This past March ranked as the 13th warmest March in 144 years of records for Iowa, continuing a trend of warmer-than-normal weather for the lower 48 states that goes back into the latter part of 2015. The three month fall (September through November) and winter (December through February) periods were the warmest since 1895.

In the Tropical Pacific one of the strongest El Ninos since 1950, which peaked in intensity during late 2015, has continued to weaken this spring.

Transition to La Nina

Further weakening is forecast to...