From what I can determine for a foreign financial account for which you have signature authority, you do not need to file Form 8938 unless you have an interest in the account, however you will need to file an FBAR if the account exceeds the $10,000 at any time during the calendar year.
For the FBAR Signature authority: you have authority to control the disposition of the assets in the account by direct communication with the financial institution maintaining the account.
