Heavy rain incoming: Atmospheric river pushes into Portland Wednesday

PORTLAND, Ore. (KOIN) — The greater Portland area is forecast to see 2 inches of rain between Wednesday and Thursday as a stronger-than-expected atmospheric river moves into Northwest Oregon and Southwest Washington.

More rain will be possible in the mountains and on the coast. Meteorologists predict 2 to 5 inches of rain in the Willapa Hills, along the Coast Range and in the Cascades. Between 1.5 and 3 inches of rain is possible on the coast. The National Weather Service warns that the heavy rain may cause minor flooding along roadways.

“The main concern with this event is the potential for urban flooding in areas of poor drainage,” the NWS stated. “Officials and property owners should do what they can to clear storm drains of fallen leaves before the rain arrives Wednesday. Minor flooding of a few small streams is possible, but flooding of rivers and larger creeks is unlikely.”

KOIN 6 Meteorologist Kelley Bayern reports that Wednesday morning sprinkles will build to a steady downpour by nighttime.

A second, potentially less powerful atmospheric river will move into the region on Saturday.

“Expect light showers to trickle in this morning with soggier conditions tonight through Thursday morning,” Bayern said. “Urban flooding and rainwater ponding on roadways is certainly possible. Brief dry day on Friday with another strong system arriving over the weekend. We'll be back under rainy conditions by Saturday with the chance for thunderstorms across the weekend.”