A strange, dry summer should soon come to a close.
That’s according to meteorologists, who predict a parched Western Washington’s first soaking rain in months.
“We have a system coming in Friday and Saturday. It is expected to bring widespread rainfall in the area especially in the mountains,” said Mary Butwin, a National Weather Service meteorologist. “It could be a season-ending event for Western Washington.”
The forecast calls for “a notable shift to autumn” Friday with two to four inches of rain in the mountains of Western Washington and about an inch near Puget Sound.
The rainfall will close out one of the hottest and driest summers of all time and offer a reprieve from westside wildfires.
“This should end the wildfire threat at least west of the Cascade crest,” said Joe Boomgard-Zagrodnik, a postdoctoral researcher in agricultural meteorology at Washington State University.
So far, this summer has seen the lowest measurements of precipitation at Seattle-Tacoma International Airport in history with a lowly 0.13 inches of rain since June 21. The record, from June 21 through Sept. 20, is 0.5 inches and was set in 2017.
This weekend’s rain could bump this year’s totals down the charts, Butwin said, though it could remain one of the driest summers of all-time.
It’s also been the fourth-hottest meteorological summer on record, according to Boomgard-Zagrodnik. Temperatures in Seattle have been above normal for the past nine summers now.
Much of the heat this summer came early in the season and was punctuated when a record heat wave broiled the Northwest.
The heat wave — which began June 26 in Seattle — sent temperatures at Sea-Tac Airport soaring above 100 degrees for three straight days. Seattle reached 108 degrees on June 28. Normal high temperatures for Seattle in late June hover around 74 degrees.
But temperatures eased off later in the summer. A healthy onshore flow largely kept wildfire smoke out of Western Washington. Although the heat wave primed the region for wildfire, it didn’t see a rash of lightning strikes or an easterly wind pattern that could have created widespread wildfire problems in Western Washington.
“The dry, warm summer and the lack of moisture — they kind of load the dice or set the stage for wildfire but … you need a good weather event to crank up wildfires west of the Cascades and that never happened,” Boomgard-Zagrodnik said.
“This summer ended with a bit of a whimper, which is good.”
Ocean conditions in the tropics tend to determine winter precipitation and temperature patterns for the Pacific Northwest. The National Weather Service’s Climate Prediction Center says there is a 70-80% chance of a La Niña pattern this winter.
“It doesn’t guarantee that it will be a wet or snowy winter, but it definitely leans the odds pretty strongly in favor of that,” Boomgard-Zagrodnik said.