|Which Days will Storms Strike? - Science Insider
Reported September 2009
LIGHTNING STRIKES ON WEEKDAYS: In a study covering several regions of the United States, researchers found that lightning strikes are 10 to 20 percent more likely to occur on Wednesdays and Thursdays than other days of the week. Scientists think there is a relationship between aerosols released by human activity and lightning strikes during the work week. Truck traffic may be one of the main culprits, because their emissions peak around the same time.
WHAT IS LIGHTNING? Lightning is a form of static electricity. We experience static electricity every time we drag our feet on the carpet and then touch a conducting surface, like a metal doorknob. The shuffling causes our bodies to pick up extra electrons. Touching something with a positive charge, like metal, causes the electrons to "jump" across the small gap from our fingers to the object, and we experience a tiny electric shock. Similarly, lightning occurs because clouds become negatively charged as the water droplets inside rub up against each other during the natural process of evaporation and condensation, when moisture accumulates in the clouds. This charge seeks out something with a positive charge -- the ground, ideally -- and the lightning is the "spark" closing the gap between the two.
The American Meteorological Society contributed to the information contained in the TV portion of this report.
If you would like more information, please contact:
Thomas L. Bell
NASA / Goddard Space Flight Center
Greenbelt, MD 20771
American Meteorological Society
Boston, MA 02108-3693