Monitoring Oceanic Convection Using the Geostationary Lightning Mapper

The National Weather Service’s Ocean Prediction Center (OPC) and the Tropical Analysis and Forecast Branch (TAFB) at the National Hurricane Center (NHC) forecast maritime thunderstorms in “offshore zones” year-round. These thunderstorms pose daily threats to mariners that traverse the Atlantic waters off the U.S. East Coast, the Gulf of Mexico, and the Caribbean. A broad variety of marine activities are vulnerable to strong winds, building seas, and reduced visibility associated with strong convective storms. The OPC and TAFB have selected offshore convective storms as a focus area for the Satellite Proving Ground to help improve their short term prediction of thunderstorms. A variety of convection targeted GOES-R proxy products are being evaluated in operations to prepare for the increased temporal sampling, imager, derived products, and the Geostationary Lightning Mapper (GLM).

The OPC and TAFB have had to rely on satellite imagery and limited lightning strike data to identify the convective characteristics of thunderstorms in offshore waters of the Atlantic Ocean due to the limited range of radar and Very High Frequency terrestrial lightning networks. The OPC, National Environmental Satellite, Data, and Information Service (NESDIS) Center for Satellite Applications and Research (STAR), and the Cooperative Institute of Climate and Satellites (CICS) at the University of Maryland developed and demonstrated a lightning density product using the Vaisala GLD360 data. Since 2013, this gridded, 8-km product has enabled forecasters to visualize lightning cores within larger convective systems in the OPC and TAFB Offshore Zones. This density product in conjunction with GOES imagery and other Satellite PG products has enabled forecasters to identify and characterize the most intense lightning cores as it relates to potential hazards such as convective winds. As the GLM products become available for preliminary evaluations at OPC and TAFB, the forecasters are getting the first looks at how total lightning and cloud-to-ground lightning data sets can be used to diagnose the convective environment far away from radar. This presentation seeks to showcase some initial forecasters experiences using the GLM lightning data in operations.