Just what was that on the Huntsville radar

Huntsville NWS radar from Tuesday

On Tuesday, a bright blob appeared on the Huntsville NWS radar and stayed in the same spot for 9 hours.
Obviously it wasn't a thunderstorm because the bright red stayed there with no movement for such a long period.
It wasn't ground clutter because even that return will change with time.
There were lots of theories on what it could be...

Bats: sometimes millions of bats show up on radars as they come out but it would only be for a for minutes on the radar. No bats.

It was not smoke or dust.

It was not the 1,000 ladybugs released by the Huntsville Botanical Garden to fight aphids...  :)

Since the blob was centered over the Redstone Arsenal which is just southwest of Huntsville, most figured they had something to do with it.

Although there has not been official confirmation from Redstone, it looks like the culprit was chaff.  A test of radar jamming chaff particles was shot up into the sky and hung suspended there for hours. Although the chaff will usually drift with the wind, in this case it remained in the same area. Evidently there was a continuous release of the chaff for hours. Small fiberglass particles were found on the ground surrounding Redstone so this is the current theory.