Trends in United States large hail environments and observations

Abstract

Understanding trends in large hail-producing environments is an important component of estimating hail risk. Here, we use two environmental parameters, the Large Hail Parameter and the Significant Hail Parameter, to assess trends in days with environments conducive for hail ≥5 cm. From 1979 to 2017, there has been an increase in days with favorable large hail environments in central and eastern portions of the U.S. This increase has been driven primarily by an increasing frequency of days with steep mid-tropospheric lapse rates and necessary combinations of instability and vertical wind shear for severe thunderstorms. Annual large hail environment area is significantly, positively correlated with (1) large hail report area east of the Rocky Mountains, and (2) large hail radar-derived area in the Midwest and Northeast. This evidence suggests that there may be an environmental fingerprint on increasing large hail risk and expanding this risk eastward.

Practically Perfect Hindcasts of Severe Convective Storms

“…Hail also shows an impressive relative maximum ∆, with at least 15 more days per year being reported in western Kansas, Nebraska, and southwest South Dakota versus the previous 20-yr period. This is consistent with recent research examining trends in U.S. hail reports and favorable hail environments (Tang et al 2019).…”

“…For tornadoes, the aggregate consensus indicates that frequency has remained relatively constant through the most reliable portions of the climatological record (Verbout et al 2006;Kunkel et al 2013;Tippett et al 2015;Long et al 2018;Potvin et al 2019). Trends have been noted, however, in the temporal variability (Brooks et al 2014;Farney and Dixon 2015;Guo et al 2016) and spatial locations of tornado (Gensini and Brooks 2018;Moore and McGuire 2019) and hail (Tang et al 2019) reports. A more clear consensus about spatiotemporal trends in damaging convective wind gusts has yet to emerge in the literature.…”

Severe Convective Storms across Europe and the United States. Part II: ERA5 Environments Associated with Lightning, Large Hail, Severe Wind, and Tornadoes

“…Brooks et al (2003) conducted a pioneering study using model data to estimate global climatology of environments leading to severe convective storms. Subsequent work has typically focused on regional studies for the U.S. (Gensini and Ashley 2011;Tippett et al 2012Tippett et al , 2014Allen et al 2015;Gensini and Brooks 2018;Tang et al 2019, Li et al 2020, Australia (Allen et al 2011; Allen and Karoly 2014; Allen and Allen 2016) Europe (Marsh et al 2009;Púčik et al 2017;Rädler et al 2018;Taszarek et al 2018Taszarek et al , 2019, China (Li et al 2018), Southern Africa (Blamey et al 2017), and South America (Bruick et al 2019). Global aspects of CAPE, convective inhibition (CIN) and hail environments were also evaluated by Riemann-Campe et al (2009), Chen et al (2020), and Prein and Holland (2018).…”

Comparison of Convective Parameters Derived from ERA5 and MERRA-2 with Rawinsonde Data over Europe and North America

“…The choice of parameters evaluated in this study was based on indices commonly applied in studies focusing on severe thunderstorm environments and their corresponding climatologies over both Europe and the United States (Rasmussen and Blanchard 1998;Thompson et al 2003;Craven and Brooks 2004;Groenemeijer and van Delden 2007;Kaltenböck et al 2009;Gensini and Ashley 2011;Thompson et al 2012Thompson et al , 2013Allen et al 2015;Tang et al 2019;Liu et al 2020;Taszarek et al 2020Taszarek et al , 2021. For each sounding and reanalysiscollocated profile, we used temperature, humidity, pressure, height, and u and y wind.…”

“…Atmospheric reanalyses provide a best guess to the state of the past atmosphere, and unlike sparse sounding data with limited spatiotemporal resolution, they are an invaluable tool for construction of severe thunderstorm climatologies (Brooks et al 2003;Gensini and Ashley 2011;Tippett et al 2012;Thompson et al 2013;Allen and Karoly 2014;Allen et al 2015;Taszarek et al 2018;Chen et al 2020;Li et al 2020;Taszarek et al 2020), assessment of long-term historical trends (Mohr and Kunz 2013;Gensini and Brooks 2018;Rädler et al 2018;Tang et al 2019;Taszarek et al 2021), and investigation of environments associated with specific convective hazards leading to their better prediction (Thompson et al 2003(Thompson et al , 2007(Thompson et al , 2012Gropp and Davenport 2018;Coffer et al 2020;Ingrosso et al 2020;Taszarek et al 2020;Rodríguez and Bech 2021). The new ERA5 reanalysis provides higher spatial, vertical, and temporal resolution that represents convective environments with a resolution that was not available in prior global reanalysis, opening new research possibilities.…”