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 July 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
Aug 2002 0 4% 24% 36% 35% 1%
Sep 2002 1 6% 16% 39% 39% 1%
Oct 2002 2 5% 10% 32% 51% 2%
Nov 2002 3 11% 9% 34% 36% 11%
Dec 2002 4 4% 13% 19% 39% 25%
Jan 2003 5 10% 14% 17% 29% 29%
Feb 2003 6 13% 12% 24% 20% 30%
Mar 2003 7 15% 19% 21% 20% 25%
Apr 2003 8 19% 18% 21% 21% 20%
May 2003 9 16% 15% 23% 23% 23%
Jun 2003 10 15% 16% 22% 25% 22%
Jul 2003 11 18% 17% 20% 23% 21%


NINO3
Month lead-time cold cool neutral warm hot
Aug 2002 0 3% 13% 21% 49% 14%
Sep 2002 1 8% 16% 12% 47% 17%
Oct 2002 2 6% 15% 14% 48% 17%
Nov 2002 3 2% 10% 35% 43% 10%
Dec 2002 4 10% 21% 29% 35% 5%
Jan 2003 5 12% 19% 20% 31% 18%
Feb 2003 6 5% 8% 29% 32% 25%
Mar 2003 7 19% 22% 23% 22% 14%
Apr 2003 8 23% 24% 23% 17% 15%
May 2003 9 21% 20% 25% 20% 15%
Jun 2003 10 18% 22% 22% 20% 18%
Jul 2003 11 22% 20% 20% 21% 17%


NINO3.4
Month lead-time cold cool neutral warm hot
Aug 2002 0 2% 11% 23% 39% 25%
Sep 2002 1 9% 11% 23% 32% 24%
Oct 2002 2 2% 19% 23% 32% 24%
Nov 2002 3 1% 14% 22% 56% 8%
Dec 2002 4 10% 16% 17% 44% 13%
Jan 2003 5 12% 13% 20% 42% 13%
Feb 2003 6 5% 11% 19% 48% 17%
Mar 2003 7 4% 15% 28% 27% 26%
Apr 2003 8 13% 22% 25% 22% 18%
May 2003 9 16% 21% 28% 23% 12%
Jun 2003 10 21% 22% 23% 19% 16%
Jul 2003 11 17% 22% 23% 19% 18%


NINO4
Month lead-time cold cool neutral warm hot
Aug 2002 0 2% 18% 20% 11% 49%
Sep 2002 1 2% 18% 20% 19% 42%
Oct 2002 2 0% 6% 28% 47% 19%
Nov 2002 3 1% 14% 35% 35% 15%
Dec 2002 4 0% 8% 23% 29% 39%
Jan 2003 5 3% 12% 32% 34% 18%
Feb 2003 6 5% 11% 31% 31% 23%
Mar 2003 7 6% 16% 26% 27% 25%
Apr 2003 8 6% 24% 29% 27% 14%
May 2003 9 5% 22% 24% 23% 27%
Jun 2003 10 12% 22% 28% 19% 18%
Jul 2003 11 19% 23% 22% 18% 18%