Hi, I was wondering if anyone else heard/Has any knowledge they can share. I have heard what i can only describe as air raid sirens being activated today in NE Philadelphia, One set around noon and one around 1645 hours. Both sets sounded like an air raid siren being activated and then deactivated within a few seconds but done three times like that. If anyone could help id appreciate it. Id just like to add, That ive never heard it before around here so thats why it stood out so clearly on both occasions.