High Wind — Lower Garfield & Asotin, Washington

2012-12-17 · Lower Garfield & Asotin, Washington

Event narrative

A DOT site at Alpowa Summit, elevation 1775 feet, measured sustained winds of 52 mph with a peak gust of 69 mph between 0500 and 0700 PST. The sensor continued to report sustained winds of 35 to 45 mph with gusts to 60 mph through 1400 PST. Two additional CWOP sites in Pomeroy, WA also recorded wind gusts between 57 and 60 mph. No damage was reported in the area.

Wider weather episode

A potent winter storm slammed into the Pacific Northwest from the evening hours of December 16th through sunset on December 17th. The surface low reached a peak intensity of 973 millibars while crossing into Northwestern Washington before gradually weakening and tracking east, northeast along the Canadian Border. Strong isentropic ascent coupled with orographic flow resulted in heavy wet snow across the East Slopes of the Washington Cascades Sunday evening which shifted into Northeastern Washington overnight into Monday morning. A strong low-level jet on the eastern periphery of the low ushered a tongue of warm air into Eastern Washington overnight. This lead from a transition of heavy snow to rain for most locations between Grand Coulee and Spokane. Snowfall amounts along the Highway 2 corridor from Spokane to Wenatchee ranged from two to six inches. Snowfall totals across the The East Slopes of the Washington Cascades and northern mountains ranged from six to thirteen inches in the valleys to over a foot in the mountains. Strong winds also accompanied this storm. The combination of gusty winds and heavy wet snow lead to numerous downed trees in the East Slopes of the Cascades resulting in several road closures and numerous power outages. The strongest winds were experienced across the West Plains, Palouse, Columbia Basin, and Northeast Mountains. The winds knocked down a pair of large trees in the Spokane Area and snapped numerous tree limbs resulting in 7300 power outages.

Source: NOAA Storm Events Database, event_id 423328. Narrative written by the NWS forecast office that issued the report.