Thunderstorm Wind — Jewell, Kansas

2023-09-21 · near Mankato, Jewell, Kansas

Event narrative

Wind gusts estimated to be near 60 MPH caused minor tree damage in Mankato.

Wider weather episode

Although the majority of severe thunderstorm activity within the general region on the afternoon of Thursday the 21st into the early morning of Friday the 22nd focused only 25-50 miles north and west of this six-county North Central Kansas area, parts of the local domain still endured a glancing blow of strong to marginally-severe storms, occurring in two distinct rounds. Ground truth reports were limited, but were highlighted by: wind gusts of 60 MPH near Woodruff (unofficial mesonet) and also in Mankato (estimated)...with tree damage noted; quarter size hail eight miles west of Phillipsburg. Elsewhere within the area, radar-data-based Severe Thunderstorm Warnings included parts of eastern Mitchell and Jewell counties, along with much of Smith County, but yielded no verifying reports. In addition to the hail/wind, much of primarily Phillips, Smith and Jewell counties observed heavy rainfall (widespread coverage of 1.50-2.50 per NWS/CoCoRaHS observers and AHPS analysis). Due in part to recent dryness, widespread/impactful flooding was not an issue, although some rural Phillips County roads reportedly had brief water issues.

Breaking down event evolution/timing and starting with the big picture in the mid-upper levels, forcing was on the weak side, with only subtle, low-amplitude disturbances drifting into the Central Plains from the west-southwest, well downstream from an expansive parent upper low churning away over the northwestern United States. Locally, the first round of strong to severe activity unfolded between 3-5 p.m. CDT as a pair of isolated storms erupted over Mitchell and Jewell counties before departing North Central Kansas off to the north and east (these storms yielded a report of penny size hail north of Asherville). This initial round, which evolved into more widespread activity slightly north of the state line in Nebraska, fired up within a diffuse surface warm frontal zone, in an environment characterized by temperatures in the 80s (F) and dewpoints in the low-mid 60s. The mesoscale environment was primed for severe storms, featuring healthy mixed-layer CAPE of 2000-3000 J/kg, but somewhat modest deep-layer wind shear of only 30-35 knots (prompting slower storm motions). Once this early round of isolated convection exited, North Central Kansas remained largely storm-free well into the evening (during which time severe weather focused slightly north and west within south central NE/northwest KS). But then, between 9:30-11:30 p.m. CDT, the southern reaches of a developing mesoscale convective system (MCS) rolled eastward through much of Phillips/Smith counties, aided by the development of a 30-40 knot low level jet, and also featuring an embedded supercell that briefly affected western Phillips County before weakening. Between 11:30 p.m. and 1 a.m. CDT, the most intense part of the MCS charged through Jewell County before exiting eastward out of the local domain and ending the severe weather threat for the night. In its wake, a large shield of trailing stratiform rain with a few embedded, weak storms persisted within North Central Kansas for a few more hours, but the vast majority of the area was precipitation-free by 3 a.m. CDT on the 22nd.

View location on OpenStreetMap → (39.7900, -98.2100)

Source: NOAA Storm Events Database, event_id 1137092. Narrative written by the NWS forecast office that issued the report.