Sadly this is a common situation. They appear to hold off making any public notice (including often on their own "service dashboards") until support forums are screaming with upset users.

Google App Engine has had numerous outages like this, the only one I can find any public documentation for being a 6 hour outage in 2012: http://googleappengine.blogspot.co.uk/2012/10/about-todays-a... (and let's not forget the old-style Datastore corruption incident, where every App Engine user got to manually merge split-brain database tables after a messed up failover)