Flood Watch Issued For NCW, Chelan County

The National Weather Service (NWS) Office in Spokane has issued a Flood Watch for portions of North Central Washington, including all of Chelan County.

The watch will go into effect tonight (Monday, Dec. 4) at 10:00 and is currently scheduled to expire at 10 p.m. on Wednesday (Dec. 6).

NWS meteorologist Steven Van Horn says the watch is being enacted due to the forecasted arrival of a wet weather system over the region.

"What we're looking at is what we (NWS) refer(s) to as an 'atmospheric river'. It's a deep fetch of moisture that in this case is originating from the subtropics of the Pacific Ocean. It usually brings milder temperatures and a lot moisture with it."

The pattern is expected to elevate snow levels and create the potential for the rapid melting of recent snowfall at elevations below 5,000 feet.

Winter Is Here, Forest Service Cautions Drivers On Hazards

The excessive runoff from these events may result in the flooding of rivers, creeks, streams, and other low-lying and flood-prone locations. There will also be an increased risk for rockslides and mudslides in steep terrain.

Van Horn says the early-December weather system is consistent with climatological predictions for an El Niño winter.

"This pattern is consistent with an El Niño year. Ones where we have these deep troughs of pressure from the Gulf of Alaska that will at times bring some of that more subtropical moisture into our region. It just depends on where the subtropical jet (stream) sets up. For this one at least, it is setting up over the Pacific Northwest."

The Central Cascade Mountains could see up to five inches of rain over the 48-hour watch period, while places like Leavenworth and the Upper Wenatchee Valley could receive as much as an inch or more between late today and early Wednesday.