ALERT: One of the strongest storms on record ahead for coastal Southwest Canada/Northwest U.S. Sunday night.
Fig. 1: GFS projects a record (since 1950) 941.7 MB low-pressure system off the Washington coastline on Sunday, October 24, 2021.
Northwest U.S. storm discussion: Unofficially, the strongest storm in Northeast Pacific History is forecast for Sunday night by the GFS model (Fig. 1). The GFS forecast indicates a 941.7 MB low will be located about 450 miles due west of Portland, OR at that time. The storm system is in response to a 500 DM height upper trough off the Northwest U.S. Coast. Currently, a 516 DM height upper trough has produced a 947 MB low pressure off the southwest Alaska Coast.
GFS projects a large area of 50-60 mph sustained wind at 10 meters Sunday night just-off the Washington Coast (Fig. 2). Given the central pressure of this storm, sustained hurricane force wind is possible offshore. Wind gusts to hurricane force could reach the coast. ECM indicates 944.3 MB with this storm and implicates northern California, Oregon and Washington to B.C. for strongest wind/heaviest rain (Fig. 3).
Offshore wave heights should be immense with this storm. Conservative forecasts by GFS indicate 12 to 13-meter wave heights Saturday afternoon off the Northwest U.S. Coast (Fig. 4).
Fig. 2: GFS forecasts 50-60 mph sustained wind just off the coast of the Pacific Northwest late Sunday evening.
Fig. 3: ECM projection of strongest onshore weather associated with offshore historic storm on Sunday.
Fig. 4: GFS forecasts 12 to 13-meter wave heights off the Northwest Coast Saturday.