19th International Lightning Detection Conference 24-25 April • Tucson, Arizona, USA 1st International Lightning Meteorology Conference 2006 26-27 April • Tucson, Arizona, USA LIGHTNING DECISION SUPPORT FOR PUBLIC SAFETY
Ronald J. Sznaider, Jim Foerster CCM, James Block CCM
DTN-Meteorlogix, 11400 Rupp Drive, Minneapolis, MN 55337
Real-time lightning information, merged with other meteorological data sets, is successfully being used by DTN-Meteorlogix to provide enhanced public safety in a variety of outdoor sporting and recreation venues. DTN-Meteorlogix provides weather forecasting, display, and decision support to a variety of private, collegiate, and professional sporting organizations including the PGA Tour. The use and integration of Vaisala lightning information, with other meteorological data sets, has become an integral part of effective weather safety decision support and is discussed in this document.
1.0 Introduction The danger of lightning is real. Golf pro Lee Trevino has quipped, “If you are caught on a golf course during a storm and are afraid of lightning, hold up a one-iron. Not even God can hit a one- iron”. Joking aside, the author of this quote was himself struck by lightning during a tournament near Chicago in the 1975 Western Open along with golfers Jerry Heard and Bobby Nichols. Later, during the 1991 U.S. Open at Hazeltine National near Minneapolis, spectators were struck and death resulted. These situations are only two of the more visible ones over the past few decades, however many others have also occurred, with lightning being the #2 storm killer in the United States. With only flash floods killing more, on average lightning deaths are ahead of other highly visible weather disasters such as tornadoes, blizzards and hurricanes. And if not killed by a lightning strike, survivors often have life-long injuries or disabilities.
Lightning is often the single most significant and dangerous weather event for personal safety at outdoor events. The unique nature and significant safety concerns associated with outdoor public events require an advanced system of instrumentation components that provide a very clear and accurate assessment of a localized lightning threat. Rather than relying on any one single technology, the DTN-Meteorlogix lightning protection methodology utilizes independent and complementary technologies, sometimes combined with professional on-site meteorologists, to insure maximum protection and to minimize risk.
DTN-Meteorlogix, the nation’s leading business weather organization, is now utilizing Vaisala real-time lightning information to provide improved severe weather services to their clients. Examples include improved monitoring and alerting of severe weather threats, enhanced communication of storms containing the threat of lightning to the general public through television media outlets, and improved outage response time at electric energy organizations. The combination of lightning data with other appropriate real-time meteorological data sets is producing intriguing synergies and possibilities of providing improved severe weather management to the business world.
1 2.0 Meteorological data sets used to enhance public safety
2.1 Weather Radar Starting in the early 1990’s, the National Weather Service (NWS) began to deploy a national network of new Doppler weather radar systems. Code-named WSR-88D (Weather Surveillance Radar 1988-Doppler), they have come to be commonly referred to as the NEXRAD (Next Generation Radar) system. With a maximum range of over 240 nautical miles (primarily limited by physical characteristics of radar beams curving away from the earth’s surface as distance increases), the NEXRAD network of nearly 150 systems can monitor most of the United States with a contiguous 1-kilometer spatial resolution.
The NEXRAD radar introduced a new series of data sets making possible the automated tracking of individual storms. A series of complex meteorological algorithms identify individual clusters of storms, and perform a pattern recognition correlation on recent data to determine storm movement. Additional algorithms calculate the attributes of individual storms, including the likelihood of the presence of hail, damaging winds, and potential developing tornadoes. Using this information, it is now possible for utilities to pinpoint the precise location of a storm cell, where it is moving, and what assets it will affect, along with an Estimated Time of Arrival (ETA). Storms that are in a utility’s service area can be monitored and tracked in near real-time since the radar data is updated every five minutes. The NEXRAD radar displays showing individual storm tracks provides excellent identification of areas of intense precipitation and storms capable of producing damaging winds. The radar displays do not however provide an accurate depiction of which storms may have associated electrical activity.
Radar Display with storm tracking
2 2.2 Lightning In addition to weather radar information, for many years separate displays of lightning activity have been used by a variety of businesses to identify locations of cloud to ground lightning strikes. These stand-alone lightning displays might represent location, polarity, and age through a combination of different symbols and colors. These displays would provide an unambiguous depiction of where lightning activity was occurring, but would not necessarily address whether or not the lightning activity was also associated with heavy rain, hail, or high wind events.
Traditional Cloud-to-ground lightning activity on basic map background
2.3 Merge of Lightning and Weather Radar information The combination of real-time lightning information with NEXRAD weather radar information forms the ideal synergy of representing both the location and spatial intensity of cloud-to-ground lightning activity along with precipitation intensity. Additional supplemental official severe weather warnings, as issued by the NWS, provide additional context to the situation.
DTN-Meteorlogix utilizes the National Lightning Detection Network (NLDN) to ascertain the movement of clusters of existing lightning producing storms. The NLDN is particularly useful in monitoring thunderstorms that maintain their history of lightning activity and have consistent movement. The NLDN is used to provide advance warning of the development and movement of lightning activity that may threaten outdoor recreation events later in the day.
The NLDN has been recently upgraded to detect cloud-to-cloud lightning activity, frequently a precursor to the dangerous cloud-to-ground strikes. The ability to monitor this activity provide more time to anticipate the conditions which frequently precede the occurrence of cloud-to- ground lightning leading to better event management. This capability is especially valuable at events in the western US where thunderstorms can build over the mountains and rapidly move over the event.
3 Advanced representation of NLDN lightning information, integrated with NEXRAD Doppler radar, surface observations, and areas of official NWS warnings
2.4 Case Study: PGA Tour lightning protection DTN-Meteorlogix is the official weather forecaster of the PGA Tour. The safety of players, tour officials, and the general public is of paramount importance. Due to the significant safety concerns and risks associated with operating the PGA Tour events, it is absolutely essential to provide a state of the art lightning protection solution that can support the effective management of suspensions and resumptions of play. In addition to the use of the upgraded NLDN, DTN- Meteorlogix also employs a state of the art real time lightning detection system on site at each PGA Tour event. This advanced instrumentation is appropriate for the stringent safety requirements of the PGA Tour, while providing the accuracy and lead time needed for safe reliable course evacuation. The Vaisala SA-20 real time lightning detection system is used to support the most critical decision making situations. In addition to providing the instantaneous detection of cloud-to-ground activity, this type of instrument has the unique ability to accurately measure inter-cloud activity during the building stages of a thunderstorm, whether it is overhead or in the distance. This capability is significant because the cloud-to-cloud activity is often the precursor to cloud-to-ground strikes. The extended 50 nautical mile effective range of the SA-20 instrument also makes possible advance warning of rapidly moving and rapidly developing storms, a definite requirement when evacuation of many thousands of spectators is necessary.
DTN-Meteorlogix introduced the use of SA-20 systems at PGA Tour events during the latter half of 2005. The SA-20 performed superbly providing numerous cases where play was correctly suspended based on the presence of cloud-to-cloud lightning in fast approaching storms. For example, at the NEC Invitational in Akron play was suspended when the SA-20 detected intra- cloud lightning in an area of developing storms over 20 miles away heading for the course. This indication was well before any cloud-to-ground lightning had actually occurred and before there was any indication of local charge in the air at the site. The SA-20 provided expert real-time onsite guidance that avoided a safety incident.
4
The presence of experienced on-site meteorologists having access to Doppler weather radar displays, the upgraded NLDN showing additional types of electrical discharges which often show signatures prior to ground strikes, along with an onsite SA-20 system, combine to provide the most comprehensive state of the art approach to lightning protection for the PGA Tour in 2006.
Example of Archived Lightning Display within the DTN-Meteorlogix Weather Sentry web-based weather display system
3.0 Conclusion DTN-Meteorlogix utilizes real-time Vaisala lightning information, merged with other real-time weather data, to form a common operational view that makes possible enhanced public safety for a variety of outdoor sporting and recreation venues. This use of lightning information provides significant added value to the DTN-Meteorlogix weather forecasting, display, and decision support for a variety of private, collegiate, and professional sporting organizations including the PGA Tour.
Please see www.meteorlogix.com for more information
5