Fire-effective Low-level Thermal Ridges on the Southern Great Plains

Low-level thermal ridges (LLTRs) have been identified as common meteorological features associated with wildfires in grass-dominated fuelscapes on the southern Great Plains. Analogous to the well-documented fire-effectiveness of West Coast thermal troughs, LLTRs on the Plains have a dramatic influence on wildland fire. Identification of these features in proximity to midlevel wind maxima has proven useful in forecasting the evolution, intensity, and areal scope of regional wildfire outbreaks. This study will provide detailed meteorological analyses of fire-effective LLTRs on the southern Great Plains. The National Centers for Environmental Prediction's North American Regional Reanalysis and National Center for Atmospheric Research Data Reanalysis are used to investigate atmospheric characteristics of LLTRs associated with 11 widespread and destructive wildfire episodes on the southern Great Plains between 2006 and 2014. Atmospheric coupling of kinematic and thermodynamic processes that influence fire effectiveness are illustrated by a vertical profile and cross section. Composites and conceptual models derived from the analyses for conflagrations on the windward side of pronounced LLTRs are used for applications in forecasting southern Great Plains wildfire outbreaks. Examples illustrating the operational utility of LLTRs in wildland fire prediction are presented. Finally, comparative observations of environments with differing fire effectiveness are shown to suggest physical influences that exacerbate surface wildland fire behavior in proximity to these atmospheric features.