SEATTLE – No rest for the weary in the Pacific Northwest. On the heels of a deadly Pineapple Express storm this week that brought several inches of rain and sent multiple rivers over their banks and into nearby neighborhoods, a new atmospheric river storm looms for the weekend.
WHAT IS A ‘PINEAPPLE EXPRESS’?
Heavy rain will return to the region from late Friday into Saturday, adding more water to swollen rivers that have mostly returned to their banks after reaching moderate to even record flood levels on Tuesday and Wednesday but are still running high.
This atmospheric river differs in three ways from its predecessor: It’s a bit weaker, it’s moving faster, and it isn’t anywhere near as warm as the record-breaking temperatures that brought snow levels over 8,000 feet earlier this week. Those changes will keep snow levels lower, meaning less water will immediately reach the rivers.
On the other hand, the return of impactful snow to the mountains and their passes will present travel challenges to those heading into the passes.
There are still some lingering showers in the region on Thursday as floodwaters continue to recede. Lingering Flood Warnings remain in effect for a handful of rivers into Thursday afternoon across western Washington and western Oregon.
After a break in the weather Friday, the next atmospheric river arrives in the Northwest on Saturday with steady moderate to heavy rain in the lowlands and increasing mountain snow.
By Sunday, about another 0.5-2 inches of rain is likely in the Interstate 5 corridor in Washington and Oregon, with another 2-5 inches of rain expecte along the coastal regions and their mountains.
“This is a lot of heavy rain kind of moving in and butting up against the Coastal Range and Olympic Mountains … so that’s going to add to the flood factor there,” FOX Weather Meteorologist Britta Merwin said.
So far, it appears any new flooding impacts will be minor but still bear watching.
“Given saturated ground conditions and rivers/streams still running well above average, would expect some additional flooding impacts with this event,” NOAA’s Weather Prediction Center wrote while placing that area in a Level 2 out of 4 risk for flash flooding Saturday. “Snow levels are lower with this event, so the majority of impacts should be along the coastal ranges of northwest (Oregon) and western (Washington) into portions of the (Olympic Mountains).”
Travel impacts will also return to the mountains, with as much as 10-15 inches of fresh snow into Sunday in the Washington Cascades. Snow will spread east into parts of the inland Northwest and far northern Rockies, with moderate snow accumulations likely around Spokane, Washington, and northern Idaho from late Saturday into Sunday.
The long-range forecast shows a break in the weather early next week as a brief ridge of high pressure allows the region to wring out.