Type of Document	Thesis
Author	Saunders, Peter Adebayo
Author's Email Address	pas03e@fsu.edu
URN	etd-07212010-162419
Title	Development and Evaluation of Mesoscale Lightning Threat Guidance for Operational Use at NWS Offices
Degree	Master of Science
Department	Earth, Ocean & Atmospheric Science, Department of
Advisory Committee	Advisor Name Title Henry E. Fuelberg Committee Chair Andew I. Watson Committee Member Guosheng Liu Committee Member Philip Sura Committee Member
Keywords	Statistical Studies Lightning Forecasts
Date of Defense	2010-05-18
Availability	unrestricted
Abstract The purpose of this study is to test a perfect prognosis scheme used to develop lightning guidance for the warm season (May-September) for three regions of the country (Colorado, Washington, D.C., and Oregon). This guidance product is developed on a 10 × 10 km grid at 3-hourly intervals. Four seasons of RUC20 analyses and NLDN data are used to develop BLR equations for predicting one or more flashes (PROB ≥ 1), as well as predicting the amount of lightning (PROB ≥ T) for each 3-h period. RUC analyses of differing geopotential heights for each region and a map typing procedure to develop lightning frequencies for five dominant flow regimes are implemented to capture small-scale enhancements due to local forcing that are not well resolved by NWP models. Binary logistic regression (BLR) is used to develop equations for forecasting one or more flashes, while a negative binomial (NB) statistical model is used to predict the amount of lightning, conditional on one or more flashes occurring. The map-type frequencies are used as candidate predictors for both the BLR and NB models. RUC-analyzed parameters describing moisture, temperature, wind and stability also are used as candidate predictors in the PP equations. The perfect prognosis scheme is evaluated using independent data from mesoscale models during the 2009 warm season. Output from the National Centers for Environmental Prediction (NCEP) 13-km RUC (RUC13) and the NCEP 12-km North American Mesoscale Model is used to evaluate the performance of the new lightning guidance products. The goal is to beat lightning forecasts that are attained from climatology and persistence alone for each region. For most forecast periods, there is good agreement between the model forecasts and observed lightning verification. Brier score analysis indicates that our models beat climatology in forecasting one or more flashes, as well as the amount of lightning. Reliability also indicates that our models perform well for forecasting one or more flashes, but not for forecasting the amount of lightning. The goal is to make the technique a fully operational guidance product that can be used for NWS offices in these three regions.
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