Hail — Hamilton, Nebraska

2022-06-04 · near Aurora, Hamilton, Nebraska

Event narrative

Quarter to golf ball size hail was reported across Aurora.

Wider weather episode

Mainly between 7 p.m. and midnight CDT on this Saturday evening, isolated to scattered severe thunderstorms roamed various parts of South Central Nebraska, but with the overall-greatest coverage focused within the north half of the area (counties along/north of I-80). These storms yielded several reports of hail up to golf ball size, along with localized heavy rain, but no reports of damaging winds. Portions of Merrick and Hamilton counties bore the brunt of hail during the evening, as two separate, slow-moving supercells drifted slowly southward, one mainly between 7:00-9:30 p.m. CDT and the next mainly between 10 p.m. and midnight CDT. During this first round, the main hail swath generally tracked between Central City and Marquette, with a spotter in Marquette reporting intermittent golf ball size hail for 20 minutes. The later storm followed a similar path (again pounding Marquette with golf ball size stones), but this one drifted farther south down Highway 14, dropping quarter to golf ball size hail in the Aurora area before weakening. Elsewhere within the coverage area, quarter size hail was confirmed between Wolbach and Cushing, and also near Stromsburg. Radar data strongly suggested that hail to at least quarter size also likely fell within the following counties (but without ground-truth verification): southern Valley and Greeley, northern Sherman, northeastern Dawson and Buffalo, and various parts of Nance. Rainfall-wise, the greatest concentration of at least 1.50-2.50 inches was (not surprisingly) within a north-south stripe through Merrick/Hamilton counties. Although localized totals of 3+ likely occurred (the highest official measured tally was 2.81 from an NeRAIN gauge in Aurora), there were no confirmed reports of significant flooding.

Breaking down event evolution/timing, the first storms of the afternoon actually developed both slightly west and east of northern portions of South Central Nebraska between 5-6 p.m. CDT, initiating along a west-southwest to east-northeast oriented quasi-stationary surface front. Between 7-8 p.m. CDT the first strong to severe storms within the local area got underway, either developing near the aforementioned front or drifting in from the west. For the next several hours, a mix of severe multicell and splitting supercell storms continued to track across counties primarily along/north of I-80 (Furnas County in the far southwestern local area narrowly avoided a large severe storm that impacted much of Red Willow County). Just as the clock struck midnight, the final two severe-warned storms of the night (over northeast Buffalo/southern Hamilton counties) began to weaken considerably, and by 2 a.m. CDT on the 5th the vast majority of South Central Nebraska was storm-free for the night. In the mid-upper levels, this event was fairly weakly forced, as the region resided under broad west-northwest flow containing only subtle waves, but with sufficient deep layer wind shear (around 35 knots). At the surface, afternoon temperatures climbed well into the 80s F, which combined with dewpoints rising into the low-60s F to promote healthy mixed-layer CAPE around 2000 J/kg. This combo of strong instability and adequate deep layer shear proved sufficient for robust convection in the vicinity of the aforementioned frontal zone.

View location on OpenStreetMap → (40.8700, -98.0000)

Source: NOAA Storm Events Database, event_id 1032793. Narrative written by the NWS forecast office that issued the report.