Florida Precipitation and ENSO

Todd Richards, Graduate Student
richards@coaps.fsu.edu

Winter (December-January-Febuary) historical precipitation histograms for El Niño (red), El Viejo (blue), and Neutral (green) events.

Seasonal mean precipitation data from 1950 to 1987 for 25 stations in Florida were used to examine precipitation anomalies for each category of ENSO. Marginal probabilities were calculated to reveal the potential for receiving much above or below normal given the occurrence of a particular ENSO extreme (i.e. El Viejo).

It was found that the occurrence of El Niño greatly increased the probability of receiving greater than one standard deviation above the overall mean precipitation during the wintertime "seasons" (October/November/December through March/April/May) at every station. Also, El Viejo increased the probability of mean seasonal precipitation being one standard deviation below the overall mean during the winter. The impact made on mean seasonal precipitation by El Viejo was as strong or stronger than the impact made by El Niño.

The follow map shows the geographical distribution of the data. Clicking on the red locator dot will the winter histogram for the selected city.

04 October 1994