Atmospheric rivers to wash away sunny Portland skies

PORTLAND, Ore. (KOIN) — Get outside and get your share of the sunshine over the next few days because, after Halloween, the weather in the Portland region is going to be downright spooky... or at least pretty soggy.

The clear skies and chilly mornings are expected to give way to potentially powerful, back-to-back rainstorms starting Wednesday and lasting through the end of the week.

KOIN 6 Meteorologist Kelley Bayern says that an atmospheric river will bring significant rain to the Portland area by Thursday. The National Weather Service predicts that the initial storm will be followed by a second atmospheric river on Friday night or Saturday. Each storm is expected to drop at least an inch of rain across the Willamette Valley.

“Big weather change is coming this week,” Bayern said. “We will flip back into a soggy pattern across the Pacific Northwest as a moderate to strong atmospheric river arrives on Thursday. Expect stormy conditions through the weekend too. Weather models will adjust, but forecast 3-plus inches around Portland by Monday.”

The arrival of the rain should also mean warmer nights. After multiple nights of freezing temperatures, overnight lows in should be in the low 40s to low 50s.

“We're back under the sun today for another gorgeous afternoon (Monday),” Bayern said. “Highs will stay chilly in the upper 50s to near 60 degrees with a breeze across East Portland today. We stay dry through Halloween evening.”