OT Weather radar

  • Thread starter Thread starter John Doe
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KR said:
John Doe <jdoe usenetlove.invalid> wrote:

Nice !
Click to expand...

Once it's configured, the path Map -- Play animates the most
recent radar images.

You can make the background black. Except for the small strip of
radar locations listed on the left, radar can fill nearly the
entire screen. I sometimes keep it on for a while before leaving
home, to get an idea of if and how rain is moving in the area.
Also when serious storms are in the area (unless there is serious
lightning). At least once, I have used my ultraportable personal
computer with its wireless hotspot connection during an outrageous
storm, hail like we had never seen (or heard) before. So I was
able to see the monster moving out of the area.

Depending on the radar location(s) you have displayed... You can
see bats coming out of their caves, around sunset. Looks like
smoke rings. The only other unusual display that I've noticed is
what sometimes looks like waves preceding (going before) rain
masses. Looks like small ocean waves overlapping each other as
they move onto a beach. I was told they are downward moving air
masses, or something like that.
 
Another thing you'll notice is when they turn up radar
sensitivity. You will see lots of dusty looking stuff that's not
rain. And it usually doesn't move much. I think they turn up the
sensitivity so that they can see more, so that they can tell
what's going to happen. But probably only when there is no rain
in the area.
 
John said:
Another thing you'll notice is when they turn up radar
sensitivity. You will see lots of dusty looking stuff that's not
rain. And it usually doesn't move much. I think they turn up the
sensitivity so that they can see more, so that they can tell
what's going to happen. But probably only when there is no rain
in the area.
Click to expand...

It's probably Doppler Radar like our national weather service uses.

It's supposed to sense rain moving in the sky, at a certain height.
There is something called "virga rain", which is a rain which falls
but evaporates before hitting the ground. If you have some of that,
the Doppler radar picks up the rain at 10,000 feet, but then if
you're walking down the street, you get nothing. We get that occasionally
here. (I wouldn't have known this, except the local TV weather
forecaster mentions it ahead of time when it's going to happen.)

If you have high altitude cloud structure, like thunderheads to 40,000
feet, this sometimes shows up on Doppler radar as strange reflections.
You might see a cone shaped artifact on the plot, or a "circle of dust"
on the plot. And that's a thunderhead moving near the radar station.
Or lots and lots of high altitude cloud (which you can verify with
the satellite view of your area).

The plot sensitivity has to be adjusted, and pretty carefully. Our system
used to have occasional problems with that, and the plot would show
drizzle, when in fact it was cloudy but dry. Whatever they've done with
the software, it's better than it used to be. At one time, our plot used
to show the "threshold" setting the software used. They've removed that
now, so there's no annotation for the setting being used (because
now it "just works").

The only kind of weather it doesn't help with, is "popup thunderstorms",
which look like popcorn which grows out of nothing. You can have a clear
screen, have a weather forecast of possible thunderstorms, and see
nothing on the plot. And then nuclei form on the screen and they grow.
If I go out for exercise, that's the time I get soaked :-) Come back
and look at that screen, and it's full of cells moving through the
area. Most other kinds of rain, you can see the structures ahead of time.

Paul
 
Paul said:
John Doe wrote:

It's probably Doppler Radar like our national weather service
uses.
Click to expand...

I think they get it from the National Weather Service website here
in the US. There are over 50 choices for output on the PC version.
Fewer on my iPhone. Stuff like "base reflectivity" "base velocity"
"specific differential phase" and so on. They all produce
different displays for the weather. The trick is to figure out
which Greek term best lets you know when there's rain in the area.
It's supposed to sense rain moving in the sky, at a certain
height. There is something called "virga rain", which is a rain
which falls but evaporates before hitting the ground. If you
have some of that, the Doppler radar picks up the rain at 10,000
feet, but then if you're walking down the street, you get
nothing. We get that occasionally here. (I wouldn't have known
this, except the local TV weather forecaster mentions it ahead
of time when it's going to happen.)

If you have high altitude cloud structure, like thunderheads to
40,000 feet, this sometimes shows up on Doppler radar as strange
reflections. You might see a cone shaped artifact on the plot,
or a "circle of dust" on the plot. And that's a thunderhead
moving near the radar station. Or lots and lots of high altitude
cloud (which you can verify with the satellite view of your
area).

The plot sensitivity has to be adjusted, and pretty carefully.
Our system used to have occasional problems with that, and the
plot would show drizzle, when in fact it was cloudy but dry.
Whatever they've done with the software, it's better than it
used to be. At one time, our plot used to show the "threshold"
setting the software used. They've removed that now, so there's
no annotation for the setting being used (because now it "just
works").
Click to expand...

What I'm talking about is a switch. When there is no rain in the
area, they hit a switch that greatly increases radar sensitivity.
I think it's controllable on each individual radar tower.
The only kind of weather it doesn't help with, is "popup
thunderstorms", which look like popcorn which grows out of
nothing. You can have a clear screen, have a weather forecast of
possible thunderstorms, and see nothing on the plot. And then
nuclei form on the screen and they grow. If I go out for
exercise, that's the time I get soaked :-) Come back and look at
that screen, and it's full of cells moving through the area.
Most other kinds of rain, you can see the structures ahead of
time.
Click to expand...

Fortunately, rain materializing overhead is unusual. As it moves,
it does change shape and it increases or decreases in intensity.

I had the program going before that monster hailstorm hit us a
year ago. As it approached, the storm was increasing, but I had no
idea it was going to drop golf ball size hail on us. I don't think
anybody knew that monster was coming. Roofers made a fortune.

--
 
I think they get it from the National Weather Service website here
in the US. There are over 50 choices for output on the PC version.
Fewer on my iPhone. Stuff like "base reflectivity" "base velocity"
"specific differential phase" and so on. They all produce
different displays for the weather. The trick is to figure out
which Greek term best lets you know when there's rain in the area.












What I'm talking about is a switch. When there is no rain in the
area, they hit a switch that greatly increases radar sensitivity.
I think it's controllable on each individual radar tower.


Fortunately, rain materializing overhead is unusual. As it moves,
it does change shape and it increases or decreases in intensity.

I had the program going before that monster hailstorm hit us a
year ago. As it approached, the storm was increasing, but I had no
idea it was going to drop golf ball size hail on us. I don't think
anybody knew that monster was coming. Roofers made a fortune.
Click to expand...


Vaguely remember in the early 1970's when we got hit by hailstones
about 6" diameter. A lot of people had the old fibro/asbestos
sheeting that shattered and it just went straight through, then
through the ceiling (which often was made of the same stuff). The
only safe place was under the bed, as the mattress would take most of
the impact.
Was no real warning back then, except the sky turned a funny green
before it happened.

The good old corrugated iron roof held up a lot better, though lots of
dents, some splits and small holes.

Roofers did make a fortune, as did panelbeaters.
 
Once it's configured, the path Map -- Play animates the most
recent radar images.

You can make the background black. Except for the small strip of
radar locations listed on the left, radar can fill nearly the
entire screen. I sometimes keep it on for a while before leaving
home, to get an idea of if and how rain is moving in the area.
Also when serious storms are in the area (unless there is serious
lightning). At least once, I have used my ultraportable personal
computer with its wireless hotspot connection during an outrageous
storm, hail like we had never seen (or heard) before. So I was
able to see the monster moving out of the area.

Depending on the radar location(s) you have displayed... You can
see bats coming out of their caves, around sunset. Looks like
smoke rings. The only other unusual display that I've noticed is
what sometimes looks like waves preceding (going before) rain
masses. Looks like small ocean waves overlapping each other as
they move onto a beach. I was told they are downward moving air
masses, or something like that.
Click to expand...


They have one here, that has been in use for many years, and is very
useful, though it only does rainfall. Your comments above explain
why we
occasionally see light rain when there is nothing there.

http://www.bom.gov.au/products/IDR083.loop.shtml


The radar is on a mountain near the small town of Theebine, where you
can see the installation.

The radar installation looks like a giant golf ball on a tower, but
the round dome is actually an enclosure for a rotating parabolic dish
inside.

From memory it is a doppler system.
 
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