The first major Pacific storm of the season blew onshore into Washington and Oregon Saturday, bringing heavy rain, high winds and an assortment of warnings and advisories and some snow to higher elevations.
Heavy rains and strong gusty winds were reported up and down the coast from the Seattle area to as far south as northern California. Strong winds in the Portland metro area downed trees and knocked out power to more than 25,000 customers Saturday. Rainfall amounts set records for the date which included:
Seattle-Tacoma Airport: 1.71 inches (previous record 1.65 inches set Sept. 22, 1978 and Sept. 30, 1953)
Olympia, Wash. Airport: 2.93 inches (previous record 1.67 inches set Sept. 17, 2010)
Astoria, Ore.: 3.16 inches (previous record 2.67 inches set Sept. 16, 1997)
A series of frontal waves rotating around an intense area of low pressure in the southern Gulf of Alaska were responsible for the late September storm, and another strong impulse was expected to move onshore this Sunday evening. Another round of heavy rain, strong winds and potential flooding was expected to drive inland and continue across the region through early Tuesday.
Mountain snows are expected to continue to be significant mostly above about 6,000 ft. due to a relatively warm, sub tropical westerly flow. This next impulse should lower snow levels to 4,500 ft. by Monday morning.
Along the coast, storm force wind warnings are in effect through Monday morning for southeasterly gales upwards of 40 to 55 mph with higher gusts. These warnings extend from the Canadian border south to near Coos Bay, Oregon to include offshore waters as well as Washington's Puget Sound and Hood Canal.
Winter storm watches and advisories continue for most of Washington's Cascade range through Monday for heavy snow showers with accumulations of 1 to 2 feet by Tuesday morning.
Additionally, high wind warnings are posted for much of western Washington and Oregon, and inland areas of southern Oregon. Sustained winds in the 30 -45 mph range with gusts upwards of 55 mph are forecast to develop this evening.
Late in September, strong westerly winds aloft in conjunction with intense surface and upper air disturbances can be expected to bring moderately stormy conditions to the Pacific Northwest. Deep cyclones in the Gulf of Alaska also tend to pile up air around them, creating high pressure and sunny, warm conditions further south. Los Angeles and vicinity should continue to be under the influence of dry, stable air for the next few days, as high pressure over New Mexico/Arizona/Colorado only weakens slightly.