WRAL WeatherCenter Blog

Still a mystery

Posted January 7, 2011 4:28 p.m. EST

Yesterday, we brought you our meteorological mystery, a series of interesting echoes on the DUALDoppler5000.  Our initial suspicion was that it might have been a flock of birds that had been scared into flying off from a resting spot all at once.  A number of you commented, suggesting variations of the same: buzzards from cell phone towers or gulls from the landfill.  All were plausible explanations, but there was nothing that exactly matched the data we saw, so we couldn't draw any hard conclusions.

After scratching our heads, we asked Dr. Sandra Yuter, an NC State meteorology professor and expert in radar and other "remote sensing" tools, to take a look at the data.  After a preliminary assessment, she and some of her graduate students were able to rule some things out, including:

  • Birds ("It is... certainly not vultures")
  • A steam cloud
  • Anomalous propagation (what you might hear referred to on TV as "ground clutter"; although, that's not exactly correct)
  • Second trip echoes (returns from objects beyond a radar's nominal range)
  • Something related to the Shearon-Harris plant

Even with those things ruled out — including the rather popular theories about birds, buzzards, and vultures — the source of these interesting radar returns remains a mystery.  "So far every hypothesis we have come up with is inconsistent with the data," she wrote in an email this afternoon.  She and her group were not giving up on the mystery yet, and neither are we.

If it's not birds, what else might it be?