The author would like to thank Dr. George S. Young of The Pennsylvania State University’s (penn State) Department of Meteorology for reviewing each phase of the manuscript and providing invaluable help and guidance in discussions of the theory and concepts presented in this study. Thanks to Stephen Corfidi of NOAA’s SPC and Mark Thornton for reviewing a number of drafts and providing valuable insights. Special thanks to Professor Lee Grenci of Penn State’s Department of Meteorology for reviewing this manuscript and particularly for bringing the question of undular bore origins and dynamics in the western Gulf of Mexico to my attention. Finally, many thanks to Michael Foner for reviewing this manuscript; this work is dedicated to your memory.
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One of the most difficult aspects of forecasting undular bores in this region is the paucity of meteorological observations, as most bores occur over the open water where there are scant surface and upper-air observations. Also, the relatively short duration for undular bores, usually 3–8 h, relative to the standard twice-daily radiosonde ascents, makes it difficult to use radiosonde observations to examine conditions during bore passage. Observed soundings, except for rare exceptions, are limited to 0000 and 1200 UTC daily. Since most bores over the western GOM region form between 0600 and 1200 UTC but have dissipated by 0000 UTC, the initial state of the atmosphere and inversion layer can usually be verified by radiosonde data, but the lifting produced by the bore cannot. Interpolated soundings from model output are typically the only resource for validating changes in the atmosphere produced by a bore in the absence of an observed sounding. Detailed interpolated data from NOAA/Air Resources Laboratory (ARL) and the Rapid Update Cycle (RUC) model are particularly useful approximations and were used extensively in this study. Also, as skew-T diagrams are point specific, it is critical that multiple locations along the expected path be examined. Finally, data from model forecasts for the original and lifted inversion heights are invaluable in ascertaining the forecast state of the atmosphere when a bore is expected, particularly anticipated temperature profiles, but they are spatially and temporally limited in coverage due to their source from 1- or 3-hourly model output with spatial grid limitations that are too large to represent a mesoscale undular bore event. Thus, it is only these data taken together with all recommended forecast parameters that provide a cumulative indication that such an event is likely to occur.