Forecasting the end of lightning is one of the most important operational weather challenges at Cape Canaveral Air Force Station (CCAFS) and NASA Kennedy Space center (KSC). The Air Force’s 45th Weather Squadron (45 WS) provides comprehensive meteorological services to operations at these locations. There is little objective guidance on how to predict the end of lightning, so 45 WS must be conservative in ending their lightning advisories to ensure personnel safety and resource protection. One of the 45 WS strategic goals is to terminate lightning advisories sooner, to reduce costs and delays in processing for space launch while maintaining the current high level of safety.

The 45 WS teamed with KSC to begin the ‘Statistical Forecasting Of Lightning Cessation’ project, which was funded under the NASA Faculty Fellowship Program. This project brought Dr. Glover from the department of computer sciences and mathematics at Oral Roberts University to CCAFS/KSC for 9 weeks during the summer of 2004. Phase-1 of the project had two goals: 1) create a climatology of the times between last and next-to-last lightning flashes, and 2) determine if curve fitting to lightning flash rates in the decaying phase of thunderstorms could be used to predict the time when the probability of another flash drops below some low operational threshold. The first goal was designed to provide some immediate object guidance to the forecasters on ending lightning advisories. The results for the first goal were not deemed operationally useful by 45 WS at this time due to unavoidable limitations in the data sampling: only cloud-to-ground strikes used, all thunderstorms in a 10 NM radius considered together rather than individually, and storms moving out of/into the sample area weren’t considered. However, the technique has potential if the sampling issues can be overcome. The second goal was designed as a proof-of-concept for future techniques. The results strongly indicated that the time series of lightning flash rate in decaying thunderstorms has the potential to reliably predict when the probability of future flashes will fall below some low operational threshold. The long-term vision is a system that will automatically analyze lightning flashes from individual storms in real-time, identify which are decaying and display the time until the probability of another flash falls below some low operational threshold and flag which ones have already met that threshold and so their lightning advisories should be considered for cancellation.

Results from Phase-1 of the ‘Statistical Forecasting Of Lightning Cessation’ project will be presented, along with plans for Phase-II and Phase-III of this project. The authors encourage discussion on how to solve this under-researched part of lightning advisories, ‘how to objectively cancel a lightning advisory with high skill, while maintaining personnel safety’.

Companion papers describing the CGLSS system and applications of its database are also being submitted to this conference.