Portland, OR — The National Weather Service (NWS) Portland is warning residents across the Pacific Northwest to prepare for significant rainfall as a potential atmospheric river is expected to impact the region early next week.
According to NWS, the heaviest rainfall is forecast between Monday, December 8, and Wednesday, December 10, with moderate confidence in periods of breezy winds during the storm event. The system is expected to bring substantial rainfall, raising concerns for localized flooding, saturated ground conditions, and hazardous travel.
Heavy Rain and Flooding Concerns
Forecasters say the highest rain totals are most likely Monday through Wednesday, with some areas potentially receiving several inches of rain in a short period. The prolonged rainfall could lead to:
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Urban and small stream flooding
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Rising rivers
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Landslide risks in steep or previously burned areas
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Hazardous roadway conditions
Safety and Preparedness Guidance
NWS Portland is urging residents to take precautions now, including:
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Clearing gutters and storm drains of leaves and debris
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Securing outdoor items that could be displaced by wind
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Driving cautiously, slowing down on wet roads, using headlights, and maintaining safe following distances
Officials stress that preparation ahead of the storm can reduce damage and improve safety during the wet weather period.
Weather updates and advisories will continue to be issued as conditions evolve.
Tired of the rain? ☔️Well, we hope not because there’s plenty more rainfall on the way! A potent atmospheric river will take aim at the Pacific Northwest early next week. Take action now to clear gutters and storm drains, and be sure to drive safely on wet roadways.#wawx #orwx pic.twitter.com/FUiT4rgq3J
— NWS Portland (@NWSPortland) December 5, 2025