Emergency alerts: is there any way to silence the "severe threat alerts" and "Amber Alerts" while I'm sleeping? There are some emergency alerts I would be very grateful to receive even when I'm sleeping, but so far I've only receive alerts for things that didn't actually put me in danger or for things that I could literally do nothing to help with until I woke up the next day.  

I would like the emergency broadcasts to be silenced at night, specifically the ones in the categories "Show severe threats" and "Show AMBER alerts."  I would still like to receive these alerts (so I can do something about them in the morning if I need to), just without any sound, and just for the period while I'm sleeping.  Additionally, I would prefer to still have "Show extreme threats" and "Presidential alerts" sound at night if it is possible.

I know this is a fairly specific order and in all my searching on this subject I have found no way to silence the emergency alerts without unsubscribing from them altogether, so I don't know if this is currently possible.  But that's why I came here, to ask if there's something I've missed so far.

Please note: I am talking about the emergency broadcasts you access through "Settings," rather than the feature available in "Google Now" I've seen floating around this website.

Phone info:   model: Moto G   Android version: 5.0.2
In the Emergency Alerts stock app -> Settings, there is an option "Emergency alert tone" with subtitle "Play a sample emergency alert tone."  When you do this, it plays the tone and a dialog says "The sound you hear now will be played when you receive an emergency alert.  The alert volume matches your phone's volume."  This indicates that you could avoid the alert sounding when you are asleep simply by silencing the phone when you go to sleep (or using an app to change the volume on a schedule).  

This doesn't discriminate between different classes of alerts (e.g. make sound for some but not others); if there's an app for that (probably is) someone else can post that as an answer.