Flooding is possible through Thursday morning, particularly along the Stillaguamish River.
"It would probably be relatively minor," weather service meteorologist Johnny Burg said.
A flood watch means conditions are favorable for flooding but rivers aren't actually spilling their banks and high water is not imminent.
At the same time, forecasters are predicting a wet Halloween for children planning a night of trick or treating.
"It looks like our first possible dry day is Friday," Burg said.
Heavy rain over the west slopes of the Cascade Range through Wednesday could drive the most flood-prone rivers above flood stage. Rainfall in the mountains likely will range from 2 to 5 inches. With the snow level around 7,000 to 8,000 feet, that means roughly 1 to 2 inches of rain is expected over the lowlands.
"We are always monitoring the river levels," Arlington spokeswoman Kristin Banfield said Tuesday.
The Stillaguamish River was listed as an area to watch as are the Nooksack and Skagit rivers to the north.
The rainfall in the lowlands also could cause street flooding in poorly drained areas or where storm drains are covered by leaves, the weather service said.
October's possible minor flooding is probably a good reminder for people to prepare for more serious flooding that often occurs in November and December, Burg said.
That means people should monitor the latest forecasts and be ready to act quickly if flooding is observed or a warning is issued.
Eric Stevick: 425-339-3446, email@example.com.
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