Variability in Isolated Convective Activity between Louisville, Kentucky and Nearby Rural Locations

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  • 1 Department of Geography and Geosciences, University of Louisville, Louisville, KY
  • 2 Department of Atmospheric Sciences, University of North Dakota, Grand Forks, ND
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Abstract

This study analyzes the frequency of strong, isolated convective cells in the vicinity of Louisville, Kentucky. Data from the Severe Weather Data Inventory (SWDI) are used to compare the frequency of convective activity over Louisville to the observed frequency at nearby rural locations from 2003–2019. The results show that Louisville experiences significantly more isolated convective activity compared to the rural locations. The difference in convective activity between Louisville and the rural locations is strongest during summer, with peak differences occurring between May and August. Compared to the rural locations, Louisville experiences more isolated convective activity in the afternoon and early evening, but less activity after midnight and into the early morning. Isolated convective events over Louisville are most likely during quiescent synoptic conditions, while rural events are more likely during active synoptic patterns.

To determine if these differences can be attributed primarily to urban effects, two additional cities are shown for comparison—Nashville, Tennessee and Cincinnati, Ohio. Both Nashville and Cincinnati experience more isolated convective activity than all five of their nearby rural comparison areas, but the results for both are statistically significant at four of the five rural locations. In addition, the analysis of Cincinnati includes a sixth comparison site that overlaps the urbanized area of Columbus, Ohio. For that location, differences in convective activity are not statistically significant.

Corresponding Author Address: Jason Naylor, Department of Geography and Geosciences, University of Louisville, Louisville, KY, 40292. Email: jason.naylor@louisville.edu

Abstract

This study analyzes the frequency of strong, isolated convective cells in the vicinity of Louisville, Kentucky. Data from the Severe Weather Data Inventory (SWDI) are used to compare the frequency of convective activity over Louisville to the observed frequency at nearby rural locations from 2003–2019. The results show that Louisville experiences significantly more isolated convective activity compared to the rural locations. The difference in convective activity between Louisville and the rural locations is strongest during summer, with peak differences occurring between May and August. Compared to the rural locations, Louisville experiences more isolated convective activity in the afternoon and early evening, but less activity after midnight and into the early morning. Isolated convective events over Louisville are most likely during quiescent synoptic conditions, while rural events are more likely during active synoptic patterns.

To determine if these differences can be attributed primarily to urban effects, two additional cities are shown for comparison—Nashville, Tennessee and Cincinnati, Ohio. Both Nashville and Cincinnati experience more isolated convective activity than all five of their nearby rural comparison areas, but the results for both are statistically significant at four of the five rural locations. In addition, the analysis of Cincinnati includes a sixth comparison site that overlaps the urbanized area of Columbus, Ohio. For that location, differences in convective activity are not statistically significant.

Corresponding Author Address: Jason Naylor, Department of Geography and Geosciences, University of Louisville, Louisville, KY, 40292. Email: jason.naylor@louisville.edu
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