. ..
The first thing you need to understand is that the weather you see on the
396 is several minutes old...possibly as much as eleven minutes. So you
need to watch the display and figure out which way the echoes are going,
and plan on passing them on the upwind side. Then you need to realize
that radar reflects only decent size rain droplets, not vertical
currents, not the tops of clouds, not turbulence. Bottom line is: Stay
well clear of anything green...yellow and red go without saying. If you
have to get into the green, make the incursion as short as possible.

Saw a revealing presentation at a NATCA controller's conference. They
showed a slide with several large cells being displayed, and indicated
the position of a 172 when the scenario began. The pilot told the
controller that if he could have a certain heading, he would be clear of
the cell he saw on his screen and could proceed to his destination.
Unfortunately, by the time he got to the geographical area which was nice
and clear on his cockpit display at the time he asked for the heading,
the cell had moved directly into his path with predictable results. The
message to the controllers in attendance was "What the pilot sees in the
cockpit and real life are two different things."

Bob Gardner

"Dan" wrote in message
oups.com...

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

Dan