Hey Adam,
Here's how I believe you can do this:
1. First, you will want to write the lightning strikes to a local feature service if their not already. For example, if you are polling a service from NOAA for lightning strikes, set up GeoEvent to write this to a feature service in your ArcGIS Server instance. Make sure this feature service has editor tracking enabled. You will want to specify to delete features every 10 mins in the GeoEvent Output and choose the editor tracking LastUpdated field. Ex:
2. Then, set up this service as a Synchronized GeoFence:
In this example, the service is polled every 30 seconds and if there are features, it will create a geofence.
3. Create an Input to poll your Tower Buffer Areas. Be sure to specify a TRACK_ID in the GeoEvent Definition for this input.
4. Create a GeoEvent service like the following:
The Incident Detector is set up to check if any tower area contains a lightning strike:
The Expiry Time is set to a really high value, because we don't want the incident to close when there could be lightning strikes.
5. I have two Filters added called Started and Ended. These use the incident GeoEvent Definition and check if the status field is either Started or Ended. Ex:
When a lightning strike is found within the tower area the status will be Started. You will set an e-mail output from this Filter to alert the staff there has been a lightning strike detected.
When there are no lightning strikes detected within the tower area the status will be changed to Ended. You will create another e-mail output from this Filter to alert the staff all is clear. Remember, we have the lightning strikes being deleted every 10 mins from the feature service. When they are deleted, the synchronized geofence will update accordingly.
Hopefully this makes sense.