As part of the Cirrus Regional Study of Tropical Anvils and Cirrus Layers - Florida Area Cirrus Experiment (CRYSTAL-FACE), a number of thunderstorms were observed in July, 2002, by research aircraft. Observations of cloud-to-ground (CG) lightning were available from the National Lightning Detection Network (NLDN) for the project's duration. Estimates of intracloud (IC) flashes were made based on a combination of climatological IC/CG ratios and deviations from average weak positive flash rates. Selected CRYSTAL-FACE storms were simulated using the PSU/NCAR mesoscale model (MM5) in cloud-resolving mode with a horizontal resolution of 2 km. Output fields from the MM5 were used to drive an offline cloud scale chemical transport model (CSCTM) developed at the University of Maryland which employs a photochemical ozone mechanism. Flashrates derived from NLDN observations were used to generate a parameterized lightning NO_x source in the CSCTM. An estimate of NO_x production per lightning flash was obtained by comparing in situ anvil chemical observations with model results. The effect of lightning produced NO_x on ozone and other species was analyzed by comparing a simulation including lightning NO_x production with a simulation which did not include a source of lightning NO_x. In order to estimate the effects of lightning NO_x on downstream ozone production in the 24 hours following the convection, a chemistry-only version of the CSCTM was employed.