Atmospheric river to bring heavy rain, flooding concerns

WESTERN WASHINGTON — After a lull between systems, Monday and Tuesday will be the two most active weather days in the seven-day forecast.

Watches, Warning, and Advisories:

• Flood Watch: Until Wednesday
• Winter Weather Advisory: 8 a.m. to 4 p.m. Monday
• Beach Hazard: South WA coast until Wednesday night

Moderate to heavy rains will move across western Washington Monday morning as the result of an atmospheric river. With a warm front moving north from southern California’s coast, snow levels jump to 8,000 to 9,000 feet.

Current computer models indicate impressive rainfall totals within a 48-hour period. Monday and Tuesday this is a look at the approximate rainfall totals across western Washington:

• Interior Lowlands: 1.5-3″
• Along the Coast: 3-5″
• Along Cascade Mountains: 5-9″
• Across the Olympics: 7-10″

*for mountain locations this takes into consideration rain falling on top of snow in higher elevations and adding to increased concerns of flooding due to runoff.

A Flood Watch is active across nearly all of Western Washington and will remain active through Wednesday. Heavier rain and excessive runoff increase risks for flooding of rivers, creeks, streams and other low-lying areas and flood-prone locations.

Urban and street flooding is also likely. For drivers and rush-hour commuters, be prepared for delays and potential detours should flooding or weather-related crashes occur.

With the rain on Monday into Tuesday also comes breezy conditions. Tuesday’s wind gusts could reach 30 to 40 mph.

Along the coast, large waves build closer to 20 feet Tuesday and may run up the beach. More info can be found at this link.

Moderate to heavy rain tapers into showers Wednesday. Rain totals are much weaker looking to only add maybe a few hundredths of an inch, maybe a tenth of an inch.

More showers on Thursday and Friday morning with a ridge bringing a break from all the action Friday afternoon and evening.

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