Radar and lightning analyses of gigantic jet-producing storms

Abstract

An analysis of the storm structure and evolution associated with six gigantic jets was conducted. Three of these gigantic jets were observed within detection range of very high-frequency lightning mapping networks. All six were within range of operational radars and two-dimensional lightning network coverage: five within the National Lightning Detection Network and one within the Global Lighting Detection network. Most of the storms producing the jets formed in a high CAPE, low lifted index environments and had maximum reflectivity values of 54 to 62 dBZ and 10-dBZ echo tops reaching 14-17 km. Most storms were near the highest lighting flash rate and peak storm intensity with an overshooting echo top just before or after the time of the jet. The overshooting top and strong intensification may have indicated a convective surge which allowed the upper positive charge to mix with a negatively charged screening layer that became depleted. Intra-cloud lightning initiating in the mid-level negative region could have exited upward through the recently depleted positive region, producing a gigantic jet.