The right sign for "appear"
depends on your meaning.
If you mean appear as in "show up" there is a specific sign for "showing up."
SHOW-UP or "pop-up"
Note: I've seen some ASL teachers use the "pop up" sign (above) as part of the
concept of a "pop quiz." I don't have a problem with that but personally I
prefer to sign SURPRISE Q-U-I-Z instead
If you mean "appear" as in "it appears that..." then you should use the
Also see: SEEM