Total posts : 45366
Obviously, something has changed and if this is caused by the storm it may not be a problem with your FM system.
Many times hum on an FM signal results from the signal being picked up by wall wart powersupplies and due to the non-linear components inside the FM can be radiated with hum imposed.
Try unplugging wall warts around your home. Maybe one was damaged by the power surges/cycling.