"Wyatt Emmerich" wrote:
Why the huge contrast between the on-board and the Nexrad return?
Perhaps the Nexrad was picking up water far above me, while the
on-board was looking ahead (I was at 5,000.)

Perhaps, but I have seen persistant false weather depictions on my
WxWorks NEXRAD display a couple of times.
--
Dan
C172RG at BFM