I was browsing the NEXRAD radar feeds (I'm not an expert, just figuring them out) and I came across the following signature (visit the link to view the radar image)


The radar in question was operating in clear air mode and the "ray" varies from about 0-16 dBZ. There were several of these all covering the Midwest, and I picked up one as far west as Kansas, at about the same return signal strength. Further west they weren't visible.

Could this be caused by a cosmic phenomenon?


I'm tracking it across the United States right now. I'll be following it below with updates.

  • 9:16 PM: appears on KIND Indianapolis composite reflectivity
  • 9:30 PM: appears on KSGF Springfield base tilt 1 and 2, KICT Wichita base tilt 2
  • 9:31 PM: updated KSGF now shows only on base tilt 1, not 2
  • 9:34 PM: now appears only on KICT Wichita base tilt 3? This doesn't make sense if it's a "stationary" cosmic object, that would mean it should be shifting to lower tilts. Might just be an outlier
  • 9:37 PM: visible now on KDDC Dodge City base tilt 4, KICT tilts 2 and 3. Also now appears on KAMA Amarillo base tilts 4 and 3 (weaker on 3)
  • 9:43 PM: visible on KICT base tilt 2 only

1 Answer 1


It most likely is a cosmic phenomenon more commonly known under the name "sunrise".

Quoting this page http://www.bom.gov.au/australia/radar/about/radarfaq.shtml)

"Near sunrise and sunset the radar antenna momentarily scans the sun. On occasions this can be seen as a pencil line radiating out from the centre of the image in the direction of the sun."

I didn't check the times and geography but that would seem to explain why you can track it around stations.

  • $\begingroup$ It's certainly possible. I checked the sun's angle against the radar locations at one point and I didn't think it was within the tilt angles at those times, but it does seem like the most likely source. Unless I made a mistake calculating the angles… I was in a bit of a hurry. ;) $\endgroup$
    – jfm429
    Jun 6, 2012 at 6:18

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