Hail — Madison, Montana

2021-07-22 · near Ennis Big Sky Arpt, Madison, Montana

Event narrative

Hail up to 3/4 inch in diameter reported by a trained spotter visiting the area.

Wider weather episode

An unstable southwesterly flow developed ahead of an approaching Pacific trough and brought strong to severe thunderstorms over a three day period. Surface based CAPE routinely exceeded 1000 j/kg as steep mid-level lapse rates above 8C/km were common. Dry sub-cloud layers helped produce strong thunderstorm wind gusts and effective shear well above 30 kts was enough for quarter size hail and larger. The peak in severe weather occurred on Wednesday July 21st as the main energy associated with the trough moved through the region.

View location on OpenStreetMap → (45.2898, -111.3996)

Source: NOAA Storm Events Database, event_id 972553. Narrative written by the NWS forecast office that issued the report.