A Climatology of Elevated Convection Initiation at Night: Severe and non-severe storms

The mechanisms for the formation and sustenance of nocturnal elevated convection over the Great Plains during the warm season are not well understood. This study formulates a climatology of elevated convection initiation (CI) events at night over the central Great Plains between 1996 and 2014, during the months of April through July. The primary source of data was an archive of WSR-88D data maintained by NCAR. Much of the motivation for this study is the upcoming PECAN (Plains Elevated Convection At Night) field program to be conducted during the late spring and summer of 2015. Part of the study includes an investigation of nocturnal CI events that eventually produce severe weather. Three different CI modes were considered: linear, areal, and single cell. CI events at night were documented during the time span noted above, and surface data were examined for these events to identify any nearby surface boundaries. Elevated CI events were those that occurred with no nearby surface boundary present, or those that formed on the “cold side” of surface boundaries, more than 20 km away. NOAA's National Climatic Data Center (NCDC) Storm Data archive was then utilized to identify any of these cases that were associated with severe weather reports. The frequency of occurrence of severe storms associated with each mode of elevated CI at night will be discussed.