Cities Divide and Multiply Storms
Research shows that cities may not only trigger storms, but also split them into smaller storms that re-converge and amplify downwind of the urban area.
A team of scientists from Purdue University analyzed 10 years of data from storms around the Indianapolis metropolitan area and found that about 60 percent of the daytime thunderstorms seemed to change characteristics as they approached and passed over the city. “Quite often, we see storms approach the city, split around it, and come back together on the other side to create a more intense storm,” said Dev Niyogi, lead author of the findings reported in the Journal of Applied Meteorology and Climatology.
Niyogi, who also is Indiana's state climatologist, said most of the storms that followed the pattern occurred during the daytime and preceded or came with a cold front. Additionally, members of the team ran model simulations of the conditions that preceded the storms. They ran the model normally, and then with the Indianapolis urban area removed from the simulation.
KIMBRA CUTLIP is a freelance writer and former assistant editor for Weatherwise.