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El Nino - Southern Oscillation (ENSO) Observations and Forecast Trends
This graph displays the recent past  NINO 3.4 index values and the range of Nino 3.4 values predicted for the future illustrating the uncertainty in the forecast.  The Niño 3.4 Index represents the SST anomalies in degrees Celsius over the Region bounded by 120°W-170°W and 5°S- 5°N.
This graph displays the recent past NINO 3.0 index values and the range of Nino 3.0 values predicted for the future illustrating the uncertainty in the forecast.  The Niño 3.0 Index represents the SST anomalies in degrees Celsius over the Region bounded by 90°W-150°W and 5°S- 5°N.
nino3.4-high-low.jpg (26874 bytes)

This monthly record high-low chart of the Nino 3.4 index illustrates that the most extreme values occur from October through February, or during fall and winter and much of what is generally considered the Florida dry season.

nino3.4-frequency.jpg (36116 bytes)

The value that is actually used to characterize the state of the Nino 3.4 or Nino 3.0 indices for the purposes of the experimental forecast graphic is the average of the index from May through April which encompass the experimental dry season forecasts that are valid from November through April. In other words, the state of Nino 3.4 or 3.0 from May through April is used to predict seasonal storminess and rainfall from November through April. The graph shows the frequency distribution of these average Nino 3.4 values from 1960 to 2000.

A graph of the yearly plot of the computed average Nino 3.4 values is shown above to illustrate the significant season-to-season variability that can occur. (Note that for example: 1960 is the 1960-61 prediction season that runs from May 1960 through April 1961).

The charts below ranks the average Nino 3.4 and Nino 3.0 values for the 12 months from May through April (based on 1970-2000 normals) for the last 43 seasons from 1960 through 2002.  The rank and percentile of the predicted average Nino 3.0 and Nino 3.4 for the current forecast season is indicated by the color on the graphs below.

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Florida region seasonal forecast development:  Bart Hagemeyer.
Web layout and page production:  Jacklyn Rhea Almeida.

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 Page last modified July 24, 2005
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