Forecast 08/18

The ocean forecast continues to show the plume turning northward today, with the outer edge of the plume passing the mouth of Grays Harbor by tonight.

Monday, the extended forecast predicts that the plume will reach WB-5 strongly, and WB-9 and GH-5 weakly.

The extended ocean forecast continues to show the winds changing on Monday and the plume beginning to turn southward. By Tuesday, the forecast shows the core of the plume south of the Columbia River mouth, with the residue of the earlier plumes that ran north of the mouth spreading into a wide band along the coast, with 31 psu water reaching out to 124 30 W, 45 38 N (WB-19 on the Willapa Bay line).

As always, the extended forecast should be treated with caution.

In the estuary, the estuary forecast is not able to push salinity past Tongue Point, but we are seeing salinity of up to 7 psu at Mott Basin. For temperature, the ocean end member in the forecast is too warm, and the river end member is too cold. This can be seen in the salinity-temperature diagram for red26.

The preferred ocean forecast is actually predicting the estuary end members correctly, so the issue in the estuary forecast does not appear to be a problem with the ocean forecasts handling of the bottom water near the Columbia River mouth.