Toward a useful intraseasonal forecast Hai Lin Making a skillful prediction beyond one week remains a great challenge. In contrast to short range weather forecasting and seasonal prediction, the study and development of prediction methods on an intraseasonal time scale have been weak. There are several recent international programs aimed at developing a "seamless" prediction capability for the coupled ocean-atmosphere system covering time scales of days to decades. Intraseasonal variability is one of the most important components. This talk explores several aspects that are relevant to improving predictions from a week to a season in advance. Specifically, the Madden-Julian Oscillation (MJO), the role of the stratosphere, the influence of the tropics and their representation in numerical models, especially in GEM, are discussed.