Comparing the ratio of cloud-to-cloud and cloud-to-ground lightning strokes in severe weather events on different geographic scales

Cloud-to-cloud (CC) and cloud-to-ground (CG) lightning strokes occur during all types of severe weather events. The question is what is the ratio of CC to CG lightning stroke changes when outbreaks get larger?  The problem is not knowing if CC or CG lightning strokes occur more during widespread, regional or local scale severe weather events. It is important to know this information because institutions such as the National Weather Service can use lightning research for public safety. In this study, severe weather is defined by preliminary hail and tornado reports from the Storm Prediction Center (http://www.spc.noaa.gov/climo/online/). Widespread severe weather is defined as that occurring in a region greater than five states, with each individual state being approximately 75,000 square miles. Regional severe weather was considered to involve an area of three to five states and local severe weather was considered to involve an area of one to two states. The focus area encompasses contiguous states with severe weather outbreaks that occurred on April 26, 2016, May 6, 2015 and March 13, 2016. The radar and lightning data is taken from Norman, OK (widespread case and regional case) and Little Rock, AK (local case). The hypothesis is that ratio of more CC and CG lighting strokes will occur per storm reported event with widespread severe weather events because there should be a greater number of and more intense updrafts occurring in the storms. Research is being completed by using Unidata’s Integrated Data Viewer (IDV) and lightning data from Vaisala, Inc., and is still ongoing. Preliminary results are presented here.