Thunderstorm Wind in Howard County, Nebraska

Wind gusts estimated to be near 60 MPH resulted in tree damage in St. Paul.

A generally north-south oriented linear mesoscale convective system (MCS) packing strong to marginally-severe winds marched across the entirety of South Central Nebraska on this Sunday evening, prompting several gusts mainly as high as 55-65 MPH almost entirely within counties along/west of Highway 281. Fortunately, convection underwent gradual weakening while tracking farther east, with gusts typically no more than 40-50 MPH within counties along the Highway 14 and Highway 81 corridors. All measured/estimated severe-criteria gusts and limited reports of storm impacts focused along the modestly-bowed apex of the MCS...or mainly 15-30 miles either side of Interstate 80 including counties such as Dawson, Buffalo, Phelps, Kearney, Hall and Howard. A few of the highest measured wind gusts (unofficial mesonets) included: 66 MPH near Farnam and 63 MPH near both Gothenburg and in far northeastern Buffalo County. Fortunately, ground-truth damage reports were few, but included: multiple trees/large branches downed in St. Paul and a power line blown down in Kearney that contributed to a house fire.

Breaking down the meteorological background and event timing, on a positive note this MCS ultimately underachieved its forecast intensity/impacts within the 24-county South Central Nebraska domain...instead peaking in ferocity during its early stages over western Nebraska (where several more-significant gusts of 70-80+ occurred) before starting to gradually lose steam just before entering the western fringes of the local area between 7:30-8:00 p.m. CDT. The convective complex maintained a consistent forward motion over the next several hours, passing through the Highway 281 counties between 9:30-10:30 p.m. CDT and exiting the eastern fringes of South Central Nebraska between 11:30 p.m. and 12:30 a.m. CDT on the 3rd. In the big picture of the mid-upper levels, broad, quasi-zonal flow prevailed over the Central Plains, with a low-amplitude (but evident) shortwave trough shifting eastward out of Wyoming into the Dakotas and western Nebraska during the evening. At the surface, South Central Nebraska resided within a broad warm/moist sector prior to the MCS arrival, with breezy south-southeast winds ushering in low-mid 60s (F) dewpoints. As storms entered western local counties, the mesoscale environment featured around 2000 J/kg mixed-layer CAPE and effective deep layer shear around 40 knots. The somewhat rapid weakening of convection as it rolled east through the area was somewhat unexpected, but seemed tied to a decrease in deep layer shear magnitude. Although the South Central Nebraska convection was not as intense as it could have been, the potential threat was well anticipated/messaged, as SPC introduced an Enhanced Risk (level 3 of 5) for nearly the entire area on its Day 2 Convective Outlook (issued on the afternoon of the 1st) and maintained it throughout the Day 1 period.