Monday, 12 January 2009
Utility of total lightning measurements for very short term forecasts of convection growth and decay at White Sands Missile Range
Hall 5 (Phoenix Convention Center)
The National Center for Atmospheric Research (NCAR) Auto-Nowcaster (ANC) system provides very short term predictions of convection initiation, growth, decay and lightning potential to the range forecasters at the Army Test and Evaluation Command\x92s White Sands Missile Range (WSMR). At WSMR, range forecasters are responsible for issuing forecasts and hazardous weather warnings in support of range tests and routine range activities. Among the primary hazards to range activities is lightning, for which forecasters will issue warnings if lightning is expected to occur within a certain distance from test sites. To support hazardous weather warning operations, WSMR has a lightning mapping array that measures VHF sources from lightning discharges. From these data, several flash parameters such as flash rate, the height of the maximum VHF source counts, and the rate of change of VHF source count density are computed. Analysis of trends of these parameters can reveal information on the behavior of thunderstorms, such as storm growth or decay. These fields have been added to the fuzzy logic engine within the ANC to enhance the growth and decay nowcasts that the system produces. Impacts of the derived lightning fields on the forecast output from several cases will be compared against forecasts generated from the existing ANC logic in use at WSMR.
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