I've noticed that this siren has started to act strangely over the past few weeks running in full cycles of wail or air horn. I decided to see if I could catch it on video, and sure enough it gave me a nice long blast of wail before dying. The batteries in this one were checked out back in 2015 after it started to die during a thunderstorm warning. Ironically it died in wail during the warning as well. I guess they replaced one of the batteries and left the rest. One of them appears to be kicking the bucket now.
https://www.youtube.com/watch?v=FykO9wjNc2w