Flood Watch Issued for Western Washington

The National Weather Service (NWS) has issued a Flood Watch for all of Western Washington as a major tropical storm is expected to bring heavy rainfall Tuesday night and throughout the day on Wednesday.

NWS forecasters said heavy, warm rains are expected to fall in the Olympic and Cascade mountain ranges over the next 24-48 hours, and less but significant rainfall will affect the lowlands. Quickly rising snow levels in the mountains and saturated soils further downstream will likely cause flooding near major rivers. For Mercer Island, the heavier-than-normal rainfall could cause scattered landslides to occur.

Tuesday night's forecast, according to the NWS, is calling for steady rain and a low in the mid-40s with a steady south-southwest wind. But the high will shoot up to near 60 tomorrow as the tropical rain continues to fall.

A Flood Watch is issued when flooding conditions are likely but aren't imminent.

The following Flood Watch alert was issued by the NWS at 11:59 a.m. today: 

"...FLOOD WATCH REMAINS IN EFFECT FROM WEDNESDAY AFTERNOON THROUGH FRIDAY AFTERNOON..

THE FLOOD WATCH CONTINUES FOR

* PORTIONS OF WESTERN WASHINGTON...INCLUDING THE FOLLOWING COUNTIES...CLALLAM...JEFFERSON...SKAGIT...WHATCOM...KING.. LEWIS...MASON...PIERCE...SNOHOMISH...THURSTON...

* FROM WEDNESDAY AFTERNOON THROUGH FRIDAY AFTERNOON

* A WARM FRONTAL SYSTEM WILL SPREAD RAIN INTO WESTERN WASHINGTON LATER TONIGHT AND WEDNESDAY. THE FRONTAL BAND IS EXPECTED TO STALL OVER THE AREA FOR A 24 TO 48 HOUR PERIOD PRODUCING HEAVY PRECIPITATION ALONG THE COAST AND MOUNTAINS. FREEZING LEVELS WILL RISE DRAMATICALLY TO 7000-9000 FEET DURING THE PERIOD WHICH RAISES THE THREAT OF FLOODING ON SOME RIVERS.

* THE SKOKOMISH RIVER IN MASON COUNTY IS THE RIVER MOST LIKELY TO FLOOD...POSSIBLY BY LATE WEDNESDAY. HOWEVER...48 HOUR RAINFALL AMOUNTS OF UP TO 5 INCHES IN THE OLYMPICS AND 4 TO 7 INCHES IN THE CENTRAL CASCADES WILL DRIVE RIVERS SUCH AS SNOQUALMIE.. SNOHOMISH...AND STILLAGUAMISH TO FLOOD. THERE IS A CHANCE THE SNOHOMISH RIVER WILL REACH MAJOR FLOOD.

* LESS AMOUNTS OF RAINFALL ARE EXPECTED ELSEWHERE BUT WILL CAUSE SHARP RISES ON OTHER RIVES AND MAY ALSO CAUSE SOME ADDITIONAL RIVERS RUNNING OFF THE CASCADES AND OLYMPICS TO FLOOD. GRAYS HARBOR AND KITSAP COUNTIES MAY ALSO BE IMPACTED AND COULD BE ADDED TO THE FLOOD WATCH LATER. SCATTERED LANDSLIDES IN AREAS THAT RECEIVE HEAVY RAIN MAY ALSO OCCUR.

PRECAUTIONARY/PREPAREDNESS ACTIONS..

A FLOOD WATCH MEANS CONDITIONS ARE FAVORABLE FOR FLOODING BUT FLOODING IS NOT IMMINENT OR OCCURRING. MONITOR THE LATEST FORECASTS FROM THE NATIONAL WEATHER SERVICE AND BE READY TO ACT QUICKLY IF FLOODING IS OBSERVED OR A WARNING IS ISSUED."