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Probabilistic Predictions of ENSO Indices Using Statistical Models

The forecast probabilities averaged across 7 models are presented in the graphs and tables below. The graphs show the probabilities for "cold" (blue), "neutral" (green), and "hot" (red) conditions, and the horizontal lines indicate the climatological probabilities (25% each for "cold" and "hot", and 50% for "neutral"). The forecasts were produced using January 2005 observed sea-surface temperatures, and with version 4.02 of the SPEP (Statistical Probabilistic ENSO Predictions) model.

NINO1&2
Month lead-time cold cool neutral warm hot
Feb 2005 0 4% 10% 19% 6% 62%
Mar 2005 1 17% 11% 20% 15% 37%
Apr 2005 2 16% 22% 13% 13% 36%
May 2005 3 51% 12% 6% 10% 21%
Jun 2005 4 58% 16% 7% 10% 9%
Jul 2005 5 18% 10% 14% 22% 36%
Aug 2005 6 7% 9% 12% 23% 50%
Sep 2005 7 12% 7% 12% 12% 57%
Oct 2005 8 55% 5% 7% 24% 8%
Nov 2005 9 2% 1% 16% 52% 29%
Dec 2005 10 37% 19% 5% 30% 9%
Jan 2006 11 30% 34% 3% 26% 6%


NINO1&2
Season lead-time cold cool neutral warm hot
FMA 2005 0 12% 14% 17% 11% 45%
MAM 2005 1 28% 15% 13% 13% 31%
AMJ 2005 2 42% 17% 9% 11% 22%
MJJ 2005 3 42% 12% 9% 14% 22%
JJA 2005 4 28% 11% 11% 18% 32%
JAS 2005 5 12% 9% 13% 19% 47%
ASO 2005 6 25% 7% 10% 20% 38%
SON 2005 7 23% 5% 12% 29% 31%
OND 2005 8 31% 9% 9% 35% 15%
NDJ 2006 9 23% 18% 8% 36% 15%


NINO3
Month lead-time cold cool neutral warm hot
Feb 2005 0 23% 14% 18% 26% 19%
Mar 2005 1 13% 17% 25% 26% 19%
Apr 2005 2 36% 11% 12% 10% 31%
May 2005 3 27% 21% 21% 13% 17%
Jun 2005 4 46% 12% 10% 12% 21%
Jul 2005 5 47% 12% 9% 11% 20%
Aug 2005 6 46% 12% 7% 14% 21%
Sep 2005 7 41% 16% 16% 15% 12%
Oct 2005 8 19% 27% 18% 22% 13%
Nov 2005 9 33% 25% 22% 12% 8%
Dec 2005 10 11% 12% 30% 23% 24%
Jan 2006 11 32% 26% 15% 16% 12%


NINO3
Season lead-time cold cool neutral warm hot
FMA 2005 0 24% 14% 18% 21% 23%
MAM 2005 1 25% 17% 20% 16% 22%
AMJ 2005 2 36% 15% 14% 12% 23%
MJJ 2005 3 40% 15% 13% 12% 19%
JJA 2005 4 46% 12% 8% 12% 21%
JAS 2005 5 45% 14% 11% 14% 18%
ASO 2005 6 35% 19% 14% 17% 16%
SON 2005 7 31% 23% 19% 16% 11%
OND 2005 8 21% 22% 24% 19% 15%
NDJ 2006 9 25% 21% 22% 17% 14%


NINO3.4
Month lead-time cold cool neutral warm hot
Feb 2005 0 41% 2% 5% 38% 14%
Mar 2005 1 38% 7% 39% 10% 6%
Apr 2005 2 21% 15% 19% 19% 26%
May 2005 3 20% 5% 19% 21% 35%
Jun 2005 4 12% 9% 8% 21% 49%
Jul 2005 5 32% 9% 16% 15% 28%
Aug 2005 6 7% 34% 18% 12% 29%
Sep 2005 7 31% 19% 11% 14% 26%
Oct 2005 8 7% 26% 20% 21% 27%
Nov 2005 9 12% 30% 6% 23% 29%
Dec 2005 10 7% 8% 12% 32% 41%
Jan 2006 11 7% 11% 26% 22% 33%


NINO3.4
Season lead-time cold cool neutral warm hot
FMA 2005 0 33% 8% 21% 22% 16%
MAM 2005 1 26% 9% 26% 16% 23%
AMJ 2005 2 18% 10% 16% 20% 37%
MJJ 2005 3 21% 8% 15% 19% 38%
JJA 2005 4 17% 18% 14% 16% 35%
JAS 2005 5 23% 21% 15% 14% 28%
ASO 2005 6 15% 26% 16% 15% 27%
SON 2005 7 16% 25% 12% 19% 27%
OND 2005 8 9% 21% 12% 25% 32%
NDJ 2006 9 9% 16% 15% 26% 34%


NINO4
Month lead-time cold cool neutral warm hot
Feb 2005 0 32% 3% 5% 28% 32%
Mar 2005 1 32% 4% 9% 25% 30%
Apr 2005 2 31% 9% 11% 19% 31%
May 2005 3 29% 10% 14% 21% 27%
Jun 2005 4 26% 13% 9% 10% 42%
Jul 2005 5 15% 18% 20% 21% 25%
Aug 2005 6 7% 9% 28% 21% 36%
Sep 2005 7 23% 5% 19% 21% 32%
Oct 2005 8 8% 13% 22% 25% 33%
Nov 2005 9 13% 5% 4% 37% 41%
Dec 2005 10 19% 7% 9% 29% 36%
Jan 2006 11 7% 24% 21% 28% 20%


NINO4
Season lead-time cold cool neutral warm hot
FMA 2005 0 32% 5% 8% 24% 31%
MAM 2005 1 30% 8% 11% 21% 29%
AMJ 2005 2 28% 11% 11% 17% 33%
MJJ 2005 3 23% 14% 14% 17% 31%
JJA 2005 4 16% 13% 19% 17% 34%
JAS 2005 5 15% 11% 22% 21% 31%
ASO 2005 6 13% 9% 23% 22% 34%
SON 2005 7 15% 7% 15% 27% 36%
OND 2005 8 13% 8% 12% 30% 37%
NDJ 2006 9 13% 12% 11% 31% 33%