Observations of Stratiform Lightning Flashes and Their Microphysical and Kinematic Environments

During the Midlatitude Continental Convective Clouds Experiment (MC3E), combined observations of clouds and precipitation were made from airborne and ground-based in situ and remote sensing platforms. These observations were coordinated for multiple mesoscale convective systems (MCSs) that passed over the MC3E domain in northern Oklahoma. Notably, during a storm on 20 May 2011, the University of North Dakota Citation aircraft made in situ microphysical observations near the times and locations of stratiform positive cloud-to-ground (+CG) lightning flashes. These lightning flashes were mapped by the Oklahoma Lightning Mapping Array (OKLMA) and the National Lightning Detection Network, and these +CGs resulted from extremely large stratiform lightning flashes that were hundreds of km in length and lasted several seconds. Complementing these lightning observations were multiple-frequency radar and radiometric measurements from the National Aeronautics and Space Administration (NASA) ER-2 aircraft, multiple ground-based Department of Energy, NASA, and National Weather Service radars, and other MC3E instrumentation. This dataset provides an unprecedented look at kinematic and microphysical environments in the vicinity of large, powerful, and long-lived stratiform lightning flashes. Results from this and other cases will be presented, and their implications for interpreting stratiform lightning and their environments from spaceborne platforms will be discussed. In addition, we expect that the observations will help provide additional insight into the perceived requirement for full mixed-phase microphysical conditions to make lightning.