Thunderstorm Wind in Lemhi County, Idaho

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.

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.