In the 1970s, scientist Edward Lorenz famously asked whether the flapping of a butterfly’s wings in Brazil could lead to a tornado in Texas. During the decades since, the butterfly effect and chaos theory have sparked countless debates and pop culture references. But the question also holds practical importance: What do small, unpredictable events mean for the future of weather prediction? 

When the moon is high in the sky, it creates bulges in the planet’s atmosphere that creates imperceptible changes in the amount of rain that falls below. New University of Washington research to be published in Geophysical Research Letters shows that the lunar forces affect the amount of rain – though very slightly. “As far as I know, this is the first study to convincingly connect the tidal force of the moon with rainfall,” said corresponding author Tubas Kohyama, a UW doctoral student in the Department of Atmospheric Sciences. 

El Niño is fairly well understood, and by now it’s a household word. But another huge system in the tropical Indian and Pacific oceans, which wreaks similar havoc in world weather, is relatively unknown and is just beginning to be explained. University of Washington scientists have published a mathematical model that could help explain and forecast the Madden-Julian Oscillation, a massive cluster of thunderstorms that plays a role in global weather.