COLUMBIA COUNTY, It has barely rained in Columbia County all October. That changes Sunday.
Portland International Airport, the closest official weather station with monthly rain records, had logged 0.11 inch of rain this month through Oct. 23. That is 2.19 inches below normal for that stretch, according to the National Weather Service.
The dry spell shows up on the U.S. Drought Monitor too. Its Oct. 20 map rated 99 percent of Columbia County “abnormally dry,” the step just below drought. The county has been at that level since at least mid-September.
How Much Rain and When
A front reaches the coast overnight Saturday and moves inland Sunday morning, followed by showers that hang on into early Tuesday, according to the Weather Service’s Saturday afternoon forecast discussion. Another system follows late Tuesday, and a third from Wednesday through the end of the week. Forecasters said the rain won’t be constant, but there will be repeated chances.
From Sunday morning to Tuesday morning, forecasters expect 0.75 to 1.5 inches across the region, with 1.5 to 2.5 inches possible at the high end. They said even the high end is unlikely to cause flooding.
Here is what the Weather Service forecasts town by town. Most of the county should see about an inch of rain from Sunday through Friday. None of the town forecasts show gusts over 20 mph.
| Town | Rain | Fri. low | Halloween |
|---|---|---|---|
| St. Helens | 1.2 in. | 37 | 57 / 38 |
| Columbia City | 1.2 in. | 37 | 58 / 38 |
| Deer Island | 1.2 in. | 36 | 56 / 37 |
| Warren | 1.0 in. | 36 | 59 / 37 |
| Scappoose | 1.0 in. | 33 | 59 / 34 |
| Rainier | 1.1 in. | 35 | 58 / 37 |
| Prescott | 1.2 in. | 36 | 59 / 37 |
| Clatskanie | 1.1 in. | 38 | 56 / 39 |
| Vernonia | 0.9 in. | 28 | 57 / 29 |
Snow levels drop to around 5,000 feet, so anyone heading over the Cascade passes could see light snow above pass level through Wednesday.
Highs, Lows and the First Frost
Temperatures stay near normal, with highs in the 50s. Cloud cover should hold off frost along the river until late in the week, when clearer nights could bring colder temperatures, forecasters said.
The hills get cold first. Vernonia is forecast to reach freezing Wednesday night, then drop to 29 Thursday night and 28 Friday night. Scappoose lows fall into the low to mid 30s. In St. Helens, Columbia City, Deer Island, Warren, Rainier, Prescott and Clatskanie, lows stay in the mid to upper 30s.
Halloween Looks Dry
The rain tapers off by the weekend. Friday has only a slight chance of rain, and Halloween is forecast to be partly to mostly sunny across the county, with highs from 56 to 59.
Bundle the trick-or-treaters. Saturday night lows range from 39 in Clatskanie and the upper 30s along the river to 34 in Scappoose and 29 in Vernonia.
The rest of the county’s Halloween plans are in the Tribune’s Halloween guide, and the Kiwanis Children’s Fair runs 10 a.m. to 3 p.m. Halloween morning at McBride Elementary.
Burning Yard Debris
St. Helens’ fall window for backyard burning opened Oct. 24. The rules and permit details are in the Tribune’s earlier story.
The Weather Service updates its forecast several times a day at weather.gov/portland.