Thunderstorm Wind — Harrison, Iowa

2024-05-24 · near Modale, Harrison, Iowa

Event narrative

An enhanced area of straight-line wind damage with a maximum speed of 107 mph created widespread damage across nearly 13 square miles. This damage was located 4 miles west of Modale where center pivots were overturned. The damage extended eastward into the Loess Hills where numerous trees were snapped, uprooted and topped. Several power lines were downed in this area as well. Damage occurred to numerous grain bins in this area, but the most extensive and widespread damage was to trees throughout this area.

Wider weather episode

Upper-air analysis showed a trough over the northern Rockies the evening of May 23rd. That night, this trough ejected out into the central and northern Great Plains. At the surface, a low-pressure developed in western South Dakota. Extending south and southwest of this surface low into Colorado was a cold front. A secondary low-pressure center was noted in northwestern Kansas where the surface cold front intersected a dry line that extended south into western Texas.

Shortly after midnight, a line of severe thunderstorms along this cold front moved into the OAX CWA. From 05 UTC through 10 UTC, this line of storms brought widespread severe wind gusts up to 110 miles per hour and 17 spin-up tornadoes across eastern Nebraska and western Iowa. These storms continued to be severe and tornadic through the morning of the 24th, later being classified as a derecho.

Troughing over the western CONUS continued to bring southwesterly flow aloft the region even behind this first trough. By the evening of the 25th, another shortwave trough had amplified over the Great Basin and had shifted over the Rocky Mountains. Ahead of this disturbance, a low-pressure developed in northwest Kansas, with a warm front extending east-southeast across northern and eastern Kansas. The evening of the 25th, scattered strong to severe thunderstorms developed across this frontal zone in northern Kansas and generally tracked to the east-northeast. As such, scattered thunderstorms moved into southeast Nebraska after 9 PM CDT. While largely remaining below severe limits, severe straight-line winds were observed along the south and east side of the Omaha metro as a thunderstorm tracked from western Otoe into eastern Pottawattamie County. It was estimated wind gusts reached as high as 70 miles per hour with this storm, with power outages being reported due to the winds.

View location on OpenStreetMap → (41.6422, -95.9484)

Source: NOAA Storm Events Database, event_id 1181294. Narrative written by the NWS forecast office that issued the report.