Northern Alabama/Southern Middle Tennessee Severe Weather Environmental Climatology

The Huntsville, Alabama county warning forecast area (CWFA) is at risk for severe weather year-round; therefore, accurate severe weather forecasts are integral to creating a Weather-Ready Nation. The goal of this research project was to improve forecast accuracy by providing forecasters with statistical information for a thorough list of parameters used to describe severe weather environments. Accordingly, environments leading up to 131 different severe weather events that impacted the Huntsville CWFA over the past 10 years were examined; events had to generate either numerous severe reports, or at least 1 significant severe report (wind gust ≥65kt or hail ≥2”) to be included in the study. Each event was classified by the season in which it occurred and the mode (discrete, cluster of cells, QLCS) of the storm which produced the report. We found that spring and summer have the most hail and wind events. The predominant storm mode for severe hail is discrete cells; storm mode is more evenly distributed and seasonally variant for severe wind events. Results show that QLCS events can occur with lower CAPE and weaker lapse rates than discrete cells or clusters. Summer QLCS events have a northwesterly component to the low and mid-level flow, while QLCS events in other seasons have a more southerly component to the low/mid-level winds. Elevated mixed layers also appear to be less common in summer, regardless of storm mode. This presentation will also cover more detailed findings and provide insight as to how forecasters can use this information operationally. This research was done as part of the NOAA Hollings Scholarship Program.