Tornadoes, Hail, and Wind associated with Warm-Season Stationary Fronts East of the Rocky Mountains

Stationary Fronts (SFs) are defined as the slow-moving boundary between two air masses of differing temperatures (NOAA). This study was designed to explore the relationship between stationary fronts and severe weather. A total of 279 SFs were chosen from a 9 year climatology of SFs to analyze and lasted 24-48 hours. In the 9 year climatology, a 2.5 x 2.5 grid system was created in order to record the duration of a front in particular locations. The locations of the 24-48 hour fronts were then each plotted on the grid using latitude and longitude data in GIS. Storm report data from the days in which the fronts persisted was gathered from the National Weather Service’s data archive and plotted on the same map as the front, again using latitude and longitude data. Next, the reports were classified based on their location in relation to the SF. The total number of reports, both associated (common grid box with SF) and proximal (grid box surrounding SF), were counted. Those totals were then categorized by type of report (e.g. tornado, wind, or hail).

Preliminary results indicate a clear relationship between report type produced by SFs and the month in which they occur. For all types of reports, tornado, wind, and hail, the maximum median number of reports generally occurred in June, while the minimum median number of reports occurred in April and September. In general, this study shows that severe weather of all types most typically occurs along SFs that form in the mid warm-season months. Future research will explore the environmental characteristics on severe weather days and non-severe weather days associated with SFs