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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 December 2002 observed sea-surface temperatures, and with version 3.06 of the SPEP (Statistical Probabilistic ENSO Predictions) model.
NINO1&2
Month lead-time cold neutral hot
Jan 2003 0 1% 26% 73%
Feb 2003 1 4% 54% 42%
Mar 2003 2 26% 52% 22%
Apr 2003 3 30% 46% 23%
May 2003 4 30% 45% 25%
Jun 2003 5 26% 45% 29%
Jul 2003 6 35% 38% 27%
Aug 2003 7 42% 41% 17%
Sep 2003 8 47% 43% 10%
Oct 2003 9 47% 38% 15%
Nov 2003 10 51% 29% 21%
Dec 2003 11 50% 30% 20%


NINO3
Month lead-time cold neutral hot
Jan 2003 0 0% 11% 89%
Feb 2003 1 0% 13% 86%
Mar 2003 2 14% 8% 77%
Apr 2003 3 14% 35% 50%
May 2003 4 16% 46% 38%
Jun 2003 5 13% 49% 38%
Jul 2003 6 13% 54% 33%
Aug 2003 7 20% 48% 32%
Sep 2003 8 14% 47% 40%
Oct 2003 9 14% 47% 40%
Nov 2003 10 21% 46% 33%
Dec 2003 11 13% 45% 42%


NINO3.4
Month lead-time cold neutral hot
Jan 2003 0 0% 20% 79%
Feb 2003 1 0% 24% 76%
Mar 2003 2 0% 44% 56%
Apr 2003 3 2% 40% 58%
May 2003 4 21% 46% 33%
Jun 2003 5 15% 52% 32%
Jul 2003 6 45% 46% 9%
Aug 2003 7 42% 50% 9%
Sep 2003 8 45% 41% 14%
Oct 2003 9 36% 44% 20%
Nov 2003 10 44% 49% 7%
Dec 2003 11 52% 40% 7%


NINO4
Month lead-time cold neutral hot
Jan 2003 0 0% 7% 93%
Feb 2003 1 1% 15% 84%
Mar 2003 2 1% 21% 78%
Apr 2003 3 1% 47% 52%
May 2003 4 4% 42% 54%
Jun 2003 5 13% 52% 35%
Jul 2003 6 44% 44% 11%
Aug 2003 7 55% 39% 6%
Sep 2003 8 52% 43% 5%
Oct 2003 9 56% 38% 6%
Nov 2003 10 61% 33% 6%
Dec 2003 11 63% 29% 9%