Word of mouth may not always alert beachgoers of looming thunderstorms, so one Jersey Shore community plans to use sirens with high-end technology to bystanders at the earliest sights of lightning. A set of lighting-detection sirens is nearly finished being installed in Seaside Park. Their activation comes one week after a man was killed by a lightning strike. Plans of bringing the innovative system to the municipality, however, date to last year, Seaside Park Beach Patrol Capt. Jim Rankin told NJ Advance Media on Monday. Officials anticipate the devices being activated by early July, he said….