Narional Weather Service (NWS) Evaluation of Earth Networks Incorporated Total Lightning Detection Network (ENTLDN)

In early 2011, the National Weather Service (NWS) worked out an agreement with Earth Networks Incorporated (ENI) to enable the provision of data from ENI Total Lightning Detection Network (ENTLDN) to NWS. ENI has provided access to their data (real-time and archived) along with a web-based software tool, called Streamer-RT (allowed processing of the lightning data), to 17 Weather Forecast Offices (WFOs) and 2 Center Weather Service Units (CWSUs) since June 2011. ENI also provided three training sessions for the government offices during the summer of 2011. NWS Office of Science and Technology requested the WFOs and CWSUs informally evaluate the data, and provide comments on the utility of the new data as well as identify if the data could improve NWS support to a diverse customer base, especially for severe weather. Despite the relative lack of severe weather across most of the United States between June 2011 and May 2012, the weather offices were able to provide great feedback on the new lightning data, both subjective and objective. Reports from two of the WFOs revealed that large increases (i.e., jumps) in total lightning data can occur before severe weather episodes (defined as those with large hail, tornadoes and high winds), but the lead times ranged between 5 and 20 minutes. They did note that it is very important to properly define a threshold for any increases over time. There were instances where the offices observed large increases in lightning rates but with no subsequent severe weather downstream (i.e., false alarms). The Raleigh NC WFO noted that the total lightning data defined “corridors” where severe weather eventually developed downstream (better than with current CG lightning data). Many WFOs noted that the ENI data helped forecasters define which areas of cloud systems were electrified, allowing then to update Terminal Aerodrome Forecasts (TAFs), warn pilots, and adjust lightning locations and frequency. The greatest utility of the total lightning data, as observed by NWS units, was the detection of marginal convection; implementing use of data for severe convection will require additional research and application development. Many forecasters felt that tools must be developed to match the corresponding characteristics of multi-parameter radar data and lightning data when both are on Advanced Weather Interactive Processing System Version II (AWIPS II). They did see correlations between 50 & 60 dBZ reflectivity heights and total lightning rates; this will have to be examined further.