Right Now! Midwest radar showing strange returns

just go to the page with the image of the blob and there is a pull down in the upper right....you can get the loop there

[edit on 25-9-2004 by kessel]

The NOAA doppler is broken. All those signatures are center over the doppler stations and are not showing on any other doppler or other instruments. This is a computer issue.

Yes,

we have a few clouds over Chicago right now...

...but there's nothing like the big blob on the radar (and certainly no rain). The TV has been flickering like it does in a really bad thunder storm... but there has been no storm.

I often check the same site at work to see what the weather will be like on the way home. I have never seen a Doppler echo that is nearly as big or stationary. This caught my attention because it seems so strange.

What am I implying? I simply don't know. All that I know is that there are extremely weird radar returns over midwestern cities right now... and that these weird returns suddenly appeared in nearly circular formations.

In my opinion, it looks like a big storm front that is cutting across the US from the south to the northeast, following the Mississippi river valley. The reason that the radars are showing circles, is that the storm front is bigger then the range on each individual radar.

That is just my guess. I know nothing about meteorology, and only a little about radar.

Howdy...check the humidity index for each area, I bet it's high. Humidity is known to get picked up on radar, when "thick" enough. They are calling for fog here later on (Cols. OH) Got fog yet? I expect to see those blobs form here, before too long. Peace.

That would be plausible, IF 2 people hadn't said the sky is clear with stars showing xcept for a cloud here and there.

The one thing I find weird is he is getting weird reception, which wouldn't come with a computer error at a weather station.

Originally posted by Quest
The NOAA doppler is broken. All those signatures are center over the doppler stations and are not showing on any other doppler or other instruments. This is a computer issue.

Hmmnnn,
So a single error in the Doppler system can cause errors to show up across the country? I want to believe your explanation, but I have a few questions:

1) What could cause an error like this? What kind of computer error creates so many false signals?
2)Could the Doppler system make such an error after being affected from something outside the system? That is, could this error be caused by something influencing the Doppler system?
3) Is there anything that could cause this error and also cause the bizarre TV static that made this first catch my attention?
4)If it was just a glitch, how could some of the 'blops' formed by the glitch appear to jump between cities?

Though I agree that the rational explanation is that this is a computer error... I'm trying to figure out what kind of error could cause all of this to happen at once.

Moisture in the air can and does mess up reception. Lots o' water mixed with tv waves. ZZZtt.

Originally posted by Der Kapitan
Moisture in the air can and does mess up reception. Lots o' water mixed with tv waves. ZZZtt.

Yeah, but it's reasonably dry in Chicago right now.

To describe the weather here right now... we have broken clouds above us, the moon is showing, and it hasn't rained... nor does the air feel damp or humid. The clouds are thin and flat... and very wispy.

wind is picking up here, the clouds are moving in. The clouds seem to be a lot of little clouds bunched together almost a spiderweb look. The glow from the moon shows the edges in the dark sky.

This is a link to the weather page of a different Chicago station:
abclocal.go.com...
The main page doesn't show the Chicago 'blob'... But if you click on the link to the left for the Doppler image you get a picture of the same blob as seen in the NBC5 link. The only difference is that it appears to be slowly rotating.
Take that as you will. I'm pretty sure that each of these station has their own doppler radar because they announced their acquisition of Doppler radars at different times... that is, I don't think these returns are from the same radar.

Originally posted by onlyinmydreams

Doppler image you get a picture of the same blob as seen in the NBC5 link. The only difference is that it appears to be slowly rotating

Ok, that is weird, especially if the light circle is the range. Sometimes they pick up ground clutter that makes a circle around the center, but not like that, and certainly not at multiple stations at once.

Can someone save that radar loop?
I don�t know how to do it, nor do I have to space on ATS to save it.

Why don�t one of you guys call your local news station and see what their weather department has to say?

Originally posted by antipigopolist

They are in Clear Air Mode...the "green" gauge (dBZ values from -28 to +28) has nothing to do with precipitation. Follow the link or remain in the dark!

[edit on 25-9-2004 by antipigopolist]

Is it normal for a group of stations to all do that at one time?

From Anti's link:

"The dBZ values increase as the strength of the signal returned to the radar increases. Each reflectivity image you see includes one of two color scales. One scale (far left) represents dBZ values when the radar is in clear air mode (dBZ values from -28 to +28). The other scale (near left) represents dBZ values when the radar is in precipitation mode (dBZ values from 5 to 75). Notice the color on each scale remains the same in both operational modes, only the values change. The value of the dBZ depends upon the mode the radar is in at the time the image was created."

Ok... so they have possibly switched to a more sensitive mode. Why would they do this if the data was being presented to the public as an indicator of current weather conditions (wouldn't that be a switch you would want to indicate?) and why, even if you were seeing an image that was a more sensitive picture of what was going on, would this still be centered on the middle of a city?

If I understand the link correctly, Anti is saying that they switched to a level where smaller returns are portaryed as larger ones because the whole system is being more sensitive. So... wouldn't whatever is being returned still not resemble a circle? Wouldn't it look like a normal weather front instead?

I know this isn't the radar rings we saw in the past, but it reminded me of it.

If you notice in this old picture of the radar ring over arizona, you will see there are also round cloud like areas in many places.

Originally posted by onlyinmydreams

would this still be centered on the middle of a city?

I am going to guess that it is going to pick up smog over the city. Still it�s interesting, I have never seen that before. I guess you learn something new everyday.

Thanks for the links antipigopolist

Still wonder why his TV has bad reception

Yeah, thanks for the links Anti,

But I still don't understand one thing: Someone linked to a national picture that showed hurricane related weather in the southeast at the same time that it portrayed the drier weather in the midwest. What would the point be of showing a composite picture that was composed of images from two different scales?

In those national pictures we saw the blobs over major midwestern cities at the same time that the hurricanes off of Florida were portrayed. The hurricanes are obviously real, moving storms. ...It doesn't really seem to make sense to create a national weather image that makes use of two different scales at the same time.

It wouldn't be that it is just because the dopler radar receptors are just located around big cities would it?
.