This award provides funds to support the participation of research scientists and graduate students in a workshop on numerical long-range (10-30 days) weather prediction. The workshop represents a follow-on to a very successful one which was held three years ago. The workshop participants will examine ongoing issues of model behavior and systematic errors, the scale and frequency of interactions, the importance of boundary conditions. They will also consider recent results on the structure and dynamics of long-lived weather phenomena and associated wether regime transitions. The organizers hope to identify the most pressing of the outstanding problem areas in long-range weather forecasting. This award is jointly supported by NOAA and NSF.