The Climate Prediction Center has issued a La Nina watch for the fall and winter. That relates to cooler sea surface temperatures in the Pacific Ocean, and has an impact on North American weather.
Dennis Todey , Head of the Midwest Climate Hub in Ames Iowa says that prediction evolved quickly.
Todey says there are still questions about the possible effects of this development.
Todey says a La Nina has more of an impact on winter weather.
Todey says that could also lead to more snow over the northern plains this winter.