Long-Range forecast over Japan issued by JMA
JMA provides four kinds of long-range forecasts; One-month forecast, three-month outlook, warm season outlook and cold season outlook.
Forecasts of individual elements are given in three categories; below normal, near normal and above normal. The thresholds of each category are determined so that the climatological chance of occurrence for each category is 33.3% for the period from 1981 to 2010.
JMA employs a dynamical method as a major long-range forecast method.
An outline of the operational ensemble prediction system is reviewed in
Model Outline page.
Empirical/statistical methods including Canonical Correlation Analysis,
Optimal Climate Normals are also used for preparing three-month outlook, warm season outlook and cold season outlook.
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