Thunderstorm Wind in Ada County, Idaho

Numerous reports of trees downed or large branches snapped throughout the Boise metropolitan area. The two points were based on two reports that reasonably capture the south to north extent of damage, with timing estimated by radar. Reports of storm damage extend as far west as Caldwell and as far east as Boise. With the extent of damage, and measured gusts nearby, this damage was likely caused by winds of at least 60 mph. This damage was caused by the same outflow boundary associated with thunderstorms.

On May 28th, an upper low was over the Great Basin. A shortwave propagating around this low helped prime the atmosphere for thunderstorm development. A dry, well-mixed boundary layer was present over far southwest Idaho leading to a severe wind threat. Further north into the west central Idaho mountains, effective shear was to 30-40 knots. This increased the hail threat north, in addition to the wind.