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 October 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
Nov 2002 0 0% 0% 9% 53% 37%
Dec 2002 1 0% 2% 9% 37% 51%
Jan 2003 2 5% 10% 12% 35% 37%
Feb 2003 3 15% 12% 24% 21% 28%
Mar 2003 4 7% 8% 26% 29% 30%
Apr 2003 5 14% 21% 15% 24% 26%
May 2003 6 11% 19% 23% 24% 24%
Jun 2003 7 18% 18% 21% 23% 20%
Jul 2003 8 16% 21% 17% 22% 24%
Aug 2003 9 12% 19% 24% 23% 22%
Sep 2003 10 17% 15% 21% 26% 21%
Oct 2003 11 16% 16% 20% 23% 25%


NINO3
Month lead-time cold cool neutral warm hot
Nov 2002 0 0% 0% 0% 27% 73%
Dec 2002 1 0% 0% 2% 63% 34%
Jan 2003 2 0% 0% 3% 48% 49%
Feb 2003 3 0% 2% 7% 38% 52%
Mar 2003 4 1% 3% 14% 34% 48%
Apr 2003 5 9% 9% 24% 23% 35%
May 2003 6 17% 17% 19% 21% 26%
Jun 2003 7 18% 21% 22% 21% 18%
Jul 2003 8 19% 20% 20% 21% 19%
Aug 2003 9 24% 21% 23% 13% 19%
Sep 2003 10 19% 16% 25% 21% 19%
Oct 2003 11 22% 20% 20% 22% 15%


NINO3.4
Month lead-time cold cool neutral warm hot
Nov 2002 0 0% 0% 2% 39% 59%
Dec 2002 1 0% 0% 5% 35% 60%
Jan 2003 2 0% 0% 2% 33% 65%
Feb 2003 3 0% 0% 3% 35% 62%
Mar 2003 4 0% 2% 9% 28% 61%
Apr 2003 5 10% 14% 22% 26% 27%
May 2003 6 15% 11% 22% 25% 27%
Jun 2003 7 24% 26% 18% 15% 16%
Jul 2003 8 28% 20% 20% 18% 14%
Aug 2003 9 28% 22% 24% 10% 16%
Sep 2003 10 44% 11% 15% 15% 15%
Oct 2003 11 30% 19% 20% 17% 14%


NINO4
Month lead-time cold cool neutral warm hot
Nov 2002 0 0% 0% 0% 22% 78%
Dec 2002 1 0% 0% 1% 24% 75%
Jan 2003 2 0% 1% 8% 22% 70%
Feb 2003 3 0% 1% 5% 25% 69%
Mar 2003 4 1% 2% 13% 38% 46%
Apr 2003 5 1% 9% 11% 28% 52%
May 2003 6 1% 14% 17% 29% 39%
Jun 2003 7 14% 18% 26% 21% 22%
Jul 2003 8 18% 25% 21% 16% 20%
Aug 2003 9 16% 23% 23% 20% 19%
Sep 2003 10 22% 26% 22% 17% 12%
Oct 2003 11 25% 25% 21% 18% 10%