Heavy Rain — Pondera, Montana

2020-05-20 · near Ledger, Pondera, Montana

Event narrative

Rainfall total for 24 hours (7 AM Tuesday 5/19 to 7 AM Wednesday 5/20) was 1.75 inches.

Wider weather episode

A broad closed upper level low moved onto the California/Oregon coast and eventually swung northeastward through Western Montana. South to southwesterly flow ahead of this system pumped in moisture and unstable air, while diffluent flow at H300 provided upper level support. This initially brought scattered severe wind gusts and hail to portions of Central and North-central MT on May 18th and 19th. As the general forcing associated with the low approached the state on the 20th, the event transitioned to a more of a moderate to heavy stratiform rain event for all areas, although some severe weather was still reported.

View location on OpenStreetMap → (48.2700, -111.8200)

Source: NOAA Storm Events Database, event_id 889396. Narrative written by the NWS forecast office that issued the report.