An atmospheric river event is poised to bring significant rainfall to the Pacific Northwest, with meteorologists tracking a storm system extending from Hawaii to the Oregon coast.
The weather system is expected to deliver heavy precipitation and mild temperatures to Northwest Oregon and Southwest Washington starting Friday evening, peaking on Saturday night and into Sunday.
“The atmospheric river not only comes with the expected mild temperatures and heavy rain, but the extension of moisture from Hawaii to Oregon,” meteorologist Josh Cozart told local news outlet KOIN 6.
“It’s the long tail of the spiral stretching to the south that technically makes this an atmospheric river. Pushing moisture from Hawaii to the Pacific Northwest comes this weekend.”
Ted S. Warren/AP Photo
The weather event began with strong easterly winds across western Oregon and southwest Washington Friday morning, with gusts potentially reaching 30-35 mph. These down-sloping winds are expected to warm Portland area temperatures into the mid-60s under partly cloudy skies.
As Friday progresses, wind speeds will diminish and rain chances will increase after sunset, with showers intensifying during the late evening hours. This marks the beginning of what forecasters predict will be an extended period of wet weather, potentially lasting through the middle of next week.
The jury is still out on whether the rain will be a full-blown atmospheric river event or a heavy storm.
“I’ve seen that term atmospheric river put out there,” Chris Burling, lead meteorologist with the National Weather Service, Portland, told Newsweek. “I would characterize this rain that we expect this weekend to be more of just a standard frontal passage.
“Regardless, we are expecting pretty good rainfall, particularly Saturday night into Sunday, where the Portland area could see upwards of an inch of rainfall in about a 24 hour period and then will remain showery after that.”
Rainfall accumulations could approach two inches in some locations, with temperatures expected to cool into the 50s next week.
For those planning Halloween activities, there may be some cause for concern. While Halloween (October 31) shows signs of being slightly drier than the preceding days, forecasters note that scattered showers could still impact trick-or-treating plans.
As for hazards, Burling pointed out that there could be some ponding of water on roadways that people need to watch out for. “We don’t expect widespread flooding as the rivers are still at fairly low levels,” he said.
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