Environmental and Radar Characteristics of Gargantuan Hail-Producing Storms

Abstract

Storms that produce gargantuan hail (defined here as ≥ 6 inches or 15 cm in maximum dimension), although seemingly rare, can cause extensive damage to property and infrastructure, and cause injury or even death to humans and animals. Currently, we are limited in our ability to accurately predict gargantuan hail and detect gargantuan hail on radar. In this study, we analyze the environments and radar characteristics of gargantuan hail-producing storms to define the parameter space of environments in which gargantuan hail occurs, and compare environmental parameters and radar signatures in these storms to storms producing other sizes of hail. We find that traditionally used environmental parameters used for severe storms prediction, such as most unstable convective available potential energy (MUCAPE) and 0–6 km vertical wind shear, display considerable overlap between gargantuan hail-producing storm environments and those that produce smaller hail. There is a slight tendency for larger MUCAPE values for gargantuan hail cases, however. Additionally, gargantuan hail-producing storms seem to have larger low-level storm-relative winds and larger updraft widths than those storms producing smaller hail, implying updrafts less diluted by entrainment and perhaps maximizing the liquid water content available for hail growth. Moreover, radar reflectivity or products derived from it are not different from cases of smaller hail sizes. However, inferred mesocyclonic rotational velocities within the hail growth region of storms that produce gargantuan hail are significantly stronger than the rotational velocities found for smaller hail categories.

Thermodynamic Conditions during August 2022 in Catalonia: The Monthly Record of Hail Days, Hail Size and the Differences in the Climatic Values

“…Although their values were exceptional and should be an inhibitor factor of the hail generation [7,15], they were balanced by the high quantities of moisture in the atmosphere and the intense vertical updrafts. -From the climatic point of view, the positive trend of all the analysed variables agrees with most of the previous studies [7,8,10,16,24,37]. However, the contribution of the PWM looks more relevant than in other regions.…”

How Many Types of Severe Hailstorm Environments Are There Globally?

“…Melting begins as ice particles fall below the melting level, with higher levels and more moist sub-cloud air accelerating the melting process, which has a greater impact on small hail (Brimelow et al, 2017;Dessens et al, 2015;Mahoney et al, 2012;Pruppacher & Klett, 1997; R. M. Rasmussen & Heymsfield, 1987;Willis & Heymsfield, 1989). Stronger and longer-lived updrafts are also known to provide favorable conditions for the growth of large hailstones (Dennis & Kumjian, 2017;Gutierrez & Kumjian, 2021;Nelson, 1983Nelson, , 1987. Strong vertical wind shear (VWS) is needed to organize storm structure, increasing hailstorm longevity and severity (Dennis & Kumjian, 2017;Markowski & Richardson, 2010;Wallace & Hobbs, 2006;Weisman & Klemp, 1984).…”

Supercell convective environments in Spain based on ERA5: hail and non-hail differences

“…According to Markowski and Richardson (2011) WS tends to enhance the organization, severity and longevity of the deep moist convection. However, SP-HAIL low-level WS is higher than for SP-NONHAIL, favoring hail growth (Gutierrez and Kumjian, 2021).…”

“…5b) and wind convergence (Fig. 4b) trigger, enhance and reinforce deep moist convection at t 0 , favoring large hail formation over the Ebro Valley and the Mediterranean area (Gutierrez and Kumjian, 2021).…”