Information flow in ensemble weather predictions

Using several recent developments in information theory, uncertainty flow was explored using a moderate-resolution, primitive-equation atmospheric model with simplified physics. Consistent with operational experience in forecast centers and other methodologies explored in the literature, it was found that the midlatitude information flow is mainly in an easterly direction, although at low levels there is clear evidence that synoptic dynamics are important. To obtain reliable and stable results, rather large prediction ensembles were used. However, it was found that the basic qualitative results can be obtained with ensembles within present practical reach.