Enhanced Lightning Products and Services for Decision Support Operations through Improved Short Term Forecast Techniques

Lightning poses a significant threat to life and property in the United States, and especially in the state of Florida. From 1959-2009, lightning was responsible for 460 fatalities within Florida alone, accounting for more than 11% of the lightning deaths in the US. The time when people are the most at risk is when they are outside, and away from traditional warning systems. With this in mind, a project was devised to help raise public awareness of daily lightning threats, and consisted of two primary goals; 1) production of high resolution, short-term lightning storm forecasts and 2) development and issuance of experimental lightning watches and warnings for site-specific locations. The short-term lightning threat and thunderstorm outlook graphics were produced daily and displayed on the NWS Melbourne web site to increase public awareness of areas where the cloud-to-ground (CG) lightning threat was heightened throughout the day. For the experimental lightning watches/warnings, two different sites were selected each week, to simulate support which could be provided to Emergency Managers. Various meteorological data sets were interrogated such as, satellite, radar, as well as 3-dimensional, total lightning data from the Kennedy Space Center network (Lightning Detection and Ranging, LDAR) to assist in diagnosing if and when lightning was likely to occur in proximity to each site within 30 minutes. An additional tool that was utilized and evaluated was the AutoNowcaster (ANC), an expert system which assimilates data from a short range weather model (RUC), and satellite and radar data, together with forecaster-input boundaries and regimes. The ANC produces a one-hour thunderstorm initiation likelihood forecast every 5-10 minutes. For the experimental lightning watches and warnings, 30 minute and 10 minute lead times were desired and verification was based on one or more CG strikes occurring within a 5 nautical mile radius of the sites. Verification statistics (probability of detection, false alarm rate, and critical success index) were calculated for all experimental lightning watches and warnings issued. To demonstrate the real-world utility of the experimental lightning watch/warning process, two sites were specifically chosen to coincide with the location of a 1) major outdoor event attended by 75,000 spectators and a 2) full-scale Emergency Management Exercise. Experimental lightning support services were provided for each event with positive feedback received from Emergency Management personnel. Overall, the project confirmed that lightning forecast implemented to enhance public awareness. Specifically, the project validated that lightning watches and warnings can be issued with success and sufficient lead times. Furthermore, enhancing NWS Decision Support Services for the Emergency Management Community with lightning watches/warnings can be employed for site-specific locations when events warrant.