Don’t let Tuesday’s nice weather fool you — a possibly historic wind and rainstorm is headed for Western Washington late Wednesday, according to the National Weather Service.
About 4 inches of rain is expected for lowland parts of Pierce County from late Wednesday through Sunday, along with strong wind and a possibility of saltwater flooding close to Puget Sound, meteorologist Andy Haner said Tuesday.
“We are looking at quite a stormy period,” he said. “The two biggest threats are going to be wind and flooding rain.”
Two strong low-pressure systems are headed for the Pacific Northwest, the first arriving late Wednesday.
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The second, arriving Saturday, is the “revived leftovers” of a strong typhoon near Guam that’s expected to strengthen as it heads east, Haner said.
Typhoons and Pacific Ocean hurricanes (identical storms, except for which part of the ocean they are in) are taken into the westerly jet stream yearly, but this storm is expected to remain more intact than most while tracking farther south than most.
“It’s a pretty impressive setup, as far as looking at the weather is concerned,” Haner said.
That storm’s pressure is expected to be so low that it will raise the sea level, similar to how water is sucked up into a straw as a person removes the air from it, Haner said.
Differences in atmospheric pressure also generate strong winds.
Because the storm is so far out, it’s difficult for the Weather Service to determine where it’s going — one model has it headed for the Western Washington coast, Haner said, while another has it traveling 200 miles north into British Columbia.
“If the remnants of that really track close to us on Saturday, we can end up with winds strong enough to cause damage in the Tacoma area,” Haner said. “If they veer further offshore, it would be a windy day, but not memorable.”
Along with the 4 inches of rain in the lower elevations, even more is expected in higher areas, leading to expected river flooding in the region.
“I’m sure some rivers will flood, but once again, even just a slight shift in where the rain falls can change which river basin it falls into,” Haner said.
A flood watch has been issued for Mason County for Wednesday and Thursday.
Haner said people looking forward to the start of razor clam season on Washington’s coast should prepare for waves of up to 30 feet along with heavy rainfall Saturday.
He called the possible conditions “life-threatening.”