Statistical Probabilistic ENSO Forecasts

Probabilistic Forecasts of ENSO Indices Using Statistical Models

Simon J. Mason

Scripps Institution of Oceanography

The forecasts below were produced using August 2002 observed sea-surface temperatures, and with version 3.04 of the SPEF (Statistical Probabilistic ENSO Forecasts) model. Previous forecasts are available online.

NINO1&2
Month lead-time cold cool neutral warm hot
Sep 2002 0 1% 9% 26% 62% 1%
Oct 2002 1 4% 13% 13% 65% 4%
Nov 2002 2 9% 12% 25% 36% 18%
Dec 2002 3 4% 9% 16% 43% 27%
Jan 2003 4 10% 11% 15% 33% 31%
Feb 2003 5 12% 10% 28% 20% 30%
Mar 2003 6 13% 14% 23% 28% 22%
Apr 2003 7 17% 21% 23% 17% 22%
May 2003 8 15% 12% 22% 25% 26%
Jun 2003 9 16% 14% 18% 28% 24%
Jul 2003 10 22% 17% 19% 24% 18%
Aug 2003 11 18% 13% 25% 26% 18%


NINO3
Month lead-time cold cool neutral warm hot
Sep 2002 0 3% 13% 19% 52% 14%
Oct 2002 1 2% 10% 27% 50% 12%
Nov 2002 2 2% 11% 28% 48% 11%
Dec 2002 3 2% 12% 34% 45% 7%
Jan 2003 4 5% 20% 27% 34% 14%
Feb 2003 5 9% 17% 28% 31% 16%
Mar 2003 6 13% 20% 22% 25% 20%
Apr 2003 7 20% 20% 23% 19% 18%
May 2003 8 21% 23% 24% 24% 8%
Jun 2003 9 23% 31% 18% 18% 11%
Jul 2003 10 25% 26% 17% 16% 15%
Aug 2003 11 24% 17% 24% 21% 14%


NINO3.4
Month lead-time cold cool neutral warm hot
Sep 2002 0 0% 10% 25% 17% 48%
Oct 2002 1 3% 15% 15% 21% 47%
Nov 2002 2 1% 6% 22% 34% 37%
Dec 2002 3 2% 19% 19% 10% 50%
Jan 2003 4 3% 13% 16% 38% 30%
Feb 2003 5 4% 12% 18% 37% 29%
Mar 2003 6 5% 15% 22% 29% 29%
Apr 2003 7 13% 22% 24% 22% 19%
May 2003 8 16% 20% 29% 23% 11%
Jun 2003 9 20% 23% 23% 22% 12%
Jul 2003 10 16% 16% 25% 24% 20%
Aug 2003 11 29% 15% 25% 17% 13%


NINO4
Month lead-time cold cool neutral warm hot
Sep 2002 0 0% 16% 22% 9% 52%
Oct 2002 1 0% 5% 28% 44% 23%
Nov 2002 2 0% 10% 22% 17% 51%
Dec 2002 3 1% 11% 19% 20% 50%
Jan 2003 4 1% 4% 13% 23% 60%
Feb 2003 5 9% 11% 13% 28% 39%
Mar 2003 6 2% 6% 20% 35% 37%
Apr 2003 7 2% 9% 24% 29% 36%
May 2003 8 5% 16% 19% 26% 34%
Jun 2003 9 7% 16% 25% 26% 26%
Jul 2003 10 14% 17% 27% 25% 18%
Aug 2003 11 16% 19% 24% 23% 18%