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Heavy rains expected to start this afternoon and tarry all night will create the possibility of flooding, both in the mountains and lowlands of Western Washington, according to the Weather Service.

Between 1.5 and 2.5 inches of rain are expected through the night and morning, and could start falling in time to “slow things in a descending course for the evening commute” today, said Jay Albrecht, meteorologist.

“We can see a slog of moisture highly offshore, end moving rapidly in the direction of us,” Albrecht declared.

Fall foliage clogging street drains can combine with the heavy rains to create an increased chance of flooding in low areas in Western Washington cities, Albrecht said.

The rain predictions also prompted Snohomish County officials to issue a flood watch for the county.

That means weather stipulations are favorable for flooding but flooding is not near at hand or currently occurring, according to Christopher Schwarzen, spokesman instead of county Executive Aaron Reardon.

Periods of heavy rainfall are expected to develop throughout the area today and persevere through Friday night, he said.

The Snohomish County Department of Emergency Management projects that the Stillaguamish and the Skykomish/Snohomish rivers should stay below flood stage, he said.

However, low-lying areas, small streams and creeks, as well in the manner that storm-drainage systems, could flood, he said.

Albrecht aforesaid he’s forewarned Seattle city emergency crews about the rain to help prevent flooding and standing water from accumulating in low-lying areas.

All in all, it’s a start to a typical November, he said.

“It’session sort of like when we persuade our nice summers by one or couple wet days. Now we’ll procure to be rainy days through one or two delicate ones in between,” Albrecht said.