The main object of this paper is to present in one place a series of meteorological analyses to aid the interpretation of the in situ Airborne Ozone Experiment (AAOE) observations. Maps and sections of meteorological variables derived from the United Kingdom Meteorological Office global model are presentd for ER-2 and DC-8 flight days. Analyzed temperatures and winds are generally in good agreement with AAOE observations at all levels. Minor discrepancies in winds and temperatures are evident, particularly at DC-8 altitudes, and are discussed in the paper. Model analyses show temperatures at 60 ¿W cold enough to saturate water at 1 part per million by volume as late as September 14 and that following that date a sudden increase in the temperature at all levels within the vortex precludes further saturation at low water vapor mixing ratios. Maps of potential vorticity are presented on the 428-K potential temperature surface for the AAOE flight days. These show that the vortex is essentially circumpolar although there are periods when major distortions are apparent. At the 428-K potential temperature level, the area of the vortex, as defined by the areas enclosed by selected potential vorticity contours, remains approximately constant throughout the AAOE. ¿ American Geophysical Union 1989