High Wind — Western Whatcom County, Washington

2021-11-14 to 2021-11-16 · Western Whatcom County, Washington

Event narrative

Around 0200L on November 15th, strong winds caused trees to fall across Western Whatcom County, blocking all of I-5 near MP 246 for a period of time.

Wider weather episode

An atmospheric river event across the Pacific Northwest brought

deeper subtropical Pacific moisture as cyclonic flow remained present over the Gulf of Alaska and high pressure remained centered offshore southern California. Near the surface, a stationary boundary was draped from southern BC through the NW tip of

the Olympic Peninsula. A shortwave trough rounded the base of the broader cyclonic flow over the Pacific and helped induce a surface wave along the stationary frontal

boundary, which brought both a flood and wind threat to Western Washington. As the sfc wave/low deepened, south winds strengthened across the entire area, with power outages and downed trees likely. More specifically, a High Wind Warning was in effect for the Everett, Admiralty Inlet, and Western Skagit County areas. West winds of up to 60 mph

were forecast and were expected to have the potential to produce significant

tree and powerline damage. A Wind Advisory was in place for much of the rest of the area.

Source: NOAA Storm Events Database, event_id 994549. Narrative written by the NWS forecast office that issued the report.