Assessment of the Extreme Rainfall Event at Nashville, TN and the Surrounding Region on May 1–3, 2010

Abstract

This paper analyzes the May 1–3, 2010 rainfall event that affected the south‐central United States, including parts of Mississippi, Tennessee, and Kentucky. The storm is evaluated in terms of its synoptic setting, along with the temporal distributions, and spatial patterns of the rainfall. In addition, the recurrence interval of the storm is assessed and the implications for hydrologic structure designs are discussed. The event was associated with an upper‐level trough and stationary frontal boundary to the west of the rainfall region, which remained quasi‐stationary for a period of 48 h. Heavy rainfall was produced by two slow‐moving mesoscale convective complexes, combined with abundant atmospheric moisture. Storm totals exceeding 330 mm occurred within a large elongated area extending from Memphis to Nashville. Isolated rainfall totals over 480 mm were reported in some areas, with NEXRAD weather radar rainfall estimates up to 501 mm. An extreme value analysis was performed for one‐ and two‐day rainfall totals at Nashville and Brownsville, Tennessee, as well as for gridded rainfall estimates for the entire region using the Storm Precipitation Analysis System. Results suggest maximum rainfall totals for some durations during the May 1–3, 2010 event exceeded the 1,000‐year rainfall values from National Oceanic and Atmospheric Administration Atlas 14 for a large portion of the region and reached up to 80% of the probable maximum precipitation values for some area sizes and durations.

Climatology and Trends in Hourly Precipitation for the Southeast United States

“…6d), highlighting the intensity of winter precipitation across the Gulf Coast. Nonetheless, winter is when most stations experience the longest average duration of precipitation events, primarily due to frequent frontal events (Keim 1996). In spring (MAM), PH are more frequent in the northern portion of the region (Fig.…”

“…1). The region was selected because it frequently experiences extreme events (Kunkel et al 2012(Kunkel et al , 2013bKeim et al 2018), is highly vulnerable to a changing climate (Powell and Keim 2015;Carter et al 2018), is a leading producer of important crops such as oranges, cotton, tobacco, rice, and vegetables (USDA 2016), and matches the study region used by Henderson and Vega (1996), Keim (1997), and Powell and Keim (2015). The region constitutes the southeastern quadrant of the conterminous United States.…”

“…are received annually. Variability is largely explained by daytime convective rainfall (Kunkel et al 2013a), the strength and position of the Bermuda high, particularly in summer (Li et al 2011(Li et al , 2012Diem 2013;Zhu and Liang 2013), proximity to and sea surface temperatures (SSTs) of the GOM (Trenberth 1998;Trenberth et al 2003) and Atlantic Ocean, tropical cyclones (Keim 1996;Nogueira andKeim 2010, 2011;Nogueira et al 2013), and local topography. Tropical cyclones, which are important to the climatology (Simpson and Riehl 1981;Nogueira et al 2013) and cause extreme precipitation events in the SeUS (Kunkel et al 2012), were not controlled for or removed.…”

“…Periodic relocation of stations can induce discontinuities in precipitation time series and, along with other biases discussed above, may limit the ability to detect changes in the hydrologic cycle or climate change (Groisman and Legates 1994). Keim et al (2003) investigated relocation bias and its impact on temperature measurements and asserted that it is likely these biases also exist in precipitation time series. When a precipitation gauge is moved, it is probable the vegetation, proximity to buildings, or elevation also changed.…”

“…6c), where Florida and Texas have shorter average durations compared to most of the region. Longer duration events in the northeastern sector of the region are related to frontal events that often bring snow (Keim 1996). Gulf Coast locations exhibit shorter durations compared to interior locations but have higher average hourly accumulations ( Fig.…”