In support of the DoD's Gulf War Illness study, the Naval Research Laboratory has performed global and mesoscale meteorological re-analyses to provide a quantitative atmospheric characterization of the Gulf region during the period between Jan 15 and March 15, 1991. The re-analyzed fields are useful to drive dispersion models for consequence analysis and other environmental quality assessments. The reanalysis was conducted with Navy's operational global and mesoscale analysis and prediction systems: the NOGAPS and COAMPS. These models are used to support Navy and DoD operations on a daily basis. Both systems have data assimilation frontends based on a multivariate optimum interpolation to ingest conventional, satellite, and declassified observations. The global reanalysis was produced by the NOGAPS at a horizontal spatial resolution of 80 km (T159L24) with a 6-h update cycle. The global reanalyzed fields were used to provide boundary conditions for the mesoscale reanalysis. The mesoscale reanalysis was produced by a triple-nested COAMPS with a 12-h update cycle at spatial resolutions of 45, 15 and 5 km. There were 30 levels in the vertical in the COAMPS reanalysis with seven levels in the lowest 1 km of the atmosphere. Mean and perturbation momentum and thermal fields of the Gulf region during the two-month will be presented and discussed. Dominant physical processes over the region during the period will be inferred from these reanalyzed fields. Model validation and statistics of model performance will also be presented.