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 May 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
Jun 2002 0 1% 1% 11% 82% 6%
Jul 2002 1 3% 13% 20% 55% 9%
Aug 2002 2 4% 5% 33% 51% 8%
Sep 2002 3 6% 10% 32% 48% 5%
Oct 2002 4 7% 11% 25% 43% 14%
Nov 2002 5 8% 13% 19% 36% 24%
Dec 2002 6 6% 9% 20% 35% 29%
Jan 2003 7 12% 13% 15% 28% 31%
Feb 2003 8 9% 11% 36% 14% 30%
Mar 2003 9 10% 19% 13% 36% 22%
Apr 2003 10 17% 7% 20% 32% 24%
May 2003 11 23% 14% 19% 21% 23%


NINO3
Month lead-time cold cool neutral warm hot
Jun 2002 0 1% 7% 26% 45% 22%
Jul 2002 1 2% 11% 24% 37% 26%
Aug 2002 2 5% 9% 26% 35% 25%
Sep 2002 3 3% 9% 24% 36% 28%
Oct 2002 4 5% 10% 26% 34% 25%
Nov 2002 5 4% 7% 24% 34% 31%
Dec 2002 6 4% 5% 30% 32% 30%
Jan 2003 7 7% 11% 21% 28% 33%
Feb 2003 8 10% 11% 18% 28% 33%
Mar 2003 9 12% 15% 18% 25% 30%
Apr 2003 10 16% 15% 31% 17% 20%
May 2003 11 20% 23% 21% 22% 15%


NINO3.4
Month lead-time cold cool neutral warm hot
Jun 2002 0 0% 10% 18% 48% 24%
Jul 2002 1 3% 10% 22% 32% 34%
Aug 2002 2 3% 6% 17% 37% 37%
Sep 2002 3 2% 12% 20% 38% 28%
Oct 2002 4 3% 6% 29% 31% 32%
Nov 2002 5 3% 10% 21% 37% 29%
Dec 2002 6 2% 9% 20% 28% 40%
Jan 2003 7 5% 7% 29% 25% 34%
Feb 2003 8 8% 8% 25% 25% 34%
Mar 2003 9 5% 11% 29% 22% 34%
Apr 2003 10 9% 16% 24% 20% 31%
May 2003 11 14% 14% 23% 21% 27%


NINO4
Month lead-time cold cool neutral warm hot
Jun 2002 0 0% 2% 17% 28% 53%
Jul 2002 1 0% 0% 7% 40% 53%
Aug 2002 2 0% 2% 7% 41% 50%
Sep 2002 3 0% 2% 10% 42% 46%
Oct 2002 4 0% 2% 23% 35% 40%
Nov 2002 5 0% 2% 17% 42% 39%
Dec 2002 6 0% 3% 21% 36% 39%
Jan 2003 7 1% 8% 18% 27% 46%
Feb 2003 8 1% 6% 21% 30% 43%
Mar 2003 9 4% 14% 20% 32% 30%
Apr 2003 10 2% 16% 19% 27% 36%
May 2003 11 2% 21% 18% 24% 35%