This OKLMA data is processed from up to 10 stations in central Oklahoma (sensors: CDEHILMNWY), and 7 stations in southwest Oklahoma (sensors: APUBORZ). The OKLMA operates by triangulating sources of VHF (60-66 MHz) radiation emitted by lightning (and any other sources) in 80 microsecond windows in space and time, which map out the three-dimensional structure of lightning flashes. The OKLMA has been operated by National Oceanic and Atmospheric Administration / Office of Atmospheric Research / National Severe Storms Laboratory and OU/CIMMS staff. The OKLMA was installed with funding from Office of Naval Research Grant N00014-00-1-0525 and has since been funded in part by the National Oceanic and Atmospheric Administration National Severe Storms Laboratory, National Environmental Satellite, Data, and Information Service, and the National Science Foundation. Funding for this project was provided by NOAA award NA16OAR4320115. This README was last updated: 10 August 2021 #### 2) METHODS The method of data collection and performance is described in: Thomas, R. J., Krehbiel, P. R., Rison, W., Hunyady, S. J., Winn, W. P., Hamlin, T., and Harlin, J. (2004), Accuracy of the Lightning Mapping Array, J. Geophys. Res., 109, D14207, doi:10.1029/2004JD004549. Chmielewski, V. C., and Bruning, E. C. (2016), Lightning Mapping Array flash detection performance with variable receiver thresholds, J. Geophys. Res. Atmos., 121, 8600– 8614, doi:10.1002/2016JD025159. Weiss, S. A., D. R. MacGorman, E. C. Bruning, and V. C. Chmielewski, 2018: Two Methods for Correcting Range-Dependent Limitations of Lightning Mapping Arrays. J. Atmos. Oceanic Technol., 35, 1273–1282, doi:10.1175/JTECH-D-17-0213.1. The results of two processing methods are included in this dataset. The files in the “unified” directories were created by processing the OKLMA as one, unified network. The files in the “separated” directories were created by processing each of the southwest and central station clusters separately before combining the VHF solutions found by each cluster of stations per each 10 minute period into an otherwise identical datafile. #### 3) DATA INFORMATION All data is stored in tabular, fixed-width formatted files compressed with gzip and organized by case and processing method. Case 1 includes 0000-0600 UTC on 16 June 2019; Case 2 includes 0300-0700 UTC on 12 June 2019. Datafiles are organized by case then method directories. Fixed width formatting described at the end of each file's header (e.g., “Data format: 15.9f 12.8f 13.8f 9.2f 6.2f 5.1f 7x”). Each file contains 10 minutes of VHF events observed by the OKLMA and will be titled following a LYLOUT_yymmdd_HHMMSS_0600.dat.gz convention in which *yy* is the two digit year, *yy* month, *dd* day, *HH* hour, *MM* minute, *SS* second at the start of the analysis period. Each file has a series of header lines including lma_analysis version used for processing, active stations, analysis criteria, summary information, creation date and formatting information. Data entries are preceded by “\*** data ***”. **Column Names and Descriptions** 0. Time of VHF event --UTC second of the day 1. lat --decimal degrees 2. lon --decimal degrees 3. altitude --in meters above MSL 4. Reduced Chi^2 --Reduced chi^2 of the Marquart least squares solution for the VHF event 5. power --emitting power of the VHF event in dBW 6. mask --bitwise mask of the contributing stations to the VHF event solution in the order given by the Stations mask order line in the header. #### 4) SHARING AND ACCESS The data are freely available; however, OKLMA’s researchers request the dataset be cited with the DOI above if it is used in published research. This README was prepared by Vanna Chmielewski with funding provided by NOAA/Office of Oceanic and Atmospheric Research under NOAA-University of Oklahoma Cooperative Agreement #NA16OAR4320115, U.S. Department of Commerce. The statements, findings, conclusions, and recommendations are those of the author(s) and do not necessarily reflect the views of NOAA or the U.S. Department of Commerce.