A Survey of Thunderstorms That Produce Megaflashes Across the Americas

Journal Article · Mon Jun 05 00:00:00 EDT 2023 · Earth and Space Science

DOI:https://doi.org/10.1029/2023ea002920· OSTI ID:2426513

Peterson, Michael ^[1]

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1. Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)

We previously observed that long-horizontal lightning flashes exceeding 100 km in length, known as “megaflashes,” occur preferentially in certain thunderstorms. In this study, we develop a cluster feature approach for automatically documenting the evolutions of thunderstorm systems from continuous lightning observations provided by the Geostationary Lightning Mapper (GLM) on NOAA's Geostationary Operational Environmental Satellites (GOES). We apply this methodology to GOES-16 GLM observations from 2018 to mid-2022 to improve our understanding of megaflash-producing storms. We find that megaflashes occur in long-lived (median: 14 hr) storms that grow to exceptional sizes (median: 11,984 km²) while they propagate across long distances (median: 622 km) compared to ordinary storms. The first megaflashes are typically produced within 15 min of the storm reaching its peak intensity and extent. However, most megaflashes occur ≥13 hr after the initial megaflash activity, and are sufficiently close to convection to suggest initiation in the thunderstorm core (where GLM has difficulty detecting faint early light sources from megaflashes). Megaflashes generated outside of convection are rare, accounting for 2.7% of the sample using a 50 km convective distance threshold, but also tend to be larger than normal megaflashes, possibly due to having direct access to electrified stratiform clouds through which megaflashes propagate.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: 89233218CNA000001
• OSTI ID: 2426513
• Report Number(s): LA-UR--23-21738
• Journal Information: Earth and Space Science, Journal Name: Earth and Space Science Journal Issue: 6 Vol. 10; ISSN 2333-5084
• Publisher: American Geophysical Union (AGU) - Wiley
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
GLM
GOES-16
earth sciences
lightning
megaflashes
thunderstorms