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 September 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
Oct 2002 0 0% 6% 18% 71% 5%
Nov 2002 1 7% 15% 31% 38% 10%
Dec 2002 2 3% 17% 24% 37% 19%
Jan 2003 3 19% 13% 19% 28% 22%
Feb 2003 4 20% 13% 24% 21% 22%
Mar 2003 5 17% 17% 24% 21% 22%
Apr 2003 6 21% 19% 22% 20% 18%
May 2003 7 20% 17% 22% 21% 20%
Jun 2003 8 24% 15% 20% 25% 17%
Jul 2003 9 22% 18% 20% 22% 18%
Aug 2003 10 23% 20% 17% 21% 19%
Sep 2003 11 20% 19% 21% 21% 19%


NINO3
Month lead-time cold cool neutral warm hot
Oct 2002 0 0% 6% 9% 56% 29%
Nov 2002 1 0% 4% 13% 65% 18%
Dec 2002 2 1% 5% 23% 62% 9%
Jan 2003 3 2% 8% 12% 40% 37%
Feb 2003 4 2% 5% 16% 42% 35%
Mar 2003 5 8% 13% 19% 29% 32%
Apr 2003 6 17% 17% 22% 19% 24%
May 2003 7 17% 20% 18% 19% 26%
Jun 2003 8 18% 19% 22% 20% 21%
Jul 2003 9 19% 18% 22% 21% 21%
Aug 2003 10 20% 17% 23% 20% 21%
Sep 2003 11 19% 22% 19% 21% 19%


NINO3.4
Month lead-time cold cool neutral warm hot
Oct 2002 0 0% 2% 12% 30% 56%
Nov 2002 1 0% 6% 23% 64% 6%
Dec 2002 2 0% 8% 38% 50% 3%
Jan 2003 3 2% 8% 27% 52% 11%
Feb 2003 4 2% 7% 21% 35% 35%
Mar 2003 5 5% 20% 35% 25% 15%
Apr 2003 6 12% 21% 21% 25% 21%
May 2003 7 20% 16% 23% 20% 21%
Jun 2003 8 16% 20% 26% 18% 20%
Jul 2003 9 13% 24% 25% 19% 20%
Aug 2003 10 35% 12% 23% 12% 17%
Sep 2003 11 33% 13% 24% 15% 15%


NINO4
Month lead-time cold cool neutral warm hot
Oct 2002 0 0% 3% 25% 25% 48%
Nov 2002 1 0% 6% 18% 28% 47%
Dec 2002 2 0% 5% 19% 28% 48%
Jan 2003 3 4% 7% 20% 42% 28%
Feb 2003 4 8% 10% 18% 37% 26%
Mar 2003 5 4% 16% 31% 24% 24%
Apr 2003 6 4% 20% 23% 26% 26%
May 2003 7 5% 24% 24% 23% 25%
Jun 2003 8 8% 20% 27% 23% 22%
Jul 2003 9 16% 18% 25% 20% 21%
Aug 2003 10 14% 20% 23% 22% 21%
Sep 2003 11 15% 21% 21% 19% 24%