New National Weather Service (NWS) hydrologic services will be implemented in April for the Seattle Weather Forecast Office hydrologic services area.

A new river forecast/flood warning point on the Samish River will be added to the NWS’s flood warning program. The gage point will be the U.S. Geological Survey stream gage Samish River near Burlington in Skagit County. Implementation is schedule for April 15.

New river forecasts and flood warnings for the Samish River gage will address flooding along the river to the mouth at Samish Bay, including the town of Allen. Here are the flood levels for the three flood categories:

Minor Flood Flow/flood warning level…..3,000 cubic feet per second
(cfs)
Moderate Flood Flow………………….7,000 cfs
Major Flood Flow……………………11,000 cfs

In addition, new river forecasts will be provided for three rivers that are already in the flood warning program. These are the following: Pilchuck River near Snohomish Issaquah Creek at Issaquah Calawah River near Forks for the Bogachiel River near La Push.

These rivers are official flood warning locations but do not have modeled river forecasts. New river models for these locations will be implemented in early April as well. Although the Calawah River is not part of the flood warning program, forecasts for that river will be used to produce the river forecasts for the flood warning point on the Bogachiel River.

Once implemented, the river forecasts will be added to the river plots on the NWS Advanced Hydrologic Prediction Service webpage at:

https://water.weather.gov/ahps2/index.php?wfo=sew

If you would like more information about the National Weather Service hydrologic services in the Seattle area, please contact Brent Bower, Senior Service Hydrologist, at 206-526-6095.