AMES, I.A.(WNAX)- The western hemisphere has been dealing with a three year onset of La Nina, a cooling of Pacific Ocean surface temperatures that has an impact on North American weather.

Dennis Todey, Head of the Midwest Climate Hub in Ames Iowa, says it looks like a shift is developing.

Todey says they are seeing indications that shift to an El Nino could happen quickly.

An El Nino occurs when sea surface temperatures rise above normal.

Todey says seeing signs of an El Nino that quickly would be unusual.

There are concerns an El Nino could add more heat to an already warming climate.