Tom Hamill, an active AMS Member, is a research meteorologist in NOAA's Earth System Research Laboratory in Boulder, Colorado. He focuses on helping NOAA improve its global ensemble prediction systems. This has involved improving the ensemble initialization through the development of the ensemble Kalman filter (EnKF) and hybridized EnKF-variational methods, the development and testing of methods for dealing with model uncertainty, and the development and use of reforecast data sets for statistical post-processing. He is co-chair of the World Meteorological Organization's Data Assimilation and Observing Systems committee, and he has been a member of WMO's Working Group for Numerical Experimentation. Dr Hamill has served on a number of AMS committees, including Probability and Statistics, the Ad-Hoc Committee for Uncertainty in Forecasts, and the Committee on Environmental Responsibility.