Thunderstorm Wind in Jewell County, Kansas

Wind gusts estimated to be near 60 MPH resulted in some minor tree damage in Jewell.

Although this North Central Kansas area was spared a much nastier combination of wind-driven hail that walloped parts of far southern Nebraska just off to the north-northwest, it was still impacted by a pair of severe storms during the predawn hours on this Thursday...including a very long-lived supercell. All ground-truth storm reports were associated with this supercell/compact cluster as it charged across Phillips, Smith and Jewell counties between 3:45-6:00 a.m. CDT, with a sampling of reports including: measured gusts of 62 MPH near Lovewell Reservoir (unofficial mesonet) and 58 MPH at Phillipsburg airport (AWOS); quarter size hail near Long Island. Although there were no reports of significant/widespread damage, a small garage was destroyed east of Mankato and some tree damage was confirmed in Smith Center and Jewell. To the southwest of the primary supercell, a smaller isolated severe storm reached radar-indicated severe levels as it traversed the Osborne-Smith County line, but there was no ground-truth verification.

Breaking down event evolution/timing, in the mid-upper levels, although lacking any noteworthy, small-scale disturbances, broad and seasonably-strong west-southwesterly flow was in place over the Central Plains...downstream from a large scale, positively-tilted trough centered from the Northern Rockies to the Great Basin. At the surface, North Central Kansas resided slightly north of a quasi-stationary front stretched across the state from southwest-to-northeast, with resultant east-northeasterly breezes to the north of this boundary enhancing High Plains upslope flow. Turning to storm-scale details, the primary supercell that eventually slipped into the local area actually initiated/became severe roughly 280 miles off to the west-northwest during the late afternoon of the 28th...in extreme southeast Wyoming. During the evening, the intense storm slowly lumbered southeastward through the far southwestern Nebraska Panhandle into northeast Colorado. By around midnight CDT, this convection had morphed into a powerful supercell cluster/small complex as it entered far southwestern Nebraska and started tracking more due-east...riding along the northern fringes of a tight mid-level temperature gradient (generally hugging the 12C line at 700 millibars). After rolling across southwestern into far south central Nebraska for several hours, the far southern (and slightly less vigorous) fringes of the supercell cluster reached northwestern Phillips County around 3:45 a.m. CDT. Over the next few hours, it tracked east-southeast along/near the Highway 36 corridor...before exiting the local area out of eastern Jewell County by 6 a.m. CDT. Back to the southwest and in the wake of the passage of the dominant storm complex, the aforementioned briefly-severe-warned storm tracked along the Osborne-Smith County line between 5:45-6:30 a.m. CDT before weakening, with North Central Kansas almost entirely convection-free by 7 a.m. CDT. The mesoscale environment strongly supported a long-lived, persistent supercell cluster, featuring a formidable combination of at least 2000-3000 most-unstable CAPE and 50-60 knots of deep-layer wind shear. That being said, from a forecast perspective, this was not an overly-obvious setup for an early morning severe threat. Although some necessary ingredients were clearly present, short term/higher-resolution computer models (CAMs) varied considerably regarding how evening High Plains convection would evolve, and to what degree it would impact locales farther east (including North Central Kansas). The 01 UTC (8 p.m. CDT) Day 1 Convective Outlook from SPC (valid through the early morning of the 29th) highlighted only a Marginal Risk (level 1 of 5) for North Central Kansas, but also acknowledged very substantial uncertainty.