Thunderstorm Wind — Lemhi, Idaho

2013-09-05 · near North Fork, Lemhi, Idaho

Event narrative

The Kriley Creek RAWS at 5,200 ft. MSL reported a hurricane force wind gust associated with a wet multicellular thunderstorm. It also reported a 69 mph gust during the 4:51 to 5:51 pm MDT hour. Doppler radar data shows that this gust probably occurred after 5:30 pm MDT. It also showed a wind shift from a west-southwest to a north-northeast direction as the storm passed to the northeast between the 5:51 and 6:51 pm MDT observations. This potentially could be classified as a wet microburst. Power and phone outages were reported in North Fork.

Wider weather episode

Strong rising air associated with the nose of a 50 knot mid-level south-southwest jet combined with near record high moisture levels and an unstable atmosphere triggered wet multicellular thunderstorms over Lemhi County by late afternoon on September 5th. Flash flooding and power outages were the main impacts. To get an understanding how moist the air mass associated with this southwest surge was, the Boise weather balloon sounding recorded the 2nd highest moisture level (precipitable water values) on record on the evening of the 5th.

View location on OpenStreetMap → (45.3560, -113.8950)

Source: NOAA Storm Events Database, event_id 474179. Narrative written by the NWS forecast office that issued the report.