You are playing tennis just before sunset on a sultry, summer evening. you see a thunderstorm tower and anvil to the southwest of your location. you see occasional lightning but hear no thunder. about 30 minutes later, you are winning the set 5-3. you see lightning and hear thunder about 4 second after the lightning flash. the thunderstorm anvil is overhead. how far away is the lightning each time? why do you not hear it the first time? and what actions should you take?