If you're going to be outside later this afternoon and especially this evening, you'll need to keep an eye to the Western sky. Lightning can be a killer. However, if you don't have access to the latest radar, one of the easiest ways to detect nearby lightning is with an AM radio. Ever since I was a child, I have been fascinated by the sound of static on AM radio during thunderstorms.
Each stroke of lightning sends out an electromagnetic radio wave that creates a "static crash" on your AM radio receiver. When you hear these static crashes on the radio, you are actually listening to the lightning in real time. In addition, when you hear thunder outside, you are listening to the time-delayed sound of the lightning.
When I was a child, I was glued to the AM radio. It was the only source of popular music, live sporting events, and local newscasts "back in the day." We didn't have any of the modern technology of today. I quickly learned that I could hear many powerful stations East of the Mississippi River late at night. That's when I'd listen to baseball games from Cleveland, Atlanta, and Pittsburgh.
What struck me as bizarre was that I could hear static from lightning in other parts of the country even though the weather was clear where I lived. That's because lightning is propagated as radio waves by the Earth's ionosphere. So, when I heard static on KDKA in Pittsburgh, I instantly knew why the Pirates' game was being delayed by rain and thunderstorms.
When thunderstorms arrive later this afternoon, why not give it a try. You can hear the sounds of lightning best on the lower frequencies of the AM radio band. Try to find a clear spot on the dial where you can't hear any signals from any radio stations. They will interfere with your listening for static on the radio.
Then, listen for the sounds of static. Radio scientists and engineers call these sounds "static crashes." They are actually the sounds of the lightning. Watch for lightning outside. You will notice that you hear lightning on your AM radio at the exact same time you see the lightning flashes. This is because radio waves and light both travel at the speed of light, which is about 186,000 miles per second.
Fortunately, we won't hear any static on the AM radio this weekend, at least locally. It will be mostly sunny, hot, and moderately humid tomorrow and Sunday with daytime highs in the upper 80s to close to 90 degrees and nighttime lows near 70. Believe it or not, I'll still have my AM radio with me when I take my daily walks. Some habits are hard to break.
Have a good weekend.
Paul
