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 June 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
Jul 2002 0 3% 10% 44% 42% 1%
Aug 2002 1 3% 14% 41% 40% 2%
Sep 2002 2 5% 13% 39% 41% 3%
Oct 2002 3 6% 11% 32% 49% 2%
Nov 2002 4 10% 11% 27% 38% 13%
Dec 2002 5 7% 11% 22% 37% 23%
Jan 2003 6 14% 14% 16% 30% 25%
Feb 2003 7 15% 16% 24% 17% 28%
Mar 2003 8 15% 15% 22% 26% 22%
Apr 2003 9 17% 14% 23% 25% 21%
May 2003 10 16% 9% 24% 25% 25%
Jun 2003 11 16% 9% 16% 31% 29%


NINO3
Month lead-time cold cool neutral warm hot
Jul 2002 0 2% 16% 21% 29% 32%
Aug 2002 1 4% 8% 19% 37% 31%
Sep 2002 2 5% 13% 15% 40% 28%
Oct 2002 3 6% 17% 19% 31% 27%
Nov 2002 4 9% 10% 34% 37% 10%
Dec 2002 5 7% 7% 33% 29% 25%
Jan 2003 6 18% 22% 22% 20% 18%
Feb 2003 7 10% 12% 20% 24% 34%
Mar 2003 8 16% 16% 16% 18% 34%
Apr 2003 9 21% 18% 16% 17% 28%
May 2003 10 17% 19% 24% 22% 18%
Jun 2003 11 21% 24% 20% 20% 16%


NINO3.4
Month lead-time cold cool neutral warm hot
Jul 2002 0 4% 16% 18% 28% 33%
Aug 2002 1 6% 10% 25% 42% 18%
Sep 2002 2 4% 11% 18% 36% 31%
Oct 2002 3 6% 15% 17% 33% 30%
Nov 2002 4 1% 15% 29% 42% 12%
Dec 2002 5 5% 17% 24% 39% 16%
Jan 2003 6 8% 11% 31% 32% 18%
Feb 2003 7 10% 13% 29% 31% 17%
Mar 2003 8 7% 19% 30% 28% 17%
Apr 2003 9 14% 19% 25% 25% 17%
May 2003 10 18% 19% 26% 24% 13%
Jun 2003 11 23% 24% 19% 17% 16%


NINO4
Month lead-time cold cool neutral warm hot
Jul 2002 0 0% 4% 21% 26% 49%
Aug 2002 1 0% 4% 16% 35% 45%
Sep 2002 2 0% 6% 18% 39% 37%
Oct 2002 3 0% 8% 30% 42% 21%
Nov 2002 4 0% 6% 14% 47% 33%
Dec 2002 5 0% 7% 22% 31% 40%
Jan 2003 6 2% 19% 30% 28% 21%
Feb 2003 7 2% 15% 37% 27% 18%
Mar 2003 8 7% 18% 27% 27% 21%
Apr 2003 9 6% 24% 27% 27% 17%
May 2003 10 9% 26% 24% 21% 20%
Jun 2003 11 15% 20% 28% 20% 18%