NOAA flags an atmospheric river for Nov. 10–12. Portland has about a week to clear its gutters.

Portland, Ore. — Nov. 2, 2026. NOAA’s Climate Prediction Center issued a key message Monday: “An atmospheric river is expected to pull significant amounts of moisture into much of the West Coast during the second week of November.” It puts a high risk, over 60 percent, of heavy precipitation on the West Coast states from northern California through the Northwest on Nov. 10–12, “accompanied by the potential for flooding in lower elevations.” A moderate risk continues through Nov. 14.

Before that, Portland gets a mostly dry week. KATU’s Monday forecast calls for low clouds and fog under a strong inversion, a mostly dry Tuesday, light rain chances late Wednesday as a weak front reaches the coast, and another system that could arrive Friday. Rain totals for Portland itself will come from local forecasts closer to the date. What’s clear now is the order of events: a few dry days, light rain, then a storm aimed at the whole region.

The forecast

The next ten days, from a gutter’s point of view

1. Mon., Nov. 2

   Dry under low clouds

   An inversion traps cool, damp air. Highs in the 40s if clouds stay, mid to upper 50s if they clear.

2. Tue., Nov. 3

   Mostly dry

   The inversion weakens. Most of western Oregon and southwest Washington stays dry.

3. Wed., Nov. 4

   Light rain late

   A weak front approaches the coast. Any rain is expected to be light.

4. Fri., Nov. 6

   Another system possible

   KATU is tracking a system that could arrive Friday. Timing may change.

5. Tue.–Thu., Nov. 10–12

   Atmospheric river

   High risk of heavy precipitation from northern California through the Northwest, with flooding possible in lower elevations.

The CPC message also calls for high winds along the immediate coastline and a high risk of heavy snow in the Washington Cascades. This is a week-two hazards outlook, not a rain forecast for your street, so watch local forecasts as the date gets closer. Update, Nov. 9: the Weather Service now points to Friday through Sunday, Nov. 13–15, for the bigger rain, with leaf-clogged drains already causing ponding in Monday’s showers. The gutter work doesn’t need to wait for that detail.

Why it matters

What an atmospheric river does to a half-clogged gutter

NOAA describes atmospheric rivers as long, narrow regions in the atmosphere, like rivers in the sky, that carry most of the water vapor outside the tropics. The strongest ones can produce extreme rainfall and floods. For a house, the problem isn’t one heavy hour. It’s rain that keeps coming for a day or more.

On Portland homes, the first thing to fail in that kind of rain is usually the outlet. Fir needles, maple leaves and roof grit wash down the run and pile up over the hole where the downspout drops. Once that plugs, the gutter fills and water sheets over the front edge onto the fascia, the siding and the ground right next to the foundation. That’s how a gutter problem becomes a wet crawlspace. Water that does make it down the downspout still has to drain away from the house, which is why the City of Portland has rules for where disconnected downspouts can discharge.

The angle most coverage missed

The real deadline is Wednesday, not Nov. 10

Storm coverage counts down to the big day. For gutter cleaning, the date that matters is the first rain. Once roofs, rungs and leaves get wet, the job gets slower and riskier, and wet debris is heavier and harder to scoop. KATU expects light rain to start late Wednesday, with another system possibly Friday. That leaves Monday through Wednesday as the dry window, and Portland returned to standard time on Sunday, so after-work daylight is short.

The other detail is the leaves. Plenty of Portland trees aren’t done dropping. On lots with big maples, oaks or firs, a cleaning this week clears what’s there before the storm, and a second pass later in the season catches the rest. If the same trees refill the gutters every fall, that’s when gutter guards start to pay for themselves, as long as you know they reduce cleanings rather than end them.

• Work on a dry day with dry ground. Don’t set a ladder on wet lawn or leaves.

• Scoop the trough, then flush each downspout with a hose until water runs freely at the bottom.

• Watch for drips at corners and runs that hold water. Those are repairs, not cleaning.

• Stay off steep, mossy or second-story roofs, and book a pro for those.

Hiring it out

What a pre-storm gutter cleaning in Portland should include

A proper gutter cleaning in Portland clears every run by hand, clears each downspout until water flows through it, and checks hangers, seams and outlets for the problems that cause overflow. Our gutter cleaning starts at $295. Most single-story Portland homes fall between $295 and $475, and most two-story homes between $365 and $675. If the cleaning turns up a leaking seam or a sagging run, we’ll show you and price the gutter repair separately so you can decide.

You can get a price range for your address from the free virtual estimate without talking to anyone, schedule the job online, call (503) 860-6950 or contact us. West-side homeowners can start with Beaverton gutter cleaning. Property managers can see commercial gutter cleaning.