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 April 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
May 2002 0 1% 2% 16% 69% 12%
Jun 2002 1 2% 14% 13% 48% 23%
Jul 2002 2 3% 12% 15% 51% 19%
Aug 2002 3 7% 9% 25% 36% 23%
Sep 2002 4 8% 5% 27% 38% 22%
Oct 2002 5 7% 7% 20% 40% 27%
Nov 2002 6 13% 9% 22% 30% 27%
Dec 2002 7 6% 10% 24% 29% 32%
Jan 2003 8 19% 20% 19% 20% 22%
Feb 2003 9 20% 14% 18% 15% 33%
Mar 2003 10 20% 15% 19% 22% 23%
Apr 2003 11 28% 19% 13% 21% 19%


NINO3
Month lead-time cold cool neutral warm hot
May 2002 0 1% 6% 23% 43% 28%
Jun 2002 1 4% 12% 21% 35% 28%
Jul 2002 2 6% 15% 20% 32% 27%
Aug 2002 3 11% 12% 28% 30% 18%
Sep 2002 4 5% 11% 17% 35% 32%
Oct 2002 5 5% 8% 21% 35% 31%
Nov 2002 6 4% 7% 19% 39% 31%
Dec 2002 7 5% 4% 26% 32% 33%
Jan 2003 8 12% 16% 24% 26% 22%
Feb 2003 9 18% 19% 21% 21% 21%
Mar 2003 10 19% 16% 19% 25% 22%
Apr 2003 11 20% 15% 21% 19% 25%


NINO3.4
Month lead-time cold cool neutral warm hot
May 2002 0 0% 1% 26% 39% 34%
Jun 2002 1 2% 13% 20% 35% 31%
Jul 2002 2 10% 18% 20% 31% 21%
Aug 2002 3 5% 15% 21% 31% 27%
Sep 2002 4 4% 12% 19% 36% 29%
Oct 2002 5 8% 16% 36% 24% 16%
Nov 2002 6 3% 12% 19% 37% 29%
Dec 2002 7 8% 21% 35% 22% 15%
Jan 2003 8 9% 11% 27% 26% 26%
Feb 2003 9 17% 14% 32% 22% 15%
Mar 2003 10 12% 20% 31% 21% 16%
Apr 2003 11 11% 17% 26% 21% 25%


NINO4
Month lead-time cold cool neutral warm hot
May 2002 0 0% 0% 0% 23% 77%
Jun 2002 1 0% 3% 18% 33% 46%
Jul 2002 2 0% 0% 6% 30% 64%
Aug 2002 3 0% 2% 7% 37% 54%
Sep 2002 4 0% 3% 9% 34% 55%
Oct 2002 5 1% 5% 17% 41% 36%
Nov 2002 6 4% 17% 29% 27% 22%
Dec 2002 7 3% 13% 24% 30% 31%
Jan 2003 8 2% 13% 19% 27% 39%
Feb 2003 9 4% 19% 27% 22% 27%
Mar 2003 10 5% 23% 17% 29% 27%
Apr 2003 11 5% 19% 23% 24% 29%