NWC REU 2002
May 12 - July 20



Nonmeteorological Factors in Warning Verification

Kathryn Carroll, John Ferree, Jim LaDue, and Andy Wood



The purpose of this study is to increase the understanding of decision-makers on how nonmeteorological factors may impact performance improvement goals for individual forecast offices. The impacts of population density and distance to the nearest WSR-88D upon the National Weather Service warning performance measures are examined. This study focuses on warning verification for the St. Louis, Missouri County Warning Area (CWA).


No significant correlations between the performance scores and population density were found. Although no relationship was found, performance measures are likely impacted more by the density and veracity of spotter networks than by the amount of residents. There seems to be a slight correlation with radar distance and two performance measures: False Alarm Ratio and Critical Success Index. Furthermore, a collection of counties with similar population densities at varying distances were grouped together for comparison purposes with the performance measures. Results of this collection showed a more pronounced relationship for all measures. There is also a moderate correlation between the normalized number of warnings and events with both population density and distance to the nearest radar.

Paper available upon request.