On 7/27/06, Mark Endicott <mark@nashvilletn.org> wrote:
> This brings up a question. Our local NWS weather station recently upgraded
> to a new radar system. Since the new equipment has been installed they
> appear to shut it down when there is a threat of lightning. It seems to me
> that it would only be of use when the thunderstorms are in our area, we can
> look out the window and tell when it's clear. Is there something I am
> missing?
Mark,
The national radar network of WSR-88D Doppler radars has been in
operation for quite a few years now. I'm uncertain as to when the
Nashville radar was installed but the one here in Dodge City was
installied in 1991 - 15 years ago. Of course, internet communication
was in its infancy then so the public didn't get to "see" data from
the radars until the past 5 years or so. There is a lot of information
on the radars at:
http://www.srh.noaa.gov/radar/radinfo/radinfo.html
You will see that even in the "Clear Air Mode" of operation,
meteorologists are able to see many things that are going on in the
atmosphere which would otherwise be invisible. So, the radar is
actually quite useful even when there are no thunderstorms around. We
are able to use it to track fronts, outflow systems, convective
initiation (incipient thunderstorms), gravity waves...etc.
Now as to why the Nashville radar would be shut down.....
These radars are protected by a UPS (Uninteruptable Power Supply)
which is a huge bank of batteries that will run the radar for about 5
minutes - about the length of time it takes to switch from unstable
legacy power (the public grid) to generator backup power for the
radar.
A sudden power surge does horrible damage to one of these radars and
must be avoided at all cost.
Given this, these radars are seldom if ever shut down. What you are
probably loosing is the internet data feed from the radar. Rest
assured that a qualified professional is pouring over the complicated
data sets from the radar (its not just pictures of rainfall, you
know!) at all times looking for tell-tale signatures of severe storms.
The best place to get your radar data is from the National Weather
Service web page at:
http://tinyurl.com/hldw2
If this image is not current (circa 10 minutes old) then there is a
problem getting the radar data to the server, or a problem with
bandwidth (more people than the bandwidth can support trying to see
the data at the same time). Unfortunately, the NWS has taken some huge
budget hits courtesy of congress this past year so we don't have the
equipment and communications to do much better than this.
Bug your senator and congressman about getting some decent funding to
the NWS ;-)
Hope this helps...
Cheers!!
Jim
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