You can only suppress messages of severity 4 or less.
SUPRWARN
Suppresses the specified message numbers.
NOSUPRWARN
Reverses the action of SUPRWARN and allows the specified
message numbers to be displayed.
msgnum
1-4 digit message number.
If you specify an invalid message number, message ASMA318W is
issued. If you specify a message number with a severity higher than 4,
message ASMA319W is issued.