Hail in Nance County, Nebraska

It was a noisy start to this Saturday morning across northern sections of South Central Nebraska (almost entirely north of the Highway 92 corridor), as a complex of strong to marginally-severe thunderstorms rumbled through from west-to-east between 6:00-9:30 a.m. CDT, prompting a few reports of hail up to half dollar size and also dumping brief heavy rainfall of 1-2 inches (localized higher). A rundown of hail reports included: half dollar size in Ord, quarter size in Greeley, and nickel size in Belgrade and also near Fullerton. Due largely to the elevated nature of this convection, there were no known instances of damaging winds. Rainfall-wise, the majority of Valley, Greeley and the northern half of Nance County picked up 1-2in a short time, along with localized higher totals such as 2.30 in Belgrade (NWS observer).

Tracing this storm complex back to its origins, initially isolated severe storms erupted over the southwest Nebraska-far northeast Colorado border area between 2-3 a.m. CDT. During the next few hours, this convection grew upscale into a north-south oriented mesoscale convective system (MCS) as it progressed east-northeast through the heart of west-central Nebraska. Then, between 6-7 a.m. CDT, things ramped up quickly within northern parts of the local area, as the initial convective complex, along with scattered storms that suddenly flared up just ahead of it, brought widespread activity to primarily Valley/Greeley counties. Between 7-8 a.m. CDT, all convection again merged into a more cohesive linear complex as the most intense cores shifted from Greeley into northwest Nance counties. Finally, between 8:00-9:30 a.m. CDT, the southern fringes of the MCS rolled through much of northern Nance, far northeastern Merrick and extreme northern Polk counties before exiting South Central Nebraska stage right into eastern Nebraska. In the mid-upper levels, forcing was relatively strong as a pronounced shortwave trough entered western Nebraska out of Wyoming over the course of the night. As a plume of steep mid-level lapse rates overspread Nebraska late in the night (8-9 C/km), the environment became primed for robust elevated convection, with early-AM mesoscale parameters over northern parts of South Central Nebraska featuring a potent combination of around 2000 J/kg most-unstable CAPE and effective deep-layer wind shear of 40-50 knots.