[GreenKeys] ZZZZ or ZCZC?

[Jim Haynes]

Now that I have looked at the actual message - the first message is seen
to begin with ZCZC and then the ZZZZ line is a few lines down, which is
about where the precedence should be.  The second message may have had
the beginning with the ZCZC stripped off.   Well maybe the weather service
does use ZZZZ to indicate a very high precedence message - certainly a
warning of an imminent tornado should be of high precedence.