Purple Rain Radar Signature?

[silhouex]

Hey folks, 
been using the lightningmaps site for a few years now. However just tonight I saw a large purple "cloud". I've never seen this before is this a really thick cloud? Noteable the image vanished in the few minutes it took me to discover this forum. Clouds don't just vanish right? I'm pretty sure this was somewhere over the southwestern states. 
I should point out that this was at night. I know weather radar isn't as reliable at night. Also, not saying it was but the purple cloud had a shape you would expect from a splash or an explosion. 

 Are their any other colors I might see other than green, yellow, red, pink and white?
Is there a "legend" somewhere for the lightningmaps site? 

Thank you all for your replies.

edit: Interestingly the same thing happened in the same general region, tonight. I managed to get a screen shot before it disappeared. Leaning more towards some kind of error?

edit 2: Added 2nd image showing the same place moments after posting. The signature is gone again.

[kevinmcc]

Is this the thread you were talking about?

https://forum.blitzortung.org/showthread.php?tid=1689

Most colors come from sun light refraction or from lightning causing ionization or light refaction due to what is in the air.

I don't remember any discussion here about that.

[mwaters]

Are you talking about rain Doppler weather radar, or something you saw up in the sky? I assumed the former.

Purple in the Doppler weather radar on TV here signifies a very strong storm, possibly producing hail.

[silhouex]

Are you talking about rain radar, or something you saw up in the sky? I assume the former.

Purple in the rain radar here signifies a very strong storm, possibly producing hail.

Happened yet again and in seemingly the same place. Same area for sure. This is exactly what I saw.

[nerd65]

Looks like radar interference to me.

[dupreezd]

Are you talking about rain radar, or something you saw up in the sky? I assume the former.

Purple in the rain radar here signifies a very strong storm, possibly producing hail.

Happened yet again and in seemingly the same place. Same area for sure. This is exactly what I saw.

This might explain what you saw and why, a "cool" vs "hot" radar.
https://www.weather.gov/jetstream/radarprecip

[Jorgeminator]

It's radar interference. You can even see where the radar is.

   

A rough estimate places the radar somewhere in the vicinity of the Phoenix-Mesa Gateway Airport. Digging further, you'll find the affected radar on Google Maps right here: https://goo.gl/maps/uLUPk3fVZ9vnxPBP6